czm_viewport
An automatic GLSL uniform containing the viewport's x, y, width,
and height properties in an vec4's x, y, z,
and w components, respectively.
Like all automatic uniforms, czm_viewport does not need to be explicitly declared.
However, it can be explicitly declared when a shader is also used by other applications such
as a third-party authoring tool.
Example
// GLSL declaration uniform vec4 czm_viewport; // Scale the window coordinate components to [0, 1] by dividing // by the viewport's width and height. vec2 v = gl_FragCoord.xy / czm_viewport.zw;
- Context#getViewport