Simon Schneegans
54 lines
2.0 KiB
GLSL
54 lines
2.0 KiB
GLSL
// Inject some common shader snippets. It is only possible to include glsl files from the
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// "common" directory. Also, the files in the "common" directory are not allowed to
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// include any further files.
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#include "common/uniforms.glsl"
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#include "common/noise.glsl"
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uniform bool uAdditiveBlending;
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uniform vec2 uSeed;
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uniform float uScale;
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uniform float uLineWidth;
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uniform vec4 uGlowColor;
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uniform vec4 uLineColor;
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// This methods generates a procedural hexagonal pattern. It returns four values:
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// result.xy: This contains cell-relative coordinates for the given point.
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// [0, 0] is in the center of a cell, [0, 1] at the upper edge,
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// [sqrt(4.0 / 3.0), 0] at the right tip and so on.
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// result.z: This is the distance to the closest edge. This is used for shrinking
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// of the tiles and the sharp overlay lines.
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// result.w: This is the distance to the closest cell center. This is used for
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// the glow effect.
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vec4 getHexagons(vec2 p) {
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// Length of a cell's edge.
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const float edgeLength = sqrt(4.0 / 3.0);
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// The hexgrid repeats after this distance.
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const vec2 scale = vec2(3.0 * edgeLength, 2.0);
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// This is a repeating grid of scale-sized cells. Y-values are in the
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// interval [-1...1], X-value in [-1.5*edgeLength...1.5*edgeLength].
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vec2 a = mod(p, scale) - scale * 0.5;
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vec2 aAbs = abs(a);
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// This is the same as above, but offset by half scale.
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vec2 b = mod(p + scale * 0.5, scale) - scale * 0.5;
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vec2 bAbs = abs(b);
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// Distance to closer edge, diagonally or horizontally.
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// Once for cell set A and once for cell set B.
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float distA = max(aAbs.x / edgeLength + aAbs.y * 0.5, aAbs.y);
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float distB = max(bAbs.x / edgeLength + bAbs.y * 0.5, bAbs.y);
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// Minimum of both is distance to closest edge.
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float dist = 1.0 - min(distA, distB);
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// We use the radial distance to the center for glow.
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float glow = min(dot(a, a), dot(b, b)) / 1.5;
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// Take cell-relative coordinates from the closer cell.
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vec2 cellCoords = distA < distB ? a : b;
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return vec4(cellCoords, dist, glow);
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} |