What does the term "genType" mean in OpenGL/GLSL?

Question

In GLSL documentation, the term genType is used often as the type of parameters. For example, the function dot is documented as follows:

float dot(genType x,
          genType y);

double dot(genDType x,
           genDType y);

What does the term genType mean? What does it abbreviate? Is it used elsewhere than OpenGL?

Answer 1

It's a catch-all for multiple types. From the specification section 8

When the built-in functions are specified below, where the input arguments (and corresponding output) can be float , vec2 , vec3 , or vec4 , genType is used as the argument. Where the input arguments (and corresponding output) can be int , ivec2 , ivec3 , or ivec4 , genIType is used as the argument.

For reference, all the "generic" types:

• genType: floats
• genDType: double floats
• genIType: signed integers
• genUType: unsigned integers
• genBType: booleans
• mat: float matrices
• dmat: double matrices