glm::lookAt(eye, center, up);
eye 表示摄像机所在位置，
center 表示摄像机要看向的中心点的位置，即正在查看的位置(一个位置)。如果要使用方向向量D而不是中心位置，则可以简单地使用eye + D作为中心位置，其中D可以是单位向量
up 表示摄像机的三个方位向量中的up向量。
main.cpp
#define GLEW_STATIC
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include "shader.h"
#include "stb_image.h"
#include <glm.hpp>
#include <gtc/matrix_transform.hpp>
#include <gtc/type_ptr.hpp>
#include "Camera.h"
GLfloat 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
};
GLuint indices[] = {
0, 1, 3,
1, 2, 3
};
GLfloat mixAlpha = 0.2;
//十个立方体的位置向量
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)
};
Camera* myCamera = new Camera(glm::vec3(0.0f, 0.0f, 3.0f), glm::vec3(0.0f, 0.0f, -1.0f), glm::vec3(0.0f, 1.0f, 0.0f));
void mouse_callback(GLFWwindow* window, double xpos, double ypos) {
myCamera->mouseCb(xpos, ypos);
};
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
myCamera->scrollCb(xoffset, yoffset);
}
GLfloat deltaTime = 0.0f; // 当前帧与上一帧的时间差
GLfloat lastFrame = 0.0f; // 上一帧的时间
void processInput(GLFWwindow* window) {
GLfloat currentFrame = glfwGetTime();
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
if (glfwGetKey(window, GLFW_KEY_UP) == GLFW_PRESS) {
mixAlpha += 0.1;
if (mixAlpha > 1.0) mixAlpha = 1.0;
}
if (glfwGetKey(window, GLFW_KEY_DOWN) == GLFW_PRESS)
mixAlpha -= 0.1;
if (mixAlpha < 0.0) mixAlpha = 0.0;
if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS) {
myCamera->pressKeyW(deltaTime);
}
if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS) {
myCamera->pressKeyS(deltaTime);
}
if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS) {
myCamera->pressKeyA(deltaTime);
}
if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS) {
myCamera->pressKeyD(deltaTime);
}
}
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(800, 600, "test", nullptr, nullptr);
if (window == nullptr)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);//隐藏光标，并捕捉(Capture)它
glfwSetCursorPosCallback(window, mouse_callback);
glfwSetScrollCallback(window, scroll_callback);
glewExperimental = GL_TRUE;
if (glewInit() != GLEW_OK)
{
std::cout << "Failed to initialize GLEW" << std::endl;
glfwTerminate();
return -1;
}
glViewport(0, 0, 800, 600);
GLuint VAO;
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
GLuint VBO;
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
GLuint EBO;
glGenBuffers(1, &EBO);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(1);
glBindVertexArray(0);
GLuint texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
int width, height;
unsigned char* image = stbi_load("container.jpg", &width, &height, 0, 0);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
glGenerateMipmap(GL_TEXTURE_2D);
stbi_image_free(image);
glBindTexture(GL_TEXTURE_2D, 0);
GLuint texture1;
glGenTextures(1, &texture1);
glBindTexture(GL_TEXTURE_2D, texture1);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
int width1, height1;
unsigned char* image1 = stbi_load("awesomeface.png", &width1, &height1, 0, 0);
if (image1) {
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width1, height1, 0, GL_RGBA, GL_UNSIGNED_BYTE, image1);
glGenerateMipmap(GL_TEXTURE_2D);
}
else {
std::cout << "Failed to load texture" << std::endl;
}
stbi_image_free(image1);
//glm::vec3 cameraPos = glm::vec3(0.0f, 0.0f, 3.0f);//定义摄像机位置
//glm::vec3 cameraTarget = glm::vec3(0.0f, 0.0f, 0.0f);
//glm::vec3 cameraDirection = glm::normalize(cameraPos - cameraTarget);
摄像机方向，注意是指向的向量，朝z轴正向，而非注视的方向
方向向量是指向它到目标向量的相反方向，上述是摄像机指向远点(0，0，0)目标向量（z轴3.0指向0.0）的相反方向，即z轴正向。
