blob: 4df0a4b8d6bcb2dbccc9fc03744975eb48331bc7 [file] [log] [blame]
// 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.
#include <array>
#include "base/macros.h"
#include "base/threading/thread_checker.h"
#include "remoting/client/sys_opengl.h"
namespace remoting {
// This class holds zoom and pan configurations of the canvas and is used to
// draw textures on the canvas.
// Must be constructed after the OpenGL surface is created and destroyed before
// the surface is destroyed.
class GlCanvas {
// gl_version: version number of the OpenGL ES context. Either 2 or 3.
GlCanvas(int gl_version);
// Sets the transformation matrix. This matrix defines how the canvas should
// be shown on the view.
// 3 by 3 transformation matrix, [ m0, m1, m2, m3, m4, m5, m6, m7, m8 ].
// The matrix will be multiplied with the positions (with projective space,
// (x, y, 1)) to draw the textures with the right zoom and pan configuration.
// | m0, m1, m2, | | x |
// | m3, m4, m5, | * | y |
// | m6, m7, m8 | | 1 |
// For a typical transformation matrix such that m1=m3=m6=m7=0 and m8=1, m0
// and m4 defines the scaling factor of the canvas and m2 and m5 defines the
// offset of the upper-left corner in pixel.
void SetTransformationMatrix(const std::array<float, 9>& matrix);
// Sets the size of the view in pixels.
void SetViewSize(int width, int height);
// Draws the texture on the canvas. Nothing will happen if
// SetNormalizedTransformation() has not been called.
// vertex_buffer: reference to the 2x4x2 float vertex buffer.
// [ four (x, y) position of the texture vertices in pixel
// with respect to the canvas,
// four (x, y) position of the vertices in percentage
// defining the visible area of the texture ]
// alpha_multiplier: Will be multiplied with the alpha channel of the texture.
// Passing 1 means no change of the transparency of the
// texture.
void DrawTexture(int texture_id,
GLuint texture_handle,
GLuint vertex_buffer,
float alpha_multiplier);
// Returns the version number of current OpenGL ES context. Either 2 or 3.
int GetGlVersion() const;
// Returns the maximum texture resolution limitation. Neither the width nor
// the height of the texture can exceed this limitation.
int GetMaxTextureSize() const;
int gl_version_;
int max_texture_size_ = 0;
bool transformation_set_ = false;
bool view_size_set_ = false;
// Handles.
GLuint vertex_shader_;
GLuint fragment_shader_;
GLuint program_;
// Locations of the corresponding shader attributes.
GLuint transform_location_;
GLuint view_size_location_;
GLuint texture_location_;
GLuint alpha_multiplier_location_;
GLuint position_location_;
GLuint tex_cord_location_;
base::ThreadChecker thread_checker_;
} // namespace remoting