LearnOpenGL：Shaders

链接
代码：

#include <glad/glad.h>
#include <GLFW/glfw3.h>

#include <iostream>
#include <cmath>

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void pocessInput(GLFWwindow* window);

const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;

const char *vertexShaderSource = "#version 330 core\n"
"layout (location = 0) in vec3 aPos;\n"
"void main()\n"
"{\n"
"   gl_Position = vec4(aPos, 1.0);\n"
"}\0";

const char *fragmentShaderSource = "#version 330 core\n"
"out vec4 FragColor;\n"
"uniform vec4 ourColor;\n"
"void main()\n"
"{\n"
"   FragColor = ourColor;\n"
"}\n\0";

int main()
{
	glfwInit();
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

	GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "Learn OpenGL", NULL, NULL);

	if (window == NULL)
	{
		std::cout << "Failed to create GLFW window" << std::endl;
		glfwTerminate();
		return -1;
	}

	glfwMakeContextCurrent(window);
	glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
	{
		std::cout << "Failed to initialize GLAD" << std::endl;
		return -1;
	}

	//顶点着色器
	int vertexShader = glCreateShader(GL_VERTEX_SHADER);
	glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
	glCompileShader(vertexShader);

	int success;
	char InfoLog[512];
	glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
	if (!success)
	{
		glGetShaderInfoLog(vertexShader, 512, NULL, InfoLog);
		std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILES\n" << InfoLog << std::endl;
	}
	//片段着色器
	int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
	glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
	glCompileShader(fragmentShader);
	glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
	if (!success)
	{
		glGetShaderInfoLog(fragmentShader, 512, NULL, InfoLog);
		std::cout << "ERROR::SHAER::FRAGMENT::COMPILATION_FAILES\n" << InfoLog << std::endl;
	}

	//链接着色器
	int shaderProgram = glCreateProgram();
	glAttachShader(shaderProgram,vertexShader);
	glAttachShader(shaderProgram,fragmentShader);
	glLinkProgram(shaderProgram);

	//检查是否链接错误
	glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
	if (!success)
	{
		glGetProgramInfoLog(shaderProgram, 512, NULL, InfoLog);
		std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << std::endl;
	}

	glDeleteShader(vertexShader);
	glDeleteShader(fragmentShader);

	//设置顶点数据，缓冲，属性
	float vertices[] = {
		0.5f,-0.5f,0.0f,
		-0.5f,-0.5f,0.0f,
		0.0f,0.5f,0.0f
	};
	//创建顶点缓冲对象，顶点数组对象
	unsigned int VBO, VAO;
	glGenVertexArrays(1, &VAO);
	glGenBuffers(1, &VBO);
	//绑定
	glBindVertexArray(VAO);
	
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);

	glBindVertexArray(VAO);

	//循环渲染
	while (!glfwWindowShouldClose(window))
	{
		pocessInput(window);

		glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT);

		glUseProgram(shaderProgram);

		//更新Shader Uniform
		float timeValue = glfwGetTime();
		float greenValue = sin(timeValue) / 2.0f + 0.5f;
		int VertexColorLocation = glGetUniformLocation(shaderProgram, "ourColor");
		glUniform4f(VertexColorLocation, 0.0f, greenValue, 0.0f, 1.0f);

		//render the triangle
		glDrawArrays(GL_TRIANGLES, 0, 3);

		glfwSwapBuffers(window);
		glfwPollEvents();
	}
	glDeleteVertexArrays(1, &VAO);
	glDeleteBuffers(1, &VBO);

	glfwTerminate();
	return 0;
}

void pocessInput(GLFWwindow *window)
{
	if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
		glfwSetWindowShouldClose(window, true);
}

// 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);
}