camera.cpp

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

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

#include <iostream>
/*
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"

#include "shader.h"

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
void processInput(GLFWwindow* window);

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

glm::vec3 cameraPos = glm::vec3(0.0f, 0.0f, 3.0f);
glm::vec3 cameraFront = glm::vec3(0.0f, 0.0f, -1.0f);
glm::vec3 cameraUp = glm::vec3(0.0f, 1.0f, 0.0f);
float deltaTime = 0.0f; // 当前帧与上一帧的时间差
float lastFrame = 0.0f; // 上一帧的时间
float lastX = 400, lastY = 300;
bool firstMouse = true;
float yaw, pitch = 0.0;
float fov = 45.0;

int main()
{
	glfwInit();//初始化GLFW
	//第一个参数是选项的名称，第二个参数是一个int用来设置选项的值
	//3.3版本
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	//核心模式Core-profile 
	//意味着我们只能使用OpenGL功能的一个子集（没有我们已不再需要的向后兼容特性
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
	// 无边框
	glfwWindowHint(GLFW_DISCONNECTED, GL_FALSE);
	// 透明
	glfwWindowHint(GLFW_TRANSPARENT_FRAMEBUFFER, GL_TRUE);

#ifdef __APPLE__
	glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif

	// 创建窗口对象
	// 参数：宽，高，窗口标题，
	GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "ShuoLearnOpenGL", NULL, NULL);
	if (window == NULL)
	{
		std::cout << "Failed to create GLFW window" << std::endl;
		glfwTerminate();
		return -1;
	}
	glfwMakeContextCurrent(window); //通知GLFW将窗口的上下文设置为当前线程的主上下文

	// 注册回调函数，每次窗口大小被调整时调用注册的函数
	glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

	glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
	glfwSetCursorPosCallback(window, mouse_callback);
	glfwSetScrollCallback(window, scroll_callback);

	// GLAD是用来管理OpenGL的函数指针
	// 所以在调用任何OpenGL的函数之前我们需要初始化GLAD
	if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
	{
		std::cout << "Failed to initialize GLAD" << std::endl;
		return -1;
	}

	// 查询顶点属性上限
	int nrAttributes;
	glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &nrAttributes);
	std::cout << "Maximum nr of vertex attributes supported: " << nrAttributes << std::endl;

	Shader ourShader("./coordinate_system.vs", "./coordinate_system.fs");

	// 顶点数据
	float vertices[] = {
		-0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
		 0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
		 0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
		 0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
		-0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
		-0.5f, -0.5f, -0.5f,  0.0f, 0.0f,

		-0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
		 0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
		 0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
		 0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
		-0.5f,  0.5f,  0.5f,  0.0f, 1.0f,
		-0.5f, -0.5f,  0.5f,  0.0f, 0.0f,

		-0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
		-0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
		-0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
		-0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
		-0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
		-0.5f,  0.5f,  0.5f,  1.0f, 0.0f,

		 0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
		 0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
		 0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
		 0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
		 0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
		 0.5f,  0.5f,  0.5f,  1.0f, 0.0f,

		-0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
		 0.5f, -0.5f, -0.5f,  1.0f, 1.0f,
		 0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
		 0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
		-0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
		-0.5f, -0.5f, -0.5f,  0.0f, 1.0f,

		-0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
		 0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
		 0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
		 0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
		-0.5f,  0.5f,  0.5f,  0.0f, 0.0f,
		-0.5f,  0.5f, -0.5f,  0.0f, 1.0f
	};

	glm::vec3 cubePositions[] = {
		glm::vec3(0.0f,  0.0f,  0.0f),
		glm::vec3(2.0f,  5.0f, -15.0f),
		glm::vec3(-1.5f, -2.2f, -2.5f),
		glm::vec3(-3.8f, -2.0f, -12.3f),
		glm::vec3(2.4f, -0.4f, -3.5f),
		glm::vec3(-1.7f,  3.0f, -7.5f),
		glm::vec3(1.3f, -2.0f, -2.5f),
		glm::vec3(1.5f,  2.0f, -2.5f),
		glm::vec3(1.5f,  0.2f, -1.5f),
		glm::vec3(-1.3f,  1.0f, -1.5f)
	};

