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       1             : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
       2             : /* vim: set ts=8 sts=4 et sw=4 tw=80: */
       3             : /* This Source Code Form is subject to the terms of the Mozilla Public
       4             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       5             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       6             : 
       7             : #ifndef DecomposeIntoNoRepeatTriangles_h_
       8             : #define DecomposeIntoNoRepeatTriangles_h_
       9             : 
      10             : #include "GLTypes.h"
      11             : #include "nsRect.h"
      12             : #include "nsTArray.h"
      13             : 
      14             : namespace mozilla {
      15             : namespace gl {
      16             : 
      17             : /** Helper for DecomposeIntoNoRepeatTriangles
      18             :   */
      19           0 : class RectTriangles {
      20             : public:
      21             :     typedef struct { GLfloat x,y; } coord;
      22             : 
      23             :     // Always pass texture coordinates upright. If you want to flip the
      24             :     // texture coordinates emitted to the tex_coords array, set flip_y to
      25             :     // true.
      26             :     void addRect(GLfloat x0, GLfloat y0, GLfloat x1, GLfloat y1,
      27             :                  GLfloat tx0, GLfloat ty0, GLfloat tx1, GLfloat ty1,
      28             :                  bool flip_y = false);
      29             : 
      30             :     /**
      31             :       * these return a float pointer to the start of each array respectively.
      32             :       * Use it for glVertexAttribPointer calls.
      33             :       * We can return nullptr if we choose to use Vertex Buffer Objects here.
      34             :       */
      35           0 :     InfallibleTArray<coord>& vertCoords() {
      36           0 :         return mVertexCoords;
      37             :     }
      38             : 
      39           0 :     InfallibleTArray<coord>& texCoords() {
      40           0 :         return mTexCoords;
      41             :     }
      42             : 
      43           0 :     unsigned int elements() {
      44           0 :         return mVertexCoords.Length();
      45             :     }
      46             : private:
      47             :     // Reserve inline storage for one quad (2 triangles, 3 coords).
      48             :     AutoTArray<coord, 6> mVertexCoords;
      49             :     AutoTArray<coord, 6> mTexCoords;
      50             : 
      51             :     static void
      52             :     AppendRectToCoordArray(InfallibleTArray<coord>& array, GLfloat x0, GLfloat y0, GLfloat x1, GLfloat y1);
      53             : };
      54             : 
      55             : /**
      56             :   * Decompose drawing the possibly-wrapped aTexCoordRect rectangle
      57             :   * of a texture of aTexSize into one or more rectangles (represented
      58             :   * as 2 triangles) and associated tex coordinates, such that
      59             :   * we don't have to use the REPEAT wrap mode. If aFlipY is true, the
      60             :   * texture coordinates will be specified vertically flipped.
      61             :   *
      62             :   * The resulting triangle vertex coordinates will be in the space of
      63             :   * (0.0, 0.0) to (1.0, 1.0) -- transform the coordinates appropriately
      64             :   * if you need a different space.
      65             :   *
      66             :   * The resulting vertex coordinates should be drawn using GL_TRIANGLES,
      67             :   * and rects.numRects * 3 * 6
      68             :   */
      69             : void DecomposeIntoNoRepeatTriangles(const gfx::IntRect& aTexCoordRect,
      70             :                                     const gfx::IntSize& aTexSize,
      71             :                                     RectTriangles& aRects,
      72             :                                     bool aFlipY = false);
      73             : 
      74             : } // namespace gl
      75             : } // namespace mozilla
      76             : 
      77             : #endif // DecomposeIntoNoRepeatTriangles_h_