SpotShadow.cpp revision 9122b1b168d2a74d51517ed7282f4d6a8adea367
1/* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#define LOG_TAG "OpenGLRenderer" 18 19// The highest z value can't be higher than (CASTER_Z_CAP_RATIO * light.z) 20#define CASTER_Z_CAP_RATIO 0.95f 21 22// When there is no umbra, then just fake the umbra using 23// centroid * (1 - FAKE_UMBRA_SIZE_RATIO) + outline * FAKE_UMBRA_SIZE_RATIO 24#define FAKE_UMBRA_SIZE_RATIO 0.05f 25 26// When the polygon is about 90 vertices, the penumbra + umbra can reach 270 rays. 27// That is consider pretty fine tessllated polygon so far. 28// This is just to prevent using too much some memory when edge slicing is not 29// needed any more. 30#define FINE_TESSELLATED_POLYGON_RAY_NUMBER 270 31/** 32 * Extra vertices for the corner for smoother corner. 33 * Only for outer loop. 34 * Note that we use such extra memory to avoid an extra loop. 35 */ 36// For half circle, we could add EXTRA_VERTEX_PER_PI vertices. 37// Set to 1 if we don't want to have any. 38#define SPOT_EXTRA_CORNER_VERTEX_PER_PI 18 39 40// For the whole polygon, the sum of all the deltas b/t normals is 2 * M_PI, 41// therefore, the maximum number of extra vertices will be twice bigger. 42#define SPOT_MAX_EXTRA_CORNER_VERTEX_NUMBER (2 * SPOT_EXTRA_CORNER_VERTEX_PER_PI) 43 44// For each RADIANS_DIVISOR, we would allocate one more vertex b/t the normals. 45#define SPOT_CORNER_RADIANS_DIVISOR (M_PI / SPOT_EXTRA_CORNER_VERTEX_PER_PI) 46 47 48#include <math.h> 49#include <stdlib.h> 50#include <utils/Log.h> 51 52#include "ShadowTessellator.h" 53#include "SpotShadow.h" 54#include "Vertex.h" 55#include "utils/MathUtils.h" 56 57// TODO: After we settle down the new algorithm, we can remove the old one and 58// its utility functions. 59// Right now, we still need to keep it for comparison purpose and future expansion. 60namespace android { 61namespace uirenderer { 62 63static const float EPSILON = 1e-7; 64 65/** 66 * For each polygon's vertex, the light center will project it to the receiver 67 * as one of the outline vertex. 68 * For each outline vertex, we need to store the position and normal. 69 * Normal here is defined against the edge by the current vertex and the next vertex. 70 */ 71struct OutlineData { 72 Vector2 position; 73 Vector2 normal; 74 float radius; 75}; 76 77/** 78 * For each vertex, we need to keep track of its angle, whether it is penumbra or 79 * umbra, and its corresponding vertex index. 80 */ 81struct SpotShadow::VertexAngleData { 82 // The angle to the vertex from the centroid. 83 float mAngle; 84 // True is the vertex comes from penumbra, otherwise it comes from umbra. 85 bool mIsPenumbra; 86 // The index of the vertex described by this data. 87 int mVertexIndex; 88 void set(float angle, bool isPenumbra, int index) { 89 mAngle = angle; 90 mIsPenumbra = isPenumbra; 91 mVertexIndex = index; 92 } 93}; 94 95/** 96 * Calculate the angle between and x and a y coordinate. 97 * The atan2 range from -PI to PI. 98 */ 99static float angle(const Vector2& point, const Vector2& center) { 100 return atan2(point.y - center.y, point.x - center.x); 101} 102 103/** 104 * Calculate the intersection of a ray with the line segment defined by two points. 105 * 106 * Returns a negative value in error conditions. 107 108 * @param rayOrigin The start of the ray 109 * @param dx The x vector of the ray 110 * @param dy The y vector of the ray 111 * @param p1 The first point defining the line segment 112 * @param p2 The second point defining the line segment 113 * @return The distance along the ray if it intersects with the line segment, negative if otherwise 114 */ 115static float rayIntersectPoints(const Vector2& rayOrigin, float dx, float dy, 116 const Vector2& p1, const Vector2& p2) { 117 // The math below is derived from solving this formula, basically the 118 // intersection point should stay on both the ray and the edge of (p1, p2). 119 // solve([p1x+t*(p2x-p1x)=dx*t2+px,p1y+t*(p2y-p1y)=dy*t2+py],[t,t2]); 120 121 float divisor = (dx * (p1.y - p2.y) + dy * p2.x - dy * p1.x); 122 if (divisor == 0) return -1.0f; // error, invalid divisor 123 124#if DEBUG_SHADOW 125 float interpVal = (dx * (p1.y - rayOrigin.y) + dy * rayOrigin.x - dy * p1.x) / divisor; 126 if (interpVal < 0 || interpVal > 1) { 127 ALOGW("rayIntersectPoints is hitting outside the segment %f", interpVal); 128 } 129#endif 130 131 float distance = (p1.x * (rayOrigin.y - p2.y) + p2.x * (p1.y - rayOrigin.y) + 132 rayOrigin.x * (p2.y - p1.y)) / divisor; 133 134 return distance; // may be negative in error cases 135} 136 137/** 138 * Sort points by their X coordinates 139 * 140 * @param points the points as a Vector2 array. 141 * @param pointsLength the number of vertices of the polygon. 142 */ 143void SpotShadow::xsort(Vector2* points, int pointsLength) { 144 quicksortX(points, 0, pointsLength - 1); 145} 146 147/** 148 * compute the convex hull of a collection of Points 149 * 150 * @param points the points as a Vector2 array. 151 * @param pointsLength the number of vertices of the polygon. 152 * @param retPoly pre allocated array of floats to put the vertices 153 * @return the number of points in the polygon 0 if no intersection 154 */ 155int SpotShadow::hull(Vector2* points, int pointsLength, Vector2* retPoly) { 156 xsort(points, pointsLength); 157 int n = pointsLength; 158 Vector2 lUpper[n]; 159 lUpper[0] = points[0]; 160 lUpper[1] = points[1]; 161 162 int lUpperSize = 2; 163 164 for (int i = 2; i < n; i++) { 165 lUpper[lUpperSize] = points[i]; 166 lUpperSize++; 167 168 while (lUpperSize > 2 && !ccw( 169 lUpper[lUpperSize - 3].x, lUpper[lUpperSize - 3].y, 170 lUpper[lUpperSize - 2].x, lUpper[lUpperSize - 2].y, 171 lUpper[lUpperSize - 1].x, lUpper[lUpperSize - 1].y)) { 172 // Remove the middle point of the three last 173 lUpper[lUpperSize - 2].x = lUpper[lUpperSize - 1].x; 174 lUpper[lUpperSize - 2].y = lUpper[lUpperSize - 1].y; 175 lUpperSize--; 176 } 177 } 178 179 Vector2 lLower[n]; 180 lLower[0] = points[n - 1]; 181 lLower[1] = points[n - 2]; 182 183 int lLowerSize = 2; 184 185 for (int i = n - 3; i >= 0; i--) { 186 lLower[lLowerSize] = points[i]; 187 lLowerSize++; 188 189 while (lLowerSize > 2 && !ccw( 190 lLower[lLowerSize - 3].x, lLower[lLowerSize - 3].y, 191 lLower[lLowerSize - 2].x, lLower[lLowerSize - 2].y, 192 lLower[lLowerSize - 1].x, lLower[lLowerSize - 1].y)) { 193 // Remove the middle point of the three last 194 lLower[lLowerSize - 2] = lLower[lLowerSize - 1]; 195 lLowerSize--; 196 } 197 } 198 199 // output points in CW ordering 200 const int total = lUpperSize + lLowerSize - 2; 201 int outIndex = total - 1; 202 for (int i = 0; i < lUpperSize; i++) { 203 retPoly[outIndex] = lUpper[i]; 204 outIndex--; 205 } 206 207 for (int i = 1; i < lLowerSize - 1; i++) { 208 retPoly[outIndex] = lLower[i]; 209 outIndex--; 210 } 211 // TODO: Add test harness which verify that all the points are inside the hull. 212 return total; 213} 214 215/** 216 * Test whether the 3 points form a counter clockwise turn. 217 * 218 * @return true if a right hand turn 219 */ 220bool SpotShadow::ccw(float ax, float ay, float bx, float by, 221 float cx, float cy) { 222 return (bx - ax) * (cy - ay) - (by - ay) * (cx - ax) > EPSILON; 223} 224 225/** 226 * Sort points about a center point 227 * 228 * @param poly The in and out polyogon as a Vector2 array. 