gropengltexture.cpp

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/*
 * Copyright (C) Volition, Inc. 1999.  All rights reserved.
 *
 * All source code herein is the property of Volition, Inc. You may not sell 
 * or otherwise commercially exploit the source or things you created based on the 
 * source.
 *
*/

#ifdef _WIN32
#include <windows.h>
#endif

#include "bmpman/bmpman.h"
#include "cmdline/cmdline.h"
#include "ddsutils/ddsutils.h"
#include "globalincs/systemvars.h"
#include "graphics/grinternal.h"
#include "graphics/gropenglstate.h"
#include "graphics/gropengltexture.h"
#include "math/vecmat.h"
#include "osapi/osregistry.h"


static tcache_slot_opengl *Textures = NULL;
static int *Tex_used_this_frame = NULL;

int GL_texture_ram = 0;
int GL_min_texture_width = 0;
GLint GL_max_texture_width = 0;
int GL_min_texture_height = 0;
GLint GL_max_texture_height = 0;
int GL_textures_in = 0;
int GL_textures_in_frame = 0;
int GL_last_detail = -1;
GLint GL_supported_texture_units = 2;
int GL_should_preload = 0;
ubyte GL_xlat[256];
GLfloat GL_anisotropy = 1.0f;
GLfloat GL_max_anisotropy = -1.0f;
int GL_mipmap_filter = 0;
GLenum GL_texture_target = GL_TEXTURE_2D;
GLenum GL_texture_face = GL_TEXTURE_2D;
GLenum GL_texture_addressing = GL_REPEAT;
bool GL_rendering_to_texture = false;
GLint GL_max_renderbuffer_size = 0;

extern int GLOWMAP;
extern int SPECMAP;
extern int CLOAKMAP;
extern int ENVMAP;
extern int Interp_multitex_cloakmap;


// forward declarations
int opengl_free_texture(tcache_slot_opengl *t);
void opengl_free_texture_with_handle(int handle);
void opengl_tcache_get_adjusted_texture_size(int w_in, int h_in, int *w_out, int *h_out);
int opengl_create_texture_sub(int bitmap_handle, int bitmap_type, int bmap_w, int bmap_h, int tex_w, int tex_h, ubyte *data = NULL, tcache_slot_opengl *t = NULL, int base_level = 0, int resize = 0, int reload = 0);
int opengl_create_texture (int bitmap_handle, int bitmap_type, tcache_slot_opengl *tslot = NULL);

void opengl_set_additive_tex_env()
{
        GL_CHECK_FOR_ERRORS("start of set_additive_tex_env()");

        if ( Is_Extension_Enabled(OGL_ARB_TEXTURE_ENV_COMBINE) ) {
                GL_state.Texture.SetEnvCombineMode(GL_COMBINE_RGB, GL_ADD);
                GL_state.Texture.SetRGBScale(1.0f);
        } else {
                GL_state.Texture.SetEnvMode(GL_ADD);
        }

        GL_CHECK_FOR_ERRORS("end of set_additive_tex_env()");
}

void opengl_set_modulate_tex_env()
{
        GL_CHECK_FOR_ERRORS("start of set_modulate_tex_env()");

        if ( Is_Extension_Enabled(OGL_ARB_TEXTURE_ENV_COMBINE) ) {
                GL_state.Texture.SetEnvCombineMode(GL_COMBINE_RGB, GL_MODULATE);
                GL_state.Texture.SetRGBScale(4.0f);
        } else {
                GL_state.Texture.SetEnvMode(GL_MODULATE);
        }

        GL_CHECK_FOR_ERRORS("end of set_modulate_tex_env()");
}

GLfloat opengl_get_max_anisotropy()
{
        if ( !Is_Extension_Enabled(OGL_EXT_TEXTURE_FILTER_ANISOTROPIC) ) {
                return 0.0f;
        }

        if ( GL_max_anisotropy < 0.0f ) {
                glGetFloatv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &GL_max_anisotropy);
        }

        // the spec says that it should be a minimum of 2.0
        Assert( GL_max_anisotropy >= 2.0f );

        return GL_max_anisotropy;
}

void opengl_set_texture_target( GLenum target )
{
    GL_texture_target = target;
}

void opengl_tcache_init()
{
        int i;

        GL_should_preload = 1;

        GL_min_texture_width = 16;
        GL_min_texture_height = 16;

        glGetIntegerv(GL_MAX_TEXTURE_SIZE, &GL_max_texture_width);

        GL_max_texture_height = GL_max_texture_width;

        // if we are not using sections then make sure we have the min texture size available to us
        // 1024 is what we need with the standard resolutions - taylor
        if (GL_max_texture_width < 1024) {
                Error(LOCATION, "A minimum texture size of \"1024x1024\" is required for FS2_Open but only \"%ix%i\" was found.  Can not continue.", GL_max_texture_width, GL_max_texture_height);
        }

        if (Textures == NULL) {
                Textures = (tcache_slot_opengl *) vm_malloc_q(MAX_BITMAPS * sizeof(tcache_slot_opengl));
        }

        if (Tex_used_this_frame == NULL) {
                Tex_used_this_frame = (int *) vm_malloc_q(MAX_BITMAPS * sizeof(int));
        }

        if ( !Textures || !Tex_used_this_frame )
                Error(LOCATION, "Unable to allocate memory for OpenGL texture slots!");


        memset( Tex_used_this_frame, 0, MAX_BITMAPS * sizeof(int) );

        // Init the texture structures
        for (i = 0; i < MAX_BITMAPS; i++) {
                Textures[i].reset();
        }

        // check what mipmap filter we should be using
        //   0  ==  Bilinear
        //   1  ==  Trilinear
        GL_mipmap_filter = os_config_read_uint(NULL, "TextureFilter", 1);

        if (GL_mipmap_filter > 1) {
                GL_mipmap_filter = 1;
        }

        // max size (width and/or height) that we can use for framebuffer/renderbuffer
        if ( Is_Extension_Enabled(OGL_EXT_FRAMEBUFFER_OBJECT) ) {
                glGetIntegerv(GL_MAX_RENDERBUFFER_SIZE_EXT, &GL_max_renderbuffer_size);

                // if we can't do at least 128x128 then just disable FBOs
                if (GL_max_renderbuffer_size < 128) {
                        mprintf(("WARNING: Max dimensions of FBO, %ix%i, is less the required minimum!!  Extension will be disabled!\n", GL_max_renderbuffer_size, GL_max_renderbuffer_size));
                        GL_Extensions[OGL_EXT_FRAMEBUFFER_OBJECT].enabled = 0;
                }
        }

        // anisotropy
        if ( Is_Extension_Enabled(OGL_EXT_TEXTURE_FILTER_ANISOTROPIC) ) {
                // set max value first thing
                opengl_get_max_anisotropy();

                // now for the user setting
                const char *plevel = os_config_read_string( NULL, NOX("OGL_AnisotropicFilter"), NOX("1.0") );
                GL_anisotropy = (GLfloat) strtod(plevel, (char**)NULL);

                CLAMP(GL_anisotropy, 1.0f, GL_max_anisotropy);
        }

        if ( Is_Extension_Enabled(OGL_EXT_TEXTURE_LOD_BIAS) ) {
                if (GL_anisotropy > 1.0f) {
                        glTexEnvf(GL_TEXTURE_FILTER_CONTROL, GL_TEXTURE_LOD_BIAS, 0.0f);
                } else {
                        glTexEnvf(GL_TEXTURE_FILTER_CONTROL, GL_TEXTURE_LOD_BIAS, -0.75f);
                }
        }

        // set the alpha gamma settings (for fonts)
        memset( GL_xlat, 0, sizeof(GL_xlat) );

        for (i = 1; i < 15; i++) {
                GL_xlat[i] = (ubyte)(GL_xlat[i-1] + 17);
        }

