2018-11-15 17:37:32 -05:00
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#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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2018-11-15 22:23:42 -05:00
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in vec2 aTessCoord;
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in vec2 aFrom;
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in vec2 aTo;
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2018-11-15 17:37:32 -05:00
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in uint aTileIndex;
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2018-11-16 23:43:27 -05:00
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out vec2 vFrom;
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out vec2 vCtrl;
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out vec2 vTo;
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2018-11-15 17:37:32 -05:00
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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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2018-11-15 22:23:42 -05:00
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vec2 tileOrigin = computeTileOffset(aTileIndex, uFramebufferSize.x);
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2018-11-16 23:43:27 -05:00
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vec2 from = aFrom, ctrl = mix(aFrom, aTo, 0.5), to = aTo;
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vec2 dilation, position;
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bool zeroArea = abs(from.x - to.x) < 0.01;
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if (aTessCoord.x < 0.5) {
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position.x = min(min(from.x, to.x), ctrl.x);
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dilation.x = zeroArea ? 0.0 : -1.0;
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} else {
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position.x = max(max(from.x, to.x), ctrl.x);
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dilation.x = zeroArea ? 0.0 : 1.0;
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}
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if (aTessCoord.y < 0.5) {
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position.y = min(min(from.y, to.y), ctrl.y);
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dilation.y = zeroArea ? 0.0 : -1.0;
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} else {
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position.y = uTileSize.y;
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dilation.y = 0.0;
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}
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position += dilation;
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vFrom = aFrom - position;
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vCtrl = mix(aFrom, aTo, 0.5) - position;
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vTo = aTo - position;
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gl_Position = vec4((tileOrigin + position) / uFramebufferSize * 2.0 - 1.0, 0.0, 1.0);
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2018-11-15 17:37:32 -05:00
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}
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