	// 顶点数组对象
	unsigned int VAO;
	glGenVertexArrays(1, &VAO);
	// 顶点缓冲对象
	unsigned int VBO;
	glGenBuffers(1, &VBO); //参数1 number of buffer object names to be generated

	glBindVertexArray(VAO);
	// 把新创建的缓冲绑定到GL_ARRAY_BUFFER上
	// VBO的缓冲类型是GL_ARRAY_BUFFER
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	// 把之前定义的顶点数据复制到缓冲的内存中
	// 第四个参数：希望显卡如何管理给定的数据
	// GL_STATIC_DRAW ：数据不会或几乎不会改变。
	// GL_DYNAMIC_DRAW：数据会被改变很多。
	// GL_STREAM_DRAW ：数据每次绘制时都会改变。
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);


	// 1. 顶点属性index，前面在顶点着色器中使用layout(location = 0)定义了position顶点属性的位置值(Location)，它可以把顶点属性的位置值设置为0。因为我们希望把数据传递到这一个顶点属性中，所以这里传入0 
	// 2. 单个顶点属性大小（vec3）3.数据类型 4.是否标准化 
	// 5.步长Stride 在连续的顶点属性组之间的间隔 可以设置为0来让OpenGL决定具体步长是多少（只有当数值是紧密排列时才可用）
	// 6.类型是void*，所以需要进行强制类型转换。它表示位置数据在缓冲中起始位置的偏移量(Offset)。由于位置数据在数组的开头，所以这里是0
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
	glEnableVertexAttribArray(1);


	unsigned int texture1;
	unsigned int texture2;
	glGenTextures(1, &texture1);
	glBindTexture(GL_TEXTURE_2D, texture1);

	// 为当前绑定的纹理对象设置环绕、过滤方式
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	// 加载并生成纹理
	stbi_set_flip_vertically_on_load(true);
	int width, height, nrChannels;
	unsigned char* data = stbi_load("container.jpg", &width, &height, &nrChannels, 0);
	if (data)
	{
		// 纹理目标 纹理mipmap级别 纹理格式 纹理宽度 纹理高度
		// 默认0 源图格式 源图数据类型 图像数据
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
		glGenerateMipmap(GL_TEXTURE_2D);
	}
	else
	{
		std::cout << "Failed to load texture" << std::endl;
	}

	glGenTextures(1, &texture2);
	glBindTexture(GL_TEXTURE_2D, texture2);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	unsigned char* data2 = stbi_load("awesomeface.png", &width, &height, &nrChannels, 0);
	if (data2)
	{
		// 纹理目标 纹理mipmap级别 纹理格式 纹理宽度 纹理高度
		// 默认0 源图格式 源图数据类型 图像数据
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data2);
		glGenerateMipmap(GL_TEXTURE_2D);
	}
	else
	{
		std::cout << "Failed to load texture" << std::endl;
	}
	stbi_image_free(data);
	stbi_image_free(data2);

	// glVertexAttribPointer绑好了所以可以解绑
	glBindBuffer(GL_ARRAY_BUFFER, 0);
	glBindVertexArray(0);

	glEnable(GL_DEPTH_TEST);

	ourShader.use(); // 不要忘记在设置uniform变量之前激活着色器程序！
	glUniform1i(glGetUniformLocation(ourShader.ID, "texture1"), 0); // 手动设置
	ourShader.setInt("texture2", 1); // 或者使用着色器类设置

	glm::mat4 view;
	view = glm::lookAt(glm::vec3(0.0f, 0.0f, 3.0f),
		glm::vec3(0.0f, 0.0f, 0.0f),
		glm::vec3(0.0f, 1.0f, 0.0f));

	// 渲染循环
	// ----------------------------------------------------------------------------------------------------------------------------------
	// glfwWindowShouldClose函数在每次循环的开始前检查一次GLFW是否被要求退出
	// 如果是的话，该函数返回true，渲染循环将停止运行
	while (!glfwWindowShouldClose(window))
	{
		float currentFrame = glfwGetTime();
		deltaTime = currentFrame - lastFrame;
		lastFrame = currentFrame;

		// 处理输入
		processInput(window);

		// render
		//清空屏幕所用颜色
		glClearColor(0.1f, 0.1f, 0.1f, 0.0f);
		// 每次新的渲染迭代开始时清屏，否则会看到上一次迭代的渲染结果
		// 缓冲位选项：GL_COLOR_BUFFER_BIT，GL_DEPTH_BUFFER_BIT 和 GL_STENCIL_BUFFER_BIT
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, texture1);
		glActiveTexture(GL_TEXTURE1);
		glBindTexture(GL_TEXTURE_2D, texture2);

