1 | #include "ShadowMapping.h"
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2 | #include "FrameBufferObject.h"
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3 | #include "RenderState.h"
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4 | #include "RenderTraverser.h"
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5 | #include "Light.h"
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6 | #include "Polygon3.h"
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7 | #include "Polyhedron.h"
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8 |
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9 | #include <IL/il.h>
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10 | #include <assert.h>
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11 |
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12 |
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13 | using namespace std;
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14 |
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15 |
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16 | namespace CHCDemoEngine
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17 | {
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18 |
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19 |
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20 | static Polyhedron *polyhedron = NULL;
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21 |
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22 |
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23 | static void PrintGLerror(char *msg)
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24 | {
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25 | GLenum errCode;
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26 | const GLubyte *errStr;
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27 |
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28 | if ((errCode = glGetError()) != GL_NO_ERROR)
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29 | {
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30 | errStr = gluErrorString(errCode);
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31 | fprintf(stderr,"OpenGL ERROR: %s: %s\n", errStr, msg);
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32 | }
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33 | }
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34 |
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35 |
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36 |
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37 | static CGprogram sCgShadowProgram;
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38 | static CGparameter sShadowParam;
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39 |
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40 |
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41 | static void GrabDepthBuffer(float *data, GLuint depthTexture)
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42 | {
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43 | glEnable(GL_TEXTURE_2D);
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44 | glBindTexture(GL_TEXTURE_2D, depthTexture);
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45 |
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46 | glGetTexImage(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, GL_FLOAT, data);
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47 |
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48 | glBindTexture(GL_TEXTURE_2D, 0);
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49 | glDisable(GL_TEXTURE_2D);
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50 | }
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51 |
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52 |
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53 | static void ExportDepthBuffer(float *data, int size)
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54 | {
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55 | ilInit();
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56 | assert(ilGetError() == IL_NO_ERROR);
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57 |
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58 | ILstring filename = ILstring("shadow.tga");
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59 | ilRegisterType(IL_FLOAT);
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60 |
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61 | const int depth = 1;
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62 | const int bpp = 1;
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63 |
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64 | if (!ilTexImage(size, size, depth, bpp, IL_LUMINANCE, IL_FLOAT, data))
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65 | {
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66 | cerr << "IL error " << ilGetError() << endl;
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67 |
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68 | ilShutDown();
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69 | assert(ilGetError() == IL_NO_ERROR);
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70 |
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71 | return;
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72 | }
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73 |
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74 | if (!ilSaveImage(filename))
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75 | {
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76 | cerr << "TGA write error " << ilGetError() << endl;
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77 | }
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78 |
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79 | ilShutDown();
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80 | assert(ilGetError() == IL_NO_ERROR);
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81 |
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82 | cout << "exported depth buffer" << endl;
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83 | }
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84 |
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85 |
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86 |
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87 | ShadowMap::ShadowMap(Light *light, int size, const AxisAlignedBox3 &sceneBox, Camera *cam):
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88 | mSceneBox(sceneBox), mSize(size), mCamera(cam), mLight(light)
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89 | {
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90 | mFbo = new FrameBufferObject(size, size, FrameBufferObject::DEPTH_32, true);
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91 | // the diffuse color buffer
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92 | mFbo->AddColorBuffer(ColorBufferObject::BUFFER_UBYTE, ColorBufferObject::WRAP_CLAMP_TO_EDGE, ColorBufferObject::FILTER_LINEAR, false);
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93 |
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94 | mShadowCam = new Camera(mSceneBox.Size().x * 0.5f, mSceneBox.Size().y * 0.5f);
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95 | mShadowCam->SetOrtho(true);
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96 | }
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97 |
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98 |
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99 | ShadowMap::~ShadowMap()
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100 | {
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101 | DEL_PTR(mFbo);
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102 | DEL_PTR(mShadowCam);
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103 | }
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104 |
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105 |
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106 | void ShadowMap::DrawPolys()
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107 | {
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108 | if (!polyhedron) return;
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109 |
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110 | for (size_t i = 0; i < polyhedron->NumPolygons(); ++ i)
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111 | {
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112 | float r = (float)i / polyhedron->NumPolygons();
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113 | float g = 1;
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114 | float b = 1;
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115 |
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116 | glColor3f(r, g, b);
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117 |
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118 | glBegin(GL_LINE_LOOP);
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119 |
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120 | Polygon3 *poly = polyhedron->GetPolygons()[i];
