33 lines
1.2 KiB
GLSL
33 lines
1.2 KiB
GLSL
/**
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* Transforms a value for non-perspective interpolation by multiplying
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* it by w, the value used in the perspective divide. This function is
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* intended to be called in a vertex shader to compute the value of 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 fragment shader
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* must call {@link czm_readNonPerspective} to retrieve the final
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* non-perspective value.
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*
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* @name czm_writeNonPerspective
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* @glslFunction
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*
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* @param {float|vec2|vec3|vec4} value The value to be interpolated without accounting for perspective.
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* @param {float} w The perspective divide value. Usually this is the computed `gl_Position.w`.
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* @returns {float|vec2|vec3|vec4} The transformed value, intended to be stored in a `varying` and read in the
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* fragment shader with {@link czm_readNonPerspective}.
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*/
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float czm_writeNonPerspective(float value, float w) {
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return value * w;
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}
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vec2 czm_writeNonPerspective(vec2 value, float w) {
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return value * w;
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}
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vec3 czm_writeNonPerspective(vec3 value, float w) {
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return value * w;
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}
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vec4 czm_writeNonPerspective(vec4 value, float w) {
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return value * w;
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}
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