Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2012 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 "PathTessellator" |
| 18 | #define LOG_NDEBUG 1 |
| 19 | #define ATRACE_TAG ATRACE_TAG_GRAPHICS |
| 20 | |
| 21 | #define VERTEX_DEBUG 0 |
| 22 | |
| 23 | #if VERTEX_DEBUG |
| 24 | #define DEBUG_DUMP_ALPHA_BUFFER() \ |
| 25 | for (unsigned int i = 0; i < vertexBuffer.getSize(); i++) { \ |
| 26 | ALOGD("point %d at %f %f, alpha %f", \ |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 27 | i, buffer[i].x, buffer[i].y, buffer[i].alpha); \ |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 28 | } |
| 29 | #define DEBUG_DUMP_BUFFER() \ |
| 30 | for (unsigned int i = 0; i < vertexBuffer.getSize(); i++) { \ |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 31 | ALOGD("point %d at %f %f", i, buffer[i].x, buffer[i].y); \ |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 32 | } |
| 33 | #else |
| 34 | #define DEBUG_DUMP_ALPHA_BUFFER() |
| 35 | #define DEBUG_DUMP_BUFFER() |
| 36 | #endif |
| 37 | |
| 38 | #include <SkPath.h> |
| 39 | #include <SkPaint.h> |
| 40 | |
| 41 | #include <stdlib.h> |
| 42 | #include <stdint.h> |
| 43 | #include <sys/types.h> |
| 44 | |
| 45 | #include <utils/Log.h> |
| 46 | #include <utils/Trace.h> |
| 47 | |
| 48 | #include "PathTessellator.h" |
| 49 | #include "Matrix.h" |
| 50 | #include "Vector.h" |
| 51 | #include "Vertex.h" |
| 52 | |
| 53 | namespace android { |
| 54 | namespace uirenderer { |
| 55 | |
| 56 | #define THRESHOLD 0.5f |
| 57 | #define ROUND_CAP_THRESH 0.25f |
| 58 | #define PI 3.1415926535897932f |
| 59 | |
| 60 | void PathTessellator::expandBoundsForStroke(SkRect& bounds, const SkPaint* paint, |
| 61 | bool forceExpand) { |
| 62 | if (forceExpand || paint->getStyle() != SkPaint::kFill_Style) { |
| 63 | float outset = paint->getStrokeWidth() * 0.5f; |
Chris Craik | e7c69c6 | 2013-04-03 09:55:48 -0700 | [diff] [blame] | 64 | if (outset == 0) outset = 0.5f; // account for hairline |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 65 | bounds.outset(outset, outset); |
| 66 | } |
| 67 | } |
| 68 | |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 69 | inline static void copyVertex(Vertex* destPtr, const Vertex* srcPtr) { |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 70 | Vertex::set(destPtr, srcPtr->x, srcPtr->y); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 71 | } |
| 72 | |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 73 | inline static void copyAlphaVertex(AlphaVertex* destPtr, const AlphaVertex* srcPtr) { |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 74 | AlphaVertex::set(destPtr, srcPtr->x, srcPtr->y, srcPtr->alpha); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 75 | } |
| 76 | |
| 77 | /** |
| 78 | * Produces a pseudo-normal for a vertex, given the normals of the two incoming lines. If the offset |
| 79 | * from each vertex in a perimeter is calculated, the resultant lines connecting the offset vertices |
| 80 | * will be offset by 1.0 |
| 81 | * |
| 82 | * Note that we can't add and normalize the two vectors, that would result in a rectangle having an |
| 83 | * offset of (sqrt(2)/2, sqrt(2)/2) at each corner, instead of (1, 1) |
| 84 | * |
| 85 | * NOTE: assumes angles between normals 90 degrees or less |
| 86 | */ |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 87 | inline static vec2 totalOffsetFromNormals(const vec2& normalA, const vec2& normalB) { |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 88 | return (normalA + normalB) / (1 + fabs(normalA.dot(normalB))); |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * Structure used for storing useful information about the SkPaint and scale used for tessellating |
| 93 | */ |
| 94 | struct PaintInfo { |
| 95 | public: |
| 96 | PaintInfo(const SkPaint* paint, const mat4 *transform) : |
| 97 | style(paint->getStyle()), cap(paint->getStrokeCap()), isAA(paint->isAntiAlias()), |
| 98 | inverseScaleX(1.0f), inverseScaleY(1.0f), |
| 99 | halfStrokeWidth(paint->getStrokeWidth() * 0.5f), maxAlpha(1.0f) { |
| 100 | // compute inverse scales |
| 101 | if (CC_UNLIKELY(!transform->isPureTranslate())) { |
| 102 | float m00 = transform->data[Matrix4::kScaleX]; |
| 103 | float m01 = transform->data[Matrix4::kSkewY]; |
| 104 | float m10 = transform->data[Matrix4::kSkewX]; |
| 105 | float m11 = transform->data[Matrix4::kScaleY]; |
| 106 | float scaleX = sqrt(m00 * m00 + m01 * m01); |
| 107 | float scaleY = sqrt(m10 * m10 + m11 * m11); |
| 108 | inverseScaleX = (scaleX != 0) ? (1.0f / scaleX) : 1.0f; |
| 109 | inverseScaleY = (scaleY != 0) ? (1.0f / scaleY) : 1.0f; |
| 110 | } |
| 111 | |
| 112 | if (isAA && halfStrokeWidth != 0 && inverseScaleX == inverseScaleY && |
Chris Craik | 19a390b | 2013-02-27 15:43:26 -0800 | [diff] [blame] | 113 | 2 * halfStrokeWidth < inverseScaleX) { |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 114 | maxAlpha *= (2 * halfStrokeWidth) / inverseScaleX; |
| 115 | halfStrokeWidth = 0.0f; |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | SkPaint::Style style; |
| 120 | SkPaint::Cap cap; |
| 121 | bool isAA; |
| 122 | float inverseScaleX; |
| 123 | float inverseScaleY; |
| 124 | float halfStrokeWidth; |
| 125 | float maxAlpha; |
| 126 | |
| 127 | inline void scaleOffsetForStrokeWidth(vec2& offset) const { |
| 128 | if (halfStrokeWidth == 0.0f) { |
| 129 | // hairline - compensate for scale |
| 130 | offset.x *= 0.5f * inverseScaleX; |
| 131 | offset.y *= 0.5f * inverseScaleY; |
| 132 | } else { |
| 133 | offset *= halfStrokeWidth; |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | /** |
| 138 | * NOTE: the input will not always be a normal, especially for sharp edges - it should be the |
| 139 | * result of totalOffsetFromNormals (see documentation there) |
| 140 | */ |
| 141 | inline vec2 deriveAAOffset(const vec2& offset) const { |
| 142 | return vec2(offset.x * 0.5f * inverseScaleX, |
| 143 | offset.y * 0.5f * inverseScaleY); |
| 144 | } |
| 145 | |
| 146 | /** |
| 147 | * Returns the number of cap divisions beyond the minimum 2 (kButt_Cap/kSquareCap will return 0) |
