fragRayCast.glsl
1.02 KB
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
#version 330
uniform vec3 camera;
uniform float stepsize;
uniform vec3 d;
uniform vec3 ray_min;
uniform vec3 ray_max;
vec4 computeColor(vec3 p);
in vec4 gl_TexCoord[1];
out vec4 MyFragColor;
void main(void)
{
//vec3 camera = vec3(0.5, 0.5, 1);
//float stepsize = 0.001;
vec4 value;
float scalar;
//initialize the destinatino color and opacity
vec4 dst = vec4(0.0, 0.0, 0.0, 0.0);
//determine the entry position of the volume
vec3 p = gl_TexCoord[0].xyz;
//compute the ray direction
vec3 direction = p - camera;
direction = normalize(direction);
vec3 step = length(direction*(1.0/d))*direction*stepsize;
//loop for ray traversal
//for(int i=0; i<400; i++)
do
{
value = computeColor(p);
vec4 src = value;
src.rgb = src.rgb*src.a;
//ray integration
dst = (1.0 - dst.a)*src + dst;
//advance the ray position along the ray direction
p = p + step;
}while(p.x > ray_min.x && p.y > ray_min.y && p.z > ray_min.z && p.x < ray_max.x && p.y < ray_max.y && p.z < ray_max.z && dst.a < 0.99);
MyFragColor = dst;
}