glActiveTexture详解

 1 #version 330 core
 2 
 3 in vec2 _texCoord;
 4 out vec4 color;
 5 
 6 uniform sampler2D tex;
 7 
 8 void main()
 9 {
10     vec2 tc = vec2(_texCoord.x, 1-_texCoord.y);
11     color = texture(tex, tc);
12     //color = vec4(1.0f, 0.0f, 0.0f, 1.0f);
13 }

 1 #include "App.h"
 2 #include "EventWorkSpace.h"
 3 #include <SOIL/SOIL.h>
 4 
 5 class TextureTest : public EventWorkSpace
 6 {
 7 public:
 8     GLuint vao;
 9     GLuint vbo;
10     GLuint ebo;
11     Program prog;
12     GLuint tex;
13 
14     void loopInit()
15     {
16         //着色器程序编译
17         prog.addShader(Program::ShaderType::VERTEX_SHADER, "glsl/texture.vert.glsl");
18         prog.addShader(Program::ShaderType::FREGMENT_SHADER, "glsl/texture.freg.glsl");
19         prog.link();
20         //--
21 
22         //定点属性设置
23         GLfloat vertices[] = {
24             // 定点位置                // 纹理坐标
25             0.5f,  0.5f, 0.0f,        1.0f, 1.0f, // 上右
26             0.5f, -0.5f, 0.0f,        1.0f, 0.0f, // 下右
27             -0.5f, -0.5f, 0.0f,        0.0f, 0.0f, // 下左
28             -0.5f,  0.5f, 0.0f,        0.0f, 1.0f  // 上左
29         };
30         GLuint indices[] = {  
31             0, 1, 3, // 第一个三角形
32             1, 2, 3  // 第二个三角形
33         };
34 
35         glGenVertexArrays(1, &vao);
36         glBindVertexArray(vao);
37         glGenBuffers(1, &vbo);
38         glGenBuffers(1, &ebo);
39         glBindBuffer(GL_ARRAY_BUFFER, vbo);
40         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
41 
42         glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
43         glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
44         
45         glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), nullptr);
46         glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (const void *)(3 * sizeof(GLfloat)));
47         glEnableVertexAttribArray(0);
48         glEnableVertexAttribArray(1);
49         glBindVertexArray(0);
50         // --
51 
52         // 纹理生成
53         glGenTextures(1, &tex);
54         glBindTexture(GL_TEXTURE_2D, tex);
55         
56         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
57         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
58         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
59         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
60         
61         int width, height;
62         unsigned char *image = SOIL_load_image("resources/smile.png", &width, &height, 0, SOIL_LOAD_RGB);
63         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
64         glGenerateMipmap(GL_TEXTURE_2D);
65         SOIL_free_image_data(image);
66         glBindTexture(GL_TEXTURE_2D, 0);
67         //--
68 
69         glClearColor(0.6f, 0.6f, 0.6f, 1.0f);
70     }
71     void loopContent()
72     {
73         glClear(GL_COLOR_BUFFER_BIT);
74 
75         glBindTexture(GL_TEXTURE_2D, tex);
76 
77         prog.use();
78         glBindVertexArray(vao);
79         
80         glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr);
81 
82         glBindVertexArray(0);
83     }
84     
85 
86 };
87 
88 int main()
89 {
90     App::init(480, 480, "texture rectangle", false, "window.settings");
91     App::run(&TextureTest());
92     return 0;
93 }