C++?OpenGL實(shí)現(xiàn)球形的繪制
1、封裝Shader
(1)為什么要封裝Shader
封裝后,在應(yīng)對(duì)存在對(duì)個(gè)著色器程序的渲染流程時(shí),可以更方便使用不同的著色器程序,同時(shí)也可以降低代碼冗余。
(2)如何使用
如下,傳入?yún)?shù)分別為頂點(diǎn)著色器和片元著色器的路徑,在封裝了Shader類之后,我們就可以通過(guò)一行代碼去創(chuàng)建一個(gè)新的著色器對(duì)象:
Shader shader("res/shader/task3.vs","res/shader/task3.fs");
假如我們?cè)诶L制時(shí)需要切換到某個(gè)著色器并使用它,我們僅需要一行代碼:
shader.Use();
假如我們需要向著色器傳入一種類型的值,我們也僅需要一行代碼去解決它(name是著色器中的名稱,value為你希望設(shè)置的值):
SetFloat(string &name,float value)
2、繪制球模型
(1)球面頂點(diǎn)遍歷
//生成球的頂點(diǎn) for(int y = 0; y <=Y_SEGMENTS; y++) { for(int x = 0; x <= X_SEGMENTS; x++) { float xSegment = (float)x/(float)X_SEGMENTS; float ySegment = (float)y/(float)Y_SEGMENTS; float xPos = std::cos(xSegment*2.0f*PI)*std::sin(ySement*PI); float yPos = std::cos(ySegment*PI); float zPos = std::sin(xSegment*2.0f*PI)*std::sin(ySement*PI); sphereVertices.push_back(x_Pos); sphereVertices.push_back(y_Pos); sphereVertices.push_back(z_Pos); } }
(2)構(gòu)造三角形圖元
//根據(jù)球面上每一點(diǎn)的坐標(biāo),去構(gòu)造一個(gè)一個(gè)三角形頂點(diǎn)數(shù)組 for(int i=0; i<Y_SEGMENTS;i++) { for(int j=0; j<X_SEGMENTS;j++) { sphereIndices.push_back(i*(X_SEGMENTS+1)+j); sphereIndices.push_back((i+1)*(X_SEGMENTS+1)+j); sphereIndices.push_back((i+1)*(X_SEGMENTS+1)+j+1); sphereIndices.push_back(i*(X_SEGMENTS+1)+j); sphereIndices.push_back((i+1)*(X_SEGMENTS+1)+j+1); sphereIndices.push_back(i*(X_SEGMENTS+1)+j+1); } }
(3)開啟線框模式
glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);//使用線框模式繪制
(4)開啟面剔除
//開啟面剔除(只需要展示一個(gè)面,否則會(huì)有重合) glEnable(GL_CULL_FACE); glCUllFace(GL_BACK);
(5)最后
項(xiàng)目工程文件結(jié)構(gòu):
shader.h
/*** * 例程 繪制球體 (MAKE后運(yùn)行時(shí)可刪除ALL_BUILD,也可以將Task-sphere設(shè)為默認(rèn)啟動(dòng)工程) * 步驟: * 1-初始化: GLFW窗口,GLAD。 * 2-計(jì)算球體頂點(diǎn):通過(guò)數(shù)學(xué)方法計(jì)算球體的每個(gè)頂點(diǎn)坐標(biāo) * 2-數(shù)據(jù)處理: 通過(guò)球體頂點(diǎn)坐標(biāo)構(gòu)造三角形網(wǎng)格,生成并綁定VAO&VBO&EBO(準(zhǔn)備在GPU中進(jìn)行處理),設(shè)置頂點(diǎn)屬性指針(本質(zhì)上就是告訴OpenGL如何處理數(shù)據(jù))。 * 3-著色器: 給出頂點(diǎn)和片段著色器,然后鏈接為著色器程序,渲染時(shí)使用著色器程序。 * 4-渲染: 使用畫線模式畫圓,開啟面剔除,剔除背面,使用線框模式畫球 * 5-結(jié)束: 清空緩沖,交換緩沖區(qū)檢查觸發(fā)事件后釋放資源 */ #include <glad/glad.h> #include <GLFW/glfw3.h> #include <shader.h> #include <iostream> #include <math.h> #include <vector> const unsigned int screen_width = 780; const unsigned int screen_height = 780; const GLfloat PI = 3.14159265358979323846f; //將球橫縱劃分成50X50的網(wǎng)格 const int Y_SEGMENTS = 50; const int X_SEGMENTS = 50; int main() { // 初始化GLFW glfwInit(); // 初始化GLFW glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); // OpenGL版本為3.3,主次版本號(hào)均設(shè)為3 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 使用核心模式(無(wú)需向后兼容性) glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // 如果使用的是Mac OS X系統(tǒng),需加上這行 glfwWindowHint(GLFW_RESIZABLE, FALSE); // 不可改變窗口大小 // 創(chuàng)建窗口(寬、高、窗口名稱) auto window = glfwCreateWindow(screen_width, screen_height, "Sphere", nullptr, nullptr); if (window == nullptr) { // 如果窗口創(chuàng)建失敗,輸出Failed to Create OpenGL Context std::cout << "Failed to Create OpenGL