229 * @param polyLength The number of vertices of the polygon. 230 * @param center the center ctr[0] = x , ctr[1] = y to sort around. 231 */ 232void SpotShadow::sort(Vector2* poly, int polyLength, const Vector2& center) { 233 quicksortCirc(poly, 0, polyLength - 1, center); 234} 235 236/** 237 * Swap points pointed to by i and j 238 */ 239void SpotShadow::swap(Vector2* points, int i, int j) { 240 Vector2 temp = points[i]; 241 points[i] = points[j]; 242 points[j] = temp; 243} 244 245/** 246 * quick sort implementation about the center. 247 */ 248void SpotShadow::quicksortCirc(Vector2* points, int low, int high, 249 const Vector2& center) { 250 int i = low, j = high; 251 int p = low + (high - low) / 2; 252 float pivot = angle(points[p], center); 253 while (i <= j) { 254 while (angle(points[i], center) > pivot) { 255 i++; 256 } 257 while (angle(points[j], center) < pivot) { 258 j--; 259 } 260 261 if (i <= j) { 262 swap(points, i, j); 263 i++; 264 j--; 265 } 266 } 267 if (low < j) quicksortCirc(points, low, j, center); 268 if (i < high) quicksortCirc(points, i, high, center); 269} 270 271/** 272 * Sort points by x axis 273 * 274 * @param points points to sort 275 * @param low start index 276 * @param high end index 277 */ 278void SpotShadow::quicksortX(Vector2* points, int low, int high) { 279 int i = low, j = high; 280 int p = low + (high - low) / 2; 281 float pivot = points[p].x; 282 while (i <= j) { 283 while (points[i].x < pivot) { 284 i++; 285 } 286 while (points[j].x > pivot) { 287 j--; 288 } 289 290 if (i <= j) { 291 swap(points, i, j); 292 i++; 293 j--; 294 } 295 } 296 if (low < j) quicksortX(points, low, j); 297 if (i < high) quicksortX(points, i, high); 298} 299 300/** 301 * Test whether a point is inside the polygon. 302 * 303 * @param testPoint the point to test 304 * @param poly the polygon 305 * @return true if the testPoint is inside the poly. 306 */ 307bool SpotShadow::testPointInsidePolygon(const Vector2 testPoint, 308 const Vector2* poly, int len) { 309 bool c = false; 310 float testx = testPoint.x; 311 float testy = testPoint.y; 312 for (int i = 0, j = len - 1; i < len; j = i++) { 313 float startX = poly[j].x; 314 float startY = poly[j].y; 315 float endX = poly[i].x; 316 float endY = poly[i].y; 317 318 if (((endY > testy) != (startY > testy)) 319 && (testx < (startX - endX) * (testy - endY) 320 / (startY - endY) + endX)) { 321 c = !c; 322 } 323 } 324 return c; 325} 326 327/** 328 * Make the polygon turn clockwise. 329 * 330 * @param polygon the polygon as a Vector2 array. 331 * @param len the number of points of the polygon 332 */ 333void SpotShadow::makeClockwise(Vector2* polygon, int len) { 334 if (polygon == 0 || len == 0) { 335 return; 336 } 337 if (!ShadowTessellator::isClockwise(polygon, len)) { 338 reverse(polygon, len); 339 } 340} 341 342/** 343 * Reverse the polygon 344 * 345 * @param polygon the polygon as a Vector2 array 346 * @param len the number of points of the polygon 347 */ 348void SpotShadow::reverse(Vector2* polygon, int len) { 349 int n = len / 2; 350 for (int i = 0; i < n; i++) { 351 Vector2 tmp = polygon[i]; 352 int k = len - 1 - i; 353 polygon[i] = polygon[k]; 354 polygon[k] = tmp; 355 } 356} 357 358/** 359 * Compute a horizontal circular polygon about point (x , y , height) of radius 360 * (size) 361 * 362 * @param points number of the points of the output polygon. 363 * @param lightCenter the center of the light. 364 * @param size the light size. 365 * @param ret result polygon. 366 */ 367void SpotShadow::computeLightPolygon(int points, const Vector3& lightCenter, 368 float size, Vector3* ret) { 369 // TODO: Caching all the sin / cos values and store them in a look up table. 370 for (int i = 0; i < points; i++) { 371 float angle = 2 * i * M_PI / points; 372 ret[i].x = cosf(angle) * size + lightCenter.x; 373 ret[i].y = sinf(angle) * size + lightCenter.y; 374 ret[i].z = lightCenter.z; 375 } 376} 377 378/** 379 * From light center, project one vertex to the z=0 surface and get the outline. 380 * 381 * @param outline The result which is the outline position. 382 * @param lightCenter The center of light. 383 * @param polyVertex The input polygon's vertex. 384 * 385 * @return float The ratio of (polygon.z / light.z - polygon.z) 386 */ 387float SpotShadow::projectCasterToOutline(Vector2& outline, 388 const Vector3& lightCenter, const Vector3& polyVertex) { 389 float lightToPolyZ = lightCenter.z - polyVertex.z; 390 float ratioZ = CASTER_Z_CAP_RATIO; 391 if (lightToPolyZ != 0) { 392 // If any caster's vertex is almost above the light, we just keep it as 95% 393 // of the height of the light. 394 ratioZ = MathUtils::clamp(polyVertex.z / lightToPolyZ, 0.0f, CASTER_Z_CAP_RATIO); 395 } 396 397 outline.x = polyVertex.x - ratioZ * (lightCenter.x - polyVertex.x); 398 outline.y = polyVertex.y - ratioZ * (lightCenter.y - polyVertex.y); 399 return ratioZ; 400} 401 402/** 403 * Generate the shadow spot light of shape lightPoly and a object poly 404 * 405 * @param isCasterOpaque whether the caster is opaque 406 * @param lightCenter the center of the light 407 * @param lightSize the radius of the light 408 * @param poly x,y,z vertexes of a convex polygon that occludes the light source 409 * @param polyLength number of vertexes of the occluding polygon 410 * @param shadowTriangleStrip return an (x,y,alpha) triangle strip representing the shadow. Return 411 * empty strip if error. 412 */ 413void SpotShadow::createSpotShadow(bool isCasterOpaque, const Vector3& lightCenter, 414 float lightSize, const Vector3* poly, int polyLength, const Vector3& polyCentroid, 415 VertexBuffer& shadowTriangleStrip) { 416 if (CC_UNLIKELY(lightCenter.z <= 0)) { 417 ALOGW("Relative Light Z is not positive. No spot shadow!"); 418 return; 419 } 420 if (CC_UNLIKELY(polyLength < 3)) { 421#if DEBUG_SHADOW 422 ALOGW("Invalid polygon length. No spot shadow!"); 423#endif 424 return; 425 } 426 OutlineData outlineData[polyLength]; 427 Vector2 outlineCentroid; 428 // Calculate the projected outline for each polygon's vertices from the light center. 