mirror of
https://github.com/OpenSpace/OpenSpace.git
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95 lines
3.7 KiB
GLSL
95 lines
3.7 KiB
GLSL
/*****************************************************************************************
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* *
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* OpenSpace *
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* *
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* Copyright (c) 2014-2025 *
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* *
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* Permission is hereby granted, free of charge, to any person obtaining a copy of this *
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* software and associated documentation files (the "Software"), to deal in the Software *
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* without restriction, including without limitation the rights to use, copy, modify, *
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* merge, publish, distribute, sublicense, and/or sell copies of the Software, and to *
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* permit persons to whom the Software is furnished to do so, subject to the following *
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* conditions: *
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* *
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* The above copyright notice and this permission notice shall be included in all copies *
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* or substantial portions of the Software. *
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* *
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, *
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* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A *
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* PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT *
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF *
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* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE *
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* OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
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****************************************************************************************/
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#ifndef _BLENDING_GLSL_
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#define _BLENDING_GLSL_
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/**
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* Blend in src behind dst using normal blending
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* dst is premultiplied
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* src is expressed in straight RGBA
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*/
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void normalBlend(inout vec4 dst, vec4 src) {
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dst.rgb = dst.rgb + (1.f - dst.a) * src.a * src.rgb;
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dst.a = dst.a + (1.f - dst.a) * src.a;
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}
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/**
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* Blend in src behind dst using additive blending
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* dst is premultiplied
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* src is expressed in straight RGBA
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*/
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void additiveBlend(inout vec4 dst, vec4 src) {
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dst.rgb = dst.rgb + (1.f - dst.a) * src.a * src.rgb;
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}
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/**
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* Blend in src behind dst using normal blending
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* dst is premultiplied
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* src is expressed in straight RGBA
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* stepSize = 0: alpha becomes 0
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* stepSize = 1: alpha becomes src.a
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*/
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void normalBlendStep(inout vec4 dst, vec4 src, float stepSize) {
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src.a = 1.f - pow(1.f - src.a, stepSize);
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normalBlend(dst, src);
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}
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/**
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* Blend in src behind dst using addivtive blending
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* dst is premultiplied
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* src is expressed in straight RGBA
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* stepSize = 0: alpha becomes 0
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* stepSize = 1: alpha becomes src.a
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*/
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void additiveBlendStep(inout vec4 dst, vec4 src, float stepSize) {
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src.a = 1.0 - pow(1.0 - src.a, stepSize);
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additiveBlend(dst, src);
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}
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/**
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* Blend in src behind dst
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* dst is premultiplied
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* src is expressed in straight RGBA
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*/
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void blend(inout vec4 dst, vec4 src) {
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dst.rgb = dst.rgb + (1.f - dst.a) * src.a * src.rgb;
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dst.a = dst.a + (1.f - dst.a) * src.a;
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}
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/**
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* Blend in src behind dst
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* dst is premultiplied
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* src is expressed in straight RGBA
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* stepSize = 0: alpha becomes 0
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* stepSize = 1: alpha becomes src.a
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*/
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void blendStep(inout vec4 dst, vec4 src, float stepSize) {
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src.a = 1.0 - pow(1.f - src.a, stepSize);
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blend(dst, src);
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}
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#endif // _BLENDING_GLSL_
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