mirror of https://github.com/auygun/kaliber.git
62 lines
1.3 KiB
Plaintext
62 lines
1.3 KiB
Plaintext
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#ifdef GL_ES
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precision mediump float;
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#else
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#define lowp
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#define mediump
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#define highp
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#endif
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uniform highp vec2 sky_offset;
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uniform vec3 nebula_color;
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varying highp vec2 tex_coord_0;
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float random(highp vec2 p) {
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highp float sd = sin(dot(p, vec2(54.90898, 18.233)));
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return fract(sd * 2671.6182);
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}
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float nebula(in highp vec2 p) {
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highp vec2 i = floor(p);
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highp vec2 f = fract(p);
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float a = random(i);
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float b = random(i + vec2(1.0, 0.0));
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float c = random(i + vec2(0.0, 1.0));
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float d = random(i + vec2(1.0, 1.0));
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vec2 u = smoothstep(0.0, 1.0, f);
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return mix(a, b, u.x) +
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(c - a)* u.y * (1.0 - u.x) +
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(d - b) * u.x * u.y;
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}
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float stars(in highp vec2 p, float num_cells, float size) {
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highp vec2 n = p * num_cells;
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highp vec2 i = floor(n);
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vec2 a = n - i - random(i);
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a /= num_cells * size;
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float e = dot(a, a);
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return smoothstep(0.95, 1.0, (1.0 - e * 35.0));
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}
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void main() {
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highp vec2 layer1_coord = tex_coord_0 + sky_offset;
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highp vec2 layer2_coord = tex_coord_0 + sky_offset * 0.7;
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vec3 result = vec3(0.);
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float c = nebula(layer2_coord * 3.0) * 0.35 - 0.05;
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result += nebula_color * floor(c * 60.0) / 60.0;
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c = stars(layer1_coord, 8.0, 0.05);
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result += vec3(0.97, 0.74, 0.74) * c;
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c = stars(layer2_coord, 16.0, 0.025) * 0.5;
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result += vec3(0.9, 0.9, 0.95) * c;
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gl_FragColor = vec4(result, 1.0);
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}
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