| 148 | * Should only be used when stroking and drawing caps |
| 149 | */ |
| 150 | inline int capExtraDivisions() const { |
| 151 | if (cap == SkPaint::kRound_Cap) { |
| 152 | if (halfStrokeWidth == 0.0f) return 2; |
| 153 | |
| 154 | // ROUND_CAP_THRESH is the maximum error for polygonal approximation of the round cap |
| 155 | const float errConst = (-ROUND_CAP_THRESH / halfStrokeWidth + 1); |
| 156 | const float targetCosVal = 2 * errConst * errConst - 1; |
| 157 | int neededDivisions = (int)(ceilf(PI / acos(targetCosVal)/2)) * 2; |
| 158 | return neededDivisions; |
| 159 | } |
| 160 | return 0; |
| 161 | } |
| 162 | }; |
| 163 | |
| 164 | void getFillVerticesFromPerimeter(const Vector<Vertex>& perimeter, VertexBuffer& vertexBuffer) { |
| 165 | Vertex* buffer = vertexBuffer.alloc<Vertex>(perimeter.size()); |
| 166 | |
| 167 | int currentIndex = 0; |
| 168 | // zig zag between all previous points on the inside of the hull to create a |
| 169 | // triangle strip that fills the hull |
| 170 | int srcAindex = 0; |
| 171 | int srcBindex = perimeter.size() - 1; |
| 172 | while (srcAindex <= srcBindex) { |
| 173 | copyVertex(&buffer[currentIndex++], &perimeter[srcAindex]); |
| 174 | if (srcAindex == srcBindex) break; |
| 175 | copyVertex(&buffer[currentIndex++], &perimeter[srcBindex]); |
| 176 | srcAindex++; |
| 177 | srcBindex--; |
| 178 | } |
| 179 | } |
| 180 | |
| 181 | /* |
| 182 | * Fills a vertexBuffer with non-alpha vertices, zig-zagging at each perimeter point to create a |
| 183 | * tri-strip as wide as the stroke. |
| 184 | * |
| 185 | * Uses an additional 2 vertices at the end to wrap around, closing the tri-strip |
| 186 | * (for a total of perimeter.size() * 2 + 2 vertices) |
| 187 | */ |
| 188 | void getStrokeVerticesFromPerimeter(const PaintInfo& paintInfo, const Vector<Vertex>& perimeter, |
| 189 | VertexBuffer& vertexBuffer) { |
| 190 | Vertex* buffer = vertexBuffer.alloc<Vertex>(perimeter.size() * 2 + 2); |
| 191 | |
| 192 | int currentIndex = 0; |
| 193 | const Vertex* last = &(perimeter[perimeter.size() - 1]); |
| 194 | const Vertex* current = &(perimeter[0]); |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 195 | vec2 lastNormal(current->y - last->y, |
| 196 | last->x - current->x); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 197 | lastNormal.normalize(); |
| 198 | for (unsigned int i = 0; i < perimeter.size(); i++) { |
| 199 | const Vertex* next = &(perimeter[i + 1 >= perimeter.size() ? 0 : i + 1]); |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 200 | vec2 nextNormal(next->y - current->y, |
| 201 | current->x - next->x); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 202 | nextNormal.normalize(); |
| 203 | |
| 204 | vec2 totalOffset = totalOffsetFromNormals(lastNormal, nextNormal); |
| 205 | paintInfo.scaleOffsetForStrokeWidth(totalOffset); |
| 206 | |
| 207 | Vertex::set(&buffer[currentIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 208 | current->x + totalOffset.x, |
| 209 | current->y + totalOffset.y); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 210 | |
| 211 | Vertex::set(&buffer[currentIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 212 | current->x - totalOffset.x, |
| 213 | current->y - totalOffset.y); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 214 | |
| 215 | last = current; |
| 216 | current = next; |
| 217 | lastNormal = nextNormal; |
| 218 | } |
| 219 | |
| 220 | // wrap around to beginning |
| 221 | copyVertex(&buffer[currentIndex++], &buffer[0]); |
| 222 | copyVertex(&buffer[currentIndex++], &buffer[1]); |
| 223 | |
| 224 | DEBUG_DUMP_BUFFER(); |
| 225 | } |
| 226 | |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 227 | static inline void storeBeginEnd(const PaintInfo& paintInfo, const Vertex& center, |
| 228 | const vec2& normal, Vertex* buffer, int& currentIndex, bool begin) { |
| 229 | vec2 strokeOffset = normal; |
| 230 | paintInfo.scaleOffsetForStrokeWidth(strokeOffset); |
| 231 | |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 232 | vec2 referencePoint(center.x, center.y); |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 233 | if (paintInfo.cap == SkPaint::kSquare_Cap) { |
| 234 | referencePoint += vec2(-strokeOffset.y, strokeOffset.x) * (begin ? -1 : 1); |
| 235 | } |
| 236 | |
| 237 | Vertex::set(&buffer[currentIndex++], referencePoint + strokeOffset); |
| 238 | Vertex::set(&buffer[currentIndex++], referencePoint - strokeOffset); |
| 239 | } |
| 240 | |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 241 | /** |
| 242 | * Fills a vertexBuffer with non-alpha vertices similar to getStrokeVerticesFromPerimeter, except: |
| 243 | * |
| 244 | * 1 - Doesn't need to wrap around, since the input vertices are unclosed |
| 245 | * |
| 246 | * 2 - can zig-zag across 'extra' vertices at either end, to create round caps |
| 247 | */ |
| 248 | void getStrokeVerticesFromUnclosedVertices(const PaintInfo& paintInfo, |
| 249 | const Vector<Vertex>& vertices, VertexBuffer& vertexBuffer) { |
| 250 | const int extra = paintInfo.capExtraDivisions(); |
| 251 | const int allocSize = (vertices.size() + extra) * 2; |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 252 | Vertex* buffer = vertexBuffer.alloc<Vertex>(allocSize); |
| 253 | |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 254 | const int lastIndex = vertices.size() - 1; |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 255 | if (extra > 0) { |
| 256 | // tessellate both round caps |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 257 | float beginTheta = atan2( |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 258 | - (vertices[0].x - vertices[1].x), |
| 259 | vertices[0].y - vertices[1].y); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 260 | float endTheta = atan2( |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 261 | - (vertices[lastIndex].x - vertices[lastIndex - 1].x), |
| 262 | vertices[lastIndex].y - vertices[lastIndex - 1].y); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 263 | const float dTheta = PI / (extra + 1); |
| 264 | const float radialScale = 2.0f / (1 + cos(dTheta)); |
| 265 | |
