1 2 /* 3 * Copyright 2010 Google Inc. 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10 11 #ifndef GrDrawTarget_DEFINED 12 #define GrDrawTarget_DEFINED 13 14 #include "GrClip.h" 15 #include "GrColor.h" 16 #include "GrDrawState.h" 17 #include "GrMatrix.h" 18 #include "GrRefCnt.h" 19 #include "GrSamplerState.h" 20 #include "GrStencil.h" 21 #include "GrTexture.h" 22 23 #include "SkXfermode.h" 24 #include "SkTLazy.h" 25 26 class GrTexture; 27 class GrClipIterator; 28 class GrVertexBuffer; 29 class GrIndexBuffer; 30 31 class GrDrawTarget : public GrRefCnt { 32 public: 33 /** 34 * Represents the draw target capabilities. 35 */ 36 struct Caps { 37 Caps() { memset(this, 0, sizeof(Caps)); } 38 Caps(const Caps& c) { *this = c; } 39 Caps& operator= (const Caps& c) { 40 memcpy(this, &c, sizeof(Caps)); 41 return *this; 42 } 43 void print() const; 44 bool f8BitPaletteSupport : 1; 45 bool fNPOTTextureTileSupport : 1; 46 bool fTwoSidedStencilSupport : 1; 47 bool fStencilWrapOpsSupport : 1; 48 bool fHWAALineSupport : 1; 49 bool fShaderDerivativeSupport : 1; 50 bool fGeometryShaderSupport : 1; 51 bool fFSAASupport : 1; 52 bool fDualSourceBlendingSupport : 1; 53 bool fBufferLockSupport : 1; 54 int fMaxRenderTargetSize; 55 int fMaxTextureSize; 56 }; 57 58 // for convenience 59 typedef GrDrawState::StageMask StageMask; 60 61 /////////////////////////////////////////////////////////////////////////// 62 63 GrDrawTarget(); 64 virtual ~GrDrawTarget(); 65 66 /** 67 * Gets the capabilities of the draw target. 68 */ 69 const Caps& getCaps() const { return fCaps; } 70 71 /** 72 * Sets the current clip to the region specified by clip. All draws will be 73 * clipped against this clip if kClip_StateBit is enabled. 74 * 75 * Setting the clip may (or may not) zero out the client's stencil bits. 76 * 77 * @param description of the clipping region 78 */ 79 void setClip(const GrClip& clip); 80 81 /** 82 * Gets the current clip. 83 * 84 * @return the clip. 85 */ 86 const GrClip& getClip() const; 87 88 const GrDrawState& getDrawState() const { return fCurrDrawState; } 89 GrDrawState* drawState() { return &fCurrDrawState; } 90 91 /** 92 * Shortcut for drawState()->preConcatSamplerMatrices() on all enabled 93 * stages 94 * 95 * @param matrix the matrix to concat 96 */ 97 void preConcatEnabledSamplerMatrices(const GrMatrix& matrix) { 98 StageMask stageMask = this->enabledStages(); 99 this->drawState()->preConcatSamplerMatrices(stageMask, matrix); 100 } 101 102 /** 103 * Determines if blending will require a read of a dst given the current 104 * state set on the draw target 105 * 106 * @return true if the dst surface will be read at each pixel hit by the 107 * a draw operation. 108 */ 109 bool drawWillReadDst() const; 110 111 /** 112 * Color alpha and coverage are two inputs to the drawing pipeline. For some 113 * blend modes it is safe to fold the coverage into constant or per-vertex 114 * color alpha value. For other blend modes they must be handled separately. 115 * Depending on features available in the underlying 3D API this may or may 116 * not be possible. 117 * 118 * This function looks at the current blend on the draw target and the draw 119 * target's capabilities to determine whether coverage can be handled 120 * correctly. 121 */ 122 bool canApplyCoverage() const; 123 124 /** 125 * Determines whether incorporating partial pixel coverage into the constant 126 * color specified by setColor or per-vertex colors will give the right 127 * blending result. 128 */ 129 bool canTweakAlphaForCoverage() const; 130 131 /** 132 * Given the current draw state, vertex layout, and hw support, will HW AA 133 * lines be used (if line primitive type is drawn)? (Note that lines are 134 * always 1 pixel wide) 135 */ 136 bool willUseHWAALines() const; 137 138 /** 139 * Used to save and restore the GrGpu's drawing state 140 */ 141 struct SavedDrawState { 142 private: 143 SkTLazy<GrDrawState> fState; 144 friend class GrDrawTarget; 145 }; 146 147 /** 148 * Saves the current draw state. The state can be restored at a later time 149 * with restoreDrawState. 150 * 151 * See also AutoStateRestore class. 152 * 153 * @param state will hold the state after the function returns. 154 */ 155 void saveCurrentDrawState(SavedDrawState* state) const; 156 157 /** 158 * Restores previously saved draw state. The client guarantees that state 159 * was previously passed to saveCurrentDrawState and that the rendertarget 160 * and texture set at save are still valid. 161 * 162 * See also AutoStateRestore class. 