texformat.c

mesa-6.5-minigui源码

   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   0,					/* RedBits */
   0,					/* GreenBits */
   0,					/* BlueBits */
   0,					/* AlphaBits */
   0,					/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   2,					/* TexelBytes */
   _mesa_texstore_ycbcr,		/* StoreTexImageFunc */
   fetch_texel_1d_ycbcr,		/* FetchTexel1D */
   fetch_texel_2d_ycbcr,		/* FetchTexel2D */
   fetch_texel_3d_ycbcr,		/* FetchTexel3D */
   NULL,				/* FetchTexel1Df */
   NULL,				/* FetchTexel2Df */
   NULL,				/* FetchTexel3Df */
   store_texel_ycbcr			/* StoreTexel */
};

const struct gl_texture_format _mesa_texformat_ycbcr_rev = {
   MESA_FORMAT_YCBCR_REV,		/* MesaFormat */
   GL_YCBCR_MESA,			/* BaseFormat */
   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   0,					/* RedBits */
   0,					/* GreenBits */
   0,					/* BlueBits */
   0,					/* AlphaBits */
   0,					/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   2,					/* TexelBytes */
   _mesa_texstore_ycbcr,		/* StoreTexImageFunc */
   fetch_texel_1d_ycbcr_rev,		/* FetchTexel1D */
   fetch_texel_2d_ycbcr_rev,		/* FetchTexel2D */
   fetch_texel_3d_ycbcr_rev,		/* FetchTexel3D */
   NULL,				/* FetchTexel1Df */
   NULL,				/* FetchTexel2Df */
   NULL,				/* FetchTexel3Df */
   store_texel_ycbcr_rev		/* StoreTexel */
};

const struct gl_texture_format _mesa_texformat_z24_s8 = {
   MESA_FORMAT_Z24_S8,			/* MesaFormat */
   GL_DEPTH_STENCIL_EXT,		/* BaseFormat */
   GL_UNSIGNED_NORMALIZED_ARB,		/* DataType */
   0,					/* RedBits */
   0,					/* GreenBits */
   0,					/* BlueBits */
   0,					/* AlphaBits */
   0,					/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   24,					/* DepthBits */
   8,					/* StencilBits */
   4,					/* TexelBytes */
   _mesa_texstore_z24_s8,		/* StoreTexImageFunc */
   NULL,				/* FetchTexel1D */
   NULL,				/* FetchTexel2D */
   NULL,				/* FetchTexel3D */
   fetch_texel_1d_f_z24_s8,		/* FetchTexel1Df */
   fetch_texel_2d_f_z24_s8,		/* FetchTexel2Df */
   fetch_texel_3d_f_z24_s8,		/* FetchTexel3Df */
   store_texel_z24_s8			/* StoreTexel */
};

/*@}*/


/***************************************************************/
/** \name Null format (useful for proxy textures) */
/*@{*/

const struct gl_texture_format _mesa_null_texformat = {
   -1,					/* MesaFormat */
   0,					/* BaseFormat */
   GL_NONE,				/* DataType */
   0,					/* RedBits */
   0,					/* GreenBits */
   0,					/* BlueBits */
   0,					/* AlphaBits */
   0,					/* LuminanceBits */
   0,					/* IntensityBits */
   0,					/* IndexBits */
   0,					/* DepthBits */
   0,					/* StencilBits */
   0,					/* TexelBytes */
   NULL,				/* StoreTexImageFunc */
   fetch_null_texel,			/* FetchTexel1D */
   fetch_null_texel,			/* FetchTexel2D */
   fetch_null_texel,			/* FetchTexel3D */
   fetch_null_texelf,			/* FetchTexel1Df */
   fetch_null_texelf,			/* FetchTexel2Df */
   fetch_null_texelf,			/* FetchTexel3Df */
   store_null_texel			/* StoreTexel */
};

