OpenGL的孤独-1-摩杜云开发者社区

(目录)

一、Windows下的OpenGL环境搭建（VSC++环境）

1. 工具及库

GLFW OpenGL的跨平台函数库，可以屏蔽操作系统间的差异，提供统一的接口。这里我们使用OpenGL函数库，而OpenGL ES是适用于嵌入式设备——对OpenGL做了剪裁。官网 https://www.glfw.org/ 下载zip源码包。
CMake 编译工具。官网 https://cmake.org/

GLAD GLAD用来管理OpenGL的函数指针。所以在调用任何OpenGL函数之前都需要初始化GLAD：

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

官网 https://glad.dav1d.de/

将下载的zip文件解压，其中src/glad.c可以直接包含进我们的项目。

2. 测试工程

通过CMake引入GLFW及GLAD库

CMakeLists.txt的内容

# CMakeList.txt: HeadFirst 的 CMake 项目，在此处包括源代码并定义
# 项目特定的逻辑。
#
cmake_minimum_required (VERSION 3.8)

#引入外部库的路径
include_directories(./lib/glfw/include)
include_directories(./lib/glad/include)

link_directories(./lib/glfw/lib)

# Enable Hot Reload for MSVC compilers if supported.
if (POLICY CMP0141)
  cmake_policy(SET CMP0141 NEW)
  set(CMAKE_MSVC_DEBUG_INFORMATION_FORMAT "$<IF:$<AND:$<C_COMPILER_ID:MSVC>,$<CXX_COMPILER_ID:MSVC>>,$<$<CONFIG:Debug,RelWithDebInfo>:EditAndContinue>,$<$<CONFIG:Debug,RelWithDebInfo>:ProgramDatabase>>")
endif()

project ("HeadFirst")

# 将源代码添加到此项目的可执行文件。
add_executable (HeadFirst "HeadFirst.cpp" "HeadFirst.h" ./lib/glad/src/glad.c)

# 这里引入GLFW静态库
target_link_libraries(HeadFirst glfw3)

if (CMAKE_VERSION VERSION_GREATER 3.12)
  set_property(TARGET HeadFirst PROPERTY CXX_STANDARD 20)
endif()

# TODO: 如有需要，请添加测试并安装目标。

HeadFirst.h的内容

#pragma once

#include <iostream>

HeadFirst.cpp的内容

#include "HeadFirst.h"

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

using namespace std;

int main()
{
	glfwInit();
	gladLoadGLLoader((GLADloadproc)glfwGetProcAddress);

	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

	cout << "Hello OpenGL." << endl;
	return 0;
}

如果正常运行不报错，表示环境搭建正常。

二、第一个案例

HeadFirst.cpp的内容

#include "HeadFirst.h"

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

using namespace std;

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

int main()
{
#pragma region
	//初始化GLFW
	glfwInit();

	//glfwWindowHint配置GLFW
	//参数一 代表选项名称以GLFW_开头，是一系列枚举的值
	//参数二 接收一个整型，来设置这个选项的值

	//主版本号是3
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);

	//次版本号是3
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);

	//核心模式(Core-profile)，告诉GLFW我们使用的渲染模式是核心渲染模式
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

	//如果使用的是Mac OS X系统 使用这一段代码
	//glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);

	//创建一个窗口对象
	GLFWwindow* window = glfwCreateWindow(800, 600, "Hello OpenGL", NULL, NULL);
	glfwMakeContextCurrent(window);
#pragma endregion

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

	//定义定点
	float vertices[] = {
		-0.5f, -0.5f, 0.0f,
		 0.5f, -0.5f, 0.0f,
		 0.0f,  0.5f, 0.0f
	};

	//创建VAO
	unsigned int VAO;
	glGenVertexArrays(1, &VAO);
	glBindVertexArray(VAO);

	//创建VBO
	unsigned int VBO;
	glGenBuffers(1, &VBO);
	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);

	//顶点着色器
	const char* vertexShaderSource = "#version 330 core\n"
		"layout (location = 0) in vec3 aPos;\n"
		"void main()\n"
		"{\n"
		"   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
		"}\0";

	unsigned int vertexShader;
	vertexShader = glCreateShader(GL_VERTEX_SHADER);

	glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
	glCompileShader(vertexShader);

	//片段着色器
	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"
		"}\0";
		
	unsigned int fragmentShader;
	fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
	glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
	glCompileShader(fragmentShader);

	//链接VS-PS
	unsigned int shaderProgram;
	shaderProgram = glCreateProgram();

	glAttachShader(shaderProgram, vertexShader);
	glAttachShader(shaderProgram, fragmentShader);
	glLinkProgram(shaderProgram);

	glDeleteShader(vertexShader);
	glDeleteShader(fragmentShader);

	//渲染循环
	while (!glfwWindowShouldClose(window))
	{
		//处理用户的输入
		processInput(window);

		//改变窗口颜色
		glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
		glClear(GL_COLOR_BUFFER_BIT);

		//绘制三角形
		glUseProgram(shaderProgram);
		glDrawArrays(GL_TRIANGLES, 0, 3);

		//交换前后缓冲
		glfwSwapBuffers(window);
		glfwPollEvents();
	}

	glfwTerminate();
	return 0;
}

可参考：https://learnopengl-cn.github.io/