OpenGL 3.2 Internal Texture Formats

OpenGL Core 3.2 Internal Formats

Fig. 1: Base Internal Formats

Base Internal Format	RGBA, Depth, and Stencil Values	Internal Components
GL_DEPTH_COMPONENT	Depth	D
GL_DEPTH_STENCIL	Depth, Stencil	D,S
GL_RED	Red	R
GL_RG	Red,Green	R,G
GL_RGB	Red,Green,Blue	R,G,B
GL_RGBA	Red,Green,Blue,Alpha	R,G,B,A

Fig. 2a: Sized Internal Formats (Color)

Internal Format		Bits
Sized	Base	R	G	B	A	Shared
GL_R8	GL_RED	8	-	-	-	-
GL_R8_SNORM	GL_RED	s8	-	-	-	-
GL_R16	GL_RED	16	-	-	-	-
GL_R16_SNORM	GL_RED	s16	-	-	-	-
GL_RG8	GL_RG	8	8	-	-	-
GL_RG8_SNORM	GL_RG	s8	s8	-	-	-
GL_RG16	GL_RG	16	16	-	-	-
GL_RG16_SNORM	GL_RG	s16	s16	-	-	-
GL_R3_G3_B2	GL_RGB	3	3	2	-	-
GL_RGB4	GL_RGB	4	4	4	-	-
GL_RGB5	GL_RGB	5	5	5	-	-
GL_RGB8	GL_RGB	8	8	8	-	-
GL_RGB8_SNORM	GL_RGB	s8	s8	s8	-	-
GL_RGB10	GL_RGB	10	10	10	-	-
GL_RGB12	GL_RGB	12	12	12	-	-
GL_RGB16	GL_RGB	16	16	16	-	-
GL_RGB16_SNORM	GL_RGB	s16	s16	s16	-	-
GL_RGBA2	GL_RGBA	2	2	2	2	-
GL_RGBA4	GL_RGBA	4	4	4	4	-
GL_RGB5_A1	GL_RGBA	5	5	5	1	-
GL_RGBA8	GL_RGBA	8	8	8	8	-
GL_RGBA8_SNORM	GL_RGBA	s8	s8	s8	s8	-
GL_RGB10_A2	GL_RGBA	10	10	10	2	-
GL_RGBA12	GL_RGBA	12	12	12	12	-
GL_RGBA16	GL_RGBA	16	16	16	16	-
GL_RGBA16_SNORM	GL_RGBA	s16	s16	s16	s16	-
GL_SRGB8	GL_RGB	8	8	8	-	-
GL_SRGB8_ALPHA8	GL_RGBA	8	8	8	8	-
GL_R16F	GL_RED	f16	-	-	-	-
GL_RG16F	GL_RG	f16	f16	-	-	-
GL_RGB16F	GL_RGB	f16	f16	f16	-	-
GL_RGBA16F	GL_RGBA	f16	f16	f16	f16	-
GL_R32F	GL_RED	f32	-	-	-	-
GL_RG32F	GL_RG	f32	f32	-	-	-
GL_RGB32F	GL_RGB	f32	f32	f32	-	-
GL_RGBA32F	GL_RGBA	f32	f32	f32	f32	-
GL_R11F_G11F_B10F	GL_RGB	f11	f11	f10	-	-
GL_RGB9_E5	GL_RGB	9	9	9	-	5
GL_R8I	GL_RED	i8	-	-	-	-
GL_R8UI	GL_RED	ui8	-	-	-	-
GL_R16I	GL_RED	i16	-	-	-	-
GL_R16UI	GL_RED	ui16	-	-	-	-
GL_R32I	GL_RED	i32	-	-	-	-
GL_R32UI	GL_RED	ui32	-	-	-	-
GL_RG8I	GL_RG	i8	i8	-	-	-
GL_RG8UI	GL_RG	ui8	ui8	-	-	-
GL_RG16I	GL_RG	i16	i16	-	-	-
GL_RG16UI	GL_RG	ui16	ui16	-	-	-
GL_RG32I	GL_RG	i32	i32	-	-	-
GL_RG32UI	GL_RG	ui32	ui32	-	-	-
GL_RGB8I	GL_RGB	i8	i8	i8	-	-
GL_RGB8UI	GL_RGB	ui8	ui8	ui8	-	-
GL_RGB16I	GL_RGB	i16	i16	i16	-	-
GL_RGB16UI	GL_RGB	ui16	ui16	ui16	-	-
GL_RGB32I	GL_RGB	i32	i32	i32	-	-
GL_RGB32UI	GL_RGB	ui32	ui32	ui32	-	-
GL_RGBA8I	GL_RGBA	i8	i8	i8	i8	-
GL_RGBA8UI	GL_RGBA	ui8	ui8	ui8	ui8	-
GL_RGBA16I	GL_RGBA	i16	i16	i16	i16	-
GL_RGBA16UI	GL_RGBA	ui16	ui16	ui16	ui16	-
GL_RGBA32I	GL_RGBA	i32	i32	i32	i32	-
GL_RGBA32UI	GL_RGBA	ui32	ui32	ui32	ui32	-

