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