        GL_xlat[15] = GL_xlat[1];

        glGetIntegerv(GL_MAX_TEXTURE_UNITS_ARB, &GL_supported_texture_units);
        Assert( GL_supported_texture_units >= 2 );

        GL_last_detail = Detail.hardware_textures;

        GL_textures_in = 0;
        GL_textures_in_frame = 0;
}

void opengl_free_texture_with_handle(int handle)
{
        int n = bm_get_cache_slot(handle, 1);

        Tex_used_this_frame[n] = 0;
        opengl_free_texture( &Textures[n] );
}

void opengl_tcache_flush()
{
        int i;

        if ( Textures == NULL )
                return;

        for (i = 0; i < MAX_BITMAPS; i++)
                opengl_free_texture( &Textures[i] );

        if (GL_textures_in != 0) {
                mprintf(( "WARNING: VRAM is at %d instead of zero after flushing!\n", GL_textures_in ));
                GL_textures_in = 0;
        }
}

extern void opengl_kill_all_render_targets();

void opengl_tcache_shutdown()
{
        opengl_kill_all_render_targets();

        opengl_tcache_flush();

        GL_textures_in = 0;
        GL_textures_in_frame = 0;

        if (Textures != NULL) {
                vm_free(Textures);
                Textures = NULL;
        }

        if (Tex_used_this_frame != NULL) {
                vm_free(Tex_used_this_frame);
                Tex_used_this_frame = NULL;
        }
}

void opengl_tcache_frame()
{
        GL_textures_in_frame = 0;

        // make all textures as not used
        memset( Tex_used_this_frame, 0, MAX_BITMAPS * sizeof(int) );
}

extern bool GL_initted;

void opengl_free_texture_slot( int n )
{
        if ( !GL_initted ) {
                return;
        }

        Tex_used_this_frame[n] = 0;
        opengl_free_texture( &Textures[n] );
}

bool opengl_texture_slot_valid(int n, int handle)
{
        tcache_slot_opengl *t = &Textures[n];

        if (t->bitmap_handle < 0) {
                return false;
        }

        if (t->bitmap_handle != handle) {
                return false;
        }

        if ( !glIsTexture(t->texture_id) ) {
                return false;
        }

        return true;
}

int opengl_free_texture(tcache_slot_opengl *t)
{
        // Bitmap changed!!     
        if (t->texture_id) {
                // if I, or any of my children have been used this frame, bail  
                // can't use bm_get_cache_slot() here since bitmap_id probably isn't valid
                if ( (t->bitmap_handle >= 0) && Tex_used_this_frame[t->bitmap_handle % MAX_BITMAPS] ) {
                        return 0;
                }

                // ok, now we know its legal to free everything safely
                GL_state.Texture.Delete(t->texture_id);
                glDeleteTextures (1, &t->texture_id);

                GL_textures_in -= t->size;

                t->reset();
        }

        return 1;
}

void opengl_tcache_get_adjusted_texture_size(int w_in, int h_in, int *w_out, int *h_out)
{
        int i, tex_w, tex_h;

        // bogus
        if ( (w_out == NULL) ||  (h_out == NULL) ) {
                return;
        }

        // if we can support non-power-of-2 textures then just return current sizes - taylor
        if ( Is_Extension_Enabled(OGL_ARB_TEXTURE_NON_POWER_OF_TWO) ) {
                *w_out = w_in;
                *h_out = h_in;

                return;
        }

        // starting size
        tex_w = w_in;
        tex_h = h_in;

        for (i = 0; i < 16; i++) {
                if ( (tex_w > (1<<i)) && (tex_w <= (1<<(i+1))) ) {
                        tex_w = 1 << (i+1);
                        break;
                }
        }

        for (i = 0; i < 16; i++) {
                if ( (tex_h > (1<<i)) && (tex_h <= (1<<(i+1))) ) {
                        tex_h = 1 << (i+1);
                        break;
                }
        }

        CLAMP(tex_w, GL_min_texture_width, GL_max_texture_width);
        CLAMP(tex_h, GL_min_texture_height, GL_max_texture_height);

        // store the outgoing size
        *w_out = tex_w;
        *h_out = tex_h;
}

// data == start of bitmap data
// bmap_w == width of source bitmap
// bmap_h == height of source bitmap
// tex_w == width of final texture
// tex_h == height of final texture
int opengl_create_texture_sub(int bitmap_handle, int bitmap_type, int bmap_w, int bmap_h, int tex_w, int tex_h, ubyte *data, tcache_slot_opengl *t, int base_level, int resize, int reload)
{
        int ret_val = 1;
        int byte_mult = 0;
        GLenum texFormat = GL_UNSIGNED_SHORT_1_5_5_5_REV;
        GLenum glFormat = GL_BGRA;
        GLint intFormat = GL_RGBA;
        ubyte saved_bpp = 0;
        int mipmap_w = 0, mipmap_h = 0;
        int dsize = 0, doffset = 0, block_size = 0;
        int i,j,k;
        ubyte *bmp_data = data;
        ubyte *texmem = NULL, *texmemp = NULL;
        int skip_size = 0, mipmap_levels = 0;

        GL_CHECK_FOR_ERRORS("start of create_texture_sub()");

        // bogus
        if ( (t == NULL) || (bmp_data == NULL) ) {
                return 0;
        }

        int idx = bm_get_cache_slot( bitmap_handle, 1 );

        if ( Tex_used_this_frame[idx] ) {
                mprintf(( "ARGHH!!! Texture already used this frame!  Cannot free it!\n" ));
                return 0;
        }

        if ( !reload )  {
                // save the bpp since it will get reset - fixes anis being 0 bpp
                saved_bpp = t->bpp;

                // gah
                if ( !opengl_free_texture(t) ) {
                        return 0;
                }
        }

        // for everything that might use mipmaps
        mipmap_w = tex_w;
        mipmap_h = tex_h;

        if ( (bitmap_type == TCACHE_TYPE_AABITMAP) || (bitmap_type == TCACHE_TYPE_INTERFACE) ) {
                t->u_scale = (float)bmap_w / (float)tex_w;
                t->v_scale = (float)bmap_h / (float)tex_h;
        } else {
                t->u_scale = 1.0f;
                t->v_scale = 1.0f;
        }

        if ( !reload ) {
                glGenTextures (1, &t->texture_id);
        }
        
        if (t->texture_id == 0) {
                mprintf(("!!OpenGL DEBUG!! t->texture_id == 0\n"));
                return 0;
        }

        if (t->bpp == 0) {
                // it got reset, revert to saved setting
                t->bpp = saved_bpp;
        }

        // set the byte per pixel multiplier
        byte_mult = (t->bpp >> 3);

        // GL_BGRA_EXT is *much* faster with some hardware/drivers
        if (byte_mult == 4) {
                texFormat = GL_UNSIGNED_INT_8_8_8_8_REV;
                intFormat = (gr_screen.bits_per_pixel == 32) ? GL_RGBA8 : GL_RGB5_A1;
                glFormat = GL_BGRA;
        } else if (byte_mult == 3) {
                texFormat = GL_UNSIGNED_BYTE;
                intFormat = (gr_screen.bits_per_pixel == 32) ? GL_RGB8 : GL_RGB5;
                glFormat = GL_BGR;
        } else if (byte_mult == 2) {
                texFormat = GL_UNSIGNED_SHORT_1_5_5_5_REV;
                intFormat = GL_RGB5_A1;
                glFormat = GL_BGRA;
        } else if (byte_mult == 1) {
                Assertion( bitmap_type == TCACHE_TYPE_AABITMAP, "Invalid type for bitmap: %s BMPMAN handle: %d. Type expected was 0, we got %d instead.\nThis can be caused by using texture compression on a non-power-of-2 texture.\n", bm_get_filename(bitmap_handle), bitmap_handle, bitmap_type );
                texFormat = GL_UNSIGNED_BYTE;
                intFormat = GL_ALPHA;
                glFormat = GL_ALPHA;
        } else {
                texFormat = GL_UNSIGNED_SHORT_1_5_5_5_REV;
                intFormat = GL_RGBA;
                glFormat = GL_BGRA;
        }