163 * 164 * @param state the previously saved state to restore. 165 */ 166 void restoreDrawState(const SavedDrawState& state); 167 168 /** 169 * Copies the draw state from another target to this target. 170 * 171 * @param srcTarget draw target used as src of the draw state. 172 */ 173 void copyDrawState(const GrDrawTarget& srcTarget); 174 175 /** 176 * The format of vertices is represented as a bitfield of flags. 177 * Flags that indicate the layout of vertex data. Vertices always contain 178 * positions and may also contain up to GrDrawState::kMaxTexCoords sets 179 * of 2D texture * coordinates, per-vertex colors, and per-vertex coverage. 180 * Each stage can 181 * use any of the texture coordinates as its input texture coordinates or it 182 * may use the positions as texture coordinates. 183 * 184 * If no texture coordinates are specified for a stage then the stage is 185 * disabled. 186 * 187 * Only one type of texture coord can be specified per stage. For 188 * example StageTexCoordVertexLayoutBit(0, 2) and 189 * StagePosAsTexCoordVertexLayoutBit(0) cannot both be specified. 190 * 191 * The order in memory is always (position, texture coord 0, ..., color, 192 * coverage) with any unused fields omitted. Note that this means that if 193 * only texture coordinates 1 is referenced then there is no texture 194 * coordinates 0 and the order would be (position, texture coordinate 1 195 * [, color][, coverage]). 196 */ 197 198 /** 199 * Generates a bit indicating that a texture stage uses texture coordinates 200 * 201 * @param stage the stage that will use texture coordinates. 202 * @param texCoordIdx the index of the texture coordinates to use 203 * 204 * @return the bit to add to a GrVertexLayout bitfield. 205 */ 206 static int StageTexCoordVertexLayoutBit(int stage, int texCoordIdx) { 207 GrAssert(stage < GrDrawState::kNumStages); 208 GrAssert(texCoordIdx < GrDrawState::kMaxTexCoords); 209 return 1 << (stage + (texCoordIdx * GrDrawState::kNumStages)); 210 } 211 212 private: 213 static const int TEX_COORD_BIT_CNT = GrDrawState::kNumStages * 214 GrDrawState::kMaxTexCoords; 215 216 public: 217 /** 218 * Generates a bit indicating that a texture stage uses the position 219 * as its texture coordinate. 220 * 221 * @param stage the stage that will use position as texture 222 * coordinates. 223 * 224 * @return the bit to add to a GrVertexLayout bitfield. 225 */ 226 static int StagePosAsTexCoordVertexLayoutBit(int stage) { 227 GrAssert(stage < GrDrawState::kNumStages); 228 return (1 << (TEX_COORD_BIT_CNT + stage)); 229 } 230 231 private: 232 static const int STAGE_BIT_CNT = TEX_COORD_BIT_CNT + 233 GrDrawState::kNumStages; 234 235 public: 236 237 /** 238 * Additional Bits that can be specified in GrVertexLayout. 239 */ 240 enum VertexLayoutBits { 241 /* vertices have colors (GrColor) */ 242 kColor_VertexLayoutBit = 1 << (STAGE_BIT_CNT + 0), 243 /* vertices have coverage (GrColor) 244 */ 245 kCoverage_VertexLayoutBit = 1 << (STAGE_BIT_CNT + 1), 246 /* Use text vertices. (Pos and tex coords may be a different type for 247 * text [GrGpuTextVertex vs GrPoint].) 248 */ 249 kTextFormat_VertexLayoutBit = 1 << (STAGE_BIT_CNT + 2), 250 251 /* Each vertex specificies an edge. Distance to the edge is used to 252 * compute a coverage. See GrDrawState::setVertexEdgeType(). 253 */ 254 kEdge_VertexLayoutBit = 1 << (STAGE_BIT_CNT + 3), 255 // for below assert 256 kDummyVertexLayoutBit, 257 kHighVertexLayoutBit = kDummyVertexLayoutBit - 1 258 }; 259 // make sure we haven't exceeded the number of bits in GrVertexLayout. 260 GR_STATIC_ASSERT(kHighVertexLayoutBit < ((uint64_t)1 << 8*sizeof(GrVertexLayout))); 261 262 /** 263 * There are three methods for specifying geometry (vertices and optionally 264 * indices) to the draw target. When indexed drawing the indices and vertices 265 * can use a different method. Once geometry is specified it can be used for 266 * multiple drawIndexed and drawNonIndexed calls. 267 * 268 * Sometimes it is necessary to perform a draw while upstack code has 269 * already specified geometry that it isn't finished with. There are push 270 * pop methods 271 * 272 * 1. Provide a cpu array (set*SourceToArray). This is useful when the 273 * caller's client has already provided vertex data in a format 274 * the time compatible with a GrVertexLayout. The array must contain the 275 * data at set*SourceToArray is called. The source stays in effect for 276 * drawIndexed & drawNonIndexed calls until set*SourceToArray is called 277 * again or one of the other two paths is chosen. 