Don't forget: OpenGL versions are
GL_ARB_texture_swizzle and GL_ARB_texture_buffer_object are supported in the 220.127.116.1196 drivers, though they aren't listed in the extension string. I became a little suspicious after the latest driver for my AMD FirePro card also didn't list GL_ARB_texture_swizzle but claimed GL4.2 support and properly supported it, so I decided to recheck the HD4000. The shader with samplerBuffer compiled without incident, and the glTexBuffer API entry point was found. Swizzling also works properly ( glTexParameter(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_RGBA) ).