Context" << std::endl; glfwTerminate(); return -1; } glfwMakeContextCurrent(window); // 將窗口的上下文設(shè)置為當(dāng)前線程的主上下文 // 初始化GLAD,加載OpenGL函數(shù)指針地址的函數(shù) if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) { std::cout << "Failed to initialize GLAD" << std::endl; return -1; } // 指定當(dāng)前視口尺寸(前兩個(gè)參數(shù)為左下角位置,后兩個(gè)參數(shù)是渲染窗口寬、高) glViewport(0, 0, screen_width, screen_height); Shader shader("res/shader/task3.vs", "res/shader/task3.fs");//加載著色器 std::vector<float> sphereVertices; std::vector<int> sphereIndices; // 生成球的頂點(diǎn) for (int y = 0; y <= Y_SEGMENTS; y++) { for (int x = 0; x <= X_SEGMENTS; x++) { float xSegment = (float)x / (float)X_SEGMENTS; float ySegment = (float)y / (float)Y_SEGMENTS; float xPos = std::cos(xSegment * 2.0f * PI) * std::sin(ySegment * PI); float yPos = std::cos(ySegment * PI); float zPos = std::sin(xSegment * 2.0f * PI) * std::sin(ySegment * PI); sphereVertices.push_back(xPos); sphereVertices.push_back(yPos); sphereVertices.push_back(zPos); } } // 生成球的Indices for (int i = 0; i < Y_SEGMENTS; i++) { for (int j = 0; j < X_SEGMENTS; j++) { sphereIndices.push_back(i * (X_SEGMENTS+1) + j); sphereIndices.push_back((i + 1) * (X_SEGMENTS + 1) + j); sphereIndices.push_back((i + 1) * (X_SEGMENTS + 1) + j + 1); sphereIndices.push_back(i * (X_SEGMENTS + 1) + j); sphereIndices.push_back((i + 1) * (X_SEGMENTS + 1) + j + 1); sphereIndices.push_back(i * (X_SEGMENTS + 1) + j + 1); } } // 球 unsigned int VBO, VAO; glGenVertexArrays(1, &VAO); glGenBuffers(1, &VBO); //生成并綁定球體的VAO和VBO glBindVertexArray(VAO); glBindBuffer(GL_ARRAY_BUFFER, VBO); // 將頂點(diǎn)數(shù)據(jù)綁定至當(dāng)前默認(rèn)的緩沖中 glBufferData(GL_ARRAY_BUFFER, sphereVertices.size() * sizeof(float), &sphereVertices[0], GL_STATIC_DRAW); GLuint element_buffer_object; //EBO glGenBuffers(1, &element_buffer_object); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, element_buffer_object); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sphereIndices.size() * sizeof(int), &sphereIndices[0], GL_STATIC_DRAW); // 設(shè)置頂點(diǎn)屬性指針 glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0); glEnableVertexAttribArray(0); // 解綁VAO和VBO glBindBuffer(GL_ARRAY_BUFFER, 0); glBindVertexArray(0); // 渲染循環(huán) while (!glfwWindowShouldClose(window)) { // 清空顏色緩沖 glClearColor(0.0f, 0.34f, 0.57f, 1.0f); glClear(GL_COLOR_BUFFER_BIT); shader.Use(); //繪制球 //開啟面剔除(只需要展示一個(gè)面,否則會(huì)有重合) glEnable(GL_CULL_FACE); glCullFace(GL_BACK); glBindVertexArray(VAO); //使用線框模式繪制 glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); glDrawElements(GL_TRIANGLES, X_SEGMENTS*Y_SEGMENTS * 6, GL_UNSIGNED_INT, 0); //點(diǎn)陣模式繪制 //glPointSize(5); //glDrawElements(GL_POINTS, X_SEGMENTS*Y_SEGMENTS*6, GL_UNSIGNED_INT, 0); //交換緩沖并且檢查是否有觸發(fā)事件(比如鍵盤輸入、鼠標(biāo)移動(dòng)等) glfwSwapBuffers(window); glfwPollEvents(); } // 刪除VAO和VBO,EBO glDeleteVertexArrays(1, &VAO); glDeleteBuffers(1, &VBO); glDeleteBuffers(1, &element_buffer_object); // 清理所有的資源并正確退出程序 glfwTerminate(); return 0; }
shader.cpp