| 266 | int capOffset; |
| 267 | for (int i = 0; i < extra; i++) { |
| 268 | if (i < extra / 2) { |
| 269 | capOffset = extra - 2 * i - 1; |
| 270 | } else { |
| 271 | capOffset = 2 * i - extra; |
| 272 | } |
| 273 | |
| 274 | beginTheta += dTheta; |
| 275 | vec2 beginRadialOffset(cos(beginTheta), sin(beginTheta)); |
| 276 | paintInfo.scaleOffsetForStrokeWidth(beginRadialOffset); |
| 277 | Vertex::set(&buffer[capOffset], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 278 | vertices[0].x + beginRadialOffset.x, |
| 279 | vertices[0].y + beginRadialOffset.y); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 280 | |
| 281 | endTheta += dTheta; |
| 282 | vec2 endRadialOffset(cos(endTheta), sin(endTheta)); |
| 283 | paintInfo.scaleOffsetForStrokeWidth(endRadialOffset); |
| 284 | Vertex::set(&buffer[allocSize - 1 - capOffset], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 285 | vertices[lastIndex].x + endRadialOffset.x, |
| 286 | vertices[lastIndex].y + endRadialOffset.y); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 287 | } |
| 288 | } |
| 289 | |
| 290 | int currentIndex = extra; |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 291 | const Vertex* last = &(vertices[0]); |
| 292 | const Vertex* current = &(vertices[1]); |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 293 | vec2 lastNormal(current->y - last->y, |
| 294 | last->x - current->x); |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 295 | lastNormal.normalize(); |
| 296 | |
| 297 | storeBeginEnd(paintInfo, vertices[0], lastNormal, buffer, currentIndex, true); |
| 298 | |
| 299 | for (unsigned int i = 1; i < vertices.size() - 1; i++) { |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 300 | const Vertex* next = &(vertices[i + 1]); |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 301 | vec2 nextNormal(next->y - current->y, |
| 302 | current->x - next->x); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 303 | nextNormal.normalize(); |
| 304 | |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 305 | vec2 strokeOffset = totalOffsetFromNormals(lastNormal, nextNormal); |
| 306 | paintInfo.scaleOffsetForStrokeWidth(strokeOffset); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 307 | |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 308 | vec2 center(current->x, current->y); |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 309 | Vertex::set(&buffer[currentIndex++], center + strokeOffset); |
| 310 | Vertex::set(&buffer[currentIndex++], center - strokeOffset); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 311 | |
| 312 | current = next; |
| 313 | lastNormal = nextNormal; |
| 314 | } |
| 315 | |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 316 | storeBeginEnd(paintInfo, vertices[lastIndex], lastNormal, buffer, currentIndex, false); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 317 | |
| 318 | DEBUG_DUMP_BUFFER(); |
| 319 | } |
| 320 | |
| 321 | /** |
| 322 | * Populates a vertexBuffer with AlphaVertices to create an anti-aliased fill shape tessellation |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 323 | * |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 324 | * 1 - create the AA perimeter of unit width, by zig-zagging at each point around the perimeter of |
| 325 | * the shape (using 2 * perimeter.size() vertices) |
| 326 | * |
| 327 | * 2 - wrap around to the beginning to complete the perimeter (2 vertices) |
| 328 | * |
| 329 | * 3 - zig zag back and forth inside the shape to fill it (using perimeter.size() vertices) |
| 330 | */ |
| 331 | void getFillVerticesFromPerimeterAA(const PaintInfo& paintInfo, const Vector<Vertex>& perimeter, |
| 332 | VertexBuffer& vertexBuffer) { |
| 333 | AlphaVertex* buffer = vertexBuffer.alloc<AlphaVertex>(perimeter.size() * 3 + 2); |
| 334 | |
| 335 | // generate alpha points - fill Alpha vertex gaps in between each point with |
| 336 | // alpha 0 vertex, offset by a scaled normal. |
| 337 | int currentIndex = 0; |
| 338 | const Vertex* last = &(perimeter[perimeter.size() - 1]); |
| 339 | const Vertex* current = &(perimeter[0]); |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 340 | vec2 lastNormal(current->y - last->y, |
| 341 | last->x - current->x); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 342 | lastNormal.normalize(); |
| 343 | for (unsigned int i = 0; i < perimeter.size(); i++) { |
| 344 | const Vertex* next = &(perimeter[i + 1 >= perimeter.size() ? 0 : i + 1]); |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 345 | vec2 nextNormal(next->y - current->y, |
| 346 | current->x - next->x); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 347 | nextNormal.normalize(); |
| 348 | |
| 349 | // AA point offset from original point is that point's normal, such that each side is offset |
| 350 | // by .5 pixels |
| 351 | vec2 totalOffset = paintInfo.deriveAAOffset(totalOffsetFromNormals(lastNormal, nextNormal)); |
| 352 | |
| 353 | AlphaVertex::set(&buffer[currentIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 354 | current->x + totalOffset.x, |
| 355 | current->y + totalOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 356 | 0.0f); |
| 357 | AlphaVertex::set(&buffer[currentIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 358 | current->x - totalOffset.x, |
| 359 | current->y - totalOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 360 | 1.0f); |
| 361 | |
| 362 | last = current; |
| 363 | current = next; |
| 364 | lastNormal = nextNormal; |
| 365 | } |
| 366 | |
| 367 | // wrap around to beginning |
| 368 | copyAlphaVertex(&buffer[currentIndex++], &buffer[0]); |
| 369 | copyAlphaVertex(&buffer[currentIndex++], &buffer[1]); |
| 370 | |
| 371 | // zig zag between all previous points on the inside of the hull to create a |
| 372 | // triangle strip that fills the hull, repeating the first inner point to |
| 373 | // create degenerate tris to start inside path |
| 374 | int srcAindex = 0; |
| 375 | int srcBindex = perimeter.size() - 1; |
| 376 | while (srcAindex <= srcBindex) { |
| 377 | copyAlphaVertex(&buffer[currentIndex++], &buffer[srcAindex * 2 + 1]); |
