1 uniform sampler3D vol_tex;

2 uniform sampler1D xfer_tex;

3

4 const vec3 light_dir[3] = {

5 vec3(0.5, 0.5, 1.0),

6 vec3(-1.0, 0.2, 0.5),

7 vec3(-0.2, 0.0, -7.0)

8 };

9 const vec3 light_color[3] = {

10 vec3(0.9, 0.7, 0.68),

11 vec3(0.5, 0.6, 0.9),

12 vec3(0.3, 0.3, 0.3)

13 };

14

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

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

17 const float dimmer = 0.7;

18

19 void main()

20 {

21 vec3 tc = gl_TexCoord[0].xyz;

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

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

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

25

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

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

28

29 float alpha = color.a * border;

30 if(alpha < 0.001) discard;

31

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

33

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

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

36

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

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

39 vec3 hdir = normalize(vdir + ldir);

40

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

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

43

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

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

46 }

47

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

49 gl_FragColor.a = alpha;

50 }