#include "Shader.h" #include "fstream" #include "sstream" #include "iostream" Shader::Shader(const GLchar* vertex_shader_path, const GLchar* fragment_shader_path) { std::string vertex_shader_code; std::string fragment_shader_code; if (GetShaderFromFile(vertex_shader_path, fragment_shader_path, &vertex_shader_code, &fragment_shader_code)) { return; } if (LinkShader(vertex_shader_code.c_str(), fragment_shader_code.c_str())) { return; } } Shader::~Shader() { } void Shader::Use() { glUseProgram(ID); } void Shader::SetBool(const std::string &name, bool value) const { SetInt(name, (int)value); } void Shader::SetInt(const std::string &name, int value) const { glUniform1i(GetUniform(name), value); } void Shader::SetFloat(const std::string &name, float value) const { glUniform1f(GetUniform(name), value); } void Shader::SetVec2(const std::string &name, float x, float y) const { glUniform2f(GetUniform(name), x, y); } void Shader::SetVec2(const std::string &name, const glm::vec2 &value) const { SetVec2(name, value.x, value.y); } void Shader::SetVec3(const std::string &name, float x, float y, float z) const { glUniform3f(GetUniform(name), x, y, z); } void Shader::SetVec3(const std::string &name, const glm::vec3 &value) const { SetVec3(name, value.x, value.y, value.z); } void Shader::SetVec4(const std::string &name, float x, float y, float z, float w) const { glUniform4f(GetUniform(name), x, y, z, w); } void Shader::SetVec4(const std::string &name, const glm::vec4 &value) const { SetVec4(name, value.x, value.y, value.z, value.w); } void Shader::SetMat2(const std::string &name, const glm::mat2 &value) const { glUniformMatrix2fv(GetUniform(name), 1, GL_FALSE, &value[0][0]); } void Shader::SetMat3(const std::string &name, const glm::mat3 &value) const { glUniformMatrix3fv(GetUniform(name), 1, GL_FALSE, &value[0][0]); } void Shader::SetMat4(const std::string &name, const glm::mat4 &value) const { glUniformMatrix4fv(GetUniform(name), 1, GL_FALSE, &value[0][0]); } int Shader::GetShaderFromFile(const GLchar* vertex_shader_path, const GLchar* fragment_shader_path, std::string *vertex_shader_code, std::string *fragment_shader_code) { std::ifstream vertex_shader_file; std::ifstream fragment_shader_file; vertex_shader_file.exceptions(std::ifstream::badbit | std::ifstream::failbit); fragment_shader_file.exceptions(std::ifstream::badbit | std::ifstream::failbit); try { vertex_shader_file.open(vertex_shader_path); fragment_shader_file.open(fragment_shader_path); std::stringstream vertex_shader_stream, fragment_shader_stream; vertex_shader_stream << vertex_shader_file.rdbuf(); fragment_shader_stream << fragment_shader_file.rdbuf(); vertex_shader_file.close(); fragment_shader_file.close(); *vertex_shader_code = vertex_shader_stream.str(); *fragment_shader_code = fragment_shader_stream.str(); } catch (std::ifstream::failure e) { std::cout << "Load Shader File Error!" << std::endl; return -1; } return 0; } int Shader::LinkShader(const char* vertex_shader_code, const