blob: 2fd155f715ca28d14a58480909f741ed6d480361 (
plain)
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
|
#define M_1_SQRTPI 0.5641895835477563 /* 1/sqrt(pi) */
/**
* We want to know how much a pixel is covered by a line.
* We replace the square pixel with acircle of the same area and try to find the intersection area.
* The area we search is the circular segment. https://en.wikipedia.org/wiki/Circular_segment
* The formula for the area uses inverse trig function and is quite complexe. Instead,
* we approximate it by using the smoothstep function and a 1.05 factor to the disc radius.
*/
#define DISC_RADIUS (M_1_SQRTPI * 1.05)
#define GRID_LINE_SMOOTH_START (0.5 - DISC_RADIUS)
#define GRID_LINE_SMOOTH_END (0.5 + DISC_RADIUS)
bool test_occlusion()
{
return gl_FragCoord.z > texelFetch(depthTex, ivec2(gl_FragCoord.xy), 0).r;
}
float edge_step(float dist)
{
if (do_smooth_wire) {
return smoothstep(GRID_LINE_SMOOTH_START, GRID_LINE_SMOOTH_END, dist);
}
else {
return step(0.5, dist);
}
}
void main()
{
float dist = abs(geometry_out.edgeCoord) - max(sizeEdge - 0.5, 0.0);
float dist_outer = dist - max(sizeEdge, 1.0);
float mix_w = edge_step(dist);
float mix_w_outer = edge_step(dist_outer);
/* Line color & alpha. */
fragColor = mix(geometry_out.finalColorOuter,
geometry_out.finalColor,
1.0 - mix_w * geometry_out.finalColorOuter.a);
/* Line edges shape. */
fragColor.a *= 1.0 - (geometry_out.finalColorOuter.a > 0.0 ? mix_w_outer : mix_w);
fragColor.a *= test_occlusion() ? alpha : 1.0;
}
|