1//
2// Copyright (c) 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_Texture2D.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 "shader_utils.h"
18#include "texture_utils.h"
19
20class SimpleTexture2DSample : public SampleApplication
21{
22  public:
23    SimpleTexture2DSample::SimpleTexture2DSample()
24        : SampleApplication("SimpleTexture2D", 1280, 720)
25    {
26    }
27
28    virtual bool initialize()
29    {
30        const std::string vs = SHADER_SOURCE
31        (
32            attribute vec4 a_position;
33            attribute vec2 a_texCoord;
34            varying vec2 v_texCoord;
35            void main()
36            {
37                gl_Position = a_position;
38                v_texCoord = a_texCoord;
39            }
40        );
41
42        const std::string fs = SHADER_SOURCE
43        (
44            precision mediump float;
45            varying vec2 v_texCoord;
46            uniform sampler2D s_texture;
47            void main()
48            {
49                gl_FragColor = texture2D(s_texture, v_texCoord);
50            }
51        );
52
53        mProgram = CompileProgram(vs, fs);
54        if (!mProgram)
55        {
56            return false;
57        }
58
59        // Get the attribute locations
60        mPositionLoc = glGetAttribLocation(mProgram, "a_position");
61        mTexCoordLoc = glGetAttribLocation(mProgram, "a_texCoord");
62
63        // Get the sampler location
64        mSamplerLoc = glGetUniformLocation(mProgram, "s_texture");
65
66        // Load the texture
67        mTexture = CreateSimpleTexture2D();
68
69        glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
70
71        return true;
72    }
73
74    virtual void destroy()
75    {
76        glDeleteProgram(mProgram);
77        glDeleteTextures(1, &mTexture);
78    }
79
80    virtual void draw()
81    {
82        GLfloat vertices[] =
83        {
84            -0.5f,  0.5f, 0.0f,  // Position 0
85             0.0f,  0.0f,        // TexCoord 0
86            -0.5f, -0.5f, 0.0f,  // Position 1
87             0.0f,  1.0f,        // TexCoord 1
88             0.5f, -0.5f, 0.0f,  // Position 2
89             1.0f,  1.0f,        // TexCoord 2
90             0.5f,  0.5f, 0.0f,  // Position 3
91             1.0f,  0.0f         // TexCoord 3
92        };
93        GLushort indices[] = { 0, 1, 2, 0, 2, 3 };
94
95        // Set the viewport
96        glViewport(0, 0, getWindow()->getWidth(), getWindow()->getHeight());
97
98        // Clear the color buffer
99        glClear(GL_COLOR_BUFFER_BIT);
100
101        // Use the program object
102        glUseProgram(mProgram);
103
104        // Load the vertex position
105        glVertexAttribPointer(mPositionLoc, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), vertices);
106        // Load the texture coordinate
107        glVertexAttribPointer(mTexCoordLoc, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), vertices + 3);
108
109        glEnableVertexAttribArray(mPositionLoc);
110        glEnableVertexAttribArray(mTexCoordLoc);
111
112        // Bind the texture
113        glActiveTexture(GL_TEXTURE0);
114        glBindTexture(GL_TEXTURE_2D, mTexture);
115
116        // Set the texture sampler to texture unit to 0
117        glUniform1i(mSamplerLoc, 0);
118
119        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices);
120    }
121
122  private:
123    // Handle to a program object
124    GLuint mProgram;
125
126    // Attribute locations
127    GLint mPositionLoc;
128    GLint mTexCoordLoc;
129
130    // Sampler location
131    GLint mSamplerLoc;
132
133    // Texture handle
134    GLuint mTexture;
135};
136
137int main(int argc, char **argv)
138{
139    SimpleTexture2DSample app;
140    return app.run();
141}
142