278 * 279 * 2. Reserve. This is most useful when the caller has data it must 280 * transform before drawing and is not long-lived. The caller requests 281 * that the draw target make room for some amount of vertex and/or index 282 * data. The target provides ptrs to hold the vertex and/or index data. 283 * 284 * The data is writable up until the next drawIndexed, drawNonIndexed, 285 * or pushGeometrySource At this point the data is frozen and the ptrs 286 * are no longer valid. 287 * 288 * 3. Vertex and Index Buffers. This is most useful for geometry that will 289 * is long-lived. SetVertexSourceToBuffer and SetIndexSourceToBuffer are 290 * used to set the buffer and subsequent drawIndexed and drawNonIndexed 291 * calls use this source until another source is set. 292 */ 293 294 /** 295 * Reserves space for vertices. Draw target will use reserved vertices at 296 * at the next draw. 297 * 298 * If succeeds: 299 * if vertexCount > 0, *vertices will be the array 300 * of vertices to be filled by caller. The next draw will read 301 * these vertices. 302 * 303 * If a client does not already have a vertex buffer then this is the 304 * preferred way to allocate vertex data. It allows the subclass of 305 * GrDrawTarget to decide whether to put data in buffers, to group vertex 306 * data that uses the same state (e.g. for deferred rendering), etc. 307 * 308 * After the next draw or pushGeometrySource the vertices ptr is no longer 309 * valid and the geometry data cannot be further modified. The contents 310 * that were put in the reserved space can be drawn by multiple draws, 311 * however. 312 * 313 * @param vertexLayout the format of vertices (ignored if vertexCount == 0). 314 * @param vertexCount the number of vertices to reserve space for. Can be 0. 315 * @param vertices will point to reserved vertex space if vertexCount is 316 * non-zero. Illegal to pass NULL if vertexCount > 0. 317 * 318 * @return true if succeeded in allocating space for the vertices and false 319 * if not. 320 */ 321 bool reserveVertexSpace(GrVertexLayout vertexLayout, 322 int vertexCount, 323 void** vertices); 324 /** 325 * Reserves space for indices. Draw target will use the reserved indices at 326 * the next indexed draw. 327 * 328 * If succeeds: 329 * if indexCount > 0, *indices will be the array 330 * of indices to be filled by caller. The next draw will read 331 * these indices. 332 * 333 * If a client does not already have a index buffer then this is the 334 * preferred way to allocate index data. It allows the subclass of 335 * GrDrawTarget to decide whether to put data in buffers, to group index 336 * data that uses the same state (e.g. for deferred rendering), etc. 337 * 338 * After the next indexed draw or pushGeometrySource the indices ptr is no 339 * longer valid and the geometry data cannot be further modified. The 340 * contents that were put in the reserved space can be drawn by multiple 341 * draws, however. 342 * 343 * @param indexCount the number of indices to reserve space for. Can be 0. 344 * @param indices will point to reserved index space if indexCount is 345 * non-zero. Illegal to pass NULL if indexCount > 0. 346 */ 347 348 bool reserveIndexSpace(int indexCount, void** indices); 349 /** 350 * Provides hints to caller about the number of vertices and indices 351 * that can be allocated cheaply. This can be useful if caller is reserving 352 * space but doesn't know exactly how much geometry is needed. 353 * 354 * Also may hint whether the draw target should be flushed first. This is 355 * useful for deferred targets. 356 * 357 * @param vertexLayout layout of vertices caller would like to reserve 358 * @param vertexCount in: hint about how many vertices the caller would 359 * like to allocate. 360 * out: a hint about the number of vertices that can be 361 * allocated cheaply. Negative means no hint. 362 * Ignored if NULL. 363 * @param indexCount in: hint about how many indices the caller would 364 * like to allocate. 365 * out: a hint about the number of indices that can be 366 * allocated cheaply. Negative means no hint. 367 * Ignored if NULL. 368 * 369 * @return true if target should be flushed based on the input values. 370 */ 371 virtual bool geometryHints(GrVertexLayout vertexLayout, 372 int* vertexCount, 373 int* indexCount) const; 374 375 /** 376 * Sets source of vertex data for the next draw. Array must contain 377 * the vertex data when this is called. 