1 #version 120

2

3 uniform sampler3D vol_tex;

4 uniform sampler1D xfer_tex;

5

6 uniform vec3 light_dir[3] = vec3[3](

7 vec3(0.5, 0.5, 1.0),

8 vec3(-1.0, 0.2, 0.5),

9 vec3(-0.2, 0.0, -7.0)

10 );

11 uniform vec3 light_color[3] = vec3[3](

12 vec3(0.9, 0.7, 0.68),

13 vec3(0.5, 0.6, 0.9),

14 vec3(0.3, 0.3, 0.3)

15 );

16

17 const vec3 ambient = vec3(0.1, 0.1, 0.1);

18 const vec3 vdir = vec3(0.0, 0.0, 1.0);

19 const float dimmer = 0.7;

20

21 void main()

22 {

23 vec3 tc = gl_TexCoord[0].xyz;

24 float max_manh_dist = max(tc.x, max(tc.y, tc.z));

25 float min_manh_dist = min(tc.x, min(tc.y, tc.z));

26 float border = step(0.0, min_manh_dist) * (1.0 - step(1.0, max_manh_dist));

27

28 vec4 voxel = texture3D(vol_tex, gl_TexCoord[0].xyz);

29 vec4 color = texture1D(xfer_tex, voxel.a);

30

31 float alpha = color.a * border;

32 if(alpha < 0.001) discard;

33

34 vec3 norm = normalize(voxel.rgb * 2.0 - 1.0);

35

36 vec3 diffuse = vec3(0.0, 0.0, 0.0);

37 vec3 specular = vec3(0.0, 0.0, 0.0);

38

39 for(int i=0; i<3; i++) {

40 vec3 ldir = normalize(light_dir[i]);

41 vec3 hdir = normalize(vdir + ldir);

42

43 float ndotl = max(dot(norm, ldir), 0.0);

44 float ndoth = max(dot(norm, hdir), 0.0);

45

46 diffuse += light_color[i] * color.rgb * ndotl;

47 specular += light_color[i] * vec3(0.6, 0.6, 0.6) * pow(ndoth, 50.0);

48 }

49

50 gl_FragColor.rgb = ambient + (diffuse + specular) * dimmer;

51 gl_FragColor.a = alpha;

52 }