1 | /* -*- mode: c++; c-basic-offset: 4; indent-tabs-mode: nil -*- */ |
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2 | /* |
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3 | * Copyright (c) 2004-2013 HUBzero Foundation, LLC |
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4 | * |
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5 | * Authors: |
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6 | * Wei Qiao <qiaow@purdue.edu> |
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7 | */ |
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8 | |
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9 | #include "common.cg" |
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10 | |
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11 | PixelOut main(v2f IN, |
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12 | uniform sampler1D tf, |
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13 | uniform sampler3D vol_grid_s, |
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14 | uniform float4 cell_size, |
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15 | uniform float4 renderParameters) |
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16 | { |
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17 | PixelOut OUT; |
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18 | |
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19 | float tf_coord_s, tf_coord_p, tf_coord_d, tf_coord_ss; |
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20 | |
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21 | float4 twice_cell_size = cell_size*2.0; |
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22 | float4 tex_coord = IN.TexCoord; |
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23 | float4 tex_coord_a = tex_coord - float4(twice_cell_size.x, twice_cell_size.y, 0, 0); |
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24 | float4 tex_coord_b = tex_coord - float4(twice_cell_size.x, 0, twice_cell_size.z, 0); |
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25 | float4 tex_coord_c = tex_coord - float4(0, twice_cell_size.y, twice_cell_size.z, 0); |
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26 | |
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27 | float4 voxel_corner = tex3D(vol_grid_s, tex_coord); |
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28 | float4 voxel_face_center_a = tex3D(vol_grid_s, tex_coord_a); |
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29 | float4 voxel_face_center_b = tex3D(vol_grid_s, tex_coord_b); |
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30 | float4 voxel_face_center_c = tex3D(vol_grid_s, tex_coord_c); |
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31 | float sample = (voxel_corner.x + voxel_face_center_a.y + voxel_face_center_b.z + voxel_face_center_c.w)*0.25; |
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32 | |
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33 | //sample the transfer function texture |
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34 | float4 color = tex1D(tf, sample.x); |
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35 | |
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36 | if (renderParameters.x < 0.5) { |
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37 | //If single slice render, only flat shading, completely opaque. |
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38 | color.w = 1; |
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39 | } else { |
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40 | //regular volume rendering, we do FLAT SHADING |
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41 | //since all 4 components of the volume texture has been used to store orbital data, |
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42 | //there is no room to store normal vector. If we really need PHONG shading we have to pass more volumes to |
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43 | //the shader. We might add this later. |
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44 | |
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45 | //opacity is modulated by the number of total slices |
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46 | //to avoid very opaque volume when number of slices is high |
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47 | color.w = renderParameters.y * color.w / renderParameters.x; |
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48 | } |
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49 | |
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50 | OUT.Color = color; |
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51 | |
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52 | return OUT; |
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53 | } |
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