378 * 379 * @param array cpu array containing vertex data. 380 * @param size size of the vertex data. 381 * @param vertexCount the number of vertices in the array. 382 */ 383 void setVertexSourceToArray(GrVertexLayout vertexLayout, 384 const void* vertexArray, 385 int vertexCount); 386 387 /** 388 * Sets source of index data for the next indexed draw. Array must contain 389 * the indices when this is called. 390 * 391 * @param array cpu array containing index data. 392 * @param indexCount the number of indices in the array. 393 */ 394 void setIndexSourceToArray(const void* indexArray, int indexCount); 395 396 /** 397 * Sets source of vertex data for the next draw. Data does not have to be 398 * in the buffer until drawIndexed or drawNonIndexed. 399 * 400 * @param buffer vertex buffer containing vertex data. Must be 401 * unlocked before draw call. 402 * @param vertexLayout layout of the vertex data in the buffer. 403 */ 404 void setVertexSourceToBuffer(GrVertexLayout vertexLayout, 405 const GrVertexBuffer* buffer); 406 407 /** 408 * Sets source of index data for the next indexed draw. Data does not have 409 * to be in the buffer until drawIndexed or drawNonIndexed. 410 * 411 * @param buffer index buffer containing indices. Must be unlocked 412 * before indexed draw call. 413 */ 414 void setIndexSourceToBuffer(const GrIndexBuffer* buffer); 415 416 /** 417 * Resets vertex source. Drawing from reset vertices is illegal. Set vertex 418 * source to reserved, array, or buffer before next draw. May be able to free 419 * up temporary storage allocated by setVertexSourceToArray or 420 * reserveVertexSpace. 421 */ 422 void resetVertexSource(); 423 424 /** 425 * Resets index source. Indexed Drawing from reset indices is illegal. Set 426 * index source to reserved, array, or buffer before next indexed draw. May 427 * be able to free up temporary storage allocated by setIndexSourceToArray 428 * or reserveIndexSpace. 429 */ 430 void resetIndexSource(); 431 432 /** 433 * Pushes and resets the vertex/index sources. Any reserved vertex / index 434 * data is finalized (i.e. cannot be updated after the matching pop but can 435 * be drawn from). Must be balanced by a pop. 436 */ 437 void pushGeometrySource(); 438 439 /** 440 * Pops the vertex / index sources from the matching push. 441 */ 442 void popGeometrySource(); 443 444 /** 445 * Draws indexed geometry using the current state and current vertex / index 446 * sources. 447 * 448 * @param type The type of primitives to draw. 449 * @param startVertex the vertex in the vertex array/buffer corresponding 450 * to index 0 451 * @param startIndex first index to read from index src. 452 * @param vertexCount one greater than the max index. 453 * @param indexCount the number of index elements to read. The index count 454 * is effectively trimmed to the last completely 455 * specified primitive. 456 */ 457 void drawIndexed(GrPrimitiveType type, 458 int startVertex, 459 int startIndex, 460 int vertexCount, 461 int indexCount); 462 463 /** 464 * Draws non-indexed geometry using the current state and current vertex 465 * sources. 466 * 467 * @param type The type of primitives to draw. 468 * @param startVertex the vertex in the vertex array/buffer corresponding 469 * to index 0 470 * @param vertexCount one greater than the max index. 471 */ 472 void drawNonIndexed(GrPrimitiveType type, 473 int startVertex, 474 int vertexCount); 475 476 /** 477 * Helper function for drawing rects. This does not use the current index 478 * and vertex sources. After returning, the vertex and index sources may 479 * have changed. They should be reestablished before the next drawIndexed 480 * or drawNonIndexed. This cannot be called between reserving and releasing 481 * geometry. The GrDrawTarget subclass may be able to perform additional 482 * optimizations if drawRect is used rather than drawIndexed or 483 * drawNonIndexed. 484 * @param rect the rect to draw 485 * @param matrix optional matrix applied to rect (before viewMatrix) 486 * @param stageMask bitmask indicating which stages are enabled. 487 * Bit i indicates whether stage i is enabled. 488 * @param srcRects specifies rects for stages enabled by stageEnableMask. 489 * if stageEnableMask bit i is 1, srcRects is not NULL, 490 * and srcRects[i] is not NULL, then srcRects[i] will be 491 * used as coordinates for stage i. Otherwise, if stage i 492 * is enabled then rect is used as the coordinates. 493 * @param srcMatrices optional matrices applied to srcRects. If 494 * srcRect[i] is non-NULL and srcMatrices[i] is 495 * non-NULL then srcRect[i] will be transformed by 496 * srcMatrix[i]. srcMatrices can be NULL when no 497 * srcMatrices are desired. 