429 // 430 // O Light 431 // / 432 // / 433 // . Polygon vertex 434 // / 435 // / 436 // O Outline vertices 437 // 438 // Ratio = (Poly - Outline) / (Light - Poly) 439 // Outline.x = Poly.x - Ratio * (Light.x - Poly.x) 440 // Outline's radius / Light's radius = Ratio 441 442 // Compute the last outline vertex to make sure we can get the normal and outline 443 // in one single loop. 444 projectCasterToOutline(outlineData[polyLength - 1].position, lightCenter, 445 poly[polyLength - 1]); 446 447 // Take the outline's polygon, calculate the normal for each outline edge. 448 int currentNormalIndex = polyLength - 1; 449 int nextNormalIndex = 0; 450 451 for (int i = 0; i < polyLength; i++) { 452 float ratioZ = projectCasterToOutline(outlineData[i].position, 453 lightCenter, poly[i]); 454 outlineData[i].radius = ratioZ * lightSize; 455 456 outlineData[currentNormalIndex].normal = ShadowTessellator::calculateNormal( 457 outlineData[currentNormalIndex].position, 458 outlineData[nextNormalIndex].position); 459 currentNormalIndex = (currentNormalIndex + 1) % polyLength; 460 nextNormalIndex++; 461 } 462 463 projectCasterToOutline(outlineCentroid, lightCenter, polyCentroid); 464 465 int penumbraIndex = 0; 466 // Then each polygon's vertex produce at minmal 2 penumbra vertices. 467 // Since the size can be dynamic here, we keep track of the size and update 468 // the real size at the end. 469 int allocatedPenumbraLength = 2 * polyLength + SPOT_MAX_EXTRA_CORNER_VERTEX_NUMBER; 470 Vector2 penumbra[allocatedPenumbraLength]; 471 int totalExtraCornerSliceNumber = 0; 472 473 Vector2 umbra[polyLength]; 474 475 // When centroid is covered by all circles from outline, then we consider 476 // the umbra is invalid, and we will tune down the shadow strength. 477 bool hasValidUmbra = true; 478 // We need the minimal of RaitoVI to decrease the spot shadow strength accordingly. 479 float minRaitoVI = FLT_MAX; 480 481 for (int i = 0; i < polyLength; i++) { 482 // Generate all the penumbra's vertices only using the (outline vertex + normal * radius) 483 // There is no guarantee that the penumbra is still convex, but for 484 // each outline vertex, it will connect to all its corresponding penumbra vertices as 485 // triangle fans. And for neighber penumbra vertex, it will be a trapezoid. 486 // 487 // Penumbra Vertices marked as Pi 488 // Outline Vertices marked as Vi 489 // (P3) 490 // (P2) | ' (P4) 491 // (P1)' | | ' 492 // ' | | ' 493 // (P0) ------------------------------------------------(P5) 494 // | (V0) |(V1) 495 // | | 496 // | | 497 // | | 498 // | | 499 // | | 500 // | | 501 // | | 502 // | | 503 // (V3)-----------------------------------(V2) 504 int preNormalIndex = (i + polyLength - 1) % polyLength; 505 506 const Vector2& previousNormal = outlineData[preNormalIndex].normal; 507 const Vector2& currentNormal = outlineData[i].normal; 508 509 // Depending on how roundness we want for each corner, we can subdivide 510 // further here and/or introduce some heuristic to decide how much the 511 // subdivision should be. 512 int currentExtraSliceNumber = ShadowTessellator::getExtraVertexNumber( 513 previousNormal, currentNormal, SPOT_CORNER_RADIANS_DIVISOR); 514 515 int currentCornerSliceNumber = 1 + currentExtraSliceNumber; 516 totalExtraCornerSliceNumber += currentExtraSliceNumber; 517#if DEBUG_SHADOW 518 ALOGD("currentExtraSliceNumber should be %d", currentExtraSliceNumber); 519 ALOGD("currentCornerSliceNumber should be %d", currentCornerSliceNumber); 520 ALOGD("totalCornerSliceNumber is %d", totalExtraCornerSliceNumber); 521#endif 522 if (CC_UNLIKELY(totalExtraCornerSliceNumber > SPOT_MAX_EXTRA_CORNER_VERTEX_NUMBER)) { 523 currentCornerSliceNumber = 1; 524 } 525 for (int k = 0; k <= currentCornerSliceNumber; k++) { 526 Vector2 avgNormal = 527 (previousNormal * (currentCornerSliceNumber - k) + currentNormal * k) / 528 currentCornerSliceNumber; 529 avgNormal.normalize(); 530 penumbra[penumbraIndex++] = outlineData[i].position + 531 avgNormal * outlineData[i].radius; 532 } 533 534 535 // Compute the umbra by the intersection from the outline's centroid! 536 // 537 // (V) ------------------------------------ 538 // | ' | 539 // | ' | 540 // | ' (I) | 541 // | ' | 542 // | ' (C) | 543 // | | 544 // | | 545 // | | 546 // | | 547 // ------------------------------------ 548 // 549 // Connect a line b/t the outline vertex (V) and the centroid (C), it will 550 // intersect with the outline vertex's circle at point (I). 551 // Now, ratioVI = VI / VC, ratioIC = IC / VC 552 // Then the intersetion point can be computed as Ixy = Vxy * ratioIC + Cxy * ratioVI; 553 // 554 // When all of the outline circles cover the the outline centroid, (like I is 555 // on the other side of C), there is no real umbra any more, so we just fake 556 // a small area around the centroid as the umbra, and tune down the spot 557 // shadow's umbra strength to simulate the effect the whole shadow will 558 // become lighter in this case. 559 // The ratio can be simulated by using the inverse of maximum of ratioVI for 560 // all (V). 561 float distOutline = (outlineData[i].position - outlineCentroid).length(); 562 if (CC_UNLIKELY(distOutline == 0)) { 563 // If the outline has 0 area, then there is no spot shadow anyway. 564 ALOGW("Outline has 0 area, no spot shadow!"); 565 return; 566 } 567 568 float ratioVI = outlineData[i].radius / distOutline; 569 minRaitoVI = MathUtils::min(minRaitoVI, ratioVI); 570 if (ratioVI >= (1 - FAKE_UMBRA_SIZE_RATIO)) { 571 ratioVI = (1 - FAKE_UMBRA_SIZE_RATIO); 572 } 573 // When we know we don't have valid umbra, don't bother to compute the 574 // values below. But we can't skip the loop yet since we want to know the 575 // maximum ratio. 576 float ratioIC = 1 - ratioVI; 577 umbra[i] = outlineData[i].position * ratioIC + outlineCentroid * ratioVI; 578 } 579 580 hasValidUmbra = (minRaitoVI <= 1.0); 581 float shadowStrengthScale = 1.0; 582 if (!hasValidUmbra) { 583#if DEBUG_SHADOW 584 ALOGW("The object is too close to the light or too small, no real umbra!"); 585#endif 586 for (int i = 0; i < polyLength; i++) { 587 umbra[i] = outlineData[i].position * FAKE_UMBRA_SIZE_RATIO + 588 outlineCentroid * (1 - FAKE_UMBRA_SIZE_RATIO); 589 } 590 shadowStrengthScale = 1.0 / minRaitoVI; 591 } 592 593 int penumbraLength = penumbraIndex; 594 int umbraLength = polyLength; 595 596#if DEBUG_SHADOW 597 ALOGD("penumbraLength is %d , allocatedPenumbraLength %d", penumbraLength, allocatedPenumbraLength); 598 dumpPolygon(poly, polyLength, "input poly"); 599 dumpPolygon(penumbra, penumbraLength, "penumbra"); 600 dumpPolygon(umbra, umbraLength, "umbra"); 601 ALOGD("hasValidUmbra is %d and shadowStrengthScale is %f", hasValidUmbra, shadowStrengthScale); 602#endif 603 604 // The penumbra and umbra needs to be in convex shape to keep consistency 605 // and quality. 606 // Since we are still shooting rays to penumbra, it needs to be convex. 607 // Umbra can be represented as a fan from the centroid, but visually umbra 608 // looks nicer when it is convex. 609 Vector2 finalUmbra[umbraLength]; 610 Vector2 finalPenumbra[penumbraLength]; 611 int finalUmbraLength = hull(umbra, umbraLength, finalUmbra); 612 int finalPenumbraLength = hull(penumbra, penumbraLength, finalPenumbra); 613 614 generateTriangleStrip(isCasterOpaque, shadowStrengthScale, finalPenumbra, 615 finalPenumbraLength, finalUmbra, finalUmbraLength, poly, polyLength, 616 shadowTriangleStrip, outlineCentroid); 617 618} 619 620/** 621 * Converts a polygon specified with CW vertices into an array of distance-from-centroid values. 