69 lines
2.1 KiB
GLSL
69 lines
2.1 KiB
GLSL
#version 330 core
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out vec4 FragColor;
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uniform vec2 WindowSize;
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uniform float time;
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float rand(ivec2 co) {
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return fract(sin(dot(co, vec2(12.9898, 78.233))) * 43758.5453);
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}
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float cell_size = 0.1;
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#define PI 3.1415926538
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// whatever that corner contributes
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float c_dot(vec2 point, vec2 corner) {
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ivec2 c = ivec2(round(corner * 10000));
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float angle = rand(c) * 2*PI;
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vec2 random_corner_vec = vec2(cos(angle), sin(angle));
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vec2 offset = (point - corner) / cell_size;
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float dot_product = dot(random_corner_vec, offset);
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// for now just return something
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return dot_product;
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}
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float lerp(float a, float b, float x) {
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return a + x*(b-a);
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}
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// better than built in smoothstep.
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float fade(float t) {
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return ((6*t - 15)*t + 10)*t*t*t;
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}
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void main() {
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// We'll make origin in the top-left.
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vec2 uv = gl_FragCoord.xy / WindowSize;
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uv.y = 1.0 - uv.y;
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vec2 grid_edge_offset = mod(uv, cell_size);
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// c: corner
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vec2 c_tl = uv - grid_edge_offset;
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vec2 c_tr = uv - grid_edge_offset + vec2(cell_size, 0);
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vec2 c_bl = uv - grid_edge_offset + vec2(0, cell_size);
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vec2 c_br = uv - grid_edge_offset + vec2(cell_size, cell_size);
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float c_tl_dot = c_dot(uv, c_tl);
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float c_tr_dot = c_dot(uv, c_tr);
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float c_bl_dot = c_dot(uv, c_bl);
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float c_br_dot = c_dot(uv, c_br);
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// the uv within the tile (0 to 1)
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vec2 tile_uv = (uv - c_tl) / cell_size;
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// lerp index
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float u = fade(tile_uv.x);
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float v = fade(tile_uv.y);
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//float u = tile_uv.x;
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//float v = tile_uv.y;
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//float u = smoothstep(0, 1, tile_uv.x);
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//float v = smoothstep(0, 1, tile_uv.y);
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//float val = smoothstep(tile_uv.x, smoothstep(tile_uv.y, c_bl_dot, c_tl_dot), smoothstep(tile_uv.y, c_br_dot, c_tr_dot));
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float val = lerp(lerp(c_tl_dot, c_bl_dot, v), lerp(c_tr_dot, c_br_dot, v), u);
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//float val = tile_uv.y;
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//float val = c_bl_dot*2 + 0.5;
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//val = val * 20;
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float out_val = val /2 + 0.5;
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FragColor = vec4(out_val, out_val, out_val, 1);
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//float yes = 0.5 + (c_dot(uv, c_tl) + c_dot(uv, c_tr) + c_dot(uv, c_bl) + c_dot(uv, c_br)) / 2;
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//FragColor = vec4(yes, yes, yes, 1);
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}
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