        // check for compressed image types
        switch ( bm_is_compressed(bitmap_handle) ) {
                case DDS_DXT1:
                case DDS_CUBEMAP_DXT1:
                        intFormat = GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
                        block_size = 8;
                        break;

                case DDS_DXT3:
                case DDS_CUBEMAP_DXT3:
                        intFormat = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
                        block_size = 16;
                        break;

                case DDS_DXT5:
                case DDS_CUBEMAP_DXT5:
                        intFormat = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
                        block_size = 16;
                        break;
        }


        if ( bitmap_type == TCACHE_TYPE_CUBEMAP ) {
                t->texture_target = GL_TEXTURE_CUBE_MAP;
        }

        glBindTexture(t->texture_target, t->texture_id);

        GLenum min_filter = GL_LINEAR;

        if (t->mipmap_levels > 1) {
                min_filter = (GL_mipmap_filter) ? GL_LINEAR_MIPMAP_LINEAR : GL_LINEAR_MIPMAP_NEAREST;

                if ( Is_Extension_Enabled(OGL_EXT_TEXTURE_FILTER_ANISOTROPIC) ) {
                        glTexParameterf(t->texture_target, GL_TEXTURE_MAX_ANISOTROPY_EXT, GL_anisotropy);
                }
        }

        glTexParameteri(t->texture_target, GL_TEXTURE_MAX_LEVEL, t->mipmap_levels-1);
        glTexParameteri(t->texture_target, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glTexParameteri(t->texture_target, GL_TEXTURE_MIN_FILTER, min_filter);
        glTexParameteri(t->texture_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(t->texture_target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
        glTexParameteri(t->texture_target, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);

        t->wrap_mode = GL_CLAMP_TO_EDGE;

        mipmap_levels = bm_get_num_mipmaps(bitmap_handle);


        switch (bitmap_type) {
                case TCACHE_TYPE_COMPRESSED: {
                        if (block_size > 0) {
                                // size of data block (4x4)
                                dsize = ((mipmap_h + 3) / 4) * ((mipmap_w + 3) / 4) * block_size;

                                // if we are skipping mipmap levels in order to resize then we have to calc the new offset
                                for (i = 0; i < base_level; i++) {
                                        doffset += dsize;

                                        mipmap_w >>= 1;
                                        mipmap_h >>= 1;

                                        if (mipmap_w <= 0) {
                                                mipmap_w = 1;
                                        }

                                        if (mipmap_h <= 0) {
                                                mipmap_h = 1;
                                        }

                                        dsize = ((mipmap_h + 3) / 4) * ((mipmap_w + 3) / 4) * block_size;
                                }

                                skip_size = doffset;

                                if ( !reload ) {
                                        vglCompressedTexImage2D(GL_TEXTURE_2D, 0, intFormat, mipmap_w, mipmap_h, 0, dsize, bmp_data + doffset);
                                } else {
                                        vglCompressedTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, mipmap_w, mipmap_h, intFormat, dsize, bmp_data + doffset);
                                }

                                // now that the base image is done handle any mipmap levels
                                for (i = 1; i < (mipmap_levels - base_level); i++) {
                                        // adjust the data offset for the next block
                                        doffset += dsize;

                                        // reduce size by half for the next pass
                                        mipmap_w >>= 1;
                                        mipmap_h >>= 1;

                                        if (mipmap_w <= 0) {
                                                mipmap_w = 1;
                                        }

                                        if (mipmap_h <= 0) {
                                                mipmap_h = 1;
                                        }

                                        // size of data block (4x4)
                                        dsize = ((mipmap_h + 3) / 4) * ((mipmap_w + 3) / 4) * block_size;

                                        if ( !reload ) {
                                                vglCompressedTexImage2D(GL_TEXTURE_2D, i, intFormat, mipmap_w, mipmap_h, 0, dsize, bmp_data + doffset);
                                        } else {
                                                vglCompressedTexSubImage2D(GL_TEXTURE_2D, i, 0, 0, mipmap_w, mipmap_h, intFormat, dsize, bmp_data + doffset);
                                        }
                                }
                        } else {
                                Int3();
                                return 0;
                        }

                        break;
                }

                case TCACHE_TYPE_AABITMAP: {
                        texmem = (ubyte *) vm_malloc (tex_w*tex_h*byte_mult);
                        texmemp = texmem;

                        Assert( texmem != NULL );

                        int luminance = 0;
                        for (i = 0; i < tex_h; i++) {
                                for (j = 0; j < tex_w; j++) {
                                        if ( (i < bmap_h) && (j < bmap_w) ) {
                                                if ( byte_mult > 1 ) {
                                                        luminance = 0;

                                                        if ( byte_mult > 3 ) {
                                                                for (k = 0; k < 3; k++) {
                                                                        luminance += bmp_data[(i*bmap_w+j)*byte_mult+k];
                                                                }

                                                                *texmemp++ = (ubyte)((luminance / 3) * (bmp_data[(i*bmap_w+j)*byte_mult+3]/255.0f));
                                                        } else {
                                                                for (k = 0; k < byte_mult; k++) {
                                                                        luminance += bmp_data[(i*bmap_w+j)*byte_mult+k]; 
                                                                }

                                                                *texmemp++ = (ubyte)(luminance / byte_mult);
                                                        }
                                                } else {
                                                        *texmemp++ = GL_xlat[bmp_data[i*bmap_w+j]];
                                                }
                                        } else {
                                                *texmemp++ = 0;
                                        }
                                }
                        }

                        if ( !reload ) {
                                glTexImage2D (t->texture_target, 0, GL_ALPHA, tex_w, tex_h, 0, GL_ALPHA, GL_UNSIGNED_BYTE, texmem);
                        } else { // faster anis
                                glTexSubImage2D (t->texture_target, 0, 0, 0, tex_w, tex_h, GL_ALPHA, GL_UNSIGNED_BYTE, texmem);
                        }

                        if (texmem != NULL) {
                                vm_free(texmem);
                        }

                        break;
                }

                case TCACHE_TYPE_INTERFACE: {
                        // if we aren't resizing then we can just use bmp_data directly
                        if (resize) {
                                texmem = (ubyte *) vm_malloc (tex_w*tex_h*byte_mult);
                                texmemp = texmem;

                                Assert( texmem != NULL );

                                for (i = 0; i < tex_h; i++) {
                                        for (j = 0;j < tex_w; j++) {
                                                if ( (i < bmap_h) && (j < bmap_w) ) {
                                                        for (k = 0; k < byte_mult; k++) {
                                                                *texmemp++ = bmp_data[(i*bmap_w+j)*byte_mult+k];
                                                        }
                                                } else {
                                                        for (k = 0; k < byte_mult; k++) {
                                                                *texmemp++ = 0;
                                                        }
                                                }
                                        }
                                }
                        }

                        if ( !reload ) {
                                glTexImage2D (t->texture_target, 0, intFormat, mipmap_w, mipmap_h, 0, glFormat, texFormat, (resize) ? texmem : bmp_data);
                        } else { // faster anis
                                glTexSubImage2D (t->texture_target, 0, 0, 0, mipmap_w, mipmap_h, glFormat, texFormat, (resize) ? texmem : bmp_data);
                        }

                        if (texmem != NULL) {
                                vm_free(texmem);
                        }

                        break;
                }

                case TCACHE_TYPE_CUBEMAP: {
                        Assert( !resize );
                        Assert( texmem == NULL );
                        Assert( Is_Extension_Enabled(OGL_ARB_TEXTURE_CUBE_MAP) );

                        // we have to load in all 6 faces...
                        for (i = 0; i < 6; i++) {
                                doffset += dsize;