| 378 | if (srcAindex == srcBindex) break; |
| 379 | copyAlphaVertex(&buffer[currentIndex++], &buffer[srcBindex * 2 + 1]); |
| 380 | srcAindex++; |
| 381 | srcBindex--; |
| 382 | } |
| 383 | |
| 384 | DEBUG_DUMP_BUFFER(); |
| 385 | } |
| 386 | |
| 387 | /** |
| 388 | * Stores geometry for a single, AA-perimeter (potentially rounded) cap |
| 389 | * |
| 390 | * For explanation of constants and general methodoloyg, see comments for |
| 391 | * getStrokeVerticesFromUnclosedVerticesAA() below. |
| 392 | */ |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 393 | inline static void storeCapAA(const PaintInfo& paintInfo, const Vector<Vertex>& vertices, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 394 | AlphaVertex* buffer, bool isFirst, vec2 normal, int offset) { |
| 395 | const int extra = paintInfo.capExtraDivisions(); |
| 396 | const int extraOffset = (extra + 1) / 2; |
| 397 | const int capIndex = isFirst |
| 398 | ? 2 * offset + 6 + 2 * (extra + extraOffset) |
| 399 | : offset + 2 + 2 * extraOffset; |
| 400 | if (isFirst) normal *= -1; |
| 401 | |
| 402 | // TODO: this normal should be scaled by radialScale if extra != 0, see totalOffsetFromNormals() |
| 403 | vec2 AAOffset = paintInfo.deriveAAOffset(normal); |
| 404 | |
| 405 | vec2 strokeOffset = normal; |
| 406 | paintInfo.scaleOffsetForStrokeWidth(strokeOffset); |
| 407 | vec2 outerOffset = strokeOffset + AAOffset; |
| 408 | vec2 innerOffset = strokeOffset - AAOffset; |
| 409 | |
| 410 | vec2 capAAOffset; |
| 411 | if (paintInfo.cap != SkPaint::kRound_Cap) { |
| 412 | // if the cap is square or butt, the inside primary cap vertices will be inset in two |
| 413 | // directions - both normal to the stroke, and parallel to it. |
| 414 | capAAOffset = vec2(-AAOffset.y, AAOffset.x); |
| 415 | } |
| 416 | |
| 417 | // determine referencePoint, the center point for the 4 primary cap vertices |
| 418 | const Vertex* point = isFirst ? vertices.begin() : (vertices.end() - 1); |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 419 | vec2 referencePoint(point->x, point->y); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 420 | if (paintInfo.cap == SkPaint::kSquare_Cap) { |
| 421 | // To account for square cap, move the primary cap vertices (that create the AA edge) by the |
| 422 | // stroke offset vector (rotated to be parallel to the stroke) |
| 423 | referencePoint += vec2(-strokeOffset.y, strokeOffset.x); |
| 424 | } |
| 425 | |
| 426 | AlphaVertex::set(&buffer[capIndex + 0], |
| 427 | referencePoint.x + outerOffset.x + capAAOffset.x, |
| 428 | referencePoint.y + outerOffset.y + capAAOffset.y, |
| 429 | 0.0f); |
| 430 | AlphaVertex::set(&buffer[capIndex + 1], |
| 431 | referencePoint.x + innerOffset.x - capAAOffset.x, |
| 432 | referencePoint.y + innerOffset.y - capAAOffset.y, |
| 433 | paintInfo.maxAlpha); |
| 434 | |
| 435 | bool isRound = paintInfo.cap == SkPaint::kRound_Cap; |
| 436 | |
| 437 | const int postCapIndex = (isRound && isFirst) ? (2 * extraOffset - 2) : capIndex + (2 * extra); |
| 438 | AlphaVertex::set(&buffer[postCapIndex + 2], |
| 439 | referencePoint.x - outerOffset.x + capAAOffset.x, |
| 440 | referencePoint.y - outerOffset.y + capAAOffset.y, |
| 441 | 0.0f); |
| 442 | AlphaVertex::set(&buffer[postCapIndex + 3], |
| 443 | referencePoint.x - innerOffset.x - capAAOffset.x, |
| 444 | referencePoint.y - innerOffset.y - capAAOffset.y, |
| 445 | paintInfo.maxAlpha); |
| 446 | |
| 447 | if (isRound) { |
| 448 | const float dTheta = PI / (extra + 1); |
| 449 | const float radialScale = 2.0f / (1 + cos(dTheta)); |
| 450 | float theta = atan2(normal.y, normal.x); |
| 451 | int capPerimIndex = capIndex + 2; |
| 452 | |
| 453 | for (int i = 0; i < extra; i++) { |
| 454 | theta += dTheta; |
| 455 | |
| 456 | vec2 radialOffset(cos(theta), sin(theta)); |
| 457 | |
| 458 | // scale to compensate for pinching at sharp angles, see totalOffsetFromNormals() |
| 459 | radialOffset *= radialScale; |
| 460 | |
| 461 | AAOffset = paintInfo.deriveAAOffset(radialOffset); |
| 462 | paintInfo.scaleOffsetForStrokeWidth(radialOffset); |
| 463 | AlphaVertex::set(&buffer[capPerimIndex++], |
| 464 | referencePoint.x + radialOffset.x + AAOffset.x, |
| 465 | referencePoint.y + radialOffset.y + AAOffset.y, |
| 466 | 0.0f); |
| 467 | AlphaVertex::set(&buffer[capPerimIndex++], |
| 468 | referencePoint.x + radialOffset.x - AAOffset.x, |
| 469 | referencePoint.y + radialOffset.y - AAOffset.y, |
| 470 | paintInfo.maxAlpha); |
| 471 | |
| 472 | if (isFirst && i == extra - extraOffset) { |
| 473 | //copy most recent two points to first two points |
| 474 | copyAlphaVertex(&buffer[0], &buffer[capPerimIndex - 2]); |
| 475 | copyAlphaVertex(&buffer[1], &buffer[capPerimIndex - 1]); |
| 476 | |
| 477 | capPerimIndex = 2; // start writing the rest of the round cap at index 2 |
| 478 | } |
| 479 | } |
| 480 | |
| 481 | if (isFirst) { |
| 482 | const int startCapFillIndex = capIndex + 2 * (extra - extraOffset) + 4; |
| 483 | int capFillIndex = startCapFillIndex; |
| 484 | for (int i = 0; i < extra + 2; i += 2) { |
| 485 | copyAlphaVertex(&buffer[capFillIndex++], &buffer[1 + i]); |
| 486 | // TODO: to support odd numbers of divisions, break here on the last iteration |
| 487 | copyAlphaVertex(&buffer[capFillIndex++], &buffer[startCapFillIndex - 3 - i]); |
| 488 | } |
| 489 | } else { |
| 490 | int capFillIndex = 6 * vertices.size() + 2 + 6 * extra - (extra + 2); |
| 491 | for (int i = 0; i < extra + 2; i += 2) { |
| 492 | copyAlphaVertex(&buffer[capFillIndex++], &buffer[capIndex + 1 + i]); |
| 493 | // TODO: to support odd numbers of divisions, break here on the last iteration |
| 494 | copyAlphaVertex(&buffer[capFillIndex++], &buffer[capIndex + 3 + 2 * extra - i]); |
| 495 | } |
| 496 | } |
| 497 | return; |
| 498 | } |
| 499 | if (isFirst) { |
| 500 | copyAlphaVertex(&buffer[0], &buffer[postCapIndex + 2]); |
| 501 | copyAlphaVertex(&buffer[1], &buffer[postCapIndex + 3]); |
| 502 | copyAlphaVertex(&buffer[postCapIndex + 4], &buffer[1]); // degenerate tris (the only two!) |
| 503 | copyAlphaVertex(&buffer[postCapIndex + 5], &buffer[postCapIndex + 1]); |
| 504 | } else { |