622 * 623 * Returns false in error conditions 624 * 625 * @param poly Array of vertices. Note that these *must* be CW. 626 * @param polyLength The number of vertices in the polygon. 627 * @param polyCentroid The centroid of the polygon, from which rays will be cast 628 * @param rayDist The output array for the calculated distances, must be SHADOW_RAY_COUNT in size 629 */ 630bool convertPolyToRayDist(const Vector2* poly, int polyLength, const Vector2& polyCentroid, 631 float* rayDist) { 632 const int rays = SHADOW_RAY_COUNT; 633 const float step = M_PI * 2 / rays; 634 635 const Vector2* lastVertex = &(poly[polyLength - 1]); 636 float startAngle = angle(*lastVertex, polyCentroid); 637 638 // Start with the ray that's closest to and less than startAngle 639 int rayIndex = floor((startAngle - EPSILON) / step); 640 rayIndex = (rayIndex + rays) % rays; // ensure positive 641 642 for (int polyIndex = 0; polyIndex < polyLength; polyIndex++) { 643 /* 644 * For a given pair of vertices on the polygon, poly[i-1] and poly[i], the rays that 645 * intersect these will be those that are between the two angles from the centroid that the 646 * vertices define. 647 * 648 * Because the polygon vertices are stored clockwise, the closest ray with an angle 649 * *smaller* than that defined by angle(poly[i], centroid) will be the first ray that does 650 * not intersect with poly[i-1], poly[i]. 651 */ 652 float currentAngle = angle(poly[polyIndex], polyCentroid); 653 654 // find first ray that will not intersect the line segment poly[i-1] & poly[i] 655 int firstRayIndexOnNextSegment = floor((currentAngle - EPSILON) / step); 656 firstRayIndexOnNextSegment = (firstRayIndexOnNextSegment + rays) % rays; // ensure positive 657 658 // Iterate through all rays that intersect with poly[i-1], poly[i] line segment. 659 // This may be 0 rays. 660 while (rayIndex != firstRayIndexOnNextSegment) { 661 float distanceToIntersect = rayIntersectPoints(polyCentroid, 662 cos(rayIndex * step), 663 sin(rayIndex * step), 664 *lastVertex, poly[polyIndex]); 665 if (distanceToIntersect < 0) { 666#if DEBUG_SHADOW 667 ALOGW("ERROR: convertPolyToRayDist failed"); 668#endif 669 return false; // error case, abort 670 } 671 672 rayDist[rayIndex] = distanceToIntersect; 673 674 rayIndex = (rayIndex - 1 + rays) % rays; 675 } 676 lastVertex = &poly[polyIndex]; 677 } 678 679 return true; 680} 681 682/** 683 * This is only for experimental purpose. 684 * After intersections are calculated, we could smooth the polygon if needed. 685 * So far, we don't think it is more appealing yet. 686 * 687 * @param level The level of smoothness. 688 * @param rays The total number of rays. 689 * @param rayDist (In and Out) The distance for each ray. 690 * 691 */ 692void SpotShadow::smoothPolygon(int level, int rays, float* rayDist) { 693 for (int k = 0; k < level; k++) { 694 for (int i = 0; i < rays; i++) { 695 float p1 = rayDist[(rays - 1 + i) % rays]; 696 float p2 = rayDist[i]; 697 float p3 = rayDist[(i + 1) % rays]; 698 rayDist[i] = (p1 + p2 * 2 + p3) / 4; 699 } 700 } 701} 702 703/** 704 * Generate a array of the angleData for either umbra or penumbra vertices. 705 * 706 * This array will be merged and used to guide where to shoot the rays, in clockwise order. 707 * 708 * @param angleDataList The result array of angle data. 709 * 710 * @return int The maximum angle's index in the array. 711 */ 712int SpotShadow::setupAngleList(VertexAngleData* angleDataList, 713 int polyLength, const Vector2* polygon, const Vector2& centroid, 714 bool isPenumbra, const char* name) { 715 float maxAngle = FLT_MIN; 716 int maxAngleIndex = 0; 717 for (int i = 0; i < polyLength; i++) { 718 float currentAngle = angle(polygon[i], centroid); 719 if (currentAngle > maxAngle) { 720 maxAngle = currentAngle; 721 maxAngleIndex = i; 722 } 723 angleDataList[i].set(currentAngle, isPenumbra, i); 724#if DEBUG_SHADOW 725 ALOGD("%s AngleList i %d %f", name, i, currentAngle); 726#endif 727 } 728 return maxAngleIndex; 729} 730 731/** 732 * Make sure the polygons are indeed in clockwise order. 733 * 734 * Possible reasons to return false: 1. The input polygon is not setup properly. 2. The hull 735 * algorithm is not able to generate it properly. 736 * 737 * Anyway, since the algorithm depends on the clockwise, when these kind of unexpected error 738 * situation is found, we need to detect it and early return without corrupting the memory. 739 * 740 * @return bool True if the angle list is actually from big to small. 741 */ 742bool SpotShadow::checkClockwise(int indexOfMaxAngle, int listLength, VertexAngleData* angleList, 743 const char* name) { 744 int currentIndex = indexOfMaxAngle; 745#if DEBUG_SHADOW 746 ALOGD("max index %d", currentIndex); 747#endif 748 for (int i = 0; i < listLength - 1; i++) { 749 // TODO: Cache the last angle. 750 float currentAngle = angleList[currentIndex].mAngle; 751 float nextAngle = angleList[(currentIndex + 1) % listLength].mAngle; 752 if (currentAngle < nextAngle) { 753#if DEBUG_SHADOW 754 ALOGE("%s, is not CW, at index %d", name, currentIndex); 755#endif 756 return false; 757 } 758 currentIndex = (currentIndex + 1) % listLength; 759 } 760 return true; 761} 762 763/** 764 * Check the polygon is clockwise. 765 * 766 * @return bool True is the polygon is clockwise. 767 */ 768bool SpotShadow::checkPolyClockwise(int polyAngleLength, int maxPolyAngleIndex, 769 const float* polyAngleList) { 770 bool isPolyCW = true; 771 // Starting from maxPolyAngleIndex , check around to make sure angle decrease. 772 for (int i = 0; i < polyAngleLength - 1; i++) { 773 float currentAngle = polyAngleList[(i + maxPolyAngleIndex) % polyAngleLength]; 774 float nextAngle = polyAngleList[(i + maxPolyAngleIndex + 1) % polyAngleLength]; 775 if (currentAngle < nextAngle) { 776 isPolyCW = false; 777 } 778 } 779 return isPolyCW; 780} 781 782/** 783 * Given the sorted array of all the vertices angle data, calculate for each 784 * vertices, the offset value to array element which represent the start edge 785 * of the polygon we need to shoot the ray at. 786 * 787 * TODO: Calculate this for umbra and penumbra in one loop using one single array. 788 * 789 * @param distances The result of the array distance counter. 790 */ 791void SpotShadow::calculateDistanceCounter(bool needsOffsetToUmbra, int angleLength, 792 const VertexAngleData* allVerticesAngleData, int* distances) { 793 794 bool firstVertexIsPenumbra = allVerticesAngleData[0].mIsPenumbra; 795 // If we want distance to inner, then we just set to 0 when we see inner. 