czm_sunDirectionEC

An automatic GLSL uniform representing the normalized direction to the sun in eye coordinates. This is commonly used for directional lighting computations.

Like all automatic uniforms, czm_sunDirectionEC 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 vec3 czm_sunDirectionEC;

// Example
float diffuse = max(dot(czm_sunDirectionEC, normalEC), 0.0);

See:

• UniformState#getSunDirectionEC
• czm_moonDirectionEC
• czm_sunDirectionWC

Source:

• /Source/Renderer/ShaderProgram.js