Uniforms in OpenGL - hls333555/OpenGL GitHub Wiki

Uniforms are a way to get data from the CPU side(C++ in the case) into the shader.

Here are the main steps to use uniforms in OpenGL:

  • Add a variable into shader:

    uniform vec4 u_Color;

  • Below glUseProgram();, add the following code:

    int location = glGetUniformLocation(program, "u_Color");
// If uColor is not used in the fragment shader, it will return -1
//ASSERT(location != -1);
glUniform4f(location, 0.f, 1.f, 1.f, 1.f);

You can see an example in code using uniforms to achieve a flashing effect like below:

image