498 */ 499 virtual void drawRect(const GrRect& rect, 500 const GrMatrix* matrix, 501 StageMask stageMask, 502 const GrRect* srcRects[], 503 const GrMatrix* srcMatrices[]); 504 505 /** 506 * Helper for drawRect when the caller doesn't need separate src rects or 507 * matrices. 508 */ 509 void drawSimpleRect(const GrRect& rect, 510 const GrMatrix* matrix, 511 StageMask stageEnableBitfield) { 512 drawRect(rect, matrix, stageEnableBitfield, NULL, NULL); 513 } 514 515 /** 516 * Clear the render target. Ignores the clip and all other draw state 517 * (blend mode, stages, etc). Clears the whole thing if rect is NULL, 518 * otherwise just the rect. 519 */ 520 virtual void clear(const GrIRect* rect, GrColor color) = 0; 521 522 /** 523 * Returns the maximum number of edges that may be specified in a single 524 * draw call when performing edge antialiasing. This is usually limited 525 * by the number of fragment uniforms which may be uploaded. Must be a 526 * minimum of six, since a triangle's vertices each belong to two boundary 527 * edges which may be distinct. 528 */ 529 virtual int getMaxEdges() const { return 6; } 530 531 //////////////////////////////////////////////////////////////////////////// 532 533 class AutoStateRestore : ::GrNoncopyable { 534 public: 535 AutoStateRestore(); 536 AutoStateRestore(GrDrawTarget* target); 537 ~AutoStateRestore(); 538 539 /** 540 * if this object is already saving state for param target then 541 * this does nothing. Otherise, it restores previously saved state on 542 * previous target (if any) and saves current state on param target. 543 */ 544 void set(GrDrawTarget* target); 545 546 private: 547 GrDrawTarget* fDrawTarget; 548 SavedDrawState fDrawState; 549 }; 550 551 //////////////////////////////////////////////////////////////////////////// 552 553 /** 554 * Sets the view matrix to I and preconcats all stage matrices enabled in 555 * mask by the view inverse. Destructor undoes these changes. 556 */ 557 class AutoDeviceCoordDraw : ::GrNoncopyable { 558 public: 559 AutoDeviceCoordDraw(GrDrawTarget* target, StageMask stageMask); 560 ~AutoDeviceCoordDraw(); 561 private: 562 GrDrawTarget* fDrawTarget; 563 GrMatrix fViewMatrix; 564 GrMatrix fSamplerMatrices[GrDrawState::kNumStages]; 565 int fStageMask; 566 }; 567 568 //////////////////////////////////////////////////////////////////////////// 569 570 class AutoReleaseGeometry : ::GrNoncopyable { 571 public: 572 AutoReleaseGeometry(GrDrawTarget* target, 573 GrVertexLayout vertexLayout, 574 int vertexCount, 575 int indexCount); 576 AutoReleaseGeometry(); 577 ~AutoReleaseGeometry(); 578 bool set(GrDrawTarget* target, 579 GrVertexLayout vertexLayout, 580 int vertexCount, 581 int indexCount); 582 bool succeeded() const { return NULL != fTarget; } 583 void* vertices() const { GrAssert(this->succeeded()); return fVertices; } 584 void* indices() const { GrAssert(this->succeeded()); return fIndices; } 585 GrPoint* positions() const { 586 return static_cast<GrPoint*>(this->vertices()); 587 } 588 589 private: 590 void reset(); 591 592 GrDrawTarget* fTarget; 593 void* fVertices; 594 void* fIndices; 595 }; 596 597 //////////////////////////////////////////////////////////////////////////// 598 599 class AutoClipRestore : ::GrNoncopyable { 600 public: 601 AutoClipRestore(GrDrawTarget* target) { 602 fTarget = target; 603 fClip = fTarget->getClip(); 604 } 605 606 ~AutoClipRestore() { 607 fTarget->setClip(fClip); 608 } 609 private: 610 GrDrawTarget* fTarget; 611 GrClip fClip; 612 }; 613 614 //////////////////////////////////////////////////////////////////////////// 615 616 class AutoGeometryPush : ::GrNoncopyable { 617 public: 618 AutoGeometryPush(GrDrawTarget* target) { 619 GrAssert(NULL != target); 620 fTarget = target; 621 target->pushGeometrySource(); 622 } 623 ~AutoGeometryPush() { 624 fTarget->popGeometrySource(); 625 } 626 private: 627 GrDrawTarget* fTarget; 628 }; 629 630 //////////////////////////////////////////////////////////////////////////// 631 // Helpers for picking apart vertex layouts 632 633 /** 634 * Helper function to compute the size of a vertex from a vertex layout 635 * @return size of a single vertex. 636 */ 637 static size_t VertexSize(GrVertexLayout vertexLayout); 638 639 /** 640 * Helper function for determining the index of texture coordinates that 641 * is input for a texture stage. Note that a stage may instead use positions 642 * as texture coordinates, in which case the result of the function is 643 * indistinguishable from the case when the stage is disabled. 