mirror of
https://github.com/Ttanasart-pt/Pixel-Composer.git
synced 2024-09-22 05:11:17 +02:00
54 lines
1.5 KiB
GLSL
54 lines
1.5 KiB
GLSL
/*
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Triangular Grid
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03/2016
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seb chevrel
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*/
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varying vec2 v_vTexcoord;
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varying vec4 v_vColour;
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uniform vec2 dimension;
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uniform vec2 position;
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uniform vec2 scale;
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uniform float angle;
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uniform float thick;
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uniform vec4 color0;
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uniform vec4 color1;
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#define PI 3.1415926535897
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// triangle rotation matrices
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vec2 v60 = vec2(cos(PI / 3.0), sin(PI / 3.0));
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vec2 vm60 = vec2(cos(-PI / 3.0), sin(-PI / 3.0));
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mat2 rot60 = mat2(v60.x, -v60.y, v60.y, v60.x);
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mat2 rotm60 = mat2(vm60.x, -vm60.y, vm60.y, vm60.x);
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float triangleGrid(vec2 p, float stepSize, float vertexSize, float lineSize) {
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// equilateral triangle grid
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vec2 fullStep = vec2( stepSize, stepSize * v60.y);
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vec2 halfStep = fullStep / 2.0;
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vec2 grid = floor(p / fullStep);
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vec2 offset = vec2( (mod(grid.y, 2.0) == 1.0) ? halfStep.x : 0., 0.);
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// tiling
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vec2 uv = mod(p + offset, fullStep) - halfStep;
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float d2 = dot(uv, uv);
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return vertexSize / d2 + // vertices
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max( abs(lineSize / (uv * rotm60).y), // lines -60deg
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max ( abs(lineSize / (uv * rot60).y), // lines 60deg
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abs(lineSize / uv.y) )); // h lines
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}
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void main() {
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float time = 1.;
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vec2 pos = (v_vTexcoord - position) / scale, _pos;
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float ratio = dimension.x / dimension.y;
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_pos.x = pos.x * ratio * cos(angle) - pos.y * sin(angle);
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_pos.y = pos.x * ratio * sin(angle) + pos.y * cos(angle);
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vec3 color = triangleGrid(_pos, 0.1, 0., thick / 100.) * vec3(0.8, 0.8, 0.85);
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float grey = (color[0] + color[1] + color[2]) / 3.;
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gl_FragColor = (grey < 0.5)? color0 : color1;
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}
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