796 bool needsSearch = needsOffsetToUmbra ? firstVertexIsPenumbra : !firstVertexIsPenumbra; 797 int distanceCounter = 0; 798 if (needsSearch) { 799 int foundIndex = -1; 800 for (int i = (angleLength - 1); i >= 0; i--) { 801 bool currentIsOuter = allVerticesAngleData[i].mIsPenumbra; 802 // If we need distance to inner, then we need to find a inner vertex. 803 if (currentIsOuter != firstVertexIsPenumbra) { 804 foundIndex = i; 805 break; 806 } 807 } 808 LOG_ALWAYS_FATAL_IF(foundIndex == -1, "Wrong index found, means either" 809 " umbra or penumbra's length is 0"); 810 distanceCounter = angleLength - foundIndex; 811 } 812#if DEBUG_SHADOW 813 ALOGD("distances[0] is %d", distanceCounter); 814#endif 815 816 distances[0] = distanceCounter; // means never see a target poly 817 818 for (int i = 1; i < angleLength; i++) { 819 bool firstVertexIsPenumbra = allVerticesAngleData[i].mIsPenumbra; 820 // When we needs for distance for each outer vertex to inner, then we 821 // increase the distance when seeing outer vertices. Otherwise, we clear 822 // to 0. 823 bool needsIncrement = needsOffsetToUmbra ? firstVertexIsPenumbra : !firstVertexIsPenumbra; 824 // If counter is not -1, that means we have seen an other polygon's vertex. 825 if (needsIncrement && distanceCounter != -1) { 826 distanceCounter++; 827 } else { 828 distanceCounter = 0; 829 } 830 distances[i] = distanceCounter; 831 } 832} 833 834/** 835 * Given umbra and penumbra angle data list, merge them by sorting the angle 836 * from the biggest to smallest. 837 * 838 * @param allVerticesAngleData The result array of merged angle data. 839 */ 840void SpotShadow::mergeAngleList(int maxUmbraAngleIndex, int maxPenumbraAngleIndex, 841 const VertexAngleData* umbraAngleList, int umbraLength, 842 const VertexAngleData* penumbraAngleList, int penumbraLength, 843 VertexAngleData* allVerticesAngleData) { 844 845 int totalRayNumber = umbraLength + penumbraLength; 846 int umbraIndex = maxUmbraAngleIndex; 847 int penumbraIndex = maxPenumbraAngleIndex; 848 849 float currentUmbraAngle = umbraAngleList[umbraIndex].mAngle; 850 float currentPenumbraAngle = penumbraAngleList[penumbraIndex].mAngle; 851 852 // TODO: Clean this up using a while loop with 2 iterators. 853 for (int i = 0; i < totalRayNumber; i++) { 854 if (currentUmbraAngle > currentPenumbraAngle) { 855 allVerticesAngleData[i] = umbraAngleList[umbraIndex]; 856 umbraIndex = (umbraIndex + 1) % umbraLength; 857 858 // If umbraIndex round back, that means we are running out of 859 // umbra vertices to merge, so just copy all the penumbra leftover. 860 // Otherwise, we update the currentUmbraAngle. 861 if (umbraIndex != maxUmbraAngleIndex) { 862 currentUmbraAngle = umbraAngleList[umbraIndex].mAngle; 863 } else { 864 for (int j = i + 1; j < totalRayNumber; j++) { 865 allVerticesAngleData[j] = penumbraAngleList[penumbraIndex]; 866 penumbraIndex = (penumbraIndex + 1) % penumbraLength; 867 } 868 break; 869 } 870 } else { 871 allVerticesAngleData[i] = penumbraAngleList[penumbraIndex]; 872 penumbraIndex = (penumbraIndex + 1) % penumbraLength; 873 // If penumbraIndex round back, that means we are running out of 874 // penumbra vertices to merge, so just copy all the umbra leftover. 875 // Otherwise, we update the currentPenumbraAngle. 876 if (penumbraIndex != maxPenumbraAngleIndex) { 877 currentPenumbraAngle = penumbraAngleList[penumbraIndex].mAngle; 878 } else { 879 for (int j = i + 1; j < totalRayNumber; j++) { 880 allVerticesAngleData[j] = umbraAngleList[umbraIndex]; 881 umbraIndex = (umbraIndex + 1) % umbraLength; 882 } 883 break; 884 } 885 } 886 } 887} 888 889#if DEBUG_SHADOW 890/** 891 * DEBUG ONLY: Verify all the offset compuation is correctly done by examining 892 * each vertex and its neighbor. 893 */ 894static void verifyDistanceCounter(const VertexAngleData* allVerticesAngleData, 895 const int* distances, int angleLength, const char* name) { 896 int currentDistance = distances[0]; 897 for (int i = 1; i < angleLength; i++) { 898 if (distances[i] != INT_MIN) { 899 if (!((currentDistance + 1) == distances[i] 900 || distances[i] == 0)) { 901 ALOGE("Wrong distance found at i %d name %s", i, name); 902 } 903 currentDistance = distances[i]; 904 if (currentDistance != 0) { 905 bool currentOuter = allVerticesAngleData[i].mIsPenumbra; 906 for (int j = 1; j <= (currentDistance - 1); j++) { 907 bool neigborOuter = 908 allVerticesAngleData[(i + angleLength - j) % angleLength].mIsPenumbra; 909 if (neigborOuter != currentOuter) { 910 ALOGE("Wrong distance found at i %d name %s", i, name); 911 } 912 } 913 bool oppositeOuter = 914 allVerticesAngleData[(i + angleLength - currentDistance) % angleLength].mIsPenumbra; 915 if (oppositeOuter == currentOuter) { 916 ALOGE("Wrong distance found at i %d name %s", i, name); 917 } 918 } 919 } 920 } 921} 922 923/** 924 * DEBUG ONLY: Verify all the angle data compuated are is correctly done 925 */ 926static void verifyAngleData(int totalRayNumber, const VertexAngleData* allVerticesAngleData, 927 const int* distancesToInner, const int* distancesToOuter, 928 const VertexAngleData* umbraAngleList, int maxUmbraAngleIndex, int umbraLength, 929 const VertexAngleData* penumbraAngleList, int maxPenumbraAngleIndex, 930 int penumbraLength) { 931 for (int i = 0; i < totalRayNumber; i++) { 932 ALOGD("currentAngleList i %d, angle %f, isInner %d, index %d distancesToInner" 933 " %d distancesToOuter %d", i, allVerticesAngleData[i].mAngle, 934 !allVerticesAngleData[i].mIsPenumbra, 935 allVerticesAngleData[i].mVertexIndex, distancesToInner[i], distancesToOuter[i]); 936 } 937 938 verifyDistanceCounter(allVerticesAngleData, distancesToInner, totalRayNumber, "distancesToInner"); 939 verifyDistanceCounter(allVerticesAngleData, distancesToOuter, totalRayNumber, "distancesToOuter"); 940 941 for (int i = 0; i < totalRayNumber; i++) { 942 if ((distancesToInner[i] * distancesToOuter[i]) != 0) { 943 ALOGE("distancesToInner wrong at index %d distancesToInner[i] %d," 944 " distancesToOuter[i] %d", i, distancesToInner[i], distancesToOuter[i]); 945 } 946 } 947 int currentUmbraVertexIndex = 948 umbraAngleList[maxUmbraAngleIndex].mVertexIndex; 949 int currentPenumbraVertexIndex = 950 penumbraAngleList[maxPenumbraAngleIndex].mVertexIndex; 951 for (int i = 0; i < totalRayNumber; i++) { 952 if (allVerticesAngleData[i].mIsPenumbra == true) { 953 if (allVerticesAngleData[i].mVertexIndex != currentPenumbraVertexIndex) { 954 ALOGW("wrong penumbra indexing i %d allVerticesAngleData[i].mVertexIndex %d " 955 "currentpenumbraVertexIndex %d", i, 956 allVerticesAngleData[i].mVertexIndex, currentPenumbraVertexIndex); 957 } 958 currentPenumbraVertexIndex = (currentPenumbraVertexIndex + 1) % penumbraLength; 959 } else { 960 if (allVerticesAngleData[i].mVertexIndex != currentUmbraVertexIndex) { 961 ALOGW("wrong umbra indexing i %d allVerticesAngleData[i].mVertexIndex %d " 962 "currentUmbraVertexIndex %d", i, 963 allVerticesAngleData[i].mVertexIndex, currentUmbraVertexIndex); 964 } 965 currentUmbraVertexIndex = (currentUmbraVertexIndex + 1) % umbraLength; 966 } 967 } 968 for (int i = 0; i < totalRayNumber - 1; i++) { 969 float currentAngle = allVerticesAngleData[i].mAngle; 970 float nextAngle = allVerticesAngleData[(i + 1) % totalRayNumber].mAngle; 971 if (currentAngle < nextAngle) { 972 ALOGE("Unexpected angle values!, currentAngle nextAngle %f %f", currentAngle, nextAngle); 973 } 974 } 975} 976#endif 977 978/** 979 * In order to compute the occluded umbra, we need to setup the angle data list 980 * for the polygon data. Since we only store one poly vertex per polygon vertex, 981 * this array only needs to be a float array which are the angles for each vertex. 