644 * 645 * @param stage the stage to query 646 * @param vertexLayout layout to query 647 * 648 * @return the texture coordinate index or -1 if the stage doesn't use 649 * separate (non-position) texture coordinates. 650 */ 651 static int VertexTexCoordsForStage(int stage, GrVertexLayout vertexLayout); 652 653 /** 654 * Helper function to compute the offset of texture coordinates in a vertex 655 * @return offset of texture coordinates in vertex layout or -1 if the 656 * layout has no texture coordinates. Will be 0 if positions are 657 * used as texture coordinates for the stage. 658 */ 659 static int VertexStageCoordOffset(int stage, GrVertexLayout vertexLayout); 660 661 /** 662 * Helper function to compute the offset of the color in a vertex 663 * @return offset of color in vertex layout or -1 if the 664 * layout has no color. 665 */ 666 static int VertexColorOffset(GrVertexLayout vertexLayout); 667 668 /** 669 * Helper function to compute the offset of the coverage in a vertex 670 * @return offset of coverage in vertex layout or -1 if the 671 * layout has no coverage. 672 */ 673 static int VertexCoverageOffset(GrVertexLayout vertexLayout); 674 675 /** 676 * Helper function to compute the offset of the edge pts in a vertex 677 * @return offset of edge in vertex layout or -1 if the 678 * layout has no edge. 679 */ 680 static int VertexEdgeOffset(GrVertexLayout vertexLayout); 681 682 /** 683 * Helper function to determine if vertex layout contains explicit texture 684 * coordinates of some index. 685 * 686 * @param coordIndex the tex coord index to query 687 * @param vertexLayout layout to query 688 * 689 * @return true if vertex specifies texture coordinates for the index, 690 * false otherwise. 691 */ 692 static bool VertexUsesTexCoordIdx(int coordIndex, 693 GrVertexLayout vertexLayout); 694 695 /** 696 * Helper function to determine if vertex layout contains either explicit or 697 * implicit texture coordinates for a stage. 698 * 699 * @param stage the stage to query 700 * @param vertexLayout layout to query 701 * 702 * @return true if vertex specifies texture coordinates for the stage, 703 * false otherwise. 704 */ 705 static bool VertexUsesStage(int stage, GrVertexLayout vertexLayout); 706 707 /** 708 * Helper function to compute the size of each vertex and the offsets of 709 * texture coordinates and color. Determines tex coord offsets by tex coord 710 * index rather than by stage. (Each stage can be mapped to any t.c. index 711 * by StageTexCoordVertexLayoutBit.) 712 * 713 * @param vertexLayout the layout to query 714 * @param texCoordOffsetsByIdx after return it is the offset of each 715 * tex coord index in the vertex or -1 if 716 * index isn't used. (optional) 717 * @param colorOffset after return it is the offset of the 718 * color field in each vertex, or -1 if 719 * there aren't per-vertex colors. (optional) 720 * @param coverageOffset after return it is the offset of the 721 * coverage field in each vertex, or -1 if 722 * there aren't per-vertex coeverages. 723 * (optional) 724 * @param edgeOffset after return it is the offset of the 725 * edge eq field in each vertex, or -1 if 726 * there aren't per-vertex edge equations. 727 * (optional) 728 * @return size of a single vertex 729 */ 730 static int VertexSizeAndOffsetsByIdx(GrVertexLayout vertexLayout, 731 int texCoordOffsetsByIdx[GrDrawState::kMaxTexCoords], 732 int *colorOffset, 733 int *coverageOffset, 734 int* edgeOffset); 735 736 /** 737 * Helper function to compute the size of each vertex and the offsets of 738 * texture coordinates and color. Determines tex coord offsets by stage 739 * rather than by index. (Each stage can be mapped to any t.c. index 740 * by StageTexCoordVertexLayoutBit.) If a stage uses positions for 741 * tex coords then that stage's offset will be 0 (positions are always at 0). 742 * 743 * @param vertexLayout the layout to query 744 * @param texCoordOffsetsByStage after return it is the offset of each 745 * tex coord index in the vertex or -1 if 746 * index isn't used. (optional) 747 * @param colorOffset after return it is the offset of the 748 * color field in each vertex, or -1 if 749 * there aren't per-vertex colors. 750 * (optional) 751 * @param coverageOffset after return it is the offset of the 752 * coverage field in each vertex, or -1 if 753 * there aren't per-vertex coeverages. 