Implementation-Dependent API Values for GLSL

A number of new implementation-dependent values have been defined in OpenGL 2.0 to support the requirements of the OpenGL Shading Language. Each value can be queried with one of the variants of glGet.

GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS

Defines the total number of hardware units that can access texture maps from the vertex processor and the fragment processor combined. The minimum legal value is 2.

GL_MAX_DRAW_BUFFERS

Defines the maximum number of buffers that can be simultaneously written into from within a fragment shader using the special output variable array gl_FragData. This constant effectively defines the size of the gl_FragData array.

GL_MAX_FRAGMENT_UNIFORM_COMPONENTS

Defines the number of components (i.e., floating-point values) that are available for fragment shader uniform variables. The minimum legal value is 64.

GL_MAX_TEXTURE_COORDS

Defines the number of texture coordinate sets that are available. The minimum legal value is 2.

GL_MAX_TEXTURE_IMAGE_UNITS

Defines the total number of hardware units that can access texture maps from the fragment processor. The minimum legal value is 2.

GL_MAX_VARYING_FLOATS

Defines the number of floating-point variables available for varying variables. The minimum legal value is 32.

GL_MAX_VERTEX_ATTRIBS

Defines the number of active vertex attributes that are available. The minimum legal value is 16.

GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS

Defines the number of hardware units that can access texture maps from the vertex processor. The minimum legal value is 0.

GL_MAX_VERTEX_UNIFORM_COMPONENTS

Defines the number of components (i.e., floating-point values) that are available for vertex shader uniform variables. The minimum legal value is 512.