Real-Time 3D Graphics with WebGL 2 - Second Edition

Uniforms

Uniforms are available to both the vertex shader and the fragment shader. While attributes differ every time the vertex shader is invoked, uniforms are constant throughout a rendering cycle – that is, during the drawArrays or drawElements WebGL call.

Parallel Processing We process vertices in parallel; therefore, each copy/thread of the vertex shader processes a different vertex.

We can use uniforms to pass along information about lights (such as diffuse color and direction), and materials (diffuse color):

uniform vec3 uLightDirection;  // incoming light source directionuniform vec4 uLightDiffuse;    // light diffuse componentuniform vec4 uMaterialDiffuse; // material diffuse color

Again, the uniform keyword tells us that these variables ...