754 * (optional) 755 * @param edgeOffset after return it is the offset of the 756 * edge eq field in each vertex, or -1 if 757 * there aren't per-vertex edge equations. 758 * (optional) 759 * @return size of a single vertex 760 */ 761 static int VertexSizeAndOffsetsByStage(GrVertexLayout vertexLayout, 762 int texCoordOffsetsByStage[GrDrawState::kNumStages], 763 int* colorOffset, 764 int* coverageOffset, 765 int* edgeOffset); 766 767 /** 768 * Accessing positions, texture coords, or colors, of a vertex within an 769 * array is a hassle involving casts and simple math. These helpers exist 770 * to keep GrDrawTarget clients' code a bit nicer looking. 771 */ 772 773 /** 774 * Gets a pointer to a GrPoint of a vertex's position or texture 775 * coordinate. 776 * @param vertices the vetex array 777 * @param vertexIndex the index of the vertex in the array 778 * @param vertexSize the size of each vertex in the array 779 * @param offset the offset in bytes of the vertex component. 780 * Defaults to zero (corresponding to vertex position) 781 * @return pointer to the vertex component as a GrPoint 782 */ 783 static GrPoint* GetVertexPoint(void* vertices, 784 int vertexIndex, 785 int vertexSize, 786 int offset = 0) { 787 intptr_t start = GrTCast<intptr_t>(vertices); 788 return GrTCast<GrPoint*>(start + offset + 789 vertexIndex * vertexSize); 790 } 791 static const GrPoint* GetVertexPoint(const void* vertices, 792 int vertexIndex, 793 int vertexSize, 794 int offset = 0) { 795 intptr_t start = GrTCast<intptr_t>(vertices); 796 return GrTCast<const GrPoint*>(start + offset + 797 vertexIndex * vertexSize); 798 } 799 800 /** 801 * Gets a pointer to a GrColor inside a vertex within a vertex array. 802 * @param vertices the vetex array 803 * @param vertexIndex the index of the vertex in the array 804 * @param vertexSize the size of each vertex in the array 805 * @param offset the offset in bytes of the vertex color 806 * @return pointer to the vertex component as a GrColor 807 */ 808 static GrColor* GetVertexColor(void* vertices, 809 int vertexIndex, 810 int vertexSize, 811 int offset) { 812 intptr_t start = GrTCast<intptr_t>(vertices); 813 return GrTCast<GrColor*>(start + offset + 814 vertexIndex * vertexSize); 815 } 816 static const GrColor* GetVertexColor(const void* vertices, 817 int vertexIndex, 818 int vertexSize, 819 int offset) { 820 const intptr_t start = GrTCast<intptr_t>(vertices); 821 return GrTCast<const GrColor*>(start + offset + 822 vertexIndex * vertexSize); 823 } 824 825 static void VertexLayoutUnitTest(); 826 827 protected: 828 829 /** 830 * Optimizations for blending / coverage to be applied based on the current 831 * state. 832 * Subclasses that actually draw (as opposed to those that just buffer for 833 * playback) must implement the flags that replace the output color. 834 */ 835 enum BlendOptFlags { 836 /** 837 * No optimization 838 */ 839 kNone_BlendOpt = 0, 840 /** 841 * Don't draw at all 842 */ 843 kSkipDraw_BlendOptFlag = 0x2, 844 /** 845 * Emit the src color, disable HW blending (replace dst with src) 846 */ 847 kDisableBlend_BlendOptFlag = 0x4, 848 /** 849 * The coverage value does not have to be computed separately from 850 * alpha, the the output color can be the modulation of the two. 851 */ 852 kCoverageAsAlpha_BlendOptFlag = 0x1, 853 /** 854 * Instead of emitting a src color, emit coverage in the alpha channel 855 * and r,g,b are "don't cares". 856 */ 857 kEmitCoverage_BlendOptFlag = 0x10, 858 /** 859 * Emit transparent black instead of the src color, no need to compute 860 * coverage. 861 */ 862 kEmitTransBlack_BlendOptFlag = 0x8, 863 }; 864 GR_DECL_BITFIELD_OPS_FRIENDS(BlendOptFlags); 865 866 // Determines what optimizations can be applied based on the blend. 867 // The coeffecients may have to be tweaked in order for the optimization 868 // to work. srcCoeff and dstCoeff are optional params that receive the 869 // tweaked coeffecients. 