| 505 | copyAlphaVertex(&buffer[6 * vertices.size()], &buffer[postCapIndex + 1]); |
| 506 | copyAlphaVertex(&buffer[6 * vertices.size() + 1], &buffer[postCapIndex + 3]); |
| 507 | } |
| 508 | } |
| 509 | |
| 510 | /* |
| 511 | the geometry for an aa, capped stroke consists of the following: |
| 512 | |
| 513 | # vertices | function |
| 514 | ---------------------------------------------------------------------- |
| 515 | a) 2 | Start AA perimeter |
| 516 | b) 2, 2 * roundDivOff | First half of begin cap's perimeter |
| 517 | | |
| 518 | 2 * middlePts | 'Outer' or 'Top' AA perimeter half (between caps) |
| 519 | | |
| 520 | a) 4 | End cap's |
| 521 | b) 2, 2 * roundDivs, 2 | AA perimeter |
| 522 | | |
| 523 | 2 * middlePts | 'Inner' or 'bottom' AA perimeter half |
| 524 | | |
| 525 | a) 6 | Begin cap's perimeter |
| 526 | b) 2, 2*(rD - rDO + 1), | Last half of begin cap's perimeter |
| 527 | roundDivs, 2 | |
| 528 | | |
| 529 | 2 * middlePts | Stroke's full opacity center strip |
| 530 | | |
| 531 | a) 2 | end stroke |
| 532 | b) 2, roundDivs | (and end cap fill, for round) |
| 533 | |
| 534 | Notes: |
| 535 | * rows starting with 'a)' denote the Butt or Square cap vertex use, 'b)' denote Round |
| 536 | |
| 537 | * 'middlePts' is (number of points in the unclosed input vertex list, minus 2) times two |
| 538 | |
| 539 | * 'roundDivs' or 'rD' is the number of extra vertices (beyond the minimum of 2) that define the |
| 540 | round cap's shape, and is at least two. This will increase with cap size to sufficiently |
| 541 | define the cap's level of tessellation. |
| 542 | |
| 543 | * 'roundDivOffset' or 'rDO' is the point about halfway along the start cap's round perimeter, where |
| 544 | the stream of vertices for the AA perimeter starts. By starting and ending the perimeter at |
| 545 | this offset, the fill of the stroke is drawn from this point with minimal extra vertices. |
| 546 | |
| 547 | This means the outer perimeter starts at: |
| 548 | outerIndex = (2) OR (2 + 2 * roundDivOff) |
| 549 | the inner perimeter (since it is filled in reverse) starts at: |
| 550 | innerIndex = outerIndex + (4 * middlePts) + ((4) OR (4 + 2 * roundDivs)) - 1 |
| 551 | the stroke starts at: |
| 552 | strokeIndex = innerIndex + 1 + ((6) OR (6 + 3 * roundDivs - 2 * roundDivOffset)) |
| 553 | |
| 554 | The total needed allocated space is either: |
| 555 | 2 + 4 + 6 + 2 + 3 * (2 * middlePts) = 14 + 6 * middlePts = 2 + 6 * pts |
| 556 | or, for rounded caps: |
| 557 | (2 + 2 * rDO) + (4 + 2 * rD) + (2 * (rD - rDO + 1) |
| 558 | + roundDivs + 4) + (2 + roundDivs) + 3 * (2 * middlePts) |
| 559 | = 14 + 6 * middlePts + 6 * roundDivs |
| 560 | = 2 + 6 * pts + 6 * roundDivs |
| 561 | */ |
| 562 | void getStrokeVerticesFromUnclosedVerticesAA(const PaintInfo& paintInfo, |
| 563 | const Vector<Vertex>& vertices, VertexBuffer& vertexBuffer) { |
| 564 | |
| 565 | const int extra = paintInfo.capExtraDivisions(); |
| 566 | const int allocSize = 6 * vertices.size() + 2 + 6 * extra; |
| 567 | |
| 568 | AlphaVertex* buffer = vertexBuffer.alloc<AlphaVertex>(allocSize); |
| 569 | |
| 570 | const int extraOffset = (extra + 1) / 2; |
| 571 | int offset = 2 * (vertices.size() - 2); |
| 572 | // there is no outer/inner here, using them for consistency with below approach |
| 573 | int currentAAOuterIndex = 2 + 2 * extraOffset; |
| 574 | int currentAAInnerIndex = currentAAOuterIndex + (2 * offset) + 3 + (2 * extra); |
| 575 | int currentStrokeIndex = currentAAInnerIndex + 7 + (3 * extra - 2 * extraOffset); |
| 576 | |
| 577 | const Vertex* last = &(vertices[0]); |
| 578 | const Vertex* current = &(vertices[1]); |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 579 | vec2 lastNormal(current->y - last->y, |
| 580 | last->x - current->x); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 581 | lastNormal.normalize(); |
| 582 | |
| 583 | // TODO: use normal from bezier traversal for cap, instead of from vertices |
| 584 | storeCapAA(paintInfo, vertices, buffer, true, lastNormal, offset); |
| 585 | |
| 586 | for (unsigned int i = 1; i < vertices.size() - 1; i++) { |
| 587 | const Vertex* next = &(vertices[i + 1]); |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 588 | vec2 nextNormal(next->y - current->y, |
| 589 | current->x - next->x); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 590 | nextNormal.normalize(); |
| 591 | |
| 592 | vec2 totalOffset = totalOffsetFromNormals(lastNormal, nextNormal); |
| 593 | vec2 AAOffset = paintInfo.deriveAAOffset(totalOffset); |
| 594 | |
| 595 | vec2 innerOffset = totalOffset; |
| 596 | paintInfo.scaleOffsetForStrokeWidth(innerOffset); |
| 597 | vec2 outerOffset = innerOffset + AAOffset; |
| 598 | innerOffset -= AAOffset; |
| 599 | |
| 600 | AlphaVertex::set(&buffer[currentAAOuterIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 601 | current->x + outerOffset.x, |
| 602 | current->y + outerOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 603 | 0.0f); |
| 604 | AlphaVertex::set(&buffer[currentAAOuterIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 605 | current->x + innerOffset.x, |
| 606 | current->y + innerOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 607 | paintInfo.maxAlpha); |
| 608 | |
| 609 | AlphaVertex::set(&buffer[currentStrokeIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 610 | current->x + innerOffset.x, |
| 611 | current->y + innerOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 612 | paintInfo.maxAlpha); |
| 613 | AlphaVertex::set(&buffer[currentStrokeIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 614 | current->x - innerOffset.x, |
| 615 | current->y - innerOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 616 | paintInfo.maxAlpha); |
| 617 | |
| 618 | AlphaVertex::set(&buffer[currentAAInnerIndex--], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 619 | current->x - innerOffset.x, |
| 620 | current->y - innerOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 621 | paintInfo.maxAlpha); |
| 622 | AlphaVertex::set(&buffer[currentAAInnerIndex--], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 623 | current->x - outerOffset.x, |
