1 | /* -*- mode: c++; c-basic-offset: 4; indent-tabs-mode: nil -*- */ |
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2 | /* |
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3 | * ====================================================================== |
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4 | * AUTHOR: Wei Qiao <qiaow@purdue.edu> |
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5 | * Purdue Rendering and Perceptualization Lab (PURPL) |
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6 | * |
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7 | * Copyright (c) 2004-2012 HUBzero Foundation, LLC |
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8 | * |
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9 | * See the file "license.terms" for information on usage and |
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10 | * redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
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11 | * ====================================================================== |
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12 | */ |
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13 | |
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14 | #include "common.cg" |
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15 | |
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16 | /* |
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17 | * zincblende shading fragment program |
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18 | * |
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19 | * renderParams: |
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20 | * x: sample distance ratio (0 = single slice) |
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21 | * y: isosurface flag (opacity scaling on/off) |
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22 | * z: opacity scale |
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23 | */ |
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24 | PixelOut main(v2f IN, |
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25 | uniform sampler1D tf, |
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26 | uniform sampler3D volumeA, |
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27 | uniform sampler3D volumeB, |
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28 | uniform float4 cellSize, |
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29 | uniform float4x4 modelViewInv, |
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30 | uniform float4 renderParams) |
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31 | |
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32 | { |
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33 | PixelOut OUT; |
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34 | |
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35 | float4 tex_coord = mul(modelViewInv, IN.TexCoord); |
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36 | float4 twice_cell_size = cellSize * 2.0; |
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37 | |
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38 | // volumeA : outer |
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39 | // volumeB : inner |
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40 | float4 tex_coord_2 = tex_coord + float4(twice_cell_size.x, 0, twice_cell_size.z, 0); |
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41 | float4 tex_coord_3 = tex_coord + float4(0, twice_cell_size.y, twice_cell_size.z, 0); |
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42 | float4 tex_coord_4 = tex_coord + float4(twice_cell_size.x, twice_cell_size.y, 0, 0); |
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43 | float4 voxel_corner = f4tex3D(volumeB, tex_coord) + f4tex3D(volumeA, tex_coord - cellSize); |
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44 | float4 voxel_face_center_2 = f4tex3D(volumeB, tex_coord_2) + f4tex3D(volumeA, tex_coord_2 - cellSize); |
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45 | float4 voxel_face_center_3 = f4tex3D(volumeB, tex_coord_3) + f4tex3D(volumeA, tex_coord_3 - cellSize); |
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46 | float4 voxel_face_center_4 = f4tex3D(volumeB, tex_coord_4) + f4tex3D(volumeA, tex_coord_4 - cellSize); |
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47 | |
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48 | float sample = (voxel_corner.x + voxel_face_center_2.y + voxel_face_center_3.z + voxel_face_center_4.w) * 0.125; |
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49 | /* |
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50 | float4 tex_coord_a = tex_coord - float4(twice_cell_size.x, twice_cell_size.y, 0, 0); |
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51 | float4 tex_coord_b = tex_coord - float4(twice_cell_size.x, 0, twice_cell_size.z, 0); |
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52 | float4 tex_coord_c = tex_coord - float4(0, twice_cell_size.y, twice_cell_size.z, 0); |
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53 | |
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54 | float4 voxel_corner = f4tex3D(volumeA, tex_coord) + f4tex3D(volumeB, tex_coord - cellSize); |
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55 | float4 voxel_face_center_a = f4tex3D(volumeA, tex_coord_a) + f4tex3D(volumeB, tex_coord_a - cellSize); |
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56 | float4 voxel_face_center_b = f4tex3D(volumeA, tex_coord_b) + f4tex3D(volumeB, tex_coord_b - cellSize); |
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57 | float4 voxel_face_center_c = f4tex3D(volumeA, tex_coord_c) + f4tex3D(volumeB, tex_coord_c - cellSize); |
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58 | //combine 8 sampling results |
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59 | float sample = (voxel_corner.x + voxel_face_center_a.y + voxel_face_center_b.z + voxel_face_center_c.w) * 0.125; |
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60 | */ |
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61 | |
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62 | //sample transfer function texture |
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63 | float4 color = f4tex1D(tf, sample); |
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64 | |
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65 | if (renderParams.x == 0.0) { |
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66 | //If single slice render, only flat shading, completely opaque. |
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67 | color.w = 1; |
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68 | } else { |
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69 | //regular volume rendering, we do FLAT SHADING |
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70 | //since all 4 components of the volume texture has been used to store orbital data, |
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71 | //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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72 | //the shader. We might add this later. |
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73 | |
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74 | // Opacity scaling: equivalent to scaling transfer function |
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75 | color.w = color.w * renderParams.z; |
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76 | // Apply opacity correction for ratio of current sample distance |
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77 | // to data set sample distance |
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78 | color.w = (1.0 - pow((1.0 - color.w), renderParams.x)); |
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79 | } |
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80 | |
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81 | OUT.Color = color; |
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82 | return OUT; |
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83 | } |
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