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121 |
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122 | for (size_t j = 0; j < poly->mVertices.size(); ++ j)
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123 | {
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124 | Vector3 v = poly->mVertices[j];
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125 | glVertex3d(v.x, v.y, v.z);
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126 | }
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127 |
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128 | glEnd();
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129 | }
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130 | }
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131 |
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132 |
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133 | void ShadowMap::IncludeLightVolume(const Polyhedron &polyhedron,
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134 | VertexArray &frustumPoints,
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135 | const Vector3 lightDir,
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136 | const AxisAlignedBox3 &sceneBox
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137 | )
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138 | {
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139 | // we don't need closed form anymore => just store vertices
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140 | VertexArray vertices;
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141 | polyhedron.CollectVertices(vertices);
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142 |
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143 | // we 'look' at each point and calculate intersections of rays with scene bounding box
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144 | VertexArray::const_iterator it, it_end = vertices.end();
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145 |
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146 | for (it = vertices.begin(); it != it_end; ++ it)
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147 | {
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148 | Vector3 v = *it;
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149 |
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150 | frustumPoints.push_back(v);
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151 |
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152 | // hack: get point surely outside of box
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153 | v -= Magnitude(mSceneBox.Diagonal()) * lightDir;
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154 |
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155 | SimpleRay ray(v, lightDir);
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156 |
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157 | float tNear, tFar;
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158 |
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159 | if (sceneBox.Intersects(ray, tNear, tFar))
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160 | {
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161 | Vector3 newpt = ray.Extrap(tNear);
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162 | frustumPoints.push_back(newpt);
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163 | }
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164 | }
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165 | }
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166 |
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167 |
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168 | float ShadowMap::ComputeN() const
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169 | {
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170 | const float n = mShadowCam->GetNear();
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171 | const float f = mShadowCam->GetFar();
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172 |
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173 | const float d = fabs(f - n);
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174 |
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175 | const float dotProd = DotProd(mCamera->GetDirection(), mShadowCam->GetDirection());
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176 | const float sinGamma = sin(fabs(acos(dotProd)));
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177 |
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178 | return (n + sqrt(n * (n + d * sinGamma))) / sinGamma;
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179 | }
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180 |
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181 |
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182 | Matrix4x4 ShadowMap::CalcLispSMTransform(const Matrix4x4 &lightProjView, const AxisAlignedBox3 &extremalPoints)
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183 | {
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184 | Matrix4x4 lispMtx;
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185 |
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186 | ///////////////
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187 | //-- We apply the lispsm algorithm in order to calculate an optimal light projection matrix
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188 |
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189 | const float n = 1e20f;//ComputeN();
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190 |
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191 | cout << "n: " << n << endl;
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192 |
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193 | const Vector3 nearPt = mShadowCam->GetNear() * mShadowCam->GetDirection() + mShadowCam->GetPosition();
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194 |
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195 | //get the coordinates of the near camera point in light space
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196 | const Vector3 lsNear = lightProjView * nearPt;
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197 |
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198 | //c start has the x and y coordinate of e, the z coord of B.min()
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199 | const Vector3 startPt = Vector3(lsNear.x, lsNear.y, extremalPoints.Min().y);
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200 |
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201 | // the new projection center
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202 | const Vector3 unit_y = Vector3(0, 1, 0);
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203 | Vector3 projCenter = startPt - unit_y * n;
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204 |
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205 | //construct a translation that moves to the projection center
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206 | const Matrix4x4 projectionCenter = TranslationMatrix(-projCenter);
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207 |
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208 | // light space y size
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209 | const float d = fabs(extremalPoints.Max()[2] - extremalPoints.Min()[2]);
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210 |
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211 | lispMtx = GetFrustum(-1.0, 1.0, -1.0, 1.0, n, n + d);
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212 |
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213 | cout << "lispsm\n" << lispMtx << endl;
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214 |
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215 | lispMtx *= projectionCenter;
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216 |
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217 | // transform into OpenGL right handed system
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218 | Matrix4x4 scale = ScaleMatrix(1.0f, 1.0f, -1.0f);
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219 |
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220 | lispMtx *= scale;
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221 |
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222 | return IdentityMatrix();
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223 | }
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224 |
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225 |
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226 | bool ShadowMap::CalcLightProjection(Matrix4x4 &lightProj)
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227 | {
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228 | DEL_PTR(polyhedron);
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229 |
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230 |
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231 | ///////////////////
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232 | //-- First step: calc frustum clipped by scene box
