+ // Check for precompressed textures that depend on an extension
+ switch (res.getImage()->getPixelFormat()) {
+
+ // GL_EXT_texture_compression_s3tc
+ // patented, no way to decompress these
+#ifndef GL_EXT_texture_compression_s3tc
+#define GL_COMPRESSED_RGB_S3TC_DXT1_EXT 0x83F0
+#define GL_COMPRESSED_RGBA_S3TC_DXT1_EXT 0x83F1
+#define GL_COMPRESSED_RGBA_S3TC_DXT3_EXT 0x83F2
+#define GL_COMPRESSED_RGBA_S3TC_DXT5_EXT 0x83F3
+#endif
+ case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
+ case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
+ case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
+ case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
+
+ // GL_EXT_texture_sRGB
+ // patented, no way to decompress these
+#ifndef GL_EXT_texture_sRGB
+#define GL_COMPRESSED_SRGB_S3TC_DXT1_EXT 0x8C4C
+#define GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT 0x8C4D
+#define GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT 0x8C4E
+#define GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT 0x8C4F
+#endif
+ case GL_COMPRESSED_SRGB_S3TC_DXT1_EXT:
+ case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
+ case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
+ case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
+
+ // GL_TDFX_texture_compression_FXT1
+ // can decompress these in software but
+ // no code present in simgear.
+#ifndef GL_3DFX_texture_compression_FXT1
+#define GL_COMPRESSED_RGB_FXT1_3DFX 0x86B0
+#define GL_COMPRESSED_RGBA_FXT1_3DFX 0x86B1
+#endif
+ case GL_COMPRESSED_RGB_FXT1_3DFX:
+ case GL_COMPRESSED_RGBA_FXT1_3DFX:
+
+ // GL_EXT_texture_compression_rgtc
+ // can decompress these in software but
+ // no code present in simgear.
+#ifndef GL_EXT_texture_compression_rgtc
+#define GL_COMPRESSED_RED_RGTC1_EXT 0x8DBB
+#define GL_COMPRESSED_SIGNED_RED_RGTC1_EXT 0x8DBC
+#define GL_COMPRESSED_RED_GREEN_RGTC2_EXT 0x8DBD
+#define GL_COMPRESSED_SIGNED_RED_GREEN_RGTC2_EXT 0x8DBE
+#endif
+ case GL_COMPRESSED_RED_RGTC1_EXT:
+ case GL_COMPRESSED_SIGNED_RED_RGTC1_EXT:
+ case GL_COMPRESSED_RED_GREEN_RGTC2_EXT:
+ case GL_COMPRESSED_SIGNED_RED_GREEN_RGTC2_EXT:
+
+ SG_LOG(SG_IO, SG_ALERT, "Image \"" << fileName << "\"\n"
+ "uses compressed textures which cannot be supported on "
+ "some systems.\n"
+ "Please decompress this texture for improved portability.");
+ break;
+
+ default:
+ break;
+ }
+