                                // check if it's a compressed cubemap first
                                if (block_size > 0) {
                                        // size of data block (4x4)
                                        dsize = ((mipmap_h + 3) / 4) * ((mipmap_w + 3) / 4) * block_size;

                                        if ( !reload ) {
                                                vglCompressedTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X+i, 0, intFormat, mipmap_w, mipmap_h, 0, dsize, bmp_data + doffset);
                                        } else {
                                                vglCompressedTexSubImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X+i, 0, 0, 0, mipmap_w, mipmap_h, intFormat, dsize, bmp_data + doffset);
                                        }

                                        // now that the base image is done handle any mipmap levels
                                        for (j = 1; j < mipmap_levels; j++) {
                                                // adjust the data offset for the next block
                                                doffset += dsize;

                                                // reduce size by half for the next pass
                                                mipmap_w >>= 1;
                                                mipmap_h >>= 1;

                                                if (mipmap_w <= 0) {
                                                        mipmap_w = 1;
                                                }

                                                if (mipmap_h <= 0) {
                                                        mipmap_h = 1;
                                                }

                                                // size of data block (4x4)
                                                dsize = ((mipmap_h + 3) / 4) * ((mipmap_w + 3) / 4) * block_size;

                                                if ( !reload ) {
                                                        vglCompressedTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X+i, j, intFormat, mipmap_w, mipmap_h, 0, dsize, bmp_data + doffset);
                                                } else {
                                                        vglCompressedTexSubImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X+i, j, 0, 0, mipmap_w, mipmap_h, intFormat, dsize, bmp_data + doffset);
                                                }
                                        }
                                }
                                // nope, it's uncompressed...
                                else {
                                        dsize = mipmap_h * mipmap_w * byte_mult;

                                        if ( !reload ) {
                                                glTexImage2D (GL_TEXTURE_CUBE_MAP_POSITIVE_X+i, 0, intFormat, mipmap_w, mipmap_h, 0, glFormat, texFormat, bmp_data + doffset);
                                        } else { // faster anis
                                                glTexSubImage2D (GL_TEXTURE_CUBE_MAP_POSITIVE_X+i, 0, 0, 0, mipmap_w, mipmap_h, glFormat, texFormat, bmp_data + doffset);
                                        }

                                        // base image is done so now take care of any mipmap levels
                                        for (j = 1; j < mipmap_levels; j++) {
                                                doffset += dsize;
                                                mipmap_w >>= 1;
                                                mipmap_h >>= 1;

                                                if (mipmap_w <= 0) {
                                                        mipmap_w = 1;
                                                }

                                                if (mipmap_h <= 0) {
                                                        mipmap_h = 1;
                                                }

                                                dsize = mipmap_h * mipmap_w * byte_mult;

                                                if ( !reload ) {
                                                        glTexImage2D (GL_TEXTURE_CUBE_MAP_POSITIVE_X+i, j, intFormat, mipmap_w, mipmap_h, 0, glFormat, texFormat, bmp_data + doffset);
                                                } else {
                                                        glTexSubImage2D (GL_TEXTURE_CUBE_MAP_POSITIVE_X+i, j, 0, 0, mipmap_w, mipmap_h, glFormat, texFormat, bmp_data + doffset);
                                                }
                                        }
                                }

                                // reset width and height for next face
                                mipmap_w = tex_w;
                                mipmap_h = tex_h;
                        }

                        break;
                }

                default: {
                        // if we aren't resizing then we can just use bmp_data directly
                        if (resize) {
                                texmem = (ubyte *) vm_malloc (tex_w*tex_h*byte_mult);
                                texmemp = texmem;

                                Assert( texmem != NULL );
        
                                fix u, utmp, v, du, dv;

                                u = v = 0;

                                du = ( (bmap_w-1)*F1_0 ) / tex_w;
                                dv = ( (bmap_h-1)*F1_0 ) / tex_h;

                                for (j=0;j<tex_h;j++)
                                {
                                        utmp = u;
                                        for (i=0;i<tex_w;i++)
                                        {
                                                for (k = 0; k < byte_mult; k++) {
                                                        *texmemp++ = bmp_data[(f2i(v)*bmap_w+f2i(utmp))*byte_mult+k];
                                                }
                                                utmp += du;
                                        }
                                        v += dv;
                                }
                        }

                        // should never have mipmap levels if we also have to manually resize
                        if ( (mipmap_levels > 1) && resize ) {
                                Assert( texmem == NULL );
                        }

                        dsize = mipmap_h * mipmap_w * byte_mult;

                        // if we are skipping mipmap levels in order to resize then we have to calc the new offset
                        for (i = 0; i < base_level; i++) {
                                doffset += dsize;

                                mipmap_w >>= 1;
                                mipmap_h >>= 1;

                                if (mipmap_w <= 0) {
                                        mipmap_w = 1;
                                }

                                if (mipmap_h <= 0) {
                                        mipmap_h = 1;
                                }

                                dsize = mipmap_h * mipmap_w * byte_mult;
                        }

                        skip_size = doffset;

                        if ( !reload ) {
                                glTexImage2D (GL_TEXTURE_2D, 0, intFormat, mipmap_w, mipmap_h, 0, glFormat, texFormat, (texmem != NULL) ? texmem : bmp_data + doffset);
                        } else { // faster anis
                                glTexSubImage2D (GL_TEXTURE_2D, 0, 0, 0, mipmap_w, mipmap_h, glFormat, texFormat, (texmem != NULL) ? texmem : bmp_data + doffset);
                        }


                        // base image is done so now take care of any mipmap levels
                        for (i = 1; i < (mipmap_levels - base_level); i++) {
                                doffset += dsize;
                                mipmap_w >>= 1;
                                mipmap_h >>= 1;

                                if (mipmap_w <= 0) {
                                        mipmap_w = 1;
                                }

                                if (mipmap_h <= 0) {
                                        mipmap_h = 1;
                                }

                                dsize = mipmap_h * mipmap_w * byte_mult;

                                if ( !reload ) {
                                        glTexImage2D (GL_TEXTURE_2D, i, intFormat, mipmap_w, mipmap_h, 0, glFormat, texFormat, bmp_data + doffset);
                                } else {
                                        glTexSubImage2D (GL_TEXTURE_2D, i, 0, 0, mipmap_w, mipmap_h, glFormat, texFormat, bmp_data + doffset);
                                }
                        }

                        if (texmem != NULL) {
                                vm_free(texmem);
                        }

                        break;
                }
        }//end switch


        t->bitmap_handle = bitmap_handle;
        t->size = (dsize) ? ((doffset + dsize) - skip_size) : (tex_w * tex_h * byte_mult);
        t->w = (ushort)tex_w;
        t->h = (ushort)tex_h;

        GL_textures_in_frame += t->size;

        if ( !reload ) {
                GL_textures_in += t->size;
        }

        Tex_used_this_frame[idx] = 0;

        GL_CHECK_FOR_ERRORS("end of create_texture_sub()");

        return ret_val;
}

int opengl_create_texture(int bitmap_handle, int bitmap_type, tcache_slot_opengl *tslot)
{
        ubyte flags;
        bitmap *bmp;
        int final_w, final_h;
        ubyte bpp = 16;
        int reload = 0, resize = 0, base_level = 0;
        int max_levels = 0;

        GL_CHECK_FOR_ERRORS("start of create_texture()");

        if (tslot == NULL) {
                return 0;
        }

        // setup texture/bitmap flags
        flags = 0;
        switch (bitmap_type) {
                case TCACHE_TYPE_AABITMAP:
                        flags |= BMP_AABITMAP;
                        bpp = 8;
                        break;

                case TCACHE_TYPE_CUBEMAP:
                case TCACHE_TYPE_NORMAL:
                        flags |= BMP_TEX_OTHER;
                        break;

                case TCACHE_TYPE_INTERFACE:
                case TCACHE_TYPE_XPARENT:
                        flags |= BMP_TEX_XPARENT;
                        break;

                case TCACHE_TYPE_COMPRESSED:
                        switch ( bm_is_compressed(bitmap_handle) ) {
                                case DDS_DXT1:                          //dxt1
                                        bpp = 24;
                                        flags |= BMP_TEX_DXT1;
                                        break;

