59 lines
1.6 KiB
GLSL
59 lines
1.6 KiB
GLSL
#version 300 es
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// pathfinder/demo2/stencil.vs.glsl
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//
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// Copyright © 2018 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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precision highp float;
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uniform vec2 uFramebufferSize;
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uniform vec2 uTileSize;
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in vec2 aTessCoord;
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in uint aFromPx;
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in uint aToPx;
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in vec2 aFromSubpx;
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in vec2 aToSubpx;
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in uint aTileIndex;
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out vec2 vFrom;
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out vec2 vTo;
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vec2 computeTileOffset(uint tileIndex, float stencilTextureWidth) {
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uint tilesPerRow = uint(stencilTextureWidth / uTileSize.x);
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uvec2 tileOffset = uvec2(aTileIndex % tilesPerRow, aTileIndex / tilesPerRow);
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return vec2(tileOffset) * uTileSize;
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}
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void main() {
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vec2 tileOrigin = computeTileOffset(aTileIndex, uFramebufferSize.x);
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vec2 from = vec2(aFromPx & 15u, aFromPx >> 4u) + aFromSubpx;
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vec2 to = vec2(aToPx & 15u, aToPx >> 4u) + aToSubpx;
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vec2 position;
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bool zeroArea = !(abs(from.x - to.x) > 0.1) || !(abs(uTileSize.y - min(from.y, to.y)) > 0.1);
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if (aTessCoord.x < 0.5)
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position.x = floor(min(from.x, to.x));
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else
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position.x = ceil(max(from.x, to.x));
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if (aTessCoord.y < 0.5)
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position.y = floor(min(from.y, to.y));
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else
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position.y = uTileSize.y;
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vFrom = from - position;
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vTo = to - position;
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if (zeroArea)
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gl_Position = vec4(0.0);
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else
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gl_Position = vec4((tileOrigin + position) / uFramebufferSize * 2.0 - 1.0, 0.0, 1.0);
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}
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