| 624 | current->y - outerOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 625 | 0.0f); |
| 626 | |
| 627 | current = next; |
| 628 | lastNormal = nextNormal; |
| 629 | } |
| 630 | |
| 631 | // TODO: use normal from bezier traversal for cap, instead of from vertices |
| 632 | storeCapAA(paintInfo, vertices, buffer, false, lastNormal, offset); |
| 633 | |
| 634 | DEBUG_DUMP_ALPHA_BUFFER(); |
| 635 | } |
| 636 | |
| 637 | |
| 638 | void getStrokeVerticesFromPerimeterAA(const PaintInfo& paintInfo, const Vector<Vertex>& perimeter, |
| 639 | VertexBuffer& vertexBuffer) { |
| 640 | AlphaVertex* buffer = vertexBuffer.alloc<AlphaVertex>(6 * perimeter.size() + 8); |
| 641 | |
| 642 | int offset = 2 * perimeter.size() + 3; |
| 643 | int currentAAOuterIndex = 0; |
| 644 | int currentStrokeIndex = offset; |
| 645 | int currentAAInnerIndex = offset * 2; |
| 646 | |
| 647 | const Vertex* last = &(perimeter[perimeter.size() - 1]); |
| 648 | const Vertex* current = &(perimeter[0]); |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 649 | vec2 lastNormal(current->y - last->y, |
| 650 | last->x - current->x); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 651 | lastNormal.normalize(); |
| 652 | for (unsigned int i = 0; i < perimeter.size(); i++) { |
| 653 | const Vertex* next = &(perimeter[i + 1 >= perimeter.size() ? 0 : i + 1]); |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 654 | vec2 nextNormal(next->y - current->y, |
| 655 | current->x - next->x); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 656 | nextNormal.normalize(); |
| 657 | |
| 658 | vec2 totalOffset = totalOffsetFromNormals(lastNormal, nextNormal); |
| 659 | vec2 AAOffset = paintInfo.deriveAAOffset(totalOffset); |
| 660 | |
| 661 | vec2 innerOffset = totalOffset; |
| 662 | paintInfo.scaleOffsetForStrokeWidth(innerOffset); |
| 663 | vec2 outerOffset = innerOffset + AAOffset; |
| 664 | innerOffset -= AAOffset; |
| 665 | |
| 666 | AlphaVertex::set(&buffer[currentAAOuterIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 667 | current->x + outerOffset.x, |
| 668 | current->y + outerOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 669 | 0.0f); |
| 670 | AlphaVertex::set(&buffer[currentAAOuterIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 671 | current->x + innerOffset.x, |
| 672 | current->y + innerOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 673 | paintInfo.maxAlpha); |
| 674 | |
| 675 | AlphaVertex::set(&buffer[currentStrokeIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 676 | current->x + innerOffset.x, |
| 677 | current->y + innerOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 678 | paintInfo.maxAlpha); |
| 679 | AlphaVertex::set(&buffer[currentStrokeIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 680 | current->x - innerOffset.x, |
| 681 | current->y - innerOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 682 | paintInfo.maxAlpha); |
| 683 | |
| 684 | AlphaVertex::set(&buffer[currentAAInnerIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 685 | current->x - innerOffset.x, |
| 686 | current->y - innerOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 687 | paintInfo.maxAlpha); |
| 688 | AlphaVertex::set(&buffer[currentAAInnerIndex++], |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 689 | current->x - outerOffset.x, |
| 690 | current->y - outerOffset.y, |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 691 | 0.0f); |
| 692 | |
| 693 | last = current; |
| 694 | current = next; |
| 695 | lastNormal = nextNormal; |
| 696 | } |
| 697 | |
| 698 | // wrap each strip around to beginning, creating degenerate tris to bridge strips |
| 699 | copyAlphaVertex(&buffer[currentAAOuterIndex++], &buffer[0]); |
| 700 | copyAlphaVertex(&buffer[currentAAOuterIndex++], &buffer[1]); |
| 701 | copyAlphaVertex(&buffer[currentAAOuterIndex++], &buffer[1]); |
| 702 | |
| 703 | copyAlphaVertex(&buffer[currentStrokeIndex++], &buffer[offset]); |
| 704 | copyAlphaVertex(&buffer[currentStrokeIndex++], &buffer[offset + 1]); |
| 705 | copyAlphaVertex(&buffer[currentStrokeIndex++], &buffer[offset + 1]); |
| 706 | |
| 707 | copyAlphaVertex(&buffer[currentAAInnerIndex++], &buffer[2 * offset]); |
| 708 | copyAlphaVertex(&buffer[currentAAInnerIndex++], &buffer[2 * offset + 1]); |
| 709 | // don't need to create last degenerate tri |
| 710 | |
| 711 | DEBUG_DUMP_ALPHA_BUFFER(); |
| 712 | } |
| 713 | |
| 714 | void PathTessellator::tessellatePath(const SkPath &path, const SkPaint* paint, |
| 715 | const mat4 *transform, VertexBuffer& vertexBuffer) { |
| 716 | ATRACE_CALL(); |
| 717 | |
| 718 | const PaintInfo paintInfo(paint, transform); |
| 719 | |
| 720 | Vector<Vertex> tempVertices; |
| 721 | float threshInvScaleX = paintInfo.inverseScaleX; |
| 722 | float threshInvScaleY = paintInfo.inverseScaleY; |
| 723 | if (paintInfo.style == SkPaint::kStroke_Style) { |
| 724 | // alter the bezier recursion threshold values we calculate in order to compensate for |
| 725 | // expansion done after the path vertices are found |
| 726 | SkRect bounds = path.getBounds(); |
| 727 | if (!bounds.isEmpty()) { |
| 728 | threshInvScaleX *= bounds.width() / (bounds.width() + paint->getStrokeWidth()); |
| 729 | threshInvScaleY *= bounds.height() / (bounds.height() + paint->getStrokeWidth()); |
| 730 | } |
| 731 | } |
| 732 | |
| 733 | // force close if we're filling the path, since fill path expects closed perimeter. |
| 734 | bool forceClose = paintInfo.style != SkPaint::kStroke_Style; |
| 735 | bool wasClosed = approximatePathOutlineVertices(path, forceClose, |
| 736 | threshInvScaleX * threshInvScaleX, threshInvScaleY * threshInvScaleY, tempVertices); |
| 737 | |
| 738 | if (!tempVertices.size()) { |
| 739 | // path was empty, return without allocating vertex buffer |
| 740 | return; |
| 741 | } |
| 742 | |
| 743 | #if VERTEX_DEBUG |
| 744 | for (unsigned int i = 0; i < tempVertices.size(); i++) { |
| 745 | ALOGD("orig path: point at %f %f", |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 746 | tempVertices[i].x, tempVertices[i].y); |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 747 | } |