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233 |
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234 | polyhedron = CalcClippedFrustum(mSceneBox);
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235 |
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236 | if (!polyhedron) return false; // something is wrong
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237 |
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238 | // include the part of the light volume that "sees" the frustum
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239 | // we only require frustum vertices
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240 |
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241 | VertexArray frustumPoints;
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242 | IncludeLightVolume(*polyhedron, frustumPoints, mShadowCam->GetDirection(), mSceneBox);
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243 |
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244 |
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245 | ///////////////
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246 | //-- transform points from world view to light view and calculate extremal points
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247 |
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248 | AxisAlignedBox3 extremalPoints;
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249 | extremalPoints.Initialize();
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250 |
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251 | Matrix4x4 lightView;
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252 | mShadowCam->GetModelViewMatrix(lightView);
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253 |
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254 | VertexArray::const_iterator it, it_end = frustumPoints.end();
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255 |
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256 | for (it = frustumPoints.begin(); it != it_end; ++ it)
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257 | {
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258 | Vector3 pt = *it;
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259 | pt = lightView * pt;
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260 |
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261 | extremalPoints.Include(pt);
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262 | }
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263 |
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264 | lightProj = IdentityMatrix(); // we use directional lights
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265 |
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266 | Matrix4x4 shadowView;
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267 | mShadowCam->GetModelViewMatrix(shadowView);
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268 |
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269 | //do Light Space Perspective shadow mapping
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270 | //rotate the lightspace so that the proj light view always points upwards
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271 | //calculate a frame matrix that uses the projViewDir[light-space] as up vector
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272 | //look(from position, into the direction of the projected direction, with unchanged up-vector)
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273 | //lightProj = Math::look<REAL>(M4(),V3::ZERO(),projViewDir,V3::UNIT_Y())*lightProj
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274 |
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275 | const Matrix4x4 matLispSM =
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276 | CalcLispSMTransform(shadowView * lightProj, extremalPoints);
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277 |
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278 | lightProj *= matLispSM;
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279 |
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280 | // focus projection matrix on the extremal points => scale to unit cube
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281 | lightProj *= GetFittingProjectionMatrix(extremalPoints);
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282 |
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283 | // we have to flip the signs in order tp opengl style projection matrix
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284 | Matrix4x4 scale = ScaleMatrix(-1, -1, -1);
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285 | lightProj *= scale;
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286 |
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287 | return true;
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288 | }
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289 |
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290 |
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291 | Polyhedron *ShadowMap::CalcClippedFrustum(const AxisAlignedBox3 &box) const
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292 | {
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293 | Vector3 ftl, ftr, fbl, fbr;
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294 | Vector3 ntl, ntr, nbl, nbr;
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295 |
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296 | VertexArray sides[6];
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297 |
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298 | mCamera->ComputePoints(ftl, ftr, fbl, fbr, ntl, ntr, nbl, nbr);
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299 |
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300 | for (int i = 0; i < 6; ++ i)
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301 | sides[i].resize(4);
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302 |
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303 | // left, right
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304 | sides[0][0] = ftl; sides[0][1] = fbl; sides[0][2] = nbl; sides[0][3] = ntl;
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305 | sides[1][0] = fbr; sides[1][1] = ftr; sides[1][2] = ntr; sides[1][3] = nbr;
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306 | // bottom, top
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307 | sides[2][0] = fbl; sides[2][1] = fbr; sides[2][2] = nbr; sides[2][3] = nbl;
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308 | sides[3][0] = ftr; sides[3][1] = ftl; sides[3][2] = ntl; sides[3][3] = ntr;
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309 | // near, far
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310 | sides[4][0] = ntr; sides[4][1] = ntl; sides[4][2] = nbl; sides[4][3] = nbr;
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311 | sides[5][0] = ftl; sides[5][1] = ftr; sides[5][2] = fbr; sides[5][3] = fbl;
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312 |
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313 | //////////
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314 | //-- compute polyhedron
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315 |
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316 | PolygonContainer polygons;
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317 |
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318 | for (int i = 0; i < 6; ++ i)
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319 | {
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320 | Polygon3 *poly = new Polygon3(sides[i]);
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321 | polygons.push_back(poly);
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322 | }
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323 |
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324 | Polyhedron *p = new Polyhedron(polygons);
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325 | Polyhedron *clippedPolyhedron = box.CalcIntersection(*p);
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326 |
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327 | DEL_PTR(p);
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328 |
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329 |
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330 | return clippedPolyhedron;
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331 | }
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332 |
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333 |
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334 | void ShadowMap::ComputeShadowMap(RenderTraverser *renderer, const Matrix4x4 &projView)
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335 | {
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336 | const float xlen = Magnitude(mSceneBox.Diagonal() * 0.5f);
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337 | const float ylen = Magnitude(mSceneBox.Diagonal() * 0.5f);
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338 |
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339 | const Vector3 dir = mLight->GetDirection();
