forked from Rowland/EG
32 lines
1.1 KiB
GLSL
32 lines
1.1 KiB
GLSL
/**
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* Reads a value previously transformed with {@link czm_writeNonPerspective}
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* by dividing it by `w`, the value used in the perspective divide.
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* This function is intended to be called in a fragment shader to access a
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* `varying` that should not be subject to perspective interpolation.
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* For example, screen-space texture coordinates. The value should have been
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* previously written in the vertex shader with a call to
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* {@link czm_writeNonPerspective}.
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*
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* @name czm_readNonPerspective
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* @glslFunction
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*
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* @param {float|vec2|vec3|vec4} value The non-perspective value to be read.
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* @param {float} oneOverW One over the perspective divide value, `w`. Usually this is simply `gl_FragCoord.w`.
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* @returns {float|vec2|vec3|vec4} The usable value.
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*/
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float czm_readNonPerspective(float value, float oneOverW) {
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return value * oneOverW;
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}
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vec2 czm_readNonPerspective(vec2 value, float oneOverW) {
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return value * oneOverW;
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}
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vec3 czm_readNonPerspective(vec3 value, float oneOverW) {
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return value * oneOverW;
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}
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vec4 czm_readNonPerspective(vec4 value, float oneOverW) {
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return value * oneOverW;
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}
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