[Remoting Android] Cursor & Cursor Feedback for OpenGL Renderer

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>
+
+#include "base/macros.h"
+
+namespace remoting {
+
+// See GlCanvas::SetNormalizedTransformation for definition of the
+// transformation matrix.
+//
+// Converts a pixel based transformation matrix to a texture coordinates based
+// transformation matrix.
+// 3 by 3 transformation matrix, [ m0, m1, m2, m3, m4, m5, m6, m7, m8 ].
+//
+// | m0, m1, m2, |   | x |
+// | m3, m4, m5, | * | y |
+// | m6, m7, m8  |   | 1 |
+void NormalizeTransformationMatrix(std::array<float, 9>& mat,

[Sergey Ulanov, 2016/07/19 00:42:48]

matrix

[Sergey Ulanov, 2016/07/19 00:42:48]

use pointer instead of a reference here and move this parameter to the end.
https://google.github.io/styleguide/cppguide.html#Reference_Arguments

Same for the FillRectangleVertexPositions()

[Yuwei, 2016/07/19 20:34:24]

Done.

+                                   int view_width,
+                                   int view_height,
+                                   int canvas_width,
+                                   int canvas_height);
+
+// 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(std::array<float, 8>& positions,
+                                  float left,
+                                  float top,
+                                  float width,
+                                  float height);
+
+// interpolates vector |dest| between [vec1, vec2].
+// dest = (1 - percent) * vec1 + percent * vec2
+// dimension: length of dest, vec1, vec2
+template<typename NumberType>
+void LinearInterpolate(NumberType* dest,

[Sergey Ulanov, 2016/07/19 00:42:48]

Do you need this as a template? It's used in only one place only fro uint8_t

[Yuwei, 2016/07/19 20:34:23]

Obsolete. Removed.

+                       const NumberType* vec1,
+                       const NumberType* vec2,
+                       float percent,
+                       int dimension) {
+  for (int i = 0; i < dimension; i++) {
+    dest[i] = (1.f - percent) * vec1[i] + percent * vec2[i];

[Sergey Ulanov, 2016/07/19 00:42:48]

you convert values from int to float and then back to int, which is slow. It's
better to do whole computation in int. 

[Yuwei, 2016/07/19 04:11:52]

Maybe something like:

((100 - percent) * vec1[i] + percent * vec2[i]) / 100

?

Anyway... This may get obsolete if I use Skia to draw the gradient

[Yuwei, 2016/07/19 20:34:23]

Removed.

+  }
+}
+
+// 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_