//glm::vec3 up = glm::vec3(0.0f, 1.0f, 0.0f);//定义一个上向量
//glm::vec3 cameraRight = glm::normalize(glm::cross(up, cameraDirection));
上向量与摄像机方向向量叉乘，获得右向量(指向摄像机空间x轴的正向)。交换叉乘顺序，则指向x轴负向。
//glm::vec3 cameraUp = glm::cross(cameraDirection, cameraRight);//摄像机x轴与z轴叉乘，获取摄像机y轴
/* 三个轴加一个平移向量可创建lookAt矩阵，以此矩阵乘任何向量，即可将向量变换至摄像机的坐标空间。
lookAt矩阵[ Rx,Ry,Rz,0 [1,0,0,-Px
Ux,Uy,Uz,0 0,1,0,-Py
Dx,Dy,Dz,0 * 0,0,1,-Pz
0, 0, 0, 1] 0,0,0, 1]
R是右向量，U是上向量，D是方向向量，P为摄像机位置。
*/
/*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));*/
//lookAt直接创建观察矩阵。参数：1.摄像机位置，2.目标位置，3.上向量
Shader* testShader = new Shader("test.vert", "test.frag");
//创建模型矩阵
glm::mat4 model;
//投影矩阵
glm::mat4 projection;
glEnable(GL_DEPTH_TEST);
testShader->Use();
//给shader传值前，先激活要使用的program
while (!glfwWindowShouldClose(window))
{
processInput(window);
glfwPollEvents();
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT| GL_DEPTH_BUFFER_BIT);//清除前一帧的深度信息
/*direction.y = sin(glm::radians(pitch));
direction.x = cos(glm::radians(pitch)) * cos(glm::radians(yaw));
direction.z = cos(glm::radians(pitch)) * sin(glm::radians(yaw));*/
/*GLfloat radius = 10.0f;
GLfloat camX = sin(glfwGetTime()) * radius;
GLfloat 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));*/
//围绕场景旋转的观察矩阵
glm::mat4 view = myCamera->getViewMat4();
glUniformMatrix4fv(glGetUniformLocation(testShader->getProgram(), "view"), 1, GL_FALSE, glm::value_ptr(view));
projection = glm::perspective(glm::radians(myCamera->getFov()), 800.0f / 600.0f, 0.1f, 100.0f);
glUniformMatrix4fv(glGetUniformLocation(testShader->getProgram(), "projection"), 1, GL_FALSE, glm::value_ptr(projection));
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture);
glUniform1i(glGetUniformLocation(testShader->getProgram(), "ourTexture"), 0);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, texture1);
glUniform1i(glGetUniformLocation(testShader->getProgram(), "ourTexture1"), 1);
glUniform1f(glGetUniformLocation(testShader->getProgram(), "mixAlpha"), mixAlpha);
glBindVertexArray(VAO);
//glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
for (GLuint i = 0; i < 10; i++)
{
glm::mat4 model;
model = glm::translate(model, cubePositions[i]);
GLfloat angle = 20.0f * i;
if (i % 3 == 0) model = glm::rotate(model, angle, glm::vec3(1.0f, 0.3f, 0.5f));
glUniformMatrix4fv(glGetUniformLocation(testShader->getProgram(), "model"), 1, GL_FALSE, glm::value_ptr(model));
glDrawArrays(GL_TRIANGLES, 0, 36);
}
glBindVertexArray(0);
glfwSwapBuffers(window);
}
glfwTerminate();
return 0;
}
Camera.h
#pragma once
#ifndef CAMERA_H
#define CAMERA_H
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <glm.hpp>
#include <gtc/matrix_transform.hpp>
#include <gtc/type_ptr.hpp>
class Camera
{
public:
Camera(glm::vec3 cameraPos, glm::vec3 cameraFront, glm::vec3 cameraUp);
void mouseCb(double xpos, double ypos);
void scrollCb(double xoffset, double yoffset);
void pressKeyW(GLfloat deltaTime);
void pressKeyS(GLfloat deltaTime);
void pressKeyA(GLfloat deltaTime);
void pressKeyD(GLfloat deltaTime);
glm::mat4 getViewMat4();
GLfloat getFov() {
return this->fov; };
private:
GLfloat cameraSpeed = 0.05f;
glm::vec3 cameraPos;
glm::vec3 cameraFront;
glm::vec3 cameraUp;
GLfloat lastX = 400, lastY = 300;//鼠标初始位置
GLfloat pitch = 0.0f, yaw = -90.0f;
bool firstMouse = true;
GLfloat fov = 45.0f;
};
#endif
Camera.cpp
#include "Camera.h"
Camera::Camera(glm::vec3 cameraPos, glm::vec3 cameraFront, glm::vec3 cameraUp) {