                                case DDS_DXT3:                          //dxt3
                                        bpp = 32;
                                        flags |= BMP_TEX_DXT3;
                                        break;

                                case DDS_DXT5:                          //dxt5
                                        bpp = 32;
                                        flags |= BMP_TEX_DXT5;
                                        break;

                                case DDS_CUBEMAP_DXT1:
                                        bpp = 24;
                                        flags |= BMP_TEX_CUBEMAP;
                                        break;

                                case DDS_CUBEMAP_DXT3:
                                case DDS_CUBEMAP_DXT5:
                                        bpp = 32;
                                        flags |= BMP_TEX_CUBEMAP;
                                        break;

                                default:
                                        Assert( 0 );
                                        break;
                        }

                        break;
        }

        // lock the bitmap into the proper format
        bmp = bm_lock(bitmap_handle, bpp, flags);

        if ( bmp == NULL ) {
                mprintf(("Couldn't lock bitmap %d (%s).\n", bitmap_handle, bm_get_filename(bitmap_handle) ));
                return 0;
        }

        int max_w = bmp->w;
        int max_h = bmp->h;

        max_levels = bm_get_num_mipmaps(bitmap_handle);

        // there should only ever be one mipmap level for interface graphics!!!
        if ( (bitmap_type == TCACHE_TYPE_INTERFACE) && (max_levels > 1) ) {
                max_levels = 1;
        }

        // if we ended up locking a texture that wasn't originally compressed then this should catch it
        if ( !(bitmap_type == TCACHE_TYPE_CUBEMAP) && bm_is_compressed(bitmap_handle) ) {
                bitmap_type = TCACHE_TYPE_COMPRESSED;
        }

        if ( (Detail.hardware_textures < 4) && (bitmap_type != TCACHE_TYPE_AABITMAP) && (bitmap_type != TCACHE_TYPE_INTERFACE)
                        && ((bitmap_type != TCACHE_TYPE_COMPRESSED) || ((bitmap_type == TCACHE_TYPE_COMPRESSED) && (max_levels > 1))) )
        {
                if (max_levels == 1) {
                        // if we are going to cull the size then we need to force a resize
                        // Detail.debris_culling goes from 0 to 4.
                        max_w /= (16 >> Detail.hardware_textures);
                        max_h /= (16 >> Detail.hardware_textures);

                        CLAMP(max_w, GL_min_texture_width, GL_max_texture_width);
                        CLAMP(max_h, GL_min_texture_height, GL_max_texture_height);

                        resize = 1;
                } else {
                        // we have mipmap levels so use those as a resize point (image should already be power-of-2)
                        base_level = -(Detail.hardware_textures - 4);
                        Assert(base_level >= 0);

                        if (base_level >= max_levels) {
                                base_level = max_levels - 1;
                        }

                        Assert( (max_levels - base_level) >= 1 );
                }
        }

        // get final texture size
        opengl_tcache_get_adjusted_texture_size(max_w, max_h, &final_w, &final_h);

        // only resize if we actually need a new size, better data use and speed out of opengl_create_texture_sub()
        if ( (max_w != final_w) || (max_h != final_h) ) {
                resize = 1;
                // little safety check for later, we can't manually resize AND use mipmap resizing
                Assert( !base_level );
        }

        if ( (final_h < 1) || (final_w < 1) )       {
                mprintf(("Bitmap %s is too small at %dx%d.\n", bm_get_filename(bitmap_handle), final_w, final_h ));
                return 0;
        }

        // if this tcache slot has no bitmap
        if (tslot->bitmap_handle < 0) {
                reload = 0;
        }
        // different bitmap altogether - determine if the new one can use the old one's slot
        else if (tslot->bitmap_handle != bitmap_handle) {
                if ( (final_w == tslot->w) && (final_h == tslot->h) ) {
                        reload = 1;
                } else {
                        reload = 0;
                }
        }

        // set the bits per pixel
        tslot->bpp = bmp->bpp;

        // max number of mipmap levels (NOTE: this is the max number used by the API, not how many true mipmap levels there are in the image!!)
        tslot->mipmap_levels = (ubyte)(max_levels - base_level);

        // call the helper
        int ret_val = opengl_create_texture_sub(bitmap_handle, bitmap_type, bmp->w, bmp->h, final_w, final_h, (ubyte*)bmp->data, tslot, base_level, resize, reload);

        // unlock the bitmap
        bm_unlock(bitmap_handle);

        // if we successfully sent the texture to API memory then go ahead and dump
        // the rest of the bitmap data in system memory.
        // NOTE: this doesn't do anything for user bitmaps (like screen grabs or streamed animations)
        if (ret_val) {
                bm_unload_fast(bitmap_handle);
        }

        GL_CHECK_FOR_ERRORS("end of create_texture()");

        return ret_val;
}

// WARNING:  Needs to match what is in bm_internal.h!!!!!
#define RENDER_TARGET_DYNAMIC   17

int gr_opengl_tcache_set_internal(int bitmap_handle, int bitmap_type, float *u_scale, float *v_scale, int tex_unit = 0)
{
        int ret_val = 1;

        GL_CHECK_FOR_ERRORS("start of tcache_set_internal()");

        if (GL_last_detail != Detail.hardware_textures) {
                GL_last_detail = Detail.hardware_textures;
                opengl_tcache_flush();
        }

        int n = bm_get_cache_slot (bitmap_handle, 1);
        tcache_slot_opengl *t = &Textures[n];

        GL_state.Texture.SetActiveUnit(tex_unit);

        if (!bm_is_render_target(bitmap_handle) &&
                ((t->bitmap_handle < 0) || (bitmap_handle != t->bitmap_handle)) )
        {
                ret_val = opengl_create_texture( bitmap_handle, bitmap_type, t );
        }

        // everything went ok
        if (ret_val && t->texture_id) {
                *u_scale = t->u_scale;
                *v_scale = t->v_scale;

                GL_state.Texture.SetTarget(t->texture_target);
                GL_state.Texture.Enable(t->texture_id);

                if ( (t->wrap_mode != GL_texture_addressing) && (bitmap_type != TCACHE_TYPE_AABITMAP)
                        && (bitmap_type != TCACHE_TYPE_INTERFACE) && (bitmap_type != TCACHE_TYPE_CUBEMAP) )
                {
                        glTexParameteri(t->texture_target, GL_TEXTURE_WRAP_S, GL_texture_addressing);
                        glTexParameteri(t->texture_target, GL_TEXTURE_WRAP_T, GL_texture_addressing);
                        glTexParameteri(t->texture_target, GL_TEXTURE_WRAP_R, GL_texture_addressing);

                        t->wrap_mode = GL_texture_addressing;
                }

                Tex_used_this_frame[n]++;
        }
        // gah
        else {
                mprintf(("Texturing disabled for bitmap %d (%s) due to internal error.\n", bitmap_handle, bm_get_filename(bitmap_handle)));
                GL_state.Texture.Disable();

                return 0;
        }

        GL_CHECK_FOR_ERRORS("end of tcache_set_internal()");

        return 1;
}

int gr_opengl_tcache_set(int bitmap_handle, int bitmap_type, float *u_scale, float *v_scale, int stage)
{
        int rc = 0;

        if (bitmap_handle <= 0) {
                return 0;
        }

        GL_CHECK_FOR_ERRORS("start of tcache_set()");

