blob: 5a95f497a277a47739f3502cb8bf3e6adca5df37 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
precision mediump float;
uniform sampler2D u_texture;
uniform vec2 u_resolution;
uniform float u_step_size;
varying vec2 v_texCoord;
vec2 decodeSeed(vec4 encoded) {
float x = floor(encoded.r * 255.0 + 0.5) * 256.0 + floor(encoded.g * 255.0 + 0.5);
float y = floor(encoded.b * 255.0 + 0.5) * 256.0 + floor(encoded.a * 255.0 + 0.5);
return vec2(x, y);
}
vec4 encodeSeed(vec2 seed) {
float xHi = floor(seed.x / 256.0);
float xLo = seed.x - xHi * 256.0;
float yHi = floor(seed.y / 256.0);
float yLo = seed.y - yHi * 256.0;
return vec4(xHi / 255.0, xLo / 255.0, yHi / 255.0, yLo / 255.0);
}
bool isNoSeed(vec4 encoded) {
return encoded.r > 0.99 && encoded.g > 0.99 && encoded.b > 0.99 && encoded.a > 0.99;
}
void main() {
vec2 pixelCoord = floor(v_texCoord * u_resolution);
vec2 texelSize = 1.0 / u_resolution;
float bestDist = 1e10;
vec2 bestSeed = vec2(65535.0);
for (int dy = -1; dy <= 1; dy++) {
for (int dx = -1; dx <= 1; dx++) {
vec2 offset = vec2(float(dx), float(dy)) * u_step_size;
vec2 sampleUV = v_texCoord + offset * texelSize;
if (sampleUV.x < 0.0 || sampleUV.x > 1.0 || sampleUV.y < 0.0 || sampleUV.y > 1.0)
continue;
vec4 encoded = texture2D(u_texture, sampleUV);
if (isNoSeed(encoded))
continue;
vec2 seed = decodeSeed(encoded);
float dist = distance(pixelCoord, seed);
if (dist < bestDist) {
bestDist = dist;
bestSeed = seed;
}
}
}
if (bestDist < 1e9) {
gl_FragColor = encodeSeed(bestSeed);
} else {
gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
}
}
|