char* fragment_shader_code) { int vertex_shader = glCreateShader(GL_VERTEX_SHADER); glShaderSource(vertex_shader, 1, &vertex_shader_code, NULL); glCompileShader(vertex_shader); CheckCompileErrors(vertex_shader, "VERTEX"); int fragment_shader = glCreateShader(GL_FRAGMENT_SHADER); glShaderSource(fragment_shader, 1, &fragment_shader_code, NULL); glCompileShader(fragment_shader); CheckCompileErrors(fragment_shader, "FRAGMENT"); this->ID = glCreateProgram(); glAttachShader(ID, vertex_shader); glAttachShader(ID, fragment_shader); glLinkProgram(ID); CheckCompileErrors(ID, "PROGRAM"); glDeleteShader(vertex_shader); glDeleteShader(fragment_shader); return 0; } int Shader::GetUniform(const std::string &name) const { int position = glGetUniformLocation(ID, name.c_str()); if (position == -1) { std::cout << "uniform " << name << " set failed!" << std::endl; } return position; } void Shader::CheckCompileErrors(GLuint shader, std::string type) { GLint success; GLchar infoLog[512]; if (type == "PROGRAM") { glGetProgramiv(shader, GL_LINK_STATUS, &success); if (!success) { glGetProgramInfoLog(shader, 512, NULL, infoLog); std::cout << "ERROR::PROGRAM_LINKING_ERROR!\n" << infoLog << std::endl; } } else { glGetShaderiv(shader, GL_COMPILE_STATUS, &success); if (!success) { glGetShaderInfoLog(shader, 512, NULL, infoLog); std::cout << "ERROR::SHADER::" << type << "::COMPILATION_FAILED\n" << infoLog << std::endl; } } }
main.cpp
/*** * 例程 繪制球體 (MAKE后運(yùn)行時(shí)可刪除ALL_BUILD,也可以將Task-sphere設(shè)為默認(rèn)啟動(dòng)工程) * 步驟: * 1-初始化: GLFW窗口,GLAD。 * 2-計(jì)算球體頂點(diǎn):通過(guò)數(shù)學(xué)方法計(jì)算球體的每個(gè)頂點(diǎn)坐標(biāo) * 2-數(shù)據(jù)處理: 通過(guò)球體頂點(diǎn)坐標(biāo)構(gòu)造三角形網(wǎng)格,生成并綁定VAO&VBO&EBO(準(zhǔn)備在GPU中進(jìn)行處理),設(shè)置頂點(diǎn)屬性指針(本質(zhì)上就是告訴OpenGL如何處理數(shù)據(jù))。 * 3-著色器: 給出頂點(diǎn)和片段著色器,然后鏈接為著色器程序,渲染時(shí)使用著色器程序。 * 4-渲染: 使用畫線模式畫圓,開啟面剔除,剔除背面,使用線框模式畫球 * 5-結(jié)束: 清空緩沖,交換緩沖區(qū)檢查觸發(fā)事件后釋放資源 */ #include <glad/glad.h> #include <GLFW/glfw3.h> #include <shader.h> #include <iostream> #include <math.h> #include <vector> const unsigned int screen_width = 780; const unsigned int screen_height = 780; const GLfloat PI = 3.14159265358979323846f; //將球橫縱劃分成50X50的網(wǎng)格 const int Y_SEGMENTS = 50; const int X_SEGMENTS = 50; int main() { // 初始化GLFW glfwInit(); // 初始化GLFW glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); // OpenGL版本為3.3,主次版本號(hào)均設(shè)為3 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 使用核心模式(無(wú)需向后兼容性) glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // 如果使用的是Mac OS X系統(tǒng),需加上這行 glfwWindowHint(GLFW_RESIZABLE, FALSE); // 不可改變窗口大小 // 創(chuàng)建窗口(寬、高、窗口名稱) auto window = glfwCreateWindow(screen_width, screen_height, "Sphere", nullptr, nullptr); if (window == nullptr) { // 如果窗口創(chuàng)建失敗,輸出Failed to Create OpenGL Context std::cout << "Failed to Create OpenGL Context" << std::endl; glfwTerminate(); return -1; } glfwMakeContextCurrent(window); // 將窗口的上下文設(shè)置為當(dāng)前線程的主上下文 // 