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