        // set special type if it's so, needed to be right later, but cubemaps are special
        if ( !(bitmap_type == TCACHE_TYPE_CUBEMAP) ) {
                int type = bm_get_tcache_type(bitmap_handle);

                if (type != TCACHE_TYPE_NORMAL) {
                        bitmap_type = type;
                }
        }

        rc = gr_opengl_tcache_set_internal(bitmap_handle, bitmap_type, u_scale, v_scale, stage);

        GL_CHECK_FOR_ERRORS("end of tcache_set()");

        return rc;
}

void opengl_preload_init()
{
        if (gr_screen.mode != GR_OPENGL)
                return;

//      opengl_tcache_flush ();
}

int gr_opengl_preload(int bitmap_num, int is_aabitmap)
{
        float u_scale, v_scale;
        int retval;

        Assert( gr_screen.mode == GR_OPENGL );

        if ( !GL_should_preload ) {
                return 0;
        }

        retval = gr_opengl_tcache_set(bitmap_num, (is_aabitmap) ? TCACHE_TYPE_AABITMAP : TCACHE_TYPE_NORMAL, &u_scale, &v_scale);

        GL_state.Texture.Disable();

        if ( !retval ) {
                mprintf(("Texture upload failed!\n"));
        }

        return retval;
}

static int GL_texture_panning_enabled = 0;
void gr_opengl_set_texture_panning(float u, float v, bool enable)
{
        if (Cmdline_nohtl)
                return;

        GLint current_matrix;

        if (enable) {
                glGetIntegerv(GL_MATRIX_MODE, &current_matrix);
                glMatrixMode( GL_TEXTURE );
                glPushMatrix();
                glTranslatef( u, v, 0.0f );
                glMatrixMode(current_matrix);

                GL_texture_panning_enabled = 1;
        } else if (GL_texture_panning_enabled) {
                glGetIntegerv(GL_MATRIX_MODE, &current_matrix);
                glMatrixMode( GL_TEXTURE );
                glPopMatrix();
                glMatrixMode(current_matrix);
        
                GL_texture_panning_enabled = 0;
        }
}

void gr_opengl_set_texture_addressing(int mode)
{
        GL_CHECK_FOR_ERRORS("start of set_texture_addressing()");

        switch (mode) {
                case TMAP_ADDRESS_CLAMP:
                        GL_texture_addressing = GL_CLAMP_TO_EDGE;
                        break;

                case TMAP_ADDRESS_WRAP:
                        GL_texture_addressing = GL_REPEAT;
                        break;

                case TMAP_ADDRESS_MIRROR: {
                        if ( Is_Extension_Enabled(OGL_ARB_TEXTURE_MIRRORED_REPEAT) ) {
                                GL_texture_addressing = GL_MIRRORED_REPEAT_ARB;
                        } else {
                                GL_texture_addressing = GL_REPEAT;
                        }

                        break;
                }

                default:
                        Int3();
                        break;
        }

        GL_CHECK_FOR_ERRORS("end of set_texture_addressing()");
}

void gr_opengl_get_bitmap_from_texture(void* data_out, int bitmap_num)
{
        float u,v;

        gr_opengl_tcache_set(bitmap_num, TCACHE_TYPE_NORMAL, &u, &v);

        int n = bm_get_cache_slot(bitmap_num, 1);
        tcache_slot_opengl *ts = &Textures[n];
        
        GLenum pixel_format = GL_RGB;
        GLenum data_format = GL_UNSIGNED_BYTE;
        int bytes_per_pixel = 3 * sizeof(ubyte);

        if ( bm_has_alpha_channel(bitmap_num) ) {
                pixel_format = GL_RGBA;
                bytes_per_pixel = 4 * sizeof(ubyte);
        }

        opengl_get_texture(ts->texture_target, pixel_format, data_format, 1, ts->w, ts->h, bytes_per_pixel, data_out, 0);
}

int opengl_get_texture( GLenum target, GLenum pixel_format, GLenum data_format, int num_mipmaps, int width, int height, int bytes_per_pixel, void* image_data, int offset )
{
        int m_offset = offset;
        int m_width = width;
        int m_height = height;

        for ( int i = 0; i < num_mipmaps; i++ ) {
                glGetTexImage(target, i, pixel_format, data_format, (ubyte*)image_data + m_offset);

                m_offset += (m_width * m_height * bytes_per_pixel);

                // reduce by half for next mipmap level
                m_width >>= 1;
                m_height >>= 1;

                if (m_width < 1)
                        m_width = 1;

                if (m_height < 1)
                        m_height = 1;
        }

        return m_offset;
}

size_t opengl_export_render_target( int slot, int width, int height, int alpha, int num_mipmaps, ubyte *image_data )
{
        tcache_slot_opengl *ts = &Textures[slot];

        GL_CHECK_FOR_ERRORS("start of export_image()");

        if (!image_data) {
                mprintf(("OpenGL ERROR: Tried to export a texture without a valid export location!\n"));
                return 0;
        }

        if (!ts->texture_target) {
                mprintf(("OpenGL ERROR: Tried to export a texture for which I don't know the texture target!\n"));
                return 0;
        }

        if (ts->mipmap_levels != num_mipmaps) {
                mprintf(("OpenGL ERROR: Number of mipmap levels requested is different from number available!\n"));
                return 0;
        }

        if ( (ts->texture_target != GL_TEXTURE_2D) && (ts->texture_target != GL_TEXTURE_CUBE_MAP) ) {
                mprintf(("OpenGL ERROR: Only 2D textures and cube maps can be exported!\n"));
                return 0;
        }

        if ( (ts->w != width) && (ts->h != height) ) {
                mprintf(("OpenGL ERROR: Passed width and height do not match values for texture!\n"));
                return 0;
        }

        int faces = 1;
        int m_width = width;
        int m_height = height;
        int m_bpp = (alpha) ? 4 : 3;
        int m_offset = 0;
        GLenum target = (ts->texture_target == GL_TEXTURE_CUBE_MAP) ? GL_TEXTURE_CUBE_MAP_POSITIVE_X : GL_TEXTURE_2D;

        if (ts->texture_target == GL_TEXTURE_CUBE_MAP)
                faces = 6;

        GL_state.Texture.SetActiveUnit(0);
        GL_state.Texture.SetTarget(ts->texture_target);
        GL_state.Texture.Enable(ts->texture_id);

        for (int i = 0; i < faces; i++) {
                m_offset = opengl_get_texture(
                        target + i, 
                        (alpha) ? GL_BGRA : GL_BGR, 
                        (alpha) ? GL_UNSIGNED_INT_8_8_8_8_REV : GL_UNSIGNED_BYTE, 
                        ts->mipmap_levels, 
                        m_width, 
                        m_height, 
                        m_bpp, 
                        image_data, 
                        m_offset
                );
        }

        GL_state.Texture.Disable();

        GL_CHECK_FOR_ERRORS("end of export_image()");

        return (size_t)m_offset;
}

void gr_opengl_update_texture(int bitmap_handle, int bpp, const ubyte* data, int width, int height)
{
        GLenum texFormat, glFormat;
        int n = bm_get_cache_slot (bitmap_handle, 1);
        tcache_slot_opengl *t = &Textures[n];
        if(!t->texture_id)
                return;
        int byte_mult = (bpp >> 3);
        int true_byte_mult = (t->bpp >> 3);
        ubyte* texmem = NULL;
        // GL_BGRA_EXT is *much* faster with some hardware/drivers
        if (true_byte_mult == 4) {
                texFormat = GL_UNSIGNED_INT_8_8_8_8_REV;
                glFormat = GL_BGRA;
        } else if (true_byte_mult == 3) {
                texFormat = GL_UNSIGNED_BYTE;
                glFormat = GL_BGR;
        } else {
                texFormat = GL_UNSIGNED_SHORT_1_5_5_5_REV;
                glFormat = GL_BGRA;
        }
        if (byte_mult == 1) {
                texFormat = GL_UNSIGNED_BYTE;
                glFormat = GL_ALPHA;
                texmem = (ubyte *) vm_malloc (width*height*byte_mult);
                ubyte* texmemp = texmem;

