37 lines
1.3 KiB
GLSL
37 lines
1.3 KiB
GLSL
/*
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Copyright (C) 2021 hiimgoodpack
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#version 330 core
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in vec2 vFragCoord;
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uniform float aHorizontalOffset;
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uniform sampler2D aTexture;
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void main() {
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float distanceFromCenterSquared = dot(vFragCoord, vFragCoord);
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// alpha = 0 if fragment is outside circle
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// alpha = 1 if fragment is inside circle
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float alpha = distanceFromCenterSquared > 1 ? 0 : 1;
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// An equation which seems to work
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float specular = distanceFromCenterSquared * (-0.5f*vFragCoord.x + vFragCoord.y) + 1;
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vec2 texCoord = vFragCoord * vec2(0.5,0.5) + vec2(0.5+aHorizontalOffset,0.5);
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gl_FragColor = vec4(texture(aTexture, texCoord).xyz*specular, alpha);
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}
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