#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <iostream>
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow* window);
void render_verticle(GLFWwindow* window);
//硬编码的顶点着色器 包括位置旋转等操作
const char* vertexShaderSource = "#version 330 core \n"
"layout(location = 0) in vec3 aPos;\n"
"void main()\n"
"{"
" gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
"}\n";
//硬编码的片段着色器 主要是渲染颜色
const char* fragmentShaderSource = "#version 330 core \n"
"out vec4 FragColor;\n"
"void main()\n"
"{\n"
" FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
"}";
// settings
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;
int main()
{
// glfw: initialize and configure
// ------------------------------
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 6);
glfwWindowHint(GLFW_DECORATED, GL_FALSE);
#ifdef __APPLE__
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif
// glfw window creation
// --------------------
GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
if (window == NULL)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
// glad: load all OpenGL function pointers
// ---------------------------------------
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
std::cout << "Failed to initialize GLAD" << std::endl;
return -1;
}
// render loop
// -----------
while (!glfwWindowShouldClose(window))
{
// input
// -----
processInput(window);
// the rendering shits
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
// render a verticle
render_verticle(window);
// glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
// -------------------------------------------------------------------------------
glfwSwapBuffers(window);
glfwPollEvents();
}
// glfw: terminate, clearing all previously allocated GLFW resources.
// ------------------------------------------------------------------
glfwTerminate();
return 0;
}
// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
// ---------------------------------------------------------------------------------------------------------
void processInput(GLFWwindow* window)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
else if (glfwGetKey(window, GLFW_KEY_BACKSPACE) == GLFW_PRESS) {
std::cout << "press backspace" << std::endl;
}
}
// glfw: whenever the window size changed (by OS or user resize) this callback function executes
// ---------------------------------------------------------------------------------------------
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
// make sure the viewport matches the new window dimensions; note that width and
// height will be significantly larger than specified on retina displays.
glViewport(0, 0, width, height);
}
void render_verticle(GLFWwindow* window)
{
float vertices[] = {
-0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f,
0.0f, 0.5f, 0.0f
};
//定义并生成一个VAO 存储VBO的链表结构
unsigned int VAO;
glGenVertexArrays(1, &VAO);
//绑定VAO
glBindVertexArray(VAO);
// 定义并生成一个顶点缓冲对象 通过无符号整数引用
unsigned int VBO;
glGenBuffers(1, &VBO);
// 绑定新生成的顶点缓冲对象
glBindBuffer(GL_ARRAY_BUFFER, VBO);
// 顶点数据复制到缓冲中
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
// 编辑顶点属性
// 1. 设置顶点属性指针
//链接顶点属性 （向顶点着色器指定输入
// 1、顶点着色器中定义的location
// 2、顶点缓冲的长度
// 3、顶点数据的类型
// 4、数据是否标准化（即映射到标准化设备坐标中）
// 5、连续顶点属性组之间的间隔
// 6、初始顶点在缓冲中距离地址最开始的偏移量
// 0. 复制顶点数组到缓冲中供OpenGL使用
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
// 编译着色器
// 着色器对象同样使用无符号整数的id进行引用 此处创建
unsigned int vertexShader;
vertexShader = glCreateShader(GL_VERTEX_SHADER);
//将我们在上面写好的着色器代码附加到着色器对象上并编译
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
//编译着色器
glCompileShader(vertexShader);
//判断着色器编译是否成功 失败报错
int success;
char infoLog[512];
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
}
//片段着色器
unsigned int fragmentShader;
fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
glCompileShader(fragmentShader);
//片段着色器编译检查
glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
}
//创建着色器程序
unsigned int shaderProgram;
shaderProgram = glCreateProgram();
//添加并链接着色器
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
char programLog[512];
glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
if (!success) {
glGetProgramInfoLog(shaderProgram, 512, NULL, programLog);
std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << programLog << std::endl;
}
//着色器对象已经没用了 删除
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
//激活程序对象
glUseProgram(shaderProgram);
/*glBindVertexArray(VAO);*/
glDrawArrays(GL_TRIANGLES, 0, 3);
}
Hello Triangle Code
2024/10/9
OpenGL