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 mPostSubBufferNV = (PFNEGLPOSTSUBBUFFERNVPROC)eglGetProcAddress("eglPostSubBufferNV");
33 if (!mPostSubBufferNV)
34 {
35 std::cerr << "Could not load eglPostSubBufferNV.";
36 return false;
37 }
38
39 constexpr char kVS[] = R"(uniform mat4 u_mvpMatrix;
40 attribute vec4 a_position;
41 attribute vec2 a_texcoord;
42 varying vec2 v_texcoord;
43 void main()
44 {
45 gl_Position = u_mvpMatrix * a_position;
46 v_texcoord = a_texcoord;
47 })";
48
49 constexpr char kFS[] = R"(precision mediump float;
50 varying vec2 v_texcoord;
51 void main()
52 {
53 gl_FragColor = vec4(v_texcoord.x, v_texcoord.y, 1.0, 1.0);
54 })";
55
56 mProgram = CompileProgram(kVS, kFS);
57 if (!mProgram)
58 {
59 return false;
60 }
61
62 // Get the attribute locations
63 mPositionLoc = glGetAttribLocation(mProgram, "a_position");
64 mTexcoordLoc = glGetAttribLocation(mProgram, "a_texcoord");
65
66 // Get the uniform locations
67 mMVPMatrixLoc = glGetUniformLocation(mProgram, "u_mvpMatrix");
68
69 // Generate the geometry data
70 GenerateCubeGeometry(0.5f, &mCube);
71
72 // Set an initial rotation
73 mRotation = 45.0f;
74
75 // Clear the whole window surface to blue.
76 glClearColor(0.0f, 0.0f, 1.0f, 0.0f);
77 glClear(GL_COLOR_BUFFER_BIT);
78 SampleApplication::swap();
79
80 glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
81 glCullFace(GL_BACK);
82 glEnable(GL_CULL_FACE);
83
84 return true;
85 }
86
destroy()87 void destroy() override { glDeleteProgram(mProgram); }
88
step(float dt,double totalTime)89 void step(float dt, double totalTime) override
90 {
91 mRotation = fmod(mRotation + (dt * 40.0f), 360.0f);
92
93 Matrix4 perspectiveMatrix = Matrix4::perspective(
94 60.0f, float(getWindow()->getWidth()) / getWindow()->getHeight(), 1.0f, 20.0f);
95
96 Matrix4 modelMatrix = Matrix4::translate(angle::Vector3(0.0f, 0.0f, -2.0f)) *
97 Matrix4::rotate(mRotation, angle::Vector3(1.0f, 0.0f, 1.0f));
98
99 Matrix4 viewMatrix = Matrix4::identity();
100
101 Matrix4 mvpMatrix = perspectiveMatrix * viewMatrix * modelMatrix;
102
103 // Load the matrices
104 glUniformMatrix4fv(mMVPMatrixLoc, 1, GL_FALSE, mvpMatrix.data);
105 }
106
draw()107 void draw() override
108 {
109 // Set the viewport
110 glViewport(0, 0, getWindow()->getWidth(), getWindow()->getHeight());
111
112 // Clear the color buffer
113 glClear(GL_COLOR_BUFFER_BIT);
114
115 // Use the program object
116 glUseProgram(mProgram);
117
118 // Load the vertex position
119 glVertexAttribPointer(mPositionLoc, 3, GL_FLOAT, GL_FALSE, 0, mCube.positions.data());
120 glEnableVertexAttribArray(mPositionLoc);
121
122 // Load the texcoord data
123 glVertexAttribPointer(mTexcoordLoc, 2, GL_FLOAT, GL_FALSE, 0, mCube.texcoords.data());
124 glEnableVertexAttribArray(mTexcoordLoc);
125
126 // Draw the cube
127 glDrawElements(GL_TRIANGLES, static_cast<GLsizei>(mCube.indices.size()), GL_UNSIGNED_SHORT,
128 mCube.indices.data());
129 }
130
swap()131 void swap() override
132 {
133 // Instead of letting the application call eglSwapBuffers, call eglPostSubBufferNV here
134 // instead
135 EGLint windowWidth = static_cast<EGLint>(getWindow()->getWidth());
136 EGLint windowHeight = static_cast<EGLint>(getWindow()->getHeight());
137 EGLDisplay display = getDisplay();
138 EGLSurface surface = getSurface();
139 mPostSubBufferNV(display, surface, 60, 60, windowWidth - 120, windowHeight - 120);
140 }
141
142 private:
143 // Handle to a program object
144 GLuint mProgram;
145
146 // Attribute locations
147 GLint mPositionLoc;
148 GLint mTexcoordLoc;
149
150 // Uniform locations
151 GLuint mMVPMatrixLoc;
152
153 // Current rotation
154 float mRotation;
155
156 // Geometry data
157 CubeGeometry mCube;
158
159 // eglPostSubBufferNV entry point
160 PFNEGLPOSTSUBBUFFERNVPROC mPostSubBufferNV;
161 };
162
main(int argc,char ** argv)163 int main(int argc, char **argv)
164 {
165 PostSubBufferSample app(argc, argv);
166 return app.run();
167 }
168