Chris Dalton | e5a141d | 2020-05-19 11:57:53 -0600 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2014 Google Inc. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license that can be |
| 5 | * found in the LICENSE file. |
| 6 | */ |
| 7 | |
| 8 | #ifndef GrRectanizerPow2_DEFINED |
| 9 | #define GrRectanizerPow2_DEFINED |
| 10 | |
| 11 | #include "include/private/SkMalloc.h" |
| 12 | #include "src/core/SkIPoint16.h" |
| 13 | #include "src/core/SkMathPriv.h" |
| 14 | #include "src/gpu/GrRectanizer.h" |
| 15 | |
| 16 | // This Rectanizer quantizes the incoming rects to powers of 2. Each power |
| 17 | // of two can have, at most, one active row/shelf. Once a row/shelf for |
| 18 | // a particular power of two gets full its fRows entry is recycled to point |
| 19 | // to a new row. |
| 20 | // The skyline algorithm almost always provides a better packing. |
| 21 | // |
| 22 | // Mark this class final in an effort to avoid the vtable when this subclass is used explicitly. |
| 23 | class GrRectanizerPow2 final : public GrRectanizer { |
| 24 | public: |
| 25 | GrRectanizerPow2(int w, int h) : INHERITED(w, h) { |
| 26 | this->reset(); |
| 27 | } |
| 28 | |
| 29 | ~GrRectanizerPow2() final {} |
| 30 | |
| 31 | void reset() final { |
| 32 | fNextStripY = 0; |
| 33 | fAreaSoFar = 0; |
| 34 | sk_bzero(fRows, sizeof(fRows)); |
| 35 | } |
| 36 | |
| 37 | bool addRect(int w, int h, SkIPoint16* loc) final; |
| 38 | |
| 39 | float percentFull() const final { |
| 40 | return fAreaSoFar / ((float)this->width() * this->height()); |
| 41 | } |
| 42 | |
| 43 | private: |
| 44 | static const int kMIN_HEIGHT_POW2 = 2; |
| 45 | static const int kMaxExponent = 16; |
| 46 | |
| 47 | struct Row { |
| 48 | SkIPoint16 fLoc; |
| 49 | // fRowHeight is actually known by this struct's position in fRows |
| 50 | // but it is used to signal if there exists an open row of this height |
| 51 | int fRowHeight; |
| 52 | |
| 53 | bool canAddWidth(int width, int containerWidth) const { |
| 54 | return fLoc.fX + width <= containerWidth; |
| 55 | } |
| 56 | }; |
| 57 | |
| 58 | Row fRows[kMaxExponent]; // 0-th entry will be unused |
| 59 | |
| 60 | int fNextStripY; |
| 61 | int32_t fAreaSoFar; |
| 62 | |
| 63 | static int HeightToRowIndex(int height) { |
| 64 | SkASSERT(height >= kMIN_HEIGHT_POW2); |
| 65 | int index = 32 - SkCLZ(height - 1); |
| 66 | SkASSERT(index < kMaxExponent); |
| 67 | return index; |
| 68 | } |
| 69 | |
| 70 | bool canAddStrip(int height) const { |
| 71 | return fNextStripY + height <= this->height(); |
| 72 | } |
| 73 | |
| 74 | void initRow(Row* row, int rowHeight) { |
| 75 | row->fLoc.set(0, fNextStripY); |
| 76 | row->fRowHeight = rowHeight; |
| 77 | fNextStripY += rowHeight; |
| 78 | } |
| 79 | |
John Stiles | 7571f9e | 2020-09-02 22:42:33 -0400 | [diff] [blame] | 80 | using INHERITED = GrRectanizer; |
Chris Dalton | e5a141d | 2020-05-19 11:57:53 -0600 | [diff] [blame] | 81 | }; |
| 82 | |
| 83 | #endif |