/*@}*/


/**
 * Choose an appropriate texture format given the format, type and
 * internalFormat parameters passed to glTexImage().
 *
 * \param ctx  the GL context.
 * \param internalFormat  user's prefered internal texture format.
 * \param format  incoming image pixel format.
 * \param type  incoming image data type.
 *
 * \return a pointer to a gl_texture_format object which describes the
 * choosen texture format, or NULL on failure.
 * 
 * This is called via dd_function_table::ChooseTextureFormat.  Hardware drivers
 * will typically override this function with a specialized version.
 */
const struct gl_texture_format *
_mesa_choose_tex_format( GLcontext *ctx, GLint internalFormat,
                         GLenum format, GLenum type )
{
   (void) format;
   (void) type;

   switch (internalFormat) {
      /* RGBA formats */
      case 4:
      case GL_RGBA:
      case GL_RGB10_A2:
      case GL_RGBA12:
      case GL_RGBA16:
         return &_mesa_texformat_rgba;
      case GL_RGBA8:
         return &_mesa_texformat_rgba8888;
      case GL_RGB5_A1:
         return &_mesa_texformat_argb1555;
      case GL_RGBA2:
         return &_mesa_texformat_argb4444_rev; /* just to test another format*/
      case GL_RGBA4:
         return &_mesa_texformat_argb4444;

      /* RGB formats */
      case 3:
      case GL_RGB:
      case GL_RGB10:
      case GL_RGB12:
      case GL_RGB16:
         return &_mesa_texformat_rgb;
      case GL_RGB8:
         return &_mesa_texformat_rgb888;
      case GL_R3_G3_B2:
         return &_mesa_texformat_rgb332;
      case GL_RGB4:
         return &_mesa_texformat_rgb565_rev; /* just to test another format */
      case GL_RGB5:
         return &_mesa_texformat_rgb565;

      /* Alpha formats */
      case GL_ALPHA:
      case GL_ALPHA4:
      case GL_ALPHA12:
      case GL_ALPHA16:
         return &_mesa_texformat_alpha;
      case GL_ALPHA8:
         return &_mesa_texformat_a8;

      /* Luminance formats */
      case 1:
      case GL_LUMINANCE:
      case GL_LUMINANCE4:
      case GL_LUMINANCE12:
      case GL_LUMINANCE16:
         return &_mesa_texformat_luminance;
      case GL_LUMINANCE8:
         return &_mesa_texformat_l8;

      /* Luminance/Alpha formats */
      case 2:
      case GL_LUMINANCE_ALPHA:
      case GL_LUMINANCE4_ALPHA4:
      case GL_LUMINANCE6_ALPHA2:
      case GL_LUMINANCE12_ALPHA4:
      case GL_LUMINANCE12_ALPHA12:
      case GL_LUMINANCE16_ALPHA16:
         return &_mesa_texformat_luminance_alpha;
      case GL_LUMINANCE8_ALPHA8:
         return &_mesa_texformat_al88;

      case GL_INTENSITY:
      case GL_INTENSITY4:
      case GL_INTENSITY12:
      case GL_INTENSITY16:
         return &_mesa_texformat_intensity;
      case GL_INTENSITY8:
         return &_mesa_texformat_i8;

      case GL_COLOR_INDEX:
      case GL_COLOR_INDEX1_EXT:
      case GL_COLOR_INDEX2_EXT:
      case GL_COLOR_INDEX4_EXT:
      case GL_COLOR_INDEX12_EXT:
      case GL_COLOR_INDEX16_EXT:
      case GL_COLOR_INDEX8_EXT:
         return &_mesa_texformat_ci8;

      default:
         ; /* fallthrough */
   }

   if (ctx->Extensions.SGIX_depth_texture ||
       ctx->Extensions.ARB_depth_texture) {
      switch (internalFormat) {
         case GL_DEPTH_COMPONENT:
         case GL_DEPTH_COMPONENT24_SGIX:
         case GL_DEPTH_COMPONENT32_SGIX:
            return &_mesa_texformat_depth_component_float32;
         case GL_DEPTH_COMPONENT16_SGIX:
            return &_mesa_texformat_depth_component16;
         default:
            ; /* fallthrough */
      }
   }

