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OpenGL 3D旋转的木箱

学习自：

https://learnopengl-cn.github.io/01%20Getting%20started/08%20Coordinate%20Systems/#3d

0，首先添加glm库文件

相关方法可以参照我指定的那篇随便

1，顶点着色器shader.vs

#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec2 aTexCoord;

out vec2 TexCoord;

uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;

void main()
{
    gl_Position = projection * view * model * vec4(aPos, 1.0f);
    TexCoord = vec2(aTexCoord.x, aTexCoord.y);
}

2，片段着色器shader.fs

#version 330 core
out vec4 FragColor;

in vec2 TexCoord;

// texture samplers
uniform sampler2D texture1;
uniform sampler2D texture2;

void main()
{
    // linearly interpolate between both textures (80% container, 20% awesomeface)
    FragColor = mix(texture(texture1, TexCoord), texture(texture2, TexCoord), 0.2);
}

3，主程序

  1 #include <glad/glad.h>
  2 #include <GLFW/glfw3.h>
  3   
  4 #include <glm/glm.hpp>
  5 #include <glm/gtc/matrix_transform.hpp>
  6 #include <glm/gtc/type_ptr.hpp>
  7 
  8 #include "stb_image.h"
  9 #include "shader_s.h"
 10 #include <iostream>
 11 
 12 void framebuffer_size_callback(GLFWwindow* window, int width, int height);
 13 void processInput(GLFWwindow *window);
 14 
 15 // settings
 16 const unsigned int SCR_WIDTH = 800;
 17 const unsigned int SCR_HEIGHT = 600;
 18 
 19 int main()
 20 {
 21     // glfw: initialize and configure
 22     // ------------------------------
 23     glfwInit();
 24     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
 25     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
 26     glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 27 
 28 #ifdef __APPLE__
 29     glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // uncomment this statement to fix compilation on OS X
 30 #endif
 31 
 32     // glfw window creation
 33     // --------------------
 34     GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
 35     if (window == NULL)
 36     {
 37         std::cout << "Failed to create GLFW window" << std::endl;
 38         glfwTerminate();
 39         return -1;
 40     }
 41     glfwMakeContextCurrent(window);
 42     glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
 43 
 44     // glad: load all OpenGL function pointers
 45     // ---------------------------------------
 46     if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
 47     {
 48         std::cout << "Failed to initialize GLAD" << std::endl;
 49         return -1;
 50     }
 51 
 52     // configure global opengl state
 53     // -----------------------------
 54     glEnable(GL_DEPTH_TEST);
 55 
 56     // build and compile our shader zprogram
 57     // ------------------------------------
 58     Shader ourShader("../res/textures/texture.vs", "../res/textures/texture.fs");
 59 
 60     // set up vertex data (and buffer(s)) and configure vertex attributes
 61     // ------------------------------------------------------------------
 62     /*
 63     float vertices[] = {
 64         // 位置信息          // 颜色信息           // 纹理 coords
 65          0.5f,  0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // 右上
 66          0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // 右下
 67         -0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // 左下
 68         -0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // 左上
 69     };
 70     unsigned int indices[] = {
 71         0, 1, 3, // 第一个三角形
 72         1, 2, 3  // 第二个三角形
 73     };
 74     */
 75     float vertices[] = {
 76     -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
 77      0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
 78      0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
 79      0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
 80     -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
 81     -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
 82 
 83     -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
 84      0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
 85      0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
 86      0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
 87     -0.5f,  0.5f,  0.5f,  0.0f, 1.0f,
 88     -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
 89 
 90     -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
 91     -0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
 92     -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
 93     -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
 94     -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
 95     -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
 96 
 97      0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
 98      0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
 99      0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
100      0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
101      0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
102      0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
103 
104     -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
105      0.5f, -0.5f, -0.5f,  1.0f, 1.0f,
106      0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
107      0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
108     -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
109     -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
110 
111     -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
112      0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
113      0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
114      0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
115     -0.5f,  0.5f,  0.5f,  0.0f, 0.0f,
116     -0.5f,  0.5f, -0.5f,  0.0f, 1.0f
117     };
118     
119     unsigned int VBO, VAO;
120     glGenVertexArrays(1, &VAO);
121     glGenBuffers(1, &VBO);
122 
123     glBindVertexArray(VAO);
124 
125     glBindBuffer(GL_ARRAY_BUFFER, VBO);
126     glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
127 
128     // position attribute
129     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
130     glEnableVertexAttribArray(0);
131     // texture coord attribute