                Assert( texmem != NULL );

                int luminance = 0;
                for (int i = 0; i < height; i++) {
                        for (int j = 0; j < width; j++) {
                                if ( (i < height) && (j < width) ) {
                                        if ( true_byte_mult > 1 ) {
                                                luminance = 0;

                                                if ( true_byte_mult > 3 ) {
                                                        for (int k = 0; k < 3; k++) {
                                                                luminance += data[(i*width+j)*true_byte_mult+k];
                                                        }

                                                        *texmemp++ = (ubyte)((luminance / 3) * (data[(i*width+j)*true_byte_mult+3]/255.0f));
                                                } else {
                                                        for (int k = 0; k < true_byte_mult; k++) {
                                                                luminance += data[(i*width+j)*true_byte_mult+k]; 
                                                        }

                                                        *texmemp++ = (ubyte)(luminance / true_byte_mult);
                                                }
                                        } else {
                                                *texmemp++ = GL_xlat[data[i*width+j]];
                                        }
                                } else {
                                        *texmemp++ = 0;
                                }
                        }
                }
        }
        glBindTexture(GL_TEXTURE_2D, t->texture_id);
        glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, glFormat, texFormat, (texmem)?texmem:data);
        if (texmem != NULL)
                vm_free(texmem);
}

// -----------------------------------------------------------------------------
// GL_EXT_framebuffer_object stuff (ie, render-to-texture)
//

struct fbo_t {
        // these first vars should only be modified in opengl_make_render_target()
        GLuint renderbuffer_id;
        GLuint framebuffer_id;
        int width;
        int height;
        int ref_count;
        // these next 2 should only be modifed in opengl_set_render_target()
        int working_slot;
        int is_static;

        fbo_t() :
                renderbuffer_id(0), framebuffer_id(0), width(0), height(0),
                ref_count(0), working_slot(-1), is_static(0)
        {
        }
};

static SCP_vector<fbo_t> RenderTarget;
static fbo_t *render_target = NULL;


int opengl_check_framebuffer()
{
        GLenum status;

        status = vglCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);

        if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
                char err_txt[100] = { 0 };

                switch (status) {
                        case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_EXT:
                                strcpy_s(err_txt, "Incomplete attachments!");
                                break;

                        case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT_EXT:
                                strcpy_s(err_txt, "Missing one or more image attachments!");
                                break;

                        case GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT:
                                strcpy_s(err_txt, "Attached images do not have the same width and height!");
                                break;

                        case GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT:
                                strcpy_s(err_txt, "Attached images do not have the same internal format!");
                                break;

                        case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT:
                                strcpy_s(err_txt, "Draw buffer attachment point is NONE!");
                                break;

                        case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT:
                                strcpy_s(err_txt, "Read buffer attachment point is NONE!");
                                break;

                        case GL_FRAMEBUFFER_UNSUPPORTED_EXT:
                                strcpy_s(err_txt, "Attached images violate current FBO restrictions!");
                                break;

                        default:
                                strcpy_s(err_txt, "Unknown error!\n");
                                break;
                }

                mprintf(("Framebuffer ERROR: %s\n", err_txt));

                return (int)status;
        }

        return 0;
}

static fbo_t *opengl_get_fbo(int width, int height)
{
        size_t rt_size = RenderTarget.size();

        for (size_t i = 0; i < rt_size; i++) {
                if ( (RenderTarget[i].width == width) && (RenderTarget[i].height == height) ) {
                        return &RenderTarget[i];
                }
        }

        return NULL;
}

void opengl_kill_render_target(int slot)
{
        if ( (slot < 0) || (slot >= MAX_BITMAPS) ) {
                Int3();
                return;
        }

        // this will happen when opengl_kill_all_render_targets() gets called first on exit
        if ( RenderTarget.empty() ) {
                return;
        }

        tcache_slot_opengl *ts = &Textures[slot];
        size_t idx = 0;

        for (idx = 0; idx < RenderTarget.size(); idx++) {
                if ( (RenderTarget[idx].width == ts->w) && (RenderTarget[idx].height == ts->h) ) {
                        break;
                }
        }

        // this may happen when textures are flushed, the w and h will get reset to 0
        if ( idx >= RenderTarget.size() ) {
                return;
        }

        RenderTarget[idx].ref_count--;

        if (RenderTarget[idx].ref_count <= 0) {
                mprintf(("OpenGL: Killing off unused %ix%i render target...\n", ts->w, ts->h));

                if (RenderTarget[idx].framebuffer_id) {
                        vglDeleteFramebuffersEXT(1, &RenderTarget[idx].framebuffer_id);
                        RenderTarget[idx].framebuffer_id = 0;
                }

                if (RenderTarget[idx].renderbuffer_id) {
                        vglDeleteRenderbuffersEXT(1, &RenderTarget[idx].renderbuffer_id);
                        RenderTarget[idx].renderbuffer_id = 0;
                }

                RenderTarget.erase( RenderTarget.begin() + idx );
        } else {
                mprintf(("OpenGL: Keeping %ix%i render target with ref_count of %i.\n", ts->w, ts->h, RenderTarget[idx].ref_count));
        }
}

void opengl_kill_all_render_targets()
{
        for (size_t i = 0; i < RenderTarget.size(); i++) {
                fbo_t *fbo = &RenderTarget[i];

                if (fbo->framebuffer_id) {
                        vglDeleteFramebuffersEXT(1, &fbo->framebuffer_id);
                        fbo->framebuffer_id = 0;
                }

                if (fbo->renderbuffer_id) {
                        vglDeleteRenderbuffersEXT(1, &fbo->renderbuffer_id);
                        fbo->renderbuffer_id = 0;
                }
        }

        RenderTarget.clear();
}

int opengl_set_render_target( int slot, int face, int is_static )
{
        tcache_slot_opengl *ts = NULL;
        fbo_t *fbo = NULL;

        GL_CHECK_FOR_ERRORS("start of set_render_target()");

        if (slot < 0) {
                if ( (render_target != NULL) && (render_target->working_slot >= 0) ) {
                        if (render_target->is_static) {
                                extern void gr_opengl_bm_save_render_target(int slot);
                                gr_opengl_bm_save_render_target(render_target->working_slot);
                        }
                }

                vglFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, 0, 0);

                vglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
                vglBindRenderbufferEXT(GL_RENDERBUFFER_EXT, 0);

                if (render_target != NULL) {
                        render_target->working_slot = -1;
                        render_target->is_static = 0;
                }

                // done with this render target so lets move on
                render_target = NULL;

                GL_rendering_to_texture = false;

                GL_CHECK_FOR_ERRORS("end of set_render_target(0)");

                return 1;
        }

        ts = &Textures[slot];
        Assert( ts != NULL );

        if (!ts->texture_id) {
                Int3();
                return 0;
        }

        fbo = opengl_get_fbo(ts->w, ts->h);

        if (fbo == NULL) {
                mprintf(("Tried to get an OpenGL FBO that didn't exist!\n"));
                return 0;
        }

        if ( !vglIsFramebufferEXT(fbo->framebuffer_id) /*|| !vglIsRenderbufferEXT(fbo->renderbuffer_id)*/ ) {
                Int3();
                return 0;
        }

//      vglBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo->renderbuffer_id);
        vglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo->framebuffer_id);

        if (ts->texture_target == GL_TEXTURE_CUBE_MAP) {
                Assert( (face >= 0) && (face < 6) );
                vglFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, ts->texture_id, 0);
        } else {
                Assert( face <= 0 );
                vglFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, ts->texture_target, ts->texture_id, 0);
        }

//      vglFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, fbo->renderbuffer_id);

        if ( opengl_check_framebuffer() ) {
                Int3();
                return 0;
        }

        fbo->working_slot = slot;
        fbo->is_static = is_static;

        // save current fbo for later use
        render_target = fbo;

