Texture Atlases

The coordinates used to sample the texture atlases in a gbuffers pass are obtained in the vertex shader using the following code:

Compatibility Profile

coord = (gl_TextureMatrix[0] * gl_MultiTexCoord0).xy;

Core Profile

coord = (textureMatrix * vec4(vaUV0, 0.0, 1.0)).xy;

For more information, see gl_MultiTexCoord0.

Texture atlases are not bound in non-gbuffers passes. To access them in other passes, custom textures can be used.

uniform sampler2D gtexture

gtexture is the main texture atlas, used to obtain the albedo color of any geometry rendered in a gbuffers pass. It is usually multiplied by the result of gl_Color/vaColor (passed through from the vertex shader) to obtain the final color value.

Warning

Some shaderpacks may use other aliases such as tex, as samplers using texture names that do not exist will simply bind to the atlas. This is undefined behavior and should not be relied upon.

texture is a valid alias in #version 120, however in any newer version of GLSL this is a reserved keyword and should not be used.

uniform sampler2D normals

normals is the normal map atlas. If the resource pack does not have a texture suffixed with _n for the current geometry, or there is no resource pack loaded, then the value returned will be as follows.

Component	Value (0-255)
r	127
g	127
b	255
a	255

Note that the values returned when sampling the texture are in the 0-1 range, whereas they are displayed here in the 0-255 range.

For information on how to use these values, see PBR Standards.

uniform sampler2D specular

specular is the specular map atlas. If the resource pack does not have a texture suffixed with _s for the current geometry, or there is no resource pack loaded, then the value returned will be as follows.

Component	Value (0-255)
r	0
g	0
b	0
a	0

Note that the values returned when sampling the texture are in the 0-1 range, whereas they are displayed here in the 0-255 range.

For information on how to use these values, see PBR Standards.