132     glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
133     glEnableVertexAttribArray(1);
134 
135     //    加载并创建纹理
136     // -------------------------
137     unsigned int texture1, texture2;
138     //    第一张纹理
139 
140     glGenTextures(1, &texture1);
141     glBindTexture(GL_TEXTURE_2D, texture1);
142     //    为当前绑定的纹理对象设置环绕、过滤方式
143     //    将纹理包装设置为GL_REPEAT（默认包装方法）
144     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);    
145     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
146     //    设置纹理过滤参数
147     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
148     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
149     // 加载并生成纹理
150     int width, height, nrChannels;
151     stbi_set_flip_vertically_on_load(true); //告诉stb_image.h在y轴上翻转加载的纹理。
152 
153     unsigned char *data = stbi_load("../res/textures/container.jpg", &width, &height, &nrChannels, 0);
154     if (data)
155     {
156         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
157         glGenerateMipmap(GL_TEXTURE_2D);
158     }
159     else
160     {
161         std::cout << "Failed to load texture" << std::endl;
162     }
163     stbi_image_free(data);
164 
165 
166     // texture 2
167     glGenTextures(1, &texture2);
168     glBindTexture(GL_TEXTURE_2D, texture2);
169     // set the texture wrapping parameters
170     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);    // set texture wrapping to GL_REPEAT (default wrapping method)
171     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
172     // set texture filtering parameters
173     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
174     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
175     // load image, create texture and generate mipmaps
176     data = stbi_load("../res/textures/awesomeface.png", &width, &height, &nrChannels, 0);
177     if (data)
178     {
179         //请注意，awesomeface.png具有透明度，因此具有alpha通道，
180         //因此请务必告诉OpenGL数据类型为GL_RGBA        
181         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
182         glGenerateMipmap(GL_TEXTURE_2D);
183     }
184     else
185     {
186         std::cout << "Failed to load texture" << std::endl;
187     }
188     stbi_image_free(data);
189 
190     //告诉每个采样器的opengl它属于哪个纹理单元（只需要做一次）    
191     ourShader.use(); //激活着色器
192     // either set it manually like so:
193     glUniform1i(glGetUniformLocation(ourShader.ID, "texture1"), 0);
194     // or set it via the texture class
195     ourShader.setInt("texture2", 1);
196 
197 
198 
199     // render loop
200     // -----------
201     while (!glfwWindowShouldClose(window))
202     {
203         // input
204        // -----
205         processInput(window);
206 
207         // render
208         // ------
209         glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
210         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // also clear the depth buffer now!
211 
212         // bind textures on corresponding texture units
213         glActiveTexture(GL_TEXTURE0);
214         glBindTexture(GL_TEXTURE_2D, texture1);
215         glActiveTexture(GL_TEXTURE1);
216         glBindTexture(GL_TEXTURE_2D, texture2);
217 
218         // activate shader
219         ourShader.use();
220 
221         // create transformations
222         glm::mat4 model = glm::mat4(1.0f); // make sure to initialize matrix to identity matrix first
223         glm::mat4 view = glm::mat4(1.0f);
224         glm::mat4 projection = glm::mat4(1.0f);
225         model = glm::rotate(model, (float)glfwGetTime(), glm::vec3(0.5f, 1.0f, 0.0f));
226         view = glm::translate(view, glm::vec3(0.0f, 0.0f, -3.0f));
227         projection = glm::perspective(glm::radians(45.0f), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
228         // retrieve the matrix uniform locations
229         unsigned int modelLoc = glGetUniformLocation(ourShader.ID, "model");
230         unsigned int viewLoc = glGetUniformLocation(ourShader.ID, "view");
231         // pass them to the shaders (3 different ways)
232         glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
233         glUniformMatrix4fv(viewLoc, 1, GL_FALSE, &view[0][0]);
234         // note: currently we set the projection matrix each frame, but since the projection matrix rarely changes it's often best practice to set it outside the main loop only once.
235         ourShader.setMat4("projection", projection);
236 
237         // render box
238         glBindVertexArray(VAO);
239         glDrawArrays(GL_TRIANGLES, 0, 36);
240 
241 
242         // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
243         // -------------------------------------------------------------------------------
244         glfwSwapBuffers(window);
245         glfwPollEvents();
246     }
247 
248     // optional: de-allocate all resources once they've outlived their purpose:
249     // ------------------------------------------------------------------------
250     glDeleteVertexArrays(1, &VAO);
251     glDeleteBuffers(1, &VBO);
252     //glDeleteBuffers(1, &EBO);
253 
254     // glfw: terminate, clearing all previously allocated GLFW resources.
255     // ------------------------------------------------------------------
256     glfwTerminate();
257     return 0;
258 }
259 
260 // process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
261 // ---------------------------------------------------------------------------------------------------------
262 void processInput(GLFWwindow *window)
263 {
264     if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
265         glfwSetWindowShouldClose(window, true);
266 }
267 
268 // glfw: whenever the window size changed (by OS or user resize) this callback function executes
269 // ---------------------------------------------------------------------------------------------
270 void framebuffer_size_callback(GLFWwindow* window, int width, int height)
271 {
272     // make sure the viewport matches the new window dimensions; note that width and 
273     // height will be significantly larger than specified on retina displays.
274     glViewport(0, 0, width, height);
275 }