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340 | //const Vector3 dir(0, 0, 1);
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341 |
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342 | mShadowCam->SetDirection(dir);
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343 |
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344 | //cout << "lightdir: " << mShadowCam->GetDirection() << endl;
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345 |
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346 | // set position so that we can see the whole scene
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347 | Vector3 pos = mSceneBox.Center();
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348 |
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349 | //Matrix4x4 camView;
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350 | //mCamera->GetModelViewMatrix(camView);
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351 |
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352 | pos -= dir * Magnitude(mSceneBox.Diagonal() * 0.5f);
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353 | mShadowCam->SetPosition(pos);
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354 |
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355 | mFbo->Bind();
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356 |
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357 | glDrawBuffers(1, mrt);
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358 |
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359 | glPushAttrib(GL_VIEWPORT_BIT);
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360 | glViewport(0, 0, mSize, mSize);
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361 |
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362 | glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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363 |
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364 | glDisable(GL_LIGHTING);
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365 | glDisable(GL_TEXTURE_2D);
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366 | glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
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367 |
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368 | glPolygonOffset(1.0f, 2000.0f);
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369 | glEnable(GL_POLYGON_OFFSET_FILL);
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370 |
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371 | glShadeModel(GL_FLAT);
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372 | glEnable(GL_DEPTH_TEST);
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373 |
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374 | // setup projection
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375 | /*glMatrixMode(GL_PROJECTION);
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376 | glLoadIdentity();
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377 | glOrtho(+xlen, -xlen, +ylen, -ylen, 0.0f, Magnitude(mSceneBox.Diagonal()));
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378 |
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379 | Matrix4x4 dummyMat;
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380 | glGetFloatv(GL_PROJECTION_MATRIX, (float *)dummyMat.x);
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381 | cout << "old:\n" << dummyMat << endl;
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382 | */
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383 |
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384 | Matrix4x4 lightView, lightProj;
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385 |
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386 | mShadowCam->GetModelViewMatrix(lightView);
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387 | CalcLightProjection(lightProj);
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388 |
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389 | glMatrixMode(GL_PROJECTION);
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390 | glPushMatrix();
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391 | glLoadMatrixf((float *)lightProj.x);
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392 |
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393 | mLightProjView = lightView * lightProj;
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394 |
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395 | //cout << "new:\n" << lightProj << endl;
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396 |
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397 | glMatrixMode(GL_MODELVIEW);
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398 | glPushMatrix();
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399 | glLoadIdentity();
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400 |
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401 | mShadowCam->SetupCameraView();
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402 |
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403 |
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404 | //////////////
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405 | //-- compute texture matrix
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406 | static Matrix4x4 biasMatrix(0.5f, 0.0f, 0.0f, 0.5f,
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407 | 0.0f, 0.5f, 0.0f, 0.5f,
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408 | 0.0f, 0.0f, 0.5f, 0.5f,
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409 | 0.0f, 0.0f, 0.0f, 1.0f);
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410 |
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411 | mTextureMatrix = mLightProjView * biasMatrix;
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412 |
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413 |
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414 |
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415 |
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416 | /////////////
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417 | //-- render scene into shadow map
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418 |
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419 | renderer->RenderScene();
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420 |
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421 |
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422 | glDisable(GL_POLYGON_OFFSET_FILL);
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423 | glMatrixMode(GL_MODELVIEW);
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424 | glPopMatrix();
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425 |
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426 | glMatrixMode(GL_PROJECTION);
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427 | glPopMatrix();
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428 |
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429 | glPopAttrib();
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430 | #if 0
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431 | float *data = new float[mSize * mSize];
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432 |
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433 | GrabDepthBuffer(data, mFbo->GetDepthTex());
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434 | ExportDepthBuffer(data, mSize);
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435 |
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436 | delete [] data;
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437 |
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438 | PrintGLerror("shadow map");
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439 | #endif
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440 | FrameBufferObject::Release();
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441 | }
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442 |
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443 |
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444 | void ShadowMap::GetTextureMatrix(Matrix4x4 &m) const
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445 | {
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446 | m = mTextureMatrix;
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447 | }
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448 |
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449 |
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450 | unsigned int ShadowMap::GetShadowTexture() const
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451 | {
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452 | return mFbo->GetDepthTex();
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453 | }
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454 |
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455 |
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456 |
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457 | } // namespace
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