982 * 983 * @param polyAngleList The result list 984 * 985 * @return int The index for the maximum angle in this array. 986 */ 987int SpotShadow::setupPolyAngleList(float* polyAngleList, int polyAngleLength, 988 const Vector2* poly2d, const Vector2& centroid) { 989 int maxPolyAngleIndex = -1; 990 float maxPolyAngle = -FLT_MAX; 991 for (int i = 0; i < polyAngleLength; i++) { 992 polyAngleList[i] = angle(poly2d[i], centroid); 993 if (polyAngleList[i] > maxPolyAngle) { 994 maxPolyAngle = polyAngleList[i]; 995 maxPolyAngleIndex = i; 996 } 997 } 998 return maxPolyAngleIndex; 999} 1000 1001/** 1002 * For umbra and penumbra, given the offset info and the current ray number, 1003 * find the right edge index (the (starting vertex) for the ray to shoot at. 1004 * 1005 * @return int The index of the starting vertex of the edge. 1006 */ 1007inline int SpotShadow::getEdgeStartIndex(const int* offsets, int rayIndex, int totalRayNumber, 1008 const VertexAngleData* allVerticesAngleData) { 1009 int tempOffset = offsets[rayIndex]; 1010 int targetRayIndex = (rayIndex - tempOffset + totalRayNumber) % totalRayNumber; 1011 return allVerticesAngleData[targetRayIndex].mVertexIndex; 1012} 1013 1014/** 1015 * For the occluded umbra, given the array of angles, find the index of the 1016 * starting vertex of the edge, for the ray to shoo at. 1017 * 1018 * TODO: Save the last result to shorten the search distance. 1019 * 1020 * @return int The index of the starting vertex of the edge. 1021 */ 1022inline int SpotShadow::getPolyEdgeStartIndex(int maxPolyAngleIndex, int polyLength, 1023 const float* polyAngleList, float rayAngle) { 1024 int minPolyAngleIndex = (maxPolyAngleIndex + polyLength - 1) % polyLength; 1025 int resultIndex = -1; 1026 if (rayAngle > polyAngleList[maxPolyAngleIndex] 1027 || rayAngle <= polyAngleList[minPolyAngleIndex]) { 1028 resultIndex = minPolyAngleIndex; 1029 } else { 1030 for (int i = 0; i < polyLength - 1; i++) { 1031 int currentIndex = (maxPolyAngleIndex + i) % polyLength; 1032 int nextIndex = (maxPolyAngleIndex + i + 1) % polyLength; 1033 if (rayAngle <= polyAngleList[currentIndex] 1034 && rayAngle > polyAngleList[nextIndex]) { 1035 resultIndex = currentIndex; 1036 } 1037 } 1038 } 1039 if (CC_UNLIKELY(resultIndex == -1)) { 1040 // TODO: Add more error handling here. 1041 ALOGE("Wrong index found, means no edge can't be found for rayAngle %f", rayAngle); 1042 } 1043 return resultIndex; 1044} 1045 1046/** 1047 * Convert the incoming polygons into arrays of vertices, for each ray. 1048 * Ray only shoots when there is one vertex either on penumbra on umbra. 1049 * 1050 * Finally, it will generate vertices per ray for umbra, penumbra and optionally 1051 * occludedUmbra. 1052 * 1053 * Return true (success) when all vertices are generated 1054 */ 1055int SpotShadow::convertPolysToVerticesPerRay( 1056 bool hasOccludedUmbraArea, const Vector2* poly2d, int polyLength, 1057 const Vector2* umbra, int umbraLength, const Vector2* penumbra, 1058 int penumbraLength, const Vector2& centroid, 1059 Vector2* umbraVerticesPerRay, Vector2* penumbraVerticesPerRay, 1060 Vector2* occludedUmbraVerticesPerRay) { 1061 int totalRayNumber = umbraLength + penumbraLength; 1062 1063 // For incoming umbra / penumbra polygons, we will build an intermediate data 1064 // structure to help us sort all the vertices according to the vertices. 1065 // Using this data structure, we can tell where (the angle) to shoot the ray, 1066 // whether we shoot at penumbra edge or umbra edge, and which edge to shoot at. 1067 // 1068 // We first parse each vertices and generate a table of VertexAngleData. 1069 // Based on that, we create 2 arrays telling us which edge to shoot at. 1070 VertexAngleData allVerticesAngleData[totalRayNumber]; 1071 VertexAngleData umbraAngleList[umbraLength]; 1072 VertexAngleData penumbraAngleList[penumbraLength]; 1073 1074 int polyAngleLength = hasOccludedUmbraArea ? polyLength : 0; 1075 float polyAngleList[polyAngleLength]; 1076 1077 const int maxUmbraAngleIndex = 1078 setupAngleList(umbraAngleList, umbraLength, umbra, centroid, false, "umbra"); 1079 const int maxPenumbraAngleIndex = 1080 setupAngleList(penumbraAngleList, penumbraLength, penumbra, centroid, true, "penumbra"); 1081 const int maxPolyAngleIndex = setupPolyAngleList(polyAngleList, polyAngleLength, poly2d, centroid); 1082 1083 // Check all the polygons here are CW. 1084 bool isPolyCW = checkPolyClockwise(polyAngleLength, maxPolyAngleIndex, polyAngleList); 1085 bool isUmbraCW = checkClockwise(maxUmbraAngleIndex, umbraLength, 1086 umbraAngleList, "umbra"); 1087 bool isPenumbraCW = checkClockwise(maxPenumbraAngleIndex, penumbraLength, 1088 penumbraAngleList, "penumbra"); 1089 1090 if (!isUmbraCW || !isPenumbraCW || !isPolyCW) { 1091#if DEBUG_SHADOW 1092 ALOGE("One polygon is not CW isUmbraCW %d isPenumbraCW %d isPolyCW %d", 1093 isUmbraCW, isPenumbraCW, isPolyCW); 1094#endif 1095 return false; 1096 } 1097 1098 mergeAngleList(maxUmbraAngleIndex, maxPenumbraAngleIndex, 1099 umbraAngleList, umbraLength, penumbraAngleList, penumbraLength, 1100 allVerticesAngleData); 1101 1102 // Calculate the offset to the left most Inner vertex for each outerVertex. 1103 // Then the offset to the left most Outer vertex for each innerVertex. 1104 int offsetToInner[totalRayNumber]; 1105 int offsetToOuter[totalRayNumber]; 1106 calculateDistanceCounter(true, totalRayNumber, allVerticesAngleData, offsetToInner); 1107 calculateDistanceCounter(false, totalRayNumber, allVerticesAngleData, offsetToOuter); 1108 1109 // Generate both umbraVerticesPerRay and penumbraVerticesPerRay 1110 for (int i = 0; i < totalRayNumber; i++) { 1111 float rayAngle = allVerticesAngleData[i].mAngle; 1112 bool isUmbraVertex = !allVerticesAngleData[i].mIsPenumbra; 1113 1114 float dx = cosf(rayAngle); 1115 float dy = sinf(rayAngle); 1116 float distanceToIntersectUmbra = -1; 1117 1118 if (isUmbraVertex) { 1119 // We can just copy umbra easily, and calculate the distance for the 1120 // occluded umbra computation. 