// 		glm::mat4 model;
// 		model = glm::rotate(model, (float)glfwGetTime() * glm::radians(50.0f), glm::vec3(0.0f, 1.0f, 0.0f));
// 		glm::mat4 view;
// 		view = glm::translate(view, glm::vec3(0.0f, 0.0f, -3.0f));
		glm::mat4 projection;
		projection = glm::perspective(glm::radians(fov), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);

		ourShader.use();
// 		int modelLoc = glGetUniformLocation(ourShader.ID, "model");
// 		glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
// 		int viewLoc = glGetUniformLocation(ourShader.ID, "view");
// 		glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
		glm::mat4 view;
		view = glm::lookAt(cameraPos, cameraPos + cameraFront, cameraUp);
		ourShader.setMat4("view", view);
		int projectionLoc = glGetUniformLocation(ourShader.ID, "projection");
		glUniformMatrix4fv(projectionLoc, 1, GL_FALSE, glm::value_ptr(projection));

		glBindVertexArray(VAO);
		for (unsigned int i = 0; i < 10; i++)
		{
			glm::mat4 model;
			model = glm::translate(model, cubePositions[i]);
			float angle = 20.0f * i;
			model = glm::rotate(model, glm::radians(angle), glm::vec3(1.0f, 0.3f, 0.5f));
			ourShader.setMat4("model", model);

// 			float radius = 10.0f;
// 			float camX = sin(glfwGetTime()) * radius;
// 			float camZ = cos(glfwGetTime()) * radius;
// 			glm::mat4 view;
// 			view = glm::lookAt(glm::vec3(camX, 0.0, camZ), glm::vec3(0.0, 0.0, 0.0), glm::vec3(0.0, 1.0, 0.0));
// 			ourShader.setMat4("view", view);

			glDrawArrays(GL_TRIANGLES, 0, 36);
		}

		//glBindVertexArray(0); // no need to unbind it every time 

		//交换颜色缓冲（它是一个储存着GLFW窗口每一个像素颜色值的大缓冲）
		glfwSwapBuffers(window);
		//检查有没有触发什么事件（比如键盘输入、鼠标移动等）
		//更新窗口状态，并调用对应的回调函数（可以通过回调方法手动设置
		glfwPollEvents();
	}

	glDeleteVertexArrays(1, &VAO);
	glDeleteBuffers(1, &VBO);
	glDeleteProgram(ourShader.ID);
	glDeleteTextures(1, &texture1);
	glDeleteTextures(1, &texture2);

	// 释放删除之前分配的所有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)
{
	// 是否按下了ESC按键 没按则返回GLFW_RELEASE
	// 如果按下，设置true来关闭GLFW，因此下次循环while条件检测失败，程序关闭
	if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
		glfwSetWindowShouldClose(window, true);

	float cameraSpeed = 2.5f * deltaTime;
	if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
		cameraPos += cameraSpeed * cameraFront;
	if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
		cameraPos -= cameraSpeed * cameraFront;
	if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
		cameraPos -= glm::normalize(glm::cross(cameraFront, cameraUp)) * cameraSpeed;
	if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
		cameraPos += glm::normalize(glm::cross(cameraFront, cameraUp)) * cameraSpeed;
}

// 回调函数，每次窗口大小被调整时调用
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
	// 前两个参数：窗口左下角位置
	// 后两个参数：宽度，高度
	glViewport(0, 0, width, height);
}

void mouse_callback(GLFWwindow* window, double xpos, double ypos)
{
	if (firstMouse)
	{
		lastX = xpos;
		lastY = ypos;
		firstMouse = false;
	}

	float xoffset = xpos - lastX;
	float yoffset = lastY - ypos; // 注意这里是相反的，因为y坐标是从底部往顶部依次增大的
	lastX = xpos;
	lastY = ypos;

	float sensitivity = 0.05f;
	xoffset *= sensitivity;
	yoffset *= sensitivity;

	yaw += xoffset;
	pitch += yoffset;

	if (pitch > 89.0f)
		pitch = 89.0f;
	if (pitch < -89.0f)
		pitch = -89.0f;

	glm::vec3 front;
	front.x = cos(glm::radians(yaw)) * cos(glm::radians(pitch));
	front.y = sin(glm::radians(pitch));
	front.z = sin(glm::radians(yaw)) * cos(glm::radians(pitch));
	cameraFront = glm::normalize(front);
}

void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
	if (fov >= 1.0f && fov <= 45.0f)
		fov -= yoffset;
	if (fov <= 1.0f)
		fov = 1.0f;
	if (fov >= 45.0f)
		fov = 45.0f;
}*/