this->cameraPos = cameraPos;
this->cameraFront = cameraFront;
this->cameraUp = cameraUp;
}
//xpos和ypos代表当前鼠标的位置。储存上一帧鼠标的位置，通关当前鼠标与上一帧鼠标位置差值计算偏航角与俯仰角
void Camera::mouseCb(double xpos, double ypos) {
if (this->firstMouse)
{
this->lastX = xpos;
this->lastY = ypos;
this->firstMouse = false;
}
GLfloat xoffset = xpos - this->lastX;
GLfloat yoffset = this->lastY - ypos; // 注意这里是相反的，因为y坐标的范围是从下往上的
this->lastX = xpos;
this->lastY = ypos;
GLfloat sensitivity = 0.05f;
xoffset *= sensitivity;
yoffset *= sensitivity;
this->yaw += xoffset;
this->pitch += yoffset;
//限制不能高于89度，90度时视角会逆转
if (this->pitch > 89.0f)
this->pitch = 89.0f;
if (this->pitch < -89.0f)
this->pitch = -89.0f;
glm::vec3 front;
front.x = cos(glm::radians(this->pitch)) * cos(glm::radians(this->yaw));
front.y = sin(glm::radians(this->pitch));
front.z = cos(glm::radians(this->pitch)) * sin(glm::radians(this->yaw));
this->cameraFront = glm::normalize(front);
}
//鼠标滚轮控制视野,yoffset为滚动大小
void Camera::scrollCb(double xoffset, double yoffset)
{
if (this->fov >= 1.0f && this->fov <= 45.0f)
this->fov -= yoffset;
if (this->fov <= 1.0f)
this->fov = 1.0f;
if (this->fov >= 45.0f)
this->fov = 45.0f;
}
void Camera::pressKeyW(GLfloat deltaTime) {
this->cameraSpeed = 2.5f * deltaTime;
this->cameraPos += this->cameraSpeed * this->cameraFront;
}
void Camera::pressKeyS(GLfloat deltaTime) {
this->cameraSpeed = 2.5f * deltaTime;
this->cameraPos -= this->cameraSpeed * this->cameraFront;
}
void Camera::pressKeyA(GLfloat deltaTime) {
this->cameraSpeed = 2.5f * deltaTime;
this->cameraPos -= glm::normalize(glm::cross(this->cameraFront, this->cameraUp)) * this->cameraSpeed;
}
void Camera::pressKeyD(GLfloat deltaTime) {
this->cameraSpeed = 2.5f * deltaTime;
this->cameraPos += glm::normalize(glm::cross(this->cameraFront, this->cameraUp)) * this->cameraSpeed;
}
glm::mat4 Camera::getViewMat4() {
//摄像机位置加定义的方向向量，保证摄像机无论在哪，都会注视目标
return glm::lookAt(this->cameraPos, this->cameraPos + this->cameraFront, this->cameraUp);
}
练习一：
#include "Camera.h"
Camera::Camera(glm::vec3 cameraPos, glm::vec3 cameraFront, glm::vec3 cameraUp) {
this->cameraPos = cameraPos;
this->cameraFront = cameraFront;
this->cameraUp = cameraUp;
}
//xpos和ypos代表当前鼠标的位置。储存上一帧鼠标的位置，通关当前鼠标与上一帧鼠标位置差值计算偏航角与俯仰角
void Camera::mouseCb(double xpos, double ypos) {
if (this->firstMouse)
{
this->lastX = xpos;
this->lastY = ypos;
this->firstMouse = false;
}
GLfloat xoffset = xpos - this->lastX;
GLfloat yoffset = this->lastY - ypos; // 注意这里是相反的，因为y坐标的范围是从下往上的
this->lastX = xpos;
this->lastY = ypos;
GLfloat sensitivity = 0.05f;
xoffset *= sensitivity;
yoffset *= sensitivity;
this->yaw += xoffset;
this->pitch += yoffset;
//限制不能高于89度，90度时视角会逆转
if (this->pitch > 89.0f)
this->pitch = 89.0f;
if (this->pitch < -89.0f)
this->pitch = -89.0f;
glm::vec3 front;
front.x = cos(glm::radians(this->pitch)) * cos(glm::radians(this->yaw));
front.y = sin(glm::radians(this->pitch));
front.z = cos(glm::radians(this->pitch)) * sin(glm::radians(this->yaw));
this->cameraFront = glm::normalize(front);
}
//鼠标滚轮控制视野,yoffset为滚动大小
void Camera::scrollCb(double xoffset, double yoffset)
{
if (this->fov >= 1.0f && this->fov <= 45.0f)
this->fov -= yoffset;
if (this->fov <= 1.0f)
this->fov = 1.0f;
if (this->fov >= 45.0f)
this->fov = 45.0f;
}
void Camera::pressKeyW(GLfloat deltaTime) {
this->cameraSpeed = 2.5f * deltaTime;
this->cameraPos += this->cameraSpeed * this->cameraFront;
}
void Camera::pressKeyS(GLfloat deltaTime) {
this->cameraSpeed = 2.5f * deltaTime;