| 748 | #endif |
| 749 | |
| 750 | if (paintInfo.style == SkPaint::kStroke_Style) { |
| 751 | if (!paintInfo.isAA) { |
| 752 | if (wasClosed) { |
| 753 | getStrokeVerticesFromPerimeter(paintInfo, tempVertices, vertexBuffer); |
| 754 | } else { |
| 755 | getStrokeVerticesFromUnclosedVertices(paintInfo, tempVertices, vertexBuffer); |
| 756 | } |
| 757 | |
| 758 | } else { |
| 759 | if (wasClosed) { |
| 760 | getStrokeVerticesFromPerimeterAA(paintInfo, tempVertices, vertexBuffer); |
| 761 | } else { |
| 762 | getStrokeVerticesFromUnclosedVerticesAA(paintInfo, tempVertices, vertexBuffer); |
| 763 | } |
| 764 | } |
| 765 | } else { |
| 766 | // For kStrokeAndFill style, the path should be adjusted externally. |
| 767 | // It will be treated as a fill here. |
| 768 | if (!paintInfo.isAA) { |
| 769 | getFillVerticesFromPerimeter(tempVertices, vertexBuffer); |
| 770 | } else { |
| 771 | getFillVerticesFromPerimeterAA(paintInfo, tempVertices, vertexBuffer); |
| 772 | } |
| 773 | } |
| 774 | } |
| 775 | |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 776 | static void expandRectToCoverVertex(SkRect& rect, float x, float y) { |
| 777 | rect.fLeft = fminf(rect.fLeft, x); |
| 778 | rect.fTop = fminf(rect.fTop, y); |
| 779 | rect.fRight = fmaxf(rect.fRight, x); |
| 780 | rect.fBottom = fmaxf(rect.fBottom, y); |
| 781 | } |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 782 | static void expandRectToCoverVertex(SkRect& rect, const Vertex& vertex) { |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 783 | expandRectToCoverVertex(rect, vertex.x, vertex.y); |
Chris Craik | 6d29c8d | 2013-05-08 18:35:44 -0700 | [diff] [blame] | 784 | } |
| 785 | |
| 786 | template <class TYPE> |
| 787 | static void instanceVertices(VertexBuffer& srcBuffer, VertexBuffer& dstBuffer, |
| 788 | const float* points, int count, SkRect& bounds) { |
| 789 | bounds.set(points[0], points[1], points[0], points[1]); |
| 790 | |
| 791 | int numPoints = count / 2; |
| 792 | int verticesPerPoint = srcBuffer.getVertexCount(); |
| 793 | dstBuffer.alloc<TYPE>(numPoints * verticesPerPoint + (numPoints - 1) * 2); |
| 794 | |
| 795 | for (int i = 0; i < count; i += 2) { |
| 796 | expandRectToCoverVertex(bounds, points[i + 0], points[i + 1]); |
| 797 | dstBuffer.copyInto<TYPE>(srcBuffer, points[i + 0], points[i + 1]); |
| 798 | } |
| 799 | dstBuffer.createDegenerateSeparators<TYPE>(verticesPerPoint); |
| 800 | } |
| 801 | |
| 802 | void PathTessellator::tessellatePoints(const float* points, int count, SkPaint* paint, |
| 803 | const mat4* transform, SkRect& bounds, VertexBuffer& vertexBuffer) { |
| 804 | const PaintInfo paintInfo(paint, transform); |
| 805 | |
| 806 | // determine point shape |
| 807 | SkPath path; |
| 808 | float radius = paintInfo.halfStrokeWidth; |
| 809 | if (radius == 0.0f) radius = 0.25f; |
| 810 | |
| 811 | if (paintInfo.cap == SkPaint::kRound_Cap) { |
| 812 | path.addCircle(0, 0, radius); |
| 813 | } else { |
| 814 | path.addRect(-radius, -radius, radius, radius); |
| 815 | } |
| 816 | |
| 817 | // calculate outline |
| 818 | Vector<Vertex> outlineVertices; |
| 819 | approximatePathOutlineVertices(path, true, |
| 820 | paintInfo.inverseScaleX * paintInfo.inverseScaleX, |
| 821 | paintInfo.inverseScaleY * paintInfo.inverseScaleY, outlineVertices); |
| 822 | |
| 823 | if (!outlineVertices.size()) return; |
| 824 | |
| 825 | // tessellate, then duplicate outline across points |
| 826 | int numPoints = count / 2; |
| 827 | VertexBuffer tempBuffer; |
| 828 | if (!paintInfo.isAA) { |
| 829 | getFillVerticesFromPerimeter(outlineVertices, tempBuffer); |
| 830 | instanceVertices<Vertex>(tempBuffer, vertexBuffer, points, count, bounds); |
| 831 | } else { |
| 832 | getFillVerticesFromPerimeterAA(paintInfo, outlineVertices, tempBuffer); |
| 833 | instanceVertices<AlphaVertex>(tempBuffer, vertexBuffer, points, count, bounds); |
| 834 | } |
| 835 | |
| 836 | expandBoundsForStroke(bounds, paint, true); // force-expand bounds to incorporate stroke |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 837 | } |
| 838 | |
| 839 | void PathTessellator::tessellateLines(const float* points, int count, SkPaint* paint, |
| 840 | const mat4* transform, SkRect& bounds, VertexBuffer& vertexBuffer) { |
| 841 | ATRACE_CALL(); |
| 842 | const PaintInfo paintInfo(paint, transform); |
| 843 | |
| 844 | const int extra = paintInfo.capExtraDivisions(); |
| 845 | int numLines = count / 4; |
| 846 | int lineAllocSize; |
| 847 | // pre-allocate space for lines in the buffer, and degenerate tris in between |
| 848 | if (paintInfo.isAA) { |
| 849 | lineAllocSize = 6 * (2) + 2 + 6 * extra; |
| 850 | vertexBuffer.alloc<AlphaVertex>(numLines * lineAllocSize + (numLines - 1) * 2); |
| 851 | } else { |
| 852 | lineAllocSize = 2 * ((2) + extra); |
| 853 | vertexBuffer.alloc<Vertex>(numLines * lineAllocSize + (numLines - 1) * 2); |
| 854 | } |
| 855 | |
| 856 | Vector<Vertex> tempVertices; |
| 857 | tempVertices.push(); |
| 858 | tempVertices.push(); |
| 859 | Vertex* tempVerticesData = tempVertices.editArray(); |
| 860 | bounds.set(points[0], points[1], points[0], points[1]); |
| 861 | for (int i = 0; i < count; i += 4) { |
| 862 | Vertex::set(&(tempVerticesData[0]), points[i + 0], points[i + 1]); |
| 863 | Vertex::set(&(tempVerticesData[1]), points[i + 2], points[i + 3]); |
| 864 | |
| 865 | if (paintInfo.isAA) { |
| 866 | getStrokeVerticesFromUnclosedVerticesAA(paintInfo, tempVertices, vertexBuffer); |
| 867 | } else { |
| 868 | getStrokeVerticesFromUnclosedVertices(paintInfo, tempVertices, vertexBuffer); |
| 869 | } |
| 870 | |
| 871 | // calculate bounds |
| 872 | expandRectToCoverVertex(bounds, tempVerticesData[0]); |
| 873 | expandRectToCoverVertex(bounds, tempVerticesData[1]); |
| 874 | } |
| 875 | |
| 876 | expandBoundsForStroke(bounds, paint, true); // force-expand bounds to incorporate stroke |
| 877 | |
| 878 | // since multiple objects tessellated into buffer, separate them with degen tris |
| 879 | if (paintInfo.isAA) { |
| 880 | vertexBuffer.createDegenerateSeparators<AlphaVertex>(lineAllocSize); |
