1 //
2 // Copyright 2014 The ANGLE Project Authors. All rights reserved.
3 // Use of this source code is governed by a BSD-style license that can be
4 // found in the LICENSE file.
5 //
6
7 // Based on Simple_VertexShader.c from
8 // Book: OpenGL(R) ES 2.0 Programming Guide
9 // Authors: Aaftab Munshi, Dan Ginsburg, Dave Shreiner
10 // ISBN-10: 0321502795
11 // ISBN-13: 9780321502797
12 // Publisher: Addison-Wesley Professional
13 // URLs: http://safari.informit.com/9780321563835
14 // http://www.opengles-book.com
15
16 #include "SampleApplication.h"
17 #include "texture_utils.h"
18 #include "util/Matrix.h"
19 #include "util/geometry_utils.h"
20 #include "util/shader_utils.h"
21
22 #include <cmath>
23 #include <iostream>
24
25 class PostSubBufferSample : public SampleApplication
26 {
27 public:
PostSubBufferSample(int argc,char ** argv)28 PostSubBufferSample(int argc, char **argv) : SampleApplication("PostSubBuffer", argc, argv) {}
29
initialize()30 bool initialize() override
31 {
32 constexpr char kVS[] = R"(uniform mat4 u_mvpMatrix;
33 attribute vec4 a_position;
34 attribute vec2 a_texcoord;
35 varying vec2 v_texcoord;
36 void main()
37 {
38 gl_Position = u_mvpMatrix * a_position;
39 v_texcoord = a_texcoord;
40 })";
41
42 constexpr char kFS[] = R"(precision mediump float;
43 varying vec2 v_texcoord;
44 void main()
45 {
46 gl_FragColor = vec4(v_texcoord.x, v_texcoord.y, 1.0, 1.0);
47 })";
48
49 mProgram = CompileProgram(kVS, kFS);
50 if (!mProgram)
51 {
52 return false;
53 }
54
55 // Get the attribute locations
56 mPositionLoc = glGetAttribLocation(mProgram, "a_position");
57 mTexcoordLoc = glGetAttribLocation(mProgram, "a_texcoord");
58
59 // Get the uniform locations
60 mMVPMatrixLoc = glGetUniformLocation(mProgram, "u_mvpMatrix");
61
62 // Generate the geometry data
63 GenerateCubeGeometry(0.5f, &mCube);
64
65 // Set an initial rotation
66 mRotation = 45.0f;
67
68 // Clear the whole window surface to blue.
69 glClearColor(0.0f, 0.0f, 1.0f, 0.0f);
70 glClear(GL_COLOR_BUFFER_BIT);
71 SampleApplication::swap();
72
73 glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
74 glCullFace(GL_BACK);
75 glEnable(GL_CULL_FACE);
76
77 return true;
78 }
79
destroy()80 void destroy() override { glDeleteProgram(mProgram); }
81
step(float dt,double totalTime)82 void step(float dt, double totalTime) override
83 {
84 mRotation = fmod(mRotation + (dt * 40.0f), 360.0f);
85
86 Matrix4 perspectiveMatrix = Matrix4::perspective(
87 60.0f, float(getWindow()->getWidth()) / getWindow()->getHeight(), 1.0f, 20.0f);
88
89 Matrix4 modelMatrix = Matrix4::translate(angle::Vector3(0.0f, 0.0f, -2.0f)) *
90 Matrix4::rotate(mRotation, angle::Vector3(1.0f, 0.0f, 1.0f));
91
92 Matrix4 viewMatrix = Matrix4::identity();
93
94 Matrix4 mvpMatrix = perspectiveMatrix * viewMatrix * modelMatrix;
95
96 // Load the matrices
97 glUniformMatrix4fv(mMVPMatrixLoc, 1, GL_FALSE, mvpMatrix.data);
98 }
99
draw()100 void draw() override
101 {
102 // Set the viewport
103 glViewport(0, 0, getWindow()->getWidth(), getWindow()->getHeight());
104
105 // Clear the color buffer
106 glClear(GL_COLOR_BUFFER_BIT);
107
108 // Use the program object
109 glUseProgram(mProgram);
110
111 // Load the vertex position
112 glVertexAttribPointer(mPositionLoc, 3, GL_FLOAT, GL_FALSE, 0, mCube.positions.data());
113 glEnableVertexAttribArray(mPositionLoc);
114
115 // Load the texcoord data
116 glVertexAttribPointer(mTexcoordLoc, 2, GL_FLOAT, GL_FALSE, 0, mCube.texcoords.data());
117 glEnableVertexAttribArray(mTexcoordLoc);
118
119 // Draw the cube
120 glDrawElements(GL_TRIANGLES, static_cast<GLsizei>(mCube.indices.size()), GL_UNSIGNED_SHORT,
121 mCube.indices.data());
122 }
123
swap()124 void swap() override
125 {
126 // Instead of letting the application call eglSwapBuffers, call eglPostSubBufferNV here
127 // instead
128 EGLint windowWidth = static_cast<EGLint>(getWindow()->getWidth());
129 EGLint windowHeight = static_cast<EGLint>(getWindow()->getHeight());
130 EGLDisplay display = getDisplay();
131 EGLSurface surface = getSurface();
132 eglPostSubBufferNV(display, surface, 60, 60, windowWidth - 120, windowHeight - 120);
133 }
134
135 private:
136 // Handle to a program object
137 GLuint mProgram;
138
139 // Attribute locations
140 GLint mPositionLoc;
141 GLint mTexcoordLoc;
142
143 // Uniform locations
144 GLuint mMVPMatrixLoc;
145
146 // Current rotation
147 float mRotation;
148
149 // Geometry data
150 CubeGeometry mCube;
151 };
152
main(int argc,char ** argv)153 int main(int argc, char **argv)
154 {
155 PostSubBufferSample app(argc, argv);
156 return app.run();
157 }
158