初始化GLAD,加載OpenGL函數(shù)指針地址的函數(shù) if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) { std::cout << "Failed to initialize GLAD" << std::endl; return -1; } // 指定當(dāng)前視口尺寸(前兩個(gè)參數(shù)為左下角位置,后兩個(gè)參數(shù)是渲染窗口寬、高) glViewport(0, 0, screen_width, screen_height); Shader shader("res/shader/task3.vs", "res/shader/task3.fs");//加載著色器 std::vector<float> sphereVertices; std::vector<int> sphereIndices; // 生成球的頂點(diǎn) for (int y = 0; y <= Y_SEGMENTS; y++) { for (int x = 0; x <= X_SEGMENTS; x++) { float xSegment = (float)x / (float)X_SEGMENTS; float ySegment = (float)y / (float)Y_SEGMENTS; float xPos = std::cos(xSegment * 2.0f * PI) * std::sin(ySegment * PI); float yPos = std::cos(ySegment * PI); float zPos = std::sin(xSegment * 2.0f * PI) * std::sin(ySegment * PI); sphereVertices.push_back(xPos); sphereVertices.push_back(yPos); sphereVertices.push_back(zPos); } } // 生成球的Indices for (int i = 0; i < Y_SEGMENTS; i++) { for (int j = 0; j < X_SEGMENTS; j++) { sphereIndices.push_back(i * (X_SEGMENTS+1) + j); sphereIndices.push_back((i + 1) * (X_SEGMENTS + 1) + j); sphereIndices.push_back((i + 1) * (X_SEGMENTS + 1) + j + 1); sphereIndices.push_back(i * (X_SEGMENTS + 1) + j); sphereIndices.push_back((i + 1) * (X_SEGMENTS + 1) + j + 1); sphereIndices.push_back(i * (X_SEGMENTS + 1) + j + 1); } } // 球 unsigned int VBO, VAO; glGenVertexArrays(1, &VAO); glGenBuffers(1, &VBO); //生成并綁定球體的VAO和VBO glBindVertexArray(VAO); glBindBuffer(GL_ARRAY_BUFFER, VBO); // 將頂點(diǎn)數(shù)據(jù)綁定至當(dāng)前默認(rèn)的緩沖中 glBufferData(GL_ARRAY_BUFFER, sphereVertices.size() * sizeof(float), &sphereVertices[0], GL_STATIC_DRAW); GLuint element_buffer_object; //EBO glGenBuffers(1, &element_buffer_object); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, element_buffer_object); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sphereIndices.size() * sizeof(int), &sphereIndices[0], GL_STATIC_DRAW); // 設(shè)置頂點(diǎn)屬性指針 glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0); glEnableVertexAttribArray(0); // 解綁VAO和VBO glBindBuffer(GL_ARRAY_BUFFER, 0); glBindVertexArray(0); // 渲染循環(huán) while (!glfwWindowShouldClose(window)) { // 清空顏色緩沖 glClearColor(0.0f, 0.34f, 0.57f, 1.0f); glClear(GL_COLOR_BUFFER_BIT); shader.Use(); //繪制球 //開啟面剔除(只需要展示一個(gè)面,否則會(huì)有重合) glEnable(GL_CULL_FACE); glCullFace(GL_BACK); glBindVertexArray(VAO); //使用線框模式繪制 glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); glDrawElements(GL_TRIANGLES, X_SEGMENTS*Y_SEGMENTS * 6, GL_UNSIGNED_INT, 0); //點(diǎn)陣模式繪制 //glPointSize(5); //glDrawElements(GL_POINTS, X_SEGMENTS*Y_SEGMENTS*6, GL_UNSIGNED_INT, 0); //交換緩沖并且檢查是否有觸發(fā)事件(比如鍵盤輸入、鼠標(biāo)移動(dòng)等) glfwSwapBuffers(window); glfwPollEvents(); } // 刪除VAO和VBO,EBO glDeleteVertexArrays(1, &VAO); glDeleteBuffers(1, &VBO); glDeleteBuffers(1, &element_buffer_object); // 清理所有的資源并正確退出程序 glfwTerminate(); return 0; }
輸出結(jié)果:
以上就是C++ OpenGL實(shí)現(xiàn)球形的繪制的詳細(xì)內(nèi)容,更多關(guān)于C++ OpenGL繪制球的資料請(qǐng)關(guān)注腳本之家其它相關(guān)文章!
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