GLUniforms

We have a vertex shader with source such as this:

1 #version 130
2 
3 uniform mat4 projection;
4 uniform mat4 modelView;
5 in vec3 position;
6 
7 void main()
8 {
9    gl_Position = projection * modelView *  vec4(position, 1.0);
10 }

We have the following uniforms specification struct:

1 struct Uniforms
2 {
3    import gl3n.linalg;
4    mat4 projection;
5    mat4 modelView;
6 }

NOTE: Array uniforms are not supported at the moment, but will be supported in future.

The vertex shader above is used by a GLProgram program.

The following code builds a GLUniforms struct:

1 try
2 {
3    auto uniforms = GLUniforms!Uniforms(program);
4 }
5 catch(OpenGLException e)
6 {
7    writeln("ERROR: uniforms in a program have unexpected types: ", e);
8    return;
9 }

The GLUniforms constructor enforces that types of uniforms in program match types in Uniforms - the uniforms specification struct. Note that if program is missing any uniform, there is no error, only a logged warning, and a dummy uniform is created. This is because some GPU drivers agressively optimize and remove uniforms, and we don't want to trigger an error just because a user is running our program on a GPU we didn't test.

Finally, the following code sets the uniforms through uniforms.

// mat4 projectionMatrix, modelViewMatrix
uniforms.projection = projectionMatrix;
uniforms.modelView  = modelViewMatrix;