GL_APPLE_float_pixels
http://www.opengl.org/registry/specs/APPLE/float_pixels.txt
GL_APPLE_float_pixels
GL_HALF_APPLE 0x140B
GL_COLOR_FLOAT_APPLE 0x8A0F
GL_RGBA_FLOAT32_APPLE 0x8814
GL_RGB_FLOAT32_APPLE 0x8815
GL_ALPHA_FLOAT32_APPLE 0x8816
GL_INTENSITY_FLOAT32_APPLE 0x8817
GL_LUMINANCE_FLOAT32_APPLE 0x8818
GL_LUMINANCE_ALPHA_FLOAT32_APPLE 0x8819
GL_RGBA_FLOAT16_APPLE 0x881A
GL_RGB_FLOAT16_APPLE 0x881B
GL_ALPHA_FLOAT16_APPLE 0x881C
GL_INTENSITY_FLOAT16_APPLE 0x881D
GL_LUMINANCE_FLOAT16_APPLE 0x881E
GL_LUMINANCE_ALPHA_FLOAT16_APPLE 0x881F