1121 int startUmbraIndex = allVerticesAngleData[i].mVertexIndex; 1122 umbraVerticesPerRay[i] = umbra[startUmbraIndex]; 1123 if (hasOccludedUmbraArea) { 1124 distanceToIntersectUmbra = (umbraVerticesPerRay[i] - centroid).length(); 1125 } 1126 1127 //shoot ray to penumbra only 1128 int startPenumbraIndex = getEdgeStartIndex(offsetToOuter, i, totalRayNumber, 1129 allVerticesAngleData); 1130 float distanceToIntersectPenumbra = rayIntersectPoints(centroid, dx, dy, 1131 penumbra[startPenumbraIndex], 1132 penumbra[(startPenumbraIndex + 1) % penumbraLength]); 1133 if (distanceToIntersectPenumbra < 0) { 1134#if DEBUG_SHADOW 1135 ALOGW("convertPolyToRayDist for penumbra failed rayAngle %f dx %f dy %f", 1136 rayAngle, dx, dy); 1137#endif 1138 distanceToIntersectPenumbra = 0; 1139 } 1140 penumbraVerticesPerRay[i].x = centroid.x + dx * distanceToIntersectPenumbra; 1141 penumbraVerticesPerRay[i].y = centroid.y + dy * distanceToIntersectPenumbra; 1142 } else { 1143 // We can just copy the penumbra 1144 int startPenumbraIndex = allVerticesAngleData[i].mVertexIndex; 1145 penumbraVerticesPerRay[i] = penumbra[startPenumbraIndex]; 1146 1147 // And shoot ray to umbra only 1148 int startUmbraIndex = getEdgeStartIndex(offsetToInner, i, totalRayNumber, 1149 allVerticesAngleData); 1150 1151 distanceToIntersectUmbra = rayIntersectPoints(centroid, dx, dy, 1152 umbra[startUmbraIndex], umbra[(startUmbraIndex + 1) % umbraLength]); 1153 if (distanceToIntersectUmbra < 0) { 1154#if DEBUG_SHADOW 1155 ALOGW("convertPolyToRayDist for umbra failed rayAngle %f dx %f dy %f", 1156 rayAngle, dx, dy); 1157#endif 1158 distanceToIntersectUmbra = 0; 1159 } 1160 umbraVerticesPerRay[i].x = centroid.x + dx * distanceToIntersectUmbra; 1161 umbraVerticesPerRay[i].y = centroid.y + dy * distanceToIntersectUmbra; 1162 } 1163 1164 if (hasOccludedUmbraArea) { 1165 // Shoot the same ray to the poly2d, and get the distance. 1166 int startPolyIndex = getPolyEdgeStartIndex(maxPolyAngleIndex, polyLength, 1167 polyAngleList, rayAngle); 1168 1169 float distanceToIntersectPoly = rayIntersectPoints(centroid, dx, dy, 1170 poly2d[startPolyIndex], poly2d[(startPolyIndex + 1) % polyLength]); 1171 if (distanceToIntersectPoly < 0) { 1172 distanceToIntersectPoly = 0; 1173 } 1174 distanceToIntersectPoly = MathUtils::min(distanceToIntersectUmbra, distanceToIntersectPoly); 1175 occludedUmbraVerticesPerRay[i].x = centroid.x + dx * distanceToIntersectPoly; 1176 occludedUmbraVerticesPerRay[i].y = centroid.y + dy * distanceToIntersectPoly; 1177 } 1178 } 1179 1180#if DEBUG_SHADOW 1181 verifyAngleData(totalRayNumber, allVerticesAngleData, offsetToInner, 1182 offsetToOuter, umbraAngleList, maxUmbraAngleIndex, umbraLength, 1183 penumbraAngleList, maxPenumbraAngleIndex, penumbraLength); 1184#endif 1185 return true; // success 1186 1187} 1188 1189/** 1190 * Generate a triangle strip given two convex polygon 1191**/ 1192void SpotShadow::generateTriangleStrip(bool isCasterOpaque, float shadowStrengthScale, 1193 Vector2* penumbra, int penumbraLength, Vector2* umbra, int umbraLength, 1194 const Vector3* poly, int polyLength, VertexBuffer& shadowTriangleStrip, 1195 const Vector2& centroid) { 1196 1197 bool hasOccludedUmbraArea = false; 1198 Vector2 poly2d[polyLength]; 1199 1200 if (isCasterOpaque) { 1201 for (int i = 0; i < polyLength; i++) { 1202 poly2d[i].x = poly[i].x; 1203 poly2d[i].y = poly[i].y; 1204 } 1205 // Make sure the centroid is inside the umbra, otherwise, fall back to the 1206 // approach as if there is no occluded umbra area. 1207 if (testPointInsidePolygon(centroid, poly2d, polyLength)) { 1208 hasOccludedUmbraArea = true; 1209 } 1210 } 1211 1212 int totalRayNum = umbraLength + penumbraLength; 1213 Vector2 umbraVertices[totalRayNum]; 1214 Vector2 penumbraVertices[totalRayNum]; 1215 Vector2 occludedUmbraVertices[totalRayNum]; 1216 bool convertSuccess = convertPolysToVerticesPerRay(hasOccludedUmbraArea, poly2d, 1217 polyLength, umbra, umbraLength, penumbra, penumbraLength, 1218 centroid, umbraVertices, penumbraVertices, occludedUmbraVertices); 1219 if (!convertSuccess) { 1220 return; 1221 } 1222 1223 // Minimal value is 1, for each vertex show up once. 1224 // The bigger this value is , the smoother the look is, but more memory 1225 // is consumed. 1226 // When the ray number is high, that means the polygon has been fine 1227 // tessellated, we don't need this extra slice, just keep it as 1. 1228 int sliceNumberPerEdge = (totalRayNum > FINE_TESSELLATED_POLYGON_RAY_NUMBER) ? 1 : 2; 1229 1230 // For each polygon, we at most add (totalRayNum * sliceNumberPerEdge) vertices. 1231 int slicedVertexCountPerPolygon = totalRayNum * sliceNumberPerEdge; 1232 int totalVertexCount = slicedVertexCountPerPolygon * 2 + totalRayNum; 1233 int totalIndexCount = 2 * (slicedVertexCountPerPolygon * 2 + 2); 1234 AlphaVertex* shadowVertices = 1235 shadowTriangleStrip.alloc<AlphaVertex>(totalVertexCount); 1236 uint16_t* indexBuffer = 1237 shadowTriangleStrip.allocIndices<uint16_t>(totalIndexCount); 1238 1239 int indexBufferIndex = 0; 1240 int vertexBufferIndex = 0; 1241 1242 uint16_t slicedUmbraVertexIndex[totalRayNum * sliceNumberPerEdge]; 1243 // Should be something like 0 0 0 1 1 1 2 3 3 3... 1244 int rayNumberPerSlicedUmbra[totalRayNum * sliceNumberPerEdge]; 1245 int realUmbraVertexCount = 0; 1246 for (int i = 0; i < totalRayNum; i++) { 1247 Vector2 currentPenumbra = penumbraVertices[i]; 1248 Vector2 currentUmbra = umbraVertices[i]; 1249 1250 Vector2 nextPenumbra = penumbraVertices[(i + 1) % totalRayNum]; 1251 Vector2 nextUmbra = umbraVertices[(i + 1) % totalRayNum]; 1252 // NextUmbra/Penumbra will be done in the next loop!! 1253 for (int weight = 0; weight < sliceNumberPerEdge; weight++) { 1254 const Vector2& slicedPenumbra = (currentPenumbra * (sliceNumberPerEdge - weight) 1255 + nextPenumbra * weight) / sliceNumberPerEdge; 1256 1257 const Vector2& slicedUmbra = (currentUmbra * (sliceNumberPerEdge - weight) 1258 + nextUmbra * weight) / sliceNumberPerEdge; 1259 1260 // In the vertex buffer, we fill the Penumbra first, then umbra. 1261 indexBuffer[indexBufferIndex++] = vertexBufferIndex; 1262 AlphaVertex::set(&shadowVertices[vertexBufferIndex++], slicedPenumbra.x, 1263 slicedPenumbra.y, 0.0f); 1264 1265 // When we add umbra vertex, we need to remember its current ray number. 1266 // And its own vertexBufferIndex. This is for occluded umbra usage. 1267 indexBuffer[indexBufferIndex++] = vertexBufferIndex; 1268 rayNumberPerSlicedUmbra[realUmbraVertexCount] = i; 1269 slicedUmbraVertexIndex[realUmbraVertexCount] = vertexBufferIndex; 1270 realUmbraVertexCount++; 1271 AlphaVertex::set(&shadowVertices[vertexBufferIndex++], slicedUmbra.x, 1272 slicedUmbra.y, M_PI); 1273 } 1274 } 1275 1276 indexBuffer[indexBufferIndex++] = 0; 1277 //RealUmbraVertexIndex[0] must be 1, so we connect back well at the 1278 //beginning of occluded area. 1279 indexBuffer[indexBufferIndex++] = 1; 1280 1281 float occludedUmbraAlpha = M_PI; 1282 if (hasOccludedUmbraArea) { 1283 // Now the occludedUmbra area; 1284 int currentRayNumber = -1; 1285 int firstOccludedUmbraIndex = -1; 1286 for (int i = 0; i < realUmbraVertexCount; i++) { 1287 indexBuffer[indexBufferIndex++] = slicedUmbraVertexIndex[i]; 1288 1289 // If the occludedUmbra vertex has not been added yet, then add it. 1290 // Otherwise, just use the previously added occludedUmbra vertices. 