dandov | ecfff21 | 2014-08-04 10:02:00 -0700 | [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 SkPatchUtils_DEFINED |
| 9 | #define SkPatchUtils_DEFINED |
| 10 | |
dandov | b3c9d1c | 2014-08-12 08:34:29 -0700 | [diff] [blame] | 11 | #include "SkColorPriv.h" |
dandov | ecfff21 | 2014-08-04 10:02:00 -0700 | [diff] [blame] | 12 | #include "SkMatrix.h" |
| 13 | |
| 14 | class SK_API SkPatchUtils { |
dandov | b3c9d1c | 2014-08-12 08:34:29 -0700 | [diff] [blame] | 15 | |
dandov | ecfff21 | 2014-08-04 10:02:00 -0700 | [diff] [blame] | 16 | public: |
| 17 | /** |
dandov | b3c9d1c | 2014-08-12 08:34:29 -0700 | [diff] [blame] | 18 | * Structure that holds the vertex data related to the tessellation of a patch. It is passed |
| 19 | * as a parameter to the function getVertexData which sets the points, colors and texture |
| 20 | * coordinates of the vertices and the indices for them to be drawn as triangles. |
| 21 | */ |
| 22 | struct VertexData { |
| 23 | int fVertexCount, fIndexCount; |
| 24 | SkPoint* fPoints; |
| 25 | SkPoint* fTexCoords; |
| 26 | uint32_t* fColors; |
| 27 | uint16_t* fIndices; |
| 28 | |
| 29 | VertexData() |
| 30 | : fVertexCount(0) |
| 31 | , fIndexCount(0) |
| 32 | , fPoints(NULL) |
| 33 | , fTexCoords(NULL) |
| 34 | , fColors(NULL) |
| 35 | , fIndices(NULL) { } |
| 36 | |
| 37 | ~VertexData() { |
| 38 | SkDELETE_ARRAY(fPoints); |
| 39 | SkDELETE_ARRAY(fTexCoords); |
| 40 | SkDELETE_ARRAY(fColors); |
| 41 | SkDELETE_ARRAY(fIndices); |
| 42 | } |
| 43 | }; |
| 44 | |
| 45 | // Enums for control points based on the order specified in the constructor (clockwise). |
| 46 | enum CubicCtrlPts { |
| 47 | kTopP0_CubicCtrlPts = 0, |
| 48 | kTopP1_CubicCtrlPts = 1, |
| 49 | kTopP2_CubicCtrlPts = 2, |
| 50 | kTopP3_CubicCtrlPts = 3, |
| 51 | |
| 52 | kRightP0_CubicCtrlPts = 3, |
| 53 | kRightP1_CubicCtrlPts = 4, |
| 54 | kRightP2_CubicCtrlPts = 5, |
| 55 | kRightP3_CubicCtrlPts = 6, |
| 56 | |
| 57 | kBottomP0_CubicCtrlPts = 9, |
| 58 | kBottomP1_CubicCtrlPts = 8, |
| 59 | kBottomP2_CubicCtrlPts = 7, |
| 60 | kBottomP3_CubicCtrlPts = 6, |
| 61 | |
| 62 | kLeftP0_CubicCtrlPts = 0, |
| 63 | kLeftP1_CubicCtrlPts = 11, |
| 64 | kLeftP2_CubicCtrlPts = 10, |
| 65 | kLeftP3_CubicCtrlPts = 9, |
| 66 | }; |
| 67 | |
| 68 | // Enum for corner also clockwise. |
| 69 | enum Corner { |
| 70 | kTopLeft_Corner = 0, |
| 71 | kTopRight_Corner, |
| 72 | kBottomRight_Corner, |
| 73 | kBottomLeft_Corner |
| 74 | }; |
| 75 | |
| 76 | enum { |
| 77 | kNumCtrlPts = 12, |
| 78 | kNumCorners = 4, |
| 79 | kNumPtsCubic = 4 |
| 80 | }; |
| 81 | |
| 82 | /** |
dandov | ecfff21 | 2014-08-04 10:02:00 -0700 | [diff] [blame] | 83 | * Method that calculates a level of detail (number of subdivisions) for a patch in both axis. |
| 84 | */ |
dandov | b3c9d1c | 2014-08-12 08:34:29 -0700 | [diff] [blame] | 85 | static SkISize GetLevelOfDetail(const SkPoint cubics[12], const SkMatrix* matrix); |
| 86 | |
| 87 | /** |
| 88 | * Get the points corresponding to the top cubic of cubics. |
| 89 | */ |
| 90 | static void getTopCubic(const SkPoint cubics[12], SkPoint points[4]); |
| 91 | |
| 92 | /** |
| 93 | * Get the points corresponding to the bottom cubic of cubics. |
| 94 | */ |
| 95 | static void getBottomCubic(const SkPoint cubics[12], SkPoint points[4]); |
| 96 | |
| 97 | /** |
| 98 | * Get the points corresponding to the left cubic of cubics. |
| 99 | */ |
| 100 | static void getLeftCubic(const SkPoint cubics[12], SkPoint points[4]); |
| 101 | |
| 102 | /** |
| 103 | * Get the points corresponding to the right cubic of cubics. |
| 104 | */ |
| 105 | static void getRightCubic(const SkPoint cubics[12], SkPoint points[4]); |
| 106 | |
| 107 | /** |
| 108 | * Function that evaluates the coons patch interpolation. |
| 109 | * data refers to the pointer of the PatchData struct in which the tessellation data is set. |
| 110 | * cubics refers to the points of the cubics. |
| 111 | * lod refers the level of detail for each axis. |
| 112 | * colors refers to the corner colors that will be bilerp across the patch (optional parameter) |
| 113 | * texCoords refers to the corner texture coordinates that will be bilerp across the patch |
| 114 | (optional parameter) |
| 115 | */ |
| 116 | static bool getVertexData(SkPatchUtils::VertexData* data, const SkPoint cubics[12], |
| 117 | const SkColor colors[4], const SkPoint texCoords[4], |
| 118 | int lodX, int lodY); |
dandov | ecfff21 | 2014-08-04 10:02:00 -0700 | [diff] [blame] | 119 | }; |
| 120 | |
| 121 | #endif |