TestShader.cpp

注意一点的是，我们的着色器类，在这里要添加几个方法，我去百度了一下，找到了常用的一些方法，把各个类型的的set函数都加进来了。

  1 #include "shader_s.h"
  2 
  3 Shader::Shader(const GLchar * vertexPath, const GLchar * fragmentPath)
  4 {
  5     // 1. 从文件路径中获取顶点/片段着色器
  6     std::string vertexCode;
  7     std::string fragmentCode;
  8     std::ifstream vShaderFile;
  9     std::ifstream fShaderFile;
 10     // 保证ifstream对象可以抛出异常：
 11     vShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
 12     fShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
 13     try
 14     {
 15         // 打开文件
 16         vShaderFile.open(vertexPath);
 17         fShaderFile.open(fragmentPath);
 18         std::stringstream vShaderStream, fShaderStream;
 19         // 读取文件的缓冲内容到数据流中
 20         vShaderStream << vShaderFile.rdbuf();
 21         fShaderStream << fShaderFile.rdbuf();
 22         // 关闭文件处理器
 23         vShaderFile.close();
 24         fShaderFile.close();
 25         // 转换数据流到string
 26         vertexCode = vShaderStream.str();
 27         fragmentCode = fShaderStream.str();
 28     }
 29     catch (std::ifstream::failure e)
 30     {
 31         std::cout << "ERROR::SHADER::FILE_NOT_SUCCESFULLY_READ" << std::endl;
 32     }
 33     const char* vShaderCode = vertexCode.c_str();
 34     const char * fShaderCode = fragmentCode.c_str();
 35     // 2. 编译着色器
 36     unsigned int vertex, fragment;
 37     // 顶点着色器    vs
 38     vertex = glCreateShader(GL_VERTEX_SHADER);
 39     glShaderSource(vertex, 1, &vShaderCode, NULL);
 40     glCompileShader(vertex);
 41     checkCompileErrors(vertex, "VERTEX");
 42     // 片段着色器    fs
 43     fragment = glCreateShader(GL_FRAGMENT_SHADER);
 44     glShaderSource(fragment, 1, &fShaderCode, NULL);
 45     glCompileShader(fragment);
 46     checkCompileErrors(fragment, "FRAGMENT");
 47     // 着色器程序
 48     ID = glCreateProgram();
 49     glAttachShader(ID, vertex);
 50     glAttachShader(ID, fragment);
 51     glLinkProgram(ID);
 52     checkCompileErrors(ID, "PROGRAM");
 53     // 删除着色器，它们已经链接到我们的程序中了，已经不再需要了    glDeleteShader(vertex);
 54     glDeleteShader(fragment);
 55 }
 56 
 57 void Shader::use()
 58 {
 59     glUseProgram(ID);
 60 }
 61 
 62 void Shader::setBool(const std::string & name, bool value) const
 63 {
 64     glUniform1i(glGetUniformLocation(ID, name.c_str()), (int)value);
 65 }
 66 
 67 void Shader::setInt(const std::string & name, int value) const
 68 {
 69     glUniform1i(glGetUniformLocation(ID, name.c_str()), value);
 70 }
 71 
 72 void Shader::setFloat(const std::string & name, float value) const
 73 {
 74     glUniform1f(glGetUniformLocation(ID, name.c_str()), value);
 75 }
 76 
