1 | #include "common.cg" |
---|
2 | |
---|
3 | PixelOut main(v2f IN, |
---|
4 | uniform sampler1D tf, |
---|
5 | uniform sampler3D vol_grid_s, |
---|
6 | uniform float4 cell_size, |
---|
7 | uniform float4x4 ModelViewInv, |
---|
8 | uniform float4 renderParameters) |
---|
9 | { |
---|
10 | PixelOut OUT; |
---|
11 | |
---|
12 | float tf_coord_s, tf_coord_p, tf_coord_d, tf_coord_ss; |
---|
13 | |
---|
14 | |
---|
15 | float4 twice_cell_size = cell_size*2.0; |
---|
16 | float4 tex_coord = mul(ModelViewInv, IN.TexCoord); |
---|
17 | float4 tex_coord_a = tex_coord - float4(twice_cell_size.x, twice_cell_size.y, 0, 0); |
---|
18 | float4 tex_coord_b = tex_coord - float4(twice_cell_size.x, 0, twice_cell_size.z, 0); |
---|
19 | float4 tex_coord_c = tex_coord - float4(0, twice_cell_size.y, twice_cell_size.z, 0); |
---|
20 | |
---|
21 | |
---|
22 | float4 voxel_corner = f4tex3D(vol_grid_s, tex_coord); |
---|
23 | float4 voxel_face_center_a = f4tex3D(vol_grid_s, tex_coord_a); |
---|
24 | float4 voxel_face_center_b = f4tex3D(vol_grid_s, tex_coord_b); |
---|
25 | float4 voxel_face_center_c = f4tex3D(vol_grid_s, tex_coord_c); |
---|
26 | float sample = (voxel_corner.x + voxel_face_center_a.y + voxel_face_center_b.z + voxel_face_center_c.w)*0.25; |
---|
27 | |
---|
28 | //sample the transfer function texture |
---|
29 | float4 color = tex1D(tf, sample.x); |
---|
30 | |
---|
31 | if(renderParameters.x < 0.5) |
---|
32 | { |
---|
33 | //If single slice render, only flat shading, completely opaque. |
---|
34 | color.w = 1; |
---|
35 | } |
---|
36 | else |
---|
37 | { //regular volume rendering, we do FLAT SHADING |
---|
38 | //since all 4 components of the volume texture has been used to store orbital data, |
---|
39 | //there is no room to store normal vector. If we really need PHONG shading we have to pass more volumes to |
---|
40 | //the shader. We might add this later. |
---|
41 | |
---|
42 | //opacity is modulated by the number of total slices |
---|
43 | //to avoid very opaque volume when number of slices is high |
---|
44 | color.w = renderParameters.y * color.w / renderParameters.x; |
---|
45 | } |
---|
46 | |
---|
47 | OUT.Color = color; |
---|
48 | |
---|
49 | return OUT; |
---|
50 | } |
---|
51 | |
---|