| 881 | } else { |
| 882 | vertexBuffer.createDegenerateSeparators<Vertex>(lineAllocSize); |
| 883 | } |
| 884 | } |
| 885 | |
| 886 | /////////////////////////////////////////////////////////////////////////////// |
| 887 | // Simple path line approximation |
| 888 | /////////////////////////////////////////////////////////////////////////////// |
| 889 | |
| 890 | void pushToVector(Vector<Vertex>& vertices, float x, float y) { |
| 891 | // TODO: make this not yuck |
| 892 | vertices.push(); |
| 893 | Vertex* newVertex = &(vertices.editArray()[vertices.size() - 1]); |
| 894 | Vertex::set(newVertex, x, y); |
| 895 | } |
| 896 | |
| 897 | bool PathTessellator::approximatePathOutlineVertices(const SkPath& path, bool forceClose, |
| 898 | float sqrInvScaleX, float sqrInvScaleY, Vector<Vertex>& outputVertices) { |
| 899 | ATRACE_CALL(); |
| 900 | |
| 901 | // TODO: to support joins other than sharp miter, join vertices should be labelled in the |
| 902 | // perimeter, or resolved into more vertices. Reconsider forceClose-ing in that case. |
| 903 | SkPath::Iter iter(path, forceClose); |
| 904 | SkPoint pts[4]; |
| 905 | SkPath::Verb v; |
| 906 | while (SkPath::kDone_Verb != (v = iter.next(pts))) { |
| 907 | switch (v) { |
| 908 | case SkPath::kMove_Verb: |
| 909 | pushToVector(outputVertices, pts[0].x(), pts[0].y()); |
| 910 | ALOGV("Move to pos %f %f", pts[0].x(), pts[0].y()); |
| 911 | break; |
| 912 | case SkPath::kClose_Verb: |
| 913 | ALOGV("Close at pos %f %f", pts[0].x(), pts[0].y()); |
| 914 | break; |
| 915 | case SkPath::kLine_Verb: |
| 916 | ALOGV("kLine_Verb %f %f -> %f %f", pts[0].x(), pts[0].y(), pts[1].x(), pts[1].y()); |
| 917 | pushToVector(outputVertices, pts[1].x(), pts[1].y()); |
| 918 | break; |
| 919 | case SkPath::kQuad_Verb: |
| 920 | ALOGV("kQuad_Verb"); |
| 921 | recursiveQuadraticBezierVertices( |
| 922 | pts[0].x(), pts[0].y(), |
| 923 | pts[2].x(), pts[2].y(), |
| 924 | pts[1].x(), pts[1].y(), |
| 925 | sqrInvScaleX, sqrInvScaleY, outputVertices); |
| 926 | break; |
| 927 | case SkPath::kCubic_Verb: |
| 928 | ALOGV("kCubic_Verb"); |
| 929 | recursiveCubicBezierVertices( |
| 930 | pts[0].x(), pts[0].y(), |
| 931 | pts[1].x(), pts[1].y(), |
| 932 | pts[3].x(), pts[3].y(), |
| 933 | pts[2].x(), pts[2].y(), |
| 934 | sqrInvScaleX, sqrInvScaleY, outputVertices); |
| 935 | break; |
| 936 | default: |
| 937 | break; |
| 938 | } |
| 939 | } |
| 940 | |
| 941 | int size = outputVertices.size(); |
Romain Guy | 3380cfd | 2013-08-15 16:57:57 -0700 | [diff] [blame] | 942 | if (size >= 2 && outputVertices[0].x == outputVertices[size - 1].x && |
| 943 | outputVertices[0].y == outputVertices[size - 1].y) { |
Chris Craik | 65cd612 | 2012-12-10 17:56:27 -0800 | [diff] [blame] | 944 | outputVertices.pop(); |
| 945 | return true; |
| 946 | } |
| 947 | return false; |
| 948 | } |
| 949 | |
| 950 | /////////////////////////////////////////////////////////////////////////////// |
| 951 | // Bezier approximation |
| 952 | /////////////////////////////////////////////////////////////////////////////// |
| 953 | |
| 954 | void PathTessellator::recursiveCubicBezierVertices( |
| 955 | float p1x, float p1y, float c1x, float c1y, |
| 956 | float p2x, float p2y, float c2x, float c2y, |
| 957 | float sqrInvScaleX, float sqrInvScaleY, Vector<Vertex>& outputVertices) { |
| 958 | float dx = p2x - p1x; |
| 959 | float dy = p2y - p1y; |
| 960 | float d1 = fabs((c1x - p2x) * dy - (c1y - p2y) * dx); |
| 961 | float d2 = fabs((c2x - p2x) * dy - (c2y - p2y) * dx); |
| 962 | float d = d1 + d2; |
| 963 | |
| 964 | // multiplying by sqrInvScaleY/X equivalent to multiplying in dimensional scale factors |
| 965 | |
| 966 | if (d * d < THRESHOLD * THRESHOLD * (dx * dx * sqrInvScaleY + dy * dy * sqrInvScaleX)) { |
| 967 | // below thresh, draw line by adding endpoint |
| 968 | pushToVector(outputVertices, p2x, p2y); |
| 969 | } else { |
| 970 | float p1c1x = (p1x + c1x) * 0.5f; |
| 971 | float p1c1y = (p1y + c1y) * 0.5f; |
| 972 | float p2c2x = (p2x + c2x) * 0.5f; |
| 973 | float p2c2y = (p2y + c2y) * 0.5f; |
| 974 | |
| 975 | float c1c2x = (c1x + c2x) * 0.5f; |
| 976 | float c1c2y = (c1y + c2y) * 0.5f; |
| 977 | |
| 978 | float p1c1c2x = (p1c1x + c1c2x) * 0.5f; |
| 979 | float p1c1c2y = (p1c1y + c1c2y) * 0.5f; |
| 980 | |
| 981 | float p2c1c2x = (p2c2x + c1c2x) * 0.5f; |
| 982 | float p2c1c2y = (p2c2y + c1c2y) * 0.5f; |
| 983 | |
| 984 | float mx = (p1c1c2x + p2c1c2x) * 0.5f; |
| 985 | float my = (p1c1c2y + p2c1c2y) * 0.5f; |
| 986 | |
| 987 | recursiveCubicBezierVertices( |
| 988 | p1x, p1y, p1c1x, p1c1y, |
| 989 | mx, my, p1c1c2x, p1c1c2y, |
| 990 | sqrInvScaleX, sqrInvScaleY, outputVertices); |
| 991 | recursiveCubicBezierVertices( |
| 992 | mx, my, p2c1c2x, p2c1c2y, |
| 993 | p2x, p2y, p2c2x, p2c2y, |
| 994 | sqrInvScaleX, sqrInvScaleY, outputVertices); |
| 995 | } |
| 996 | } |
| 997 | |
| 998 | void PathTessellator::recursiveQuadraticBezierVertices( |
| 999 | float ax, float ay, |
| 1000 | float bx, float by, |
| 1001 | float cx, float cy, |
| 1002 | float sqrInvScaleX, float sqrInvScaleY, Vector<Vertex>& outputVertices) { |
| 1003 | float dx = bx - ax; |
| 1004 | float dy = by - ay; |
| 1005 | float d = (cx - bx) * dy - (cy - by) * dx; |
| 1006 | |
| 1007 | if (d * d < THRESHOLD * THRESHOLD * (dx * dx * sqrInvScaleY + dy * dy * sqrInvScaleX)) { |
| 1008 | // below thresh, draw line by adding endpoint |
| 1009 | pushToVector(outputVertices, bx, by); |
| 1010 | } else { |
| 1011 | float acx = (ax + cx) * 0.5f; |
| 1012 | float bcx = (bx + cx) * 0.5f; |
| 1013 | float acy = (ay + cy) * 0.5f; |
| 1014 | float bcy = (by + cy) * 0.5f; |
| 1015 | |
| 1016 | // midpoint |
| 1017 | float mx = (acx + bcx) * 0.5f; |
| 1018 | float my = (acy + bcy) * 0.5f; |
| 1019 | |
| 1020 | recursiveQuadraticBezierVertices(ax, ay, mx, my, acx, acy, |
| 1021 | sqrInvScaleX, sqrInvScaleY, outputVertices); |
| 1022 | recursiveQuadraticBezierVertices(mx, my, bx, by, bcx, bcy, |
| 1023 | sqrInvScaleX, sqrInvScaleY, outputVertices); |
| 1024 | } |
| 1025 | } |
| 1026 | |
| 1027 | }; // namespace uirenderer |
| 1028 | }; // namespace android |