 77 void Shader::setVec2(const std::string & name, const glm::vec2 & value) const
 78 {
 79     glUniform2fv(glGetUniformLocation(ID, name.c_str()), 1, &value[0]);
 80 }
 81 
 82 void Shader::setVec2(const std::string & name, float x, float y) const
 83 {
 84     glUniform2f(glGetUniformLocation(ID, name.c_str()), x, y);
 85 }
 86 
 87 void Shader::setVec3(const std::string & name, const glm::vec3 & value) const
 88 {
 89     glUniform3fv(glGetUniformLocation(ID, name.c_str()), 1, &value[0]);
 90 }
 91 
 92 void Shader::setVec3(const std::string & name, float x, float y, float z) const
 93 {
 94     glUniform3f(glGetUniformLocation(ID, name.c_str()), x, y, z);
 95 }
 96 
 97 void Shader::setVec4(const std::string & name, const glm::vec4 & value) const
 98 {
 99     glUniform4fv(glGetUniformLocation(ID, name.c_str()), 1, &value[0]);
100 }
101 
102 void Shader::setVec4(const std::string & name, float x, float y, float z, float w)
103 {
104     glUniform4f(glGetUniformLocation(ID, name.c_str()), x, y, z, w);
105 }
106 
107 void Shader::setMat2(const std::string & name, const glm::mat2 & mat) const
108 {
109     glUniformMatrix2fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &mat[0][0]);
110 }
111 
112 void Shader::setMat3(const std::string & name, const glm::mat3 & mat) const
113 {
114     glUniformMatrix3fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &mat[0][0]);
115 }
116 
117 void Shader::setMat4(const std::string & name, const glm::mat4 & mat) const
118 {
119     glUniformMatrix4fv(glGetUniformLocation(ID, name.c_str()), 1, GL_FALSE, &mat[0][0]);
120 }
121 
122 void Shader::checkCompileErrors(unsigned int shader, std::string type)
123 {
124     int success;
125     char infoLog[1024];
126     if (type != "PROGRAM")
127     {
128         glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
129         if (!success)
130         {
131             glGetShaderInfoLog(shader, 1024, NULL, infoLog);
132             std::cout << "ERROR::SHADER_COMPILATION_ERROR of type: " << type << "
" << infoLog << "
 -- --------------------------------------------------- -- " << std::endl;
133         }
134     }
135     else
136     {
137         glGetProgramiv(shader, GL_LINK_STATUS, &success);
138         if (!success)
139         {
140             glGetProgramInfoLog(shader, 1024, NULL, infoLog);
141             std::cout << "ERROR::PROGRAM_LINKING_ERROR of type: " << type << "
" << infoLog << "
 -- --------------------------------------------------- -- " << std::endl;
142         }
143     }
144 }

shader_s.cpp

自己把相关的类定义写道头文件中就可以了。

4，运行结果

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原文地址：https://www.cnblogs.com/icyhusky/p/10738530.html