Fig. 2a: List of sized internal color formats for OpenGL Core Profile 3.2. Highlighted rows are for textures only. Others can also be used for renderbuffers.

Notice that some of these formats have unusual numbers of bits for floating point representation:

f11: 11 bit unsigned floating point value with a 5 bit exponent and 6 bit mantissa. Range: 0 and 1×2^-15 (~0.000030) to 1.984375×2¹⁶ (130048). Decimal sig. figs.: ~1.6
f10: 10 bit unsigned floating point value with a 5 bit exponent and 5 bit mantissa. Range: 0 and 1×2^-15 (~0.000030) to 1.96875×2¹⁶ (129024). Decimal sig. figs.: ~1.3
RGB9_E5: three floating point numbers with a shared 5 bit exponent

Fig 2b: Sized Internal Formats (Depth and Stencil)

Internal Format		Bits
Sized	Base	D	S
GL_DEPTH_COMPONENT16	GL_DEPTH_COMPONENT	16	-
GL_DEPTH_COMPONENT24	GL_DEPTH_COMPONENT	24	-
GL_DEPTH_COMPONENT32	GL_DEPTH_COMPONENT	32	-
GL_DEPTH_COMPONENT32F	GL_DEPTH_COMPONENT	f32	-
GL_DEPTH24_STENCIL8	GL_DEPTH_STENCIL	24	8
GL_DEPTH32F_STENCIL8	GL_DEPTH_STENCIL	f32	8

Fig. x: List of sized internal depth and stencil formats for OpenGL Core Profile 3.2. Source: The OpenGL 3.2 Graphics System: A Specification ((Core Profile) - December 7, 2009)

Fig. 3: Compressed Internal Formats

Internal Format		Type
Compressed	Base	Type
GL_COMPRESSED_RED	GL_RED	Generic
GL_COMPRESSED_RG	GL_RG	Generic
GL_COMPRESSED_RGB	GL_RGB	Generic
GL_COMPRESSED_RGBA	GL_RGBA	Generic
GL_COMPRESSED_SRGB	GL_RGB	Generic
GL_COMPRESSED_SRGB_ALPHA	GL_RGBA	Generic
GL_COMPRESSED_RED_RGTC1	GL_RED	Specific
GL_COMPRESSED_SIGNED_RED_RGTC1	GL_RED	Specific
GL_COMPRESSED_RG_RGTC2	GL_RG	Specific
GL_COMPRESSED_SIGNED_RG_RGTC2	GL_RG	Specific

Fig. x: List of compressed color formats for OpenGL Core Profile 3.2. Compressed color formats may not be used for renderbuffers. Generic type means that the driver provider may select the compression scheme. Specific type means that the texture will be encoded using RGTC as described in Appendix C.1 of the standard. Source: The OpenGL 3.2 Graphics System: A Specification ((Core Profile) - December 7, 2009)

Reference

Segal, M., Akeley, K. (2009, December 7). Section 3.8.1 Texture Image Specification in The OpenGL 3.2 Graphics System: A Specification (Core Profile) (pp. 133-140). The Khronos Group. https://www.opengl.org/registry/doc/glspec32.core.20091207.pdf