forked from goliath/shadermeh
72 lines
2.5 KiB
GLSL
72 lines
2.5 KiB
GLSL
#define sqrt25 0.6324555320 //sqrt(2./5.)
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#define sqrt35 0.7745966692 //sqrt(3./5.)
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//edge distance of a Cube
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float cubeDist(vec3 uvw) {
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vec3 d = abs(uvw); //mirroring along axis
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return min(d.x, min(d.y, d.z))*2.; //*2. for 0-1 range
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}
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// Cube Tiling
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vec4 cubeTile(vec3 uvw) {
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vec3 grid = fract(uvw)-.5; // centered UVW coords
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float edist = cubeDist(grid); // edge distance
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//float cdist = dot(grid,grid); //squared center distance
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//vec3 id = uvw-grid; // Cells IDs
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return vec4(grid, edist);
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}
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// scaled with offset cube tiling
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vec4 cubeCell(vec3 uvw, vec3 offset, float gridRes) {
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vec4 cubeTiling = cubeTile(uvw*gridRes + offset);
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vec3 tiledUV = (cubeTiling.xyz - offset)/gridRes; //cube pixaltion
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return vec4(tiledUV,cubeTiling.w);
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}
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// rotates a vetor from SirBelfer4 (https://www.shadertoy.com/view/ssc3z4)
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vec3 rotate(vec3 v, vec3 a)
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{
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// https://math.stackexchange.com/questions/2975109/how-to-convert-euler-angles-to-quaternions-and-get-the-same-euler-angles-back-fr
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vec4 q;
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vec3 c = cos(a * 0.5), s = sin(a * 0.5);
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q.x = s.x * c.y * c.z - c.x * s.y * s.z;
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q.y = c.x * s.y * c.z + s.x * c.y * s.z;
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q.z = c.x * c.y * s.z - s.x * s.y * c.z;
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q.w = c.x * c.y * c.z + s.x * s.y * s.z;
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// https://blog.molecular-matters.com/2013/05/24/a-faster-quaternion-vector-multiplication/
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vec3 qt = 2.0 * cross(q.xyz, v);
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return v + q.w * qt + cross(q.xyz, qt);
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}
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// makes RdYlBu_r colormap with polynimal 6 https://www.shadertoy.com/view/Nd3fR2
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vec3 RdYlBu_r(float t) {
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const vec3 c0 = vec3(0.207621,0.196195,0.618832);
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const vec3 c1 = vec3(-0.088125,3.196170,-0.353302);
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const vec3 c2 = vec3(8.261232,-8.366855,14.368787);
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const vec3 c3 = vec3(-2.922476,33.244294,-43.419173);
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const vec3 c4 = vec3(-34.085327,-74.476041,37.159352);
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const vec3 c5 = vec3(50.429790,67.145621,-1.750169);
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const vec3 c6 = vec3(-21.188828,-20.935464,-6.501427);
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return c0+t*(c1+t*(c2+t*(c3+t*(c4+t*(c5+t*c6)))));
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}
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void mainImage( out vec4 fragColor, in vec2 fragCoord ) {
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vec2 uv = fragCoord/iResolution.y; //square UV pattern
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float time = (0.05*iTime); // used as z dimension
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float gridRes = 2.5; //size of cubes
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vec3 point = vec3(uv, time); //uvw cords
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//cosmetic rotate for fun triangles otherwise it looks so square
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point = rotate(point, (vec3(sqrt25,sqrt35,0.))); //vec3 must be normalized
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vec4 a = cubeCell(point, vec3(0.), gridRes);
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vec3 col = RdYlBu_r(a.w); // cosmetic Colormap
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fragColor = vec4(col, 1.);
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}
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