52 lines
1.5 KiB
GLSL
52 lines
1.5 KiB
GLSL
#version 330
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// pathfinder/shaders/tile_alpha_overlay.fs.glsl
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//
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// Copyright © 2020 The Pathfinder Project Developers.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Multiply, screen, overlay, and hard light filters.
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#extension GL_GOOGLE_include_directive : enable
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#define OVERLAY_BLEND_MODE_MULTIPLY 0
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#define OVERLAY_BLEND_MODE_SCREEN 1
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#define OVERLAY_BLEND_MODE_HARD_LIGHT 2
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#define OVERLAY_BLEND_MODE_OVERLAY 3
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precision highp float;
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uniform int uBlendMode;
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out vec4 oFragColor;
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#include "tile_alpha_sample.inc.glsl"
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void main() {
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vec4 srcRGBA = sampleSrcColor();
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vec4 destRGBA = sampleDestColor();
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bool reversed = uBlendMode == OVERLAY_BLEND_MODE_OVERLAY;
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vec3 src = reversed ? srcRGBA.rgb : destRGBA.rgb;
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vec3 dest = reversed ? destRGBA.rgb : srcRGBA.rgb;
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vec3 multiply = src * dest;
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vec3 blended;
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if (uBlendMode == OVERLAY_BLEND_MODE_MULTIPLY) {
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blended = multiply;
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} else {
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vec3 screen = dest + src - multiply;
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if (uBlendMode == OVERLAY_BLEND_MODE_SCREEN)
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blended = screen;
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else
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blended = select3(lessThanEqual(src, vec3(0.5)), multiply, screen * 2.0 - 1.0);
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}
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oFragColor = blendColors(destRGBA, srcRGBA, blended);
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}
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