86 lines
2.5 KiB
GLSL
86 lines
2.5 KiB
GLSL
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/* Infinite grid
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* Clément Foucault */
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in vec3 wPos;
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out vec4 FragColor;
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uniform mat4 ProjectionMatrix;
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uniform vec3 cameraPos;
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uniform vec4 gridSettings;
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#define gridDistance gridSettings.x
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#define gridResolution gridSettings.y
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#define gridScale gridSettings.z
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#define gridSubdiv gridSettings.w
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#define GRID_LINE_SMOOTH 1.15
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float grid(vec2 uv, vec2 fwidthUvs, float grid_size)
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{
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float half_size = grid_size / 2.0;
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/* triangular wave pattern, amplitude is [0, grid_size] */
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vec2 grid_domain = abs(mod(uv + half_size, grid_size) - half_size);
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/* modulate by the absolute rate of change of the uvs
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* (make lines have the same width under perspective) */
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grid_domain /= fwidthUvs;
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/* collapse waves and normalize */
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grid_domain.x = min(grid_domain.x, grid_domain.y) / grid_size;
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return 1.0 - smoothstep(0.0, GRID_LINE_SMOOTH / grid_size, grid_domain.x);
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}
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float axis(float u, float fwidthU, float line_size)
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{
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float axis_domain = abs(u);
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/* modulate by the absolute rate of change of the uvs
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* (make line have the same width under perspective) */
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axis_domain /= fwidthU;
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return 1.0 - smoothstep(0.0, GRID_LINE_SMOOTH, axis_domain - line_size);
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}
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void main()
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{
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vec2 fwidthUvs = fwidth(wPos.xy);
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float blend, lvl, fade;
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/* if persp */
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if (ProjectionMatrix[3][3] == 0.0) {
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float dist = distance(cameraPos, wPos);
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float log2dist = -log2(dist / (2.0 * gridDistance));
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blend = fract(log2dist / gridResolution);
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lvl = floor(log2dist / gridResolution);
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fade = 1.0 - smoothstep(0.0, gridDistance, dist - gridDistance);
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}
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else {
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/* todo find a better way */
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blend = 0.0;
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lvl = 0.0;
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fade = 1.0;
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}
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/* from smallest to biggest */
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float scaleA = gridScale * pow(gridSubdiv, min(-lvl + 1.0, 1.0));
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float scaleB = gridScale * pow(gridSubdiv, min(-lvl + 2.0, 1.0));
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float scaleC = gridScale * pow(gridSubdiv, min(-lvl + 3.0, 1.0));
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float gridA = grid(wPos.xy, fwidthUvs, scaleA);
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float gridB = grid(wPos.xy, fwidthUvs, scaleB);
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float gridC = grid(wPos.xy, fwidthUvs, scaleC);
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float xAxis = axis(wPos.y, fwidthUvs.y, 0.1); /* Swapped */
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float yAxis = axis(wPos.x, fwidthUvs.x, 0.1); /* Swapped */
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FragColor = vec4(colorGrid.rgb, gridA * blend);
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FragColor = mix(FragColor, vec4(mix(colorGrid.rgb, colorGridEmphasise.rgb, blend), 1.0), gridB);
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FragColor = mix(FragColor, vec4(colorGridEmphasise.rgb, 1.0), gridC);
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FragColor = mix(FragColor, colorGridAxisX, xAxis);
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FragColor = mix(FragColor, colorGridAxisY, yAxis);
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FragColor.a *= fade;
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}
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