[Chromoting] Implement GlRenderer

remoting/client/gl_math.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_CLIENT_OPENGL_GL_MATH_H_
 #define REMOTING_CLIENT_OPENGL_GL_MATH_H_
 
 #include <array>
 #include <string>
 
@@ skipping 10 matching lines @@
 //
 // | m0, m1, m2, |   | x |
 // | m3, m4, m5, | * | y |
 // | m6, m7, m8  |   | 1 |
 void NormalizeTransformationMatrix(int view_width,
                                    int view_height,
                                    int canvas_width,
                                    int canvas_height,
                                    std::array<float, 9>* matrix);
 
+// Transposes matrix [ m0 ,0, m2, 0, m4, m5, 0, 0, m8 ]:
+//
+// | m0,  0, m2, |   | x |
+// |  0, m4, m5, | * | y |
+// |  0,  0, m8  |   | 1 |
+//
+// Into [ m0, 0, 0, 0 ,m4, 0, m2, m5, m8 ].
+// The result is only valid if m1=m3=m6=m7=0.

[Sergey Ulanov, 2016/07/27 18:36:41]

Why do you need this requirement?

[Yuwei, 2016/07/27 18:44:01]

If I remove this constraint then I will need to swap everything on different
sides of the diagonal...

That doesn't seem expensive so I think I will just implement this...

[Yuwei, 2016/07/27 18:54:08]

Done.

+void TransposeTransformationMatrix(std::array<float, 9>* matrix);
+
 // Given left, top, width, height of a rectangle, fills |positions| with
 // coordinates of four vertices of the rectangle.
 // positions: [ x_upperleft, y_upperleft, x_lowerleft, y_lowerleft,
 //              x_upperright, y_upperright, x_lowerright, y_lowerright ]
 void FillRectangleVertexPositions(float left,
                                   float top,
                                   float width,
                                   float height,
                                   std::array<float, 8>* positions);
 
 // Returns the string representation of the matrix for debugging.
 //
 // For example:
 // [
 // 1, 0, 0,
 // 0, 1, 0,
 // 0, 0, 1,
 // ]
 std::string MatrixToString(const float* mat, int num_rows, int num_cols);
 
 }  // namespace remoting
 
 #endif  // REMOTING_CLIENT_OPENGL_GL_MATH_H_