   if (ctx->Extensions.ARB_texture_compression) {
      switch (internalFormat) {
         case GL_COMPRESSED_ALPHA_ARB:
            return &_mesa_texformat_alpha;
         case GL_COMPRESSED_LUMINANCE_ARB:
            return &_mesa_texformat_luminance;
         case GL_COMPRESSED_LUMINANCE_ALPHA_ARB:
            return &_mesa_texformat_luminance_alpha;
         case GL_COMPRESSED_INTENSITY_ARB:
            return &_mesa_texformat_intensity;
         case GL_COMPRESSED_RGB_ARB:
            if (ctx->Extensions.TDFX_texture_compression_FXT1)
               return &_mesa_texformat_rgb_fxt1;
            else if (ctx->Extensions.EXT_texture_compression_s3tc ||
                     ctx->Extensions.S3_s3tc)
               return &_mesa_texformat_rgb_dxt1;
            else
               return &_mesa_texformat_rgb;
         case GL_COMPRESSED_RGBA_ARB:
            if (ctx->Extensions.TDFX_texture_compression_FXT1)
               return &_mesa_texformat_rgba_fxt1;
            else if (ctx->Extensions.EXT_texture_compression_s3tc ||
                     ctx->Extensions.S3_s3tc)
               return &_mesa_texformat_rgba_dxt3; /* Not rgba_dxt1, see spec */
            else
               return &_mesa_texformat_rgba;
         default:
            ; /* fallthrough */
      }
   }

   if (ctx->Extensions.MESA_ycbcr_texture) {
      if (internalFormat == GL_YCBCR_MESA) {
         if (type == GL_UNSIGNED_SHORT_8_8_MESA)
            return &_mesa_texformat_ycbcr;
         else
            return &_mesa_texformat_ycbcr_rev;
      }
   }

   if (ctx->Extensions.TDFX_texture_compression_FXT1) {
      switch (internalFormat) {
         case GL_COMPRESSED_RGB_FXT1_3DFX:
            return &_mesa_texformat_rgb_fxt1;
         case GL_COMPRESSED_RGBA_FXT1_3DFX:
            return &_mesa_texformat_rgba_fxt1;
         default:
            ; /* fallthrough */
      }
   }

   if (ctx->Extensions.EXT_texture_compression_s3tc) {
      switch (internalFormat) {
         case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
            return &_mesa_texformat_rgb_dxt1;
         case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
            return &_mesa_texformat_rgba_dxt1;
         case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
            return &_mesa_texformat_rgba_dxt3;
         case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
            return &_mesa_texformat_rgba_dxt5;
         default:
            ; /* fallthrough */
      }
   }

   if (ctx->Extensions.S3_s3tc) {
      switch (internalFormat) {
         case GL_RGB_S3TC:
         case GL_RGB4_S3TC:
            return &_mesa_texformat_rgb_dxt1;
         case GL_RGBA_S3TC:
         case GL_RGBA4_S3TC:
            return &_mesa_texformat_rgba_dxt3;
         default:
            ; /* fallthrough */
      }
   }

   if (ctx->Extensions.ARB_texture_float) {
      switch (internalFormat) {
         case GL_ALPHA16F_ARB:
            return &_mesa_texformat_alpha_float16;
         case GL_ALPHA32F_ARB:
            return &_mesa_texformat_alpha_float32;
         case GL_LUMINANCE16F_ARB:
            return &_mesa_texformat_luminance_float16;
         case GL_LUMINANCE32F_ARB:
            return &_mesa_texformat_luminance_float32;
         case GL_LUMINANCE_ALPHA16F_ARB:
            return &_mesa_texformat_luminance_alpha_float16;
         case GL_LUMINANCE_ALPHA32F_ARB:
            return &_mesa_texformat_luminance_alpha_float32;
         case GL_INTENSITY16F_ARB:
            return &_mesa_texformat_intensity_float16;
         case GL_INTENSITY32F_ARB:
            return &_mesa_texformat_intensity_float32;
         case GL_RGB16F_ARB:
            return &_mesa_texformat_rgb_float16;
         case GL_RGB32F_ARB:
            return &_mesa_texformat_rgb_float32;
         case GL_RGBA16F_ARB:
            return &_mesa_texformat_rgba_float16;
         case GL_RGBA32F_ARB:
            return &_mesa_texformat_rgba_float32;
         default:
            ; /* fallthrough */
      }
   }

   if (ctx->Extensions.EXT_packed_depth_stencil) {
      switch (internalFormat) {
         case GL_DEPTH_STENCIL_EXT:
         case GL_DEPTH24_STENCIL8_EXT:
            return &_mesa_texformat_z24_s8;
         default:
            ; /* fallthrough */
      }
   }

   _mesa_problem(ctx, "unexpected format in _mesa_choose_tex_format()");
   return NULL;
}