本篇目的是学习如何在OpenGL自由观察，即设计一个类似于3dMAX，Blender，或Unity3D中常见的摄像机观察机制。具有可以用键盘前后左右上下的视角控制功能，和鼠标拖移视角的功能。
（Vries的原教程地址如下，https://learnopengl-cn.github.io/01%20Getting%20started/09%20Camera/关于OpenGL函数的详细解析及摄像机这一知识点描述请看这个教程，本篇旨在对Vires基于visual studio的编程思想做Qt平台的移植）
Qt开发平台：5.8.0
编译器：Desktop Qt 5.8.0 MSVC2015_64bit
（一）视角环绕
让我们尝试将视角动起来，像上图所示。其实很简单，在上篇学习教程的代码中只要引入lookat()//(一个封装好的类摄像机函数，具体解析看Vires的教程啦)，稍微修改一下widget.cpp函数即可。
项目组织如下：
widget.cpp
#include "widget.h"
GLuint VBO, VAO;
Triangle::Triangle(){
this->setWindowTitle("Camera");
}
Triangle::~Triangle(){
delete ourShader;
core->glDeleteVertexArrays(1, &VAO);
core->glDeleteBuffers(1, &VBO);
texture1->destroy();
texture2->destroy();
}
void Triangle::initializeGL(){
//着色器部分
core = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_3_3_Core>();
ourShader = new Shader(":/shaders/vertexshadersource.vert", ":/shaders/fragmentshadersource.frag");
//VAO，VBO数据部分
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
};
core->glGenVertexArrays(1, &VAO);//两个参数，第一个为需要创建的缓存数量。第二个为用于存储单一ID或多个ID的GLuint变量或数组的地址
core->glGenBuffers(1, &VBO);
core->glBindVertexArray(VAO);
core->glBindBuffer(GL_ARRAY_BUFFER, VBO);
core->glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
core->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
core->glEnableVertexAttribArray(0);
// texture coord attribute
core->glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
core->glEnableVertexAttribArray(1);
//纹理
//第一张箱子
texture1 = new QOpenGLTexture(QImage(":/textures/res/textures/container.jpg").mirrored(), QOpenGLTexture::GenerateMipMaps); //直接生成绑定一个2d纹理, 并生成多级纹理MipMaps
if(!texture1->isCreated()){
qDebug() << "Failed to load texture" << endl;
}
texture1->setWrapMode(QOpenGLTexture::DirectionS, QOpenGLTexture::Repeat);// 等于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
texture1->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::Repeat);// glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
texture1->setMinificationFilter(QOpenGLTexture::Linear); //等价于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
texture1->setMagnificationFilter(QOpenGLTexture::Linear); // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
//第二张笑脸
texture2 = new QOpenGLTexture(QImage(":/textures/res/textures/smile.png").mirrored(), QOpenGLTexture::GenerateMipMaps); //直接生成绑定一个2d纹理, 并生成多级纹理MipMaps
if(!texture2->isCreated()){
qDebug() << "Failed to load texture" << endl;
}
texture2->setWrapMode(QOpenGLTexture::DirectionS, QOpenGLTexture::Repeat);// 等于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
texture2->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::Repeat);// glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
texture2->setMinificationFilter(QOpenGLTexture::Linear); //等价于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
texture2->setMagnificationFilter(QOpenGLTexture::Linear); // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
//设置纹理单元编号
ourShader->use();
ourShader->setInt("texture1", 0);
ourShader->setInt("texture2", 1);
//开启计时器，返回毫秒
time.start();
//给着色器变量赋值
QMatrix4x4 projection;
// view.translate(QVector3D(0.0f, 0.0f, -3.0f));
projection.perspective(45.0f, (GLfloat)width()/(GLfloat)height(), 0.1f, 100.0f);
ourShader->use();
//ourShader->setMat4("view", view);
ourShader->setMat4("projection", projection);
//开启状态
core->glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
core->glEnable(GL_DEPTