1 // Copyright 2016 The SwiftShader Authors. All Rights Reserved. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #include "Clipper.hpp" 16 17 #include "Polygon.hpp" 18 #include "Renderer.hpp" 19 #include "Common/Debug.hpp" 20 21 namespace sw 22 { 23 Clipper::Clipper(bool symmetricNormalizedDepth) 24 { 25 n = symmetricNormalizedDepth ? -1.0f : 0.0f; 26 } 27 28 Clipper::~Clipper() 29 { 30 } 31 32 unsigned int Clipper::computeClipFlags(const float4 &v) 33 { 34 return ((v.x > v.w) ? CLIP_RIGHT : 0) | 35 ((v.y > v.w) ? CLIP_TOP : 0) | 36 ((v.z > v.w) ? CLIP_FAR : 0) | 37 ((v.x < -v.w) ? CLIP_LEFT : 0) | 38 ((v.y < -v.w) ? CLIP_BOTTOM : 0) | 39 ((v.z < n * v.w) ? CLIP_NEAR : 0) | 40 Clipper::CLIP_FINITE; // FIXME: xyz finite 41 } 42 43 bool Clipper::clip(Polygon &polygon, int clipFlagsOr, const DrawCall &draw) 44 { 45 if(clipFlagsOr & CLIP_FRUSTUM) 46 { 47 if(clipFlagsOr & CLIP_NEAR) clipNear(polygon); 48 if(polygon.n >= 3) { 49 if(clipFlagsOr & CLIP_FAR) clipFar(polygon); 50 if(polygon.n >= 3) { 51 if(clipFlagsOr & CLIP_LEFT) clipLeft(polygon); 52 if(polygon.n >= 3) { 53 if(clipFlagsOr & CLIP_RIGHT) clipRight(polygon); 54 if(polygon.n >= 3) { 55 if(clipFlagsOr & CLIP_TOP) clipTop(polygon); 56 if(polygon.n >= 3) { 57 if(clipFlagsOr & CLIP_BOTTOM) clipBottom(polygon); 58 }}}}} 59 } 60 61 if(clipFlagsOr & CLIP_USER) 62 { 63 int clipFlags = draw.clipFlags; 64 DrawData &data = *draw.data; 65 66 if(polygon.n >= 3) { 67 if(clipFlags & CLIP_PLANE0) clipPlane(polygon, data.clipPlane[0]); 68 if(polygon.n >= 3) { 69 if(clipFlags & CLIP_PLANE1) clipPlane(polygon, data.clipPlane[1]); 70 if(polygon.n >= 3) { 71 if(clipFlags & CLIP_PLANE2) clipPlane(polygon, data.clipPlane[2]); 72 if(polygon.n >= 3) { 73 if(clipFlags & CLIP_PLANE3) clipPlane(polygon, data.clipPlane[3]); 74 if(polygon.n >= 3) { 75 if(clipFlags & CLIP_PLANE4) clipPlane(polygon, data.clipPlane[4]); 76 if(polygon.n >= 3) { 77 if(clipFlags & CLIP_PLANE5) clipPlane(polygon, data.clipPlane[5]); 78 }}}}}} 79 } 80 81 return polygon.n >= 3; 82 } 83 84 void Clipper::clipNear(Polygon &polygon) 85 { 86 const float4 **V = polygon.P[polygon.i]; 87 const float4 **T = polygon.P[polygon.i + 1]; 88 89 int t = 0; 90 91 for(int i = 0; i < polygon.n; i++) 92 { 93 int j = i == polygon.n - 1 ? 0 : i + 1; 94 95 float di = V[i]->z - n * V[i]->w; 96 float dj = V[j]->z - n * V[j]->w; 97 98 if(di >= 0) 99 { 100 T[t++] = V[i]; 101 102 if(dj < 0) 103 { 104 clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj); 105 T[t++] = &polygon.B[polygon.b++]; 106 } 107 } 108 else 109 { 110 if(dj > 0) 111 { 112 clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di); 113 T[t++] = &polygon.B[polygon.b++]; 114 } 115 } 116 } 117 118 polygon.n = t; 119 polygon.i += 1; 120 } 121 122 void Clipper::clipFar(Polygon &polygon) 123 { 124 const float4 **V = polygon.P[polygon.i]; 125 const float4 **T = polygon.P[polygon.i + 1]; 126 127 int t = 0; 128 129 for(int i = 0; i < polygon.n; i++) 130 { 131 int j = i == polygon.n - 1 ? 0 : i + 1; 132 133 float di = V[i]->w - V[i]->z; 134 float dj = V[j]->w - V[j]->z; 135 136 if(di >= 0) 137 { 138 T[t++] = V[i]; 139 140 if(dj < 0) 141 { 142 clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj); 143 T[t++] = &polygon.B[polygon.b++]; 144 } 145 } 146 else 147 { 148 if(dj > 0) 149 { 150 clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di); 151 T[t++] = &polygon.B[polygon.b++]; 152 } 153 } 154 } 155 156 polygon.n = t; 157 polygon.i += 1; 158 } 159 160 void Clipper::clipLeft(Polygon &polygon) 161 { 162 const float4 **V = polygon.P[polygon.i]; 163 const float4 **T = polygon.P[polygon.i + 1]; 164 165 int t = 0; 166 167 for(int i = 0; i < polygon.n; i++) 168 { 169 int j = i == polygon.n - 1 ? 0 : i + 1; 170 171 float di = V[i]->w + V[i]->x; 172 float dj = V[j]->w + V[j]->x; 173 174 if(di >= 0) 175 { 176 T[t++] = V[i]; 177 178 if(dj < 0) 179 { 180 clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj); 181 T[t++] = &polygon.B[polygon.b++]; 182 } 183 } 184 else 185 { 186 if(dj > 0) 187 { 188 clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di); 189 T[t++] = &polygon.B[polygon.b++]; 190 } 191 } 192 } 193 194 polygon.n = t; 195 polygon.i += 1; 196 } 197 198 void Clipper::clipRight(Polygon &polygon) 199 { 200 const float4 **V = polygon.P[polygon.i]; 201 const float4 **T = polygon.P[polygon.i + 1]; 202 203 int t = 0; 204 205 for(int i = 0; i < polygon.n; i++) 206 { 207 int j = i == polygon.n - 1 ? 0 : i + 1; 208 209 float di = V[i]->w - V[i]->x; 210 float dj = V[j]->w - V[j]->x; 211 212 if(di >= 0) 213 { 214 T[t++] = V[i]; 215 216 if(dj < 0) 217 { 218 clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj); 219 T[t++] = &polygon.B[polygon.b++]; 220 } 221 } 222 else 223 { 224 if(dj > 0) 225 { 226 clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di); 227 T[t++] = &polygon.B[polygon.b++]; 228 } 229 } 230 } 231 232 polygon.n = t; 233 polygon.i += 1; 234 } 235 236 void Clipper::clipTop(Polygon &polygon) 237 { 238 const float4 **V = polygon.P[polygon.i]; 239 const float4 **T = polygon.P[polygon.i + 1]; 240 241 int t = 0; 242 243 for(int i = 0; i < polygon.n; i++) 244 { 245 int j = i == polygon.n - 1 ? 0 : i + 1; 246 247 float di = V[i]->w - V[i]->y; 248 float dj = V[j]->w - V[j]->y; 249 250 if(di >= 0) 251 { 252 T[t++] = V[i]; 253 254 if(dj < 0) 255 { 256 clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj); 257 T[t++] = &polygon.B[polygon.b++]; 258 } 259 } 260 else 261 { 262 if(dj > 0) 263 { 264 clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di); 265 T[t++] = &polygon.B[polygon.b++]; 266 } 267 } 268 } 269 270 polygon.n = t; 271 polygon.i += 1; 272 } 273 274 void Clipper::clipBottom(Polygon &polygon) 275 { 276 const float4 **V = polygon.P[polygon.i]; 277 const float4 **T = polygon.P[polygon.i + 1]; 278 279 int t = 0; 280 281 for(int i = 0; i < polygon.n; i++) 282 { 283 int j = i == polygon.n - 1 ? 0 : i + 1; 284 285 float di = V[i]->w + V[i]->y; 286 float dj = V[j]->w + V[j]->y; 287 288 if(di >= 0) 289 { 290 T[t++] = V[i]; 291 292 if(dj < 0) 293 { 294 clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj); 295 T[t++] = &polygon.B[polygon.b++]; 296 } 297 } 298 else 299 { 300 if(dj > 0) 301 { 302 clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di); 303 T[t++] = &polygon.B[polygon.b++]; 304 } 305 } 306 } 307 308 polygon.n = t; 309 polygon.i += 1; 310 } 311 312 void Clipper::clipPlane(Polygon &polygon, const Plane &p) 313 { 314 const float4 **V = polygon.P[polygon.i]; 315 const float4 **T = polygon.P[polygon.i + 1]; 316 317 int t = 0; 318 319 for(int i = 0; i < polygon.n; i++) 320 { 321 int j = i == polygon.n - 1 ? 0 : i + 1; 322 323 float di = p.A * V[i]->x + p.B * V[i]->y + p.C * V[i]->z + p.D * V[i]->w; 324 float dj = p.A * V[j]->x + p.B * V[j]->y + p.C * V[j]->z + p.D * V[j]->w; 325 326 if(di >= 0) 327 { 328 T[t++] = V[i]; 329 330 if(dj < 0) 331 { 332 clipEdge(polygon.B[polygon.b], *V[i], *V[j], di, dj); 333 T[t++] = &polygon.B[polygon.b++]; 334 } 335 } 336 else 337 { 338 if(dj > 0) 339 { 340 clipEdge(polygon.B[polygon.b], *V[j], *V[i], dj, di); 341 T[t++] = &polygon.B[polygon.b++]; 342 } 343 } 344 } 345 346 polygon.n = t; 347 polygon.i += 1; 348 } 349 350 inline void Clipper::clipEdge(float4 &Vo, const float4 &Vi, const float4 &Vj, float di, float dj) const 351 { 352 float D = 1.0f / (dj - di); 353 354 Vo.x = (dj * Vi.x - di * Vj.x) * D; 355 Vo.y = (dj * Vi.y - di * Vj.y) * D; 356 Vo.z = (dj * Vi.z - di * Vj.z) * D; 357 Vo.w = (dj * Vi.w - di * Vj.w) * D; 358 } 359 } 360