this->cameraPos -= this->cameraSpeed * this->cameraFront;
}
void Camera::pressKeyA(GLfloat deltaTime) {
this->cameraSpeed = 2.5f * deltaTime;
this->cameraPos -= glm::normalize(glm::cross(this->cameraFront, this->cameraUp)) * this->cameraSpeed;
}
void Camera::pressKeyD(GLfloat deltaTime) {
this->cameraSpeed = 2.5f * deltaTime;
this->cameraPos += glm::normalize(glm::cross(this->cameraFront, this->cameraUp)) * this->cameraSpeed;
}
glm::mat4 Camera::getViewMat4() {
//摄像机位置加定义的方向向量，保证摄像机无论在哪，都会注视目标
this->cameraPos.y = 0.0f;
return glm::lookAt(this->cameraPos, this->cameraPos + this->cameraFront, this->cameraUp);
}
练习二
#include "Camera.h"
Camera::Camera(glm::vec3 cameraPos, glm::vec3 cameraFront, glm::vec3 cameraUp) {
this->cameraPos = cameraPos;
this->cameraFront = cameraFront;
this->cameraUp = cameraUp;
}
//xpos和ypos代表当前鼠标的位置。储存上一帧鼠标的位置，通关当前鼠标与上一帧鼠标位置差值计算偏航角与俯仰角
void Camera::mouseCb(double xpos, double ypos) {
if (this->firstMouse)
{
this->lastX = xpos;
this->lastY = ypos;
this->firstMouse = false;
}
GLfloat xoffset = xpos - this->lastX;
GLfloat yoffset = this->lastY - ypos; // 注意这里是相反的，因为y坐标的范围是从下往上的
this->lastX = xpos;
this->lastY = ypos;
GLfloat sensitivity = 0.05f;
xoffset *= sensitivity;
yoffset *= sensitivity;
this->yaw += xoffset;
this->pitch += yoffset;
//限制不能高于89度，90度时视角会逆转
if (this->pitch > 89.0f)
this->pitch = 89.0f;
if (this->pitch < -89.0f)
this->pitch = -89.0f;
glm::vec3 front;
front.x = cos(glm::radians(this->pitch)) * cos(glm::radians(this->yaw));
front.y = sin(glm::radians(this->pitch));
front.z = cos(glm::radians(this->pitch)) * sin(glm::radians(this->yaw));
this->cameraFront = glm::normalize(front);
}
//鼠标滚轮控制视野,yoffset为滚动大小
void Camera::scrollCb(double xoffset, double yoffset)
{
if (this->fov >= 1.0f && this->fov <= 45.0f)
this->fov -= yoffset;
if (this->fov <= 1.0f)
this->fov = 1.0f;
if (this->fov >= 45.0f)
this->fov = 45.0f;
}
void Camera::pressKeyW(GLfloat deltaTime) {
this->cameraSpeed = 2.5f * deltaTime;
this->cameraPos += this->cameraSpeed * this->cameraFront;
}
void Camera::pressKeyS(GLfloat deltaTime) {
this->cameraSpeed = 2.5f * deltaTime;
this->cameraPos -= this->cameraSpeed * this->cameraFront;
}
void Camera::pressKeyA(GLfloat deltaTime) {
this->cameraSpeed = 2.5f * deltaTime;
this->cameraPos -= glm::normalize(glm::cross(this->cameraFront, this->cameraUp)) * this->cameraSpeed;
}
void Camera::pressKeyD(GLfloat deltaTime) {
this->cameraSpeed = 2.5f * deltaTime;
this->cameraPos += glm::normalize(glm::cross(this->cameraFront, this->cameraUp)) * this->cameraSpeed;
}
glm::mat4 Camera::getViewMat4() {
//摄像机位置加定义的方向向量，保证摄像机无论在哪，都会注视目标
this->cameraPos.y = 0.0f;
//return glm::lookAt(this->cameraPos, this->cameraPos + this->cameraFront, this->cameraUp);
glm::vec3 cameraZ = glm::normalize(cameraPos - cameraFront);
glm::vec3 cameraX = glm::normalize(glm::cross(cameraUp, cameraZ));
glm::vec3 cameraY = glm::cross(cameraZ, cameraX);
//注意：mat4是按列存储矩阵信息。即mat4数组第一行为矩阵第一列的信息。
glm::mat4 translation = glm::mat4(1.0f);
translation[0][0] = cameraX.x;
translation[0][1] = cameraY.x;
translation[0][2] = cameraZ.x;
translation[1][0] = cameraX.y;
translation[1][1] = cameraY.y;
translation[1][2] = cameraZ.y;
translation[2][0] = cameraX.z;
translation[2][1] = cameraY.z;
translation[2][2] = cameraZ.z;
glm::mat4 translation1 = glm::mat4(1.0f);
translation1[3][0] = -cameraPos.x;
translation1[3][1] = -cameraPos.y;
translation1[3][2] = -cameraPos.z;
return translation * translation1;
}