870 // Normally the function looks at the current state to see if coverage 871 // is enabled. By setting forceCoverage the caller can speculatively 872 // determine the blend optimizations that would be used if there was 873 // partial pixel coverage 874 BlendOptFlags getBlendOpts(bool forceCoverage = false, 875 GrBlendCoeff* srcCoeff = NULL, 876 GrBlendCoeff* dstCoeff = NULL) const; 877 878 // determine if src alpha is guaranteed to be one for all src pixels 879 bool srcAlphaWillBeOne() const; 880 881 enum GeometrySrcType { 882 kNone_GeometrySrcType, //<! src has not been specified 883 kReserved_GeometrySrcType, //<! src was set using reserve*Space 884 kArray_GeometrySrcType, //<! src was set using set*SourceToArray 885 kBuffer_GeometrySrcType //<! src was set using set*SourceToBuffer 886 }; 887 888 struct GeometrySrcState { 889 GeometrySrcType fVertexSrc; 890 union { 891 // valid if src type is buffer 892 const GrVertexBuffer* fVertexBuffer; 893 // valid if src type is reserved or array 894 int fVertexCount; 895 }; 896 897 GeometrySrcType fIndexSrc; 898 union { 899 // valid if src type is buffer 900 const GrIndexBuffer* fIndexBuffer; 901 // valid if src type is reserved or array 902 int fIndexCount; 903 }; 904 905 GrVertexLayout fVertexLayout; 906 }; 907 908 // given a vertex layout and a draw state, will a stage be used? 909 static bool StageWillBeUsed(int stage, GrVertexLayout layout, 910 const GrDrawState& state) { 911 return NULL != state.getTexture(stage) && 912 VertexUsesStage(stage, layout); 913 } 914 915 bool isStageEnabled(int stage) const { 916 return StageWillBeUsed(stage, this->getGeomSrc().fVertexLayout, 917 fCurrDrawState); 918 } 919 920 StageMask enabledStages() const { 921 StageMask mask = 0; 922 for (int s = 0; s < GrDrawState::kNumStages; ++s) { 923 mask |= this->isStageEnabled(s) ? 1 : 0; 924 } 925 return mask; 926 } 927 928 // Helpers for GrDrawTarget subclasses that won't have private access to 929 // SavedDrawState but need to peek at the state values. 930 static GrDrawState& accessSavedDrawState(SavedDrawState& sds) { 931 return *sds.fState.get(); 932 } 933 static const GrDrawState& accessSavedDrawState(const SavedDrawState& sds){ 934 return *sds.fState.get(); 935 } 936 937 // implemented by subclass to allocate space for reserved geom 938 virtual bool onReserveVertexSpace(GrVertexLayout vertexLayout, 939 int vertexCount, 940 void** vertices) = 0; 941 virtual bool onReserveIndexSpace(int indexCount, void** indices) = 0; 942 // implemented by subclass to handle release of reserved geom space 943 virtual void releaseReservedVertexSpace() = 0; 944 virtual void releaseReservedIndexSpace() = 0; 945 // subclass must consume array contents when set 946 virtual void onSetVertexSourceToArray(const void* vertexArray, 947 int vertexCount) = 0; 948 virtual void onSetIndexSourceToArray(const void* indexArray, 949 int indexCount) = 0; 950 // subclass is notified that geom source will be set away from an array 951 virtual void releaseVertexArray() = 0; 952 virtual void releaseIndexArray() = 0; 953 // subclass overrides to be notified just before geo src state 954 // is pushed/popped. 955 virtual void geometrySourceWillPush() = 0; 956 virtual void geometrySourceWillPop(const GeometrySrcState& restoredState) = 0; 957 // subclass called to perform drawing 958 virtual void onDrawIndexed(GrPrimitiveType type, 959 int startVertex, 960 int startIndex, 961 int vertexCount, 962 int indexCount) = 0; 963 virtual void onDrawNonIndexed(GrPrimitiveType type, 964 int startVertex, 965 int vertexCount) = 0; 966 // subclass overrides to be notified when clip is set. Must call 967 // INHERITED::clipwillBeSet 968 virtual void clipWillBeSet(const GrClip& clip); 969 970 // Helpers for drawRect, protected so subclasses that override drawRect 971 // can use them. 972 static GrVertexLayout GetRectVertexLayout(StageMask stageEnableBitfield, 973 const GrRect* srcRects[]); 974 975 static void SetRectVertices(const GrRect& rect, 976 const GrMatrix* matrix, 977 const GrRect* srcRects[], 978 const GrMatrix* srcMatrices[], 979 GrVertexLayout layout, 980 void* vertices); 981 982 // accessor for derived classes 983 const GeometrySrcState& getGeomSrc() const { 984 return fGeoSrcStateStack.back(); 985 } 986 987 GrClip fClip; 988 989 GrDrawState fCurrDrawState; 990 991 Caps fCaps; 992 993 // subclasses must call this in their destructors to ensure all vertex 994 // and index sources have been released (including those held by 995 // pushGeometrySource()) 996 void releaseGeometry(); 997 private: 998 // called by drawIndexed and drawNonIndexed. Use a negative indexCount to 999 // indicate non-indexed drawing. 1000 bool checkDraw(GrPrimitiveType type, int startVertex, 1001 int startIndex, int vertexCount, 1002 int indexCount) const; 1003 // called when setting a new vert/idx source to unref prev vb/ib 1004 void releasePreviousVertexSource(); 1005 void releasePreviousIndexSource(); 1006 1007 enum { 1008 kPreallocGeoSrcStateStackCnt = 4, 1009 }; 1010 SkSTArray<kPreallocGeoSrcStateStackCnt, 1011 GeometrySrcState, true> fGeoSrcStateStack; 1012 1013 }; 1014 1015 GR_MAKE_BITFIELD_OPS(GrDrawTarget::BlendOptFlags); 1016 1017 #endif 1018