        GL_rendering_to_texture = true;

        GL_CHECK_FOR_ERRORS("end of set_render_target()");

        return 1;
}

int opengl_make_render_target( int handle, int slot, int *w, int *h, ubyte *bpp, int *mm_lvl, int flags )
{
        Assert( !GL_rendering_to_texture );

        if (slot < 0) {
                Int3();
                return 0;
        }

        // got to have at least width and height!
        if (!w || !h) {
                Int3();
                return 0;
        }

        // size check
        if (*w > GL_max_renderbuffer_size) {
                *w = GL_max_renderbuffer_size;
        }

        if (*h > GL_max_renderbuffer_size) {
                *h = GL_max_renderbuffer_size;
        }

        tcache_slot_opengl *ts = &Textures[slot];
        fbo_t *fbo = opengl_get_fbo(*w, *h);

        GL_CHECK_FOR_ERRORS("start of make_render_target()");

        // since we only deal with one frame/render buffer, see if we need to modify what we have or use it as is
        if ( (fbo != NULL) && (fbo->width == *w) && (fbo->height == *h) ) {
                // both should be valid, but we check to catch the off-chance that something is fubar
                Assert( vglIsFramebufferEXT(fbo->framebuffer_id) /*&& vglIsRenderbufferEXT(fbo->renderbuffer_id)*/ );

                // we can use the existing FBO without modification so just setup the texture slot and move on
                if (flags & BMP_FLAG_CUBEMAP) {
                        opengl_set_texture_target( GL_TEXTURE_CUBE_MAP );
                } else {
                        opengl_set_texture_target();
                }

                glGenTextures(1, &ts->texture_id);

                GL_state.Texture.SetActiveUnit(0);
                GL_state.Texture.SetTarget(GL_texture_target);
                GL_state.Texture.Enable(ts->texture_id);

                glTexParameteri(GL_texture_target, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
                glTexParameteri(GL_texture_target, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
                glTexParameteri(GL_texture_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
                glTexParameteri(GL_texture_target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

                if (flags & BMP_FLAG_CUBEMAP) {
                        // if a cubemap then we have to initalize each face
                        for (int i = 0; i < 6; i++) {
                                glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGBA, *w, *h, 0, GL_BGRA, GL_UNSIGNED_BYTE, NULL);
                        }

                        ts->texture_target = GL_TEXTURE_CUBE_MAP;
                } else {
                        // non-cubemap so just do the normal thing
                        glTexImage2D(GL_state.Texture.GetTarget(), 0, GL_RGBA, *w, *h, 0, GL_BGRA, GL_UNSIGNED_BYTE, NULL);
                        ts->texture_target = GL_state.Texture.GetTarget();
                }

        /*      if (Cmdline_mipmap) {
                        vglGenerateMipmapEXT(GL_state.Texture.GetTarget());

                        extern int get_num_mipmap_levels(int w, int h);
                        ts->mipmap_levels = get_num_mipmap_levels(*w, *h);
                } else */
                {
                        ts->mipmap_levels = 1;
                }

                GL_state.Texture.Disable();

                ts->w = (ushort)*w;
                ts->h = (ushort)*h;
                ts->bpp = 24;
                ts->bitmap_handle = -1;//handle;
                ts->u_scale = 1.0f;
                ts->v_scale = 1.0f;

                if (bpp) {
                        *bpp = ts->bpp;
                }

                if (mm_lvl) {
                        *mm_lvl = ts->mipmap_levels;
                }

                opengl_set_texture_target();

                fbo->ref_count++;

                mprintf(("OpenGL: Reusing %ix%i FBO!\n", *w, *h));

                GL_CHECK_FOR_ERRORS("end of make_render_target(0)");

                return 1;
        }

        // now on to the good parts...

        fbo_t new_fbo;

        if (flags & BMP_FLAG_CUBEMAP) {
                opengl_set_texture_target( GL_TEXTURE_CUBE_MAP );
        } else {
                opengl_set_texture_target();
        }

        // initialize color texture
        glGenTextures(1, &ts->texture_id);

        GL_state.Texture.SetActiveUnit(0);
        GL_state.Texture.SetTarget(GL_texture_target);
        GL_state.Texture.Enable(ts->texture_id);

        glTexParameteri(GL_texture_target, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glTexParameteri(GL_texture_target, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri(GL_texture_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_texture_target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

        if (flags & BMP_FLAG_CUBEMAP) {
                // if a cubemap then we have to initalize each face
                for (int i = 0; i < 6; i++) {
                        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGBA, *w, *h, 0, GL_BGRA, GL_UNSIGNED_BYTE, NULL);
                }
        } else {
                // non-cubemap so just do the normal thing
                glTexImage2D(GL_state.Texture.GetTarget(), 0, GL_RGBA, *w, *h, 0, GL_BGRA, GL_UNSIGNED_BYTE, NULL);
        }

/*      if (Cmdline_mipmap) {
                vglGenerateMipmapEXT(GL_state.Texture.GetTarget());

                extern int get_num_mipmap_levels(int w, int h);
                ts->mipmap_levels = get_num_mipmap_levels(*w, *h);
        } else */
        {
                ts->mipmap_levels = 1;
        }

        GL_state.Texture.Disable();

        // render buffer
//      vglGenRenderbuffersEXT(1, &new_fbo.renderbuffer_id);
//      vglBindRenderbufferEXT(GL_RENDERBUFFER_EXT, new_fbo.renderbuffer_id);
//      vglRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, *w, *h);
        vglBindRenderbufferEXT(GL_RENDERBUFFER_EXT, 0);

        // frame buffer
        vglGenFramebuffersEXT(1, &new_fbo.framebuffer_id);
        vglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, new_fbo.framebuffer_id);

        if (flags & BMP_FLAG_CUBEMAP) {
                vglFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_CUBE_MAP_POSITIVE_X, ts->texture_id, 0);
        } else {
                vglFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_state.Texture.GetTarget(), ts->texture_id, 0);
        }

//      vglFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, new_fbo.renderbuffer_id);

        if ( opengl_check_framebuffer() ) {
                // Oops!!  reset everything and then bail
                mprintf(("OpenGL: Unable to create FBO!\n"));

                vglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

                GL_state.Texture.Disable();
                GL_state.Texture.Delete(ts->texture_id);
                glDeleteTextures(1, &ts->texture_id);
                ts->texture_id = 0;

                vglDeleteFramebuffersEXT(1, &new_fbo.framebuffer_id);

        //      vglDeleteRenderbuffersEXT(1, &new_fbo.renderbuffer_id);

                opengl_set_texture_target();

                return 0;
        }

        // save anything that needs saving, cleanup, and then exit
        ts->w = (ushort)*w;
        ts->h = (ushort)*h;
        ts->bpp = 24;
        ts->texture_target = GL_state.Texture.GetTarget();
        ts->bitmap_handle = -1;//handle;
        ts->u_scale = 1.0f;
        ts->v_scale = 1.0f;

        new_fbo.width = ts->w;
        new_fbo.height = ts->h;

        if (bpp) {
                *bpp = ts->bpp;
        }

        if (mm_lvl) {
                *mm_lvl = ts->mipmap_levels;
        }

        // Clear the new Texture to black with alpha 1.0
        glClearColor(0.0f,0.0f,0.0f,1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        vglBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

        new_fbo.ref_count++;

        RenderTarget.push_back(new_fbo);

        opengl_set_texture_target();


        mprintf(("OpenGL: Created %ix%i FBO!\n", ts->w, ts->h));

        GL_CHECK_FOR_ERRORS("end of make_render_target()");

        return 1;
}

GLuint opengl_get_rtt_framebuffer()
{
        if (render_target == NULL || render_target->working_slot < 0)
                return 0;
        else
                return render_target->framebuffer_id;
}

//
// End of GL_EXT_framebuffer_object stuff
// -----------------------------------------------------------------------------