1291 if (rayNumberPerSlicedUmbra[i] != currentRayNumber) { 1292 currentRayNumber++; 1293 indexBuffer[indexBufferIndex++] = vertexBufferIndex; 1294 // We need to remember the begining of the occludedUmbra vertices 1295 // to close this loop. 1296 if (currentRayNumber == 0) { 1297 firstOccludedUmbraIndex = vertexBufferIndex; 1298 } 1299 AlphaVertex::set(&shadowVertices[vertexBufferIndex++], 1300 occludedUmbraVertices[currentRayNumber].x, 1301 occludedUmbraVertices[currentRayNumber].y, 1302 occludedUmbraAlpha); 1303 } else { 1304 indexBuffer[indexBufferIndex++] = (vertexBufferIndex - 1); 1305 } 1306 } 1307 // Close the loop here! 1308 indexBuffer[indexBufferIndex++] = slicedUmbraVertexIndex[0]; 1309 indexBuffer[indexBufferIndex++] = firstOccludedUmbraIndex; 1310 } else { 1311 int lastCentroidIndex = vertexBufferIndex; 1312 AlphaVertex::set(&shadowVertices[vertexBufferIndex++], centroid.x, 1313 centroid.y, occludedUmbraAlpha); 1314 for (int i = 0; i < realUmbraVertexCount; i++) { 1315 indexBuffer[indexBufferIndex++] = slicedUmbraVertexIndex[i]; 1316 indexBuffer[indexBufferIndex++] = lastCentroidIndex; 1317 } 1318 // Close the loop here! 1319 indexBuffer[indexBufferIndex++] = slicedUmbraVertexIndex[0]; 1320 indexBuffer[indexBufferIndex++] = lastCentroidIndex; 1321 } 1322 1323#if DEBUG_SHADOW 1324 ALOGD("allocated IB %d allocated VB is %d", totalIndexCount, totalVertexCount); 1325 ALOGD("IB index %d VB index is %d", indexBufferIndex, vertexBufferIndex); 1326 for (int i = 0; i < vertexBufferIndex; i++) { 1327 ALOGD("vertexBuffer i %d, (%f, %f %f)", i, shadowVertices[i].x, shadowVertices[i].y, 1328 shadowVertices[i].alpha); 1329 } 1330 for (int i = 0; i < indexBufferIndex; i++) { 1331 ALOGD("indexBuffer i %d, indexBuffer[i] %d", i, indexBuffer[i]); 1332 } 1333#endif 1334 1335 // At the end, update the real index and vertex buffer size. 1336 shadowTriangleStrip.updateVertexCount(vertexBufferIndex); 1337 shadowTriangleStrip.updateIndexCount(indexBufferIndex); 1338 ShadowTessellator::checkOverflow(vertexBufferIndex, totalVertexCount, "Spot Vertex Buffer"); 1339 ShadowTessellator::checkOverflow(indexBufferIndex, totalIndexCount, "Spot Index Buffer"); 1340 1341 shadowTriangleStrip.setMode(VertexBuffer::kIndices); 1342 shadowTriangleStrip.computeBounds<AlphaVertex>(); 1343} 1344 1345#if DEBUG_SHADOW 1346 1347#define TEST_POINT_NUMBER 128 1348/** 1349 * Calculate the bounds for generating random test points. 1350 */ 1351void SpotShadow::updateBound(const Vector2 inVector, Vector2& lowerBound, 1352 Vector2& upperBound) { 1353 if (inVector.x < lowerBound.x) { 1354 lowerBound.x = inVector.x; 1355 } 1356 1357 if (inVector.y < lowerBound.y) { 1358 lowerBound.y = inVector.y; 1359 } 1360 1361 if (inVector.x > upperBound.x) { 1362 upperBound.x = inVector.x; 1363 } 1364 1365 if (inVector.y > upperBound.y) { 1366 upperBound.y = inVector.y; 1367 } 1368} 1369 1370/** 1371 * For debug purpose, when things go wrong, dump the whole polygon data. 1372 */ 1373void SpotShadow::dumpPolygon(const Vector2* poly, int polyLength, const char* polyName) { 1374 for (int i = 0; i < polyLength; i++) { 1375 ALOGD("polygon %s i %d x %f y %f", polyName, i, poly[i].x, poly[i].y); 1376 } 1377} 1378 1379/** 1380 * For debug purpose, when things go wrong, dump the whole polygon data. 1381 */ 1382void SpotShadow::dumpPolygon(const Vector3* poly, int polyLength, const char* polyName) { 1383 for (int i = 0; i < polyLength; i++) { 1384 ALOGD("polygon %s i %d x %f y %f", polyName, i, poly[i].x, poly[i].y); 1385 } 1386} 1387 1388/** 1389 * Test whether the polygon is convex. 1390 */ 1391bool SpotShadow::testConvex(const Vector2* polygon, int polygonLength, 1392 const char* name) { 1393 bool isConvex = true; 1394 for (int i = 0; i < polygonLength; i++) { 1395 Vector2 start = polygon[i]; 1396 Vector2 middle = polygon[(i + 1) % polygonLength]; 1397 Vector2 end = polygon[(i + 2) % polygonLength]; 1398 1399 float delta = (float(middle.x) - start.x) * (float(end.y) - start.y) - 1400 (float(middle.y) - start.y) * (float(end.x) - start.x); 1401 bool isCCWOrCoLinear = (delta >= EPSILON); 1402 1403 if (isCCWOrCoLinear) { 1404 ALOGW("(Error Type 2): polygon (%s) is not a convex b/c start (x %f, y %f)," 1405 "middle (x %f, y %f) and end (x %f, y %f) , delta is %f !!!", 1406 name, start.x, start.y, middle.x, middle.y, end.x, end.y, delta); 1407 isConvex = false; 1408 break; 1409 } 1410 } 1411 return isConvex; 1412} 1413 1414/** 1415 * Test whether or not the polygon (intersection) is within the 2 input polygons. 1416 * Using Marte Carlo method, we generate a random point, and if it is inside the 1417 * intersection, then it must be inside both source polygons. 1418 */ 1419void SpotShadow::testIntersection(const Vector2* poly1, int poly1Length, 1420 const Vector2* poly2, int poly2Length, 1421 const Vector2* intersection, int intersectionLength) { 1422 // Find the min and max of x and y. 1423 Vector2 lowerBound = {FLT_MAX, FLT_MAX}; 1424 Vector2 upperBound = {-FLT_MAX, -FLT_MAX}; 1425 for (int i = 0; i < poly1Length; i++) { 1426 updateBound(poly1[i], lowerBound, upperBound); 1427 } 1428 for (int i = 0; i < poly2Length; i++) { 1429 updateBound(poly2[i], lowerBound, upperBound); 1430 } 1431 1432 bool dumpPoly = false; 1433 for (int k = 0; k < TEST_POINT_NUMBER; k++) { 1434 // Generate a random point between minX, minY and maxX, maxY. 1435 float randomX = rand() / float(RAND_MAX); 1436 float randomY = rand() / float(RAND_MAX); 1437 1438 Vector2 testPoint; 1439 testPoint.x = lowerBound.x + randomX * (upperBound.x - lowerBound.x); 1440 testPoint.y = lowerBound.y + randomY * (upperBound.y - lowerBound.y); 1441 1442 // If the random point is in both poly 1 and 2, then it must be intersection. 1443 if (testPointInsidePolygon(testPoint, intersection, intersectionLength)) { 1444 if (!testPointInsidePolygon(testPoint, poly1, poly1Length)) { 1445 dumpPoly = true; 1446 ALOGW("(Error Type 1): one point (%f, %f) in the intersection is" 1447 " not in the poly1", 1448 testPoint.x, testPoint.y); 1449 } 1450 1451 if (!testPointInsidePolygon(testPoint, poly2, poly2Length)) { 1452 dumpPoly = true; 1453 ALOGW("(Error Type 1): one point (%f, %f) in the intersection is" 1454 " not in the poly2", 1455 testPoint.x, testPoint.y); 1456 } 1457 } 1458 } 1459 1460 if (dumpPoly) { 1461 dumpPolygon(intersection, intersectionLength, "intersection"); 1462 for (int i = 1; i < intersectionLength; i++) { 1463 Vector2 delta = intersection[i] - intersection[i - 1]; 1464 ALOGD("Intersetion i, %d Vs i-1 is delta %f", i, delta.lengthSquared()); 1465 } 1466 1467 dumpPolygon(poly1, poly1Length, "poly 1"); 1468 dumpPolygon(poly2, poly2Length, "poly 2"); 1469 } 1470} 1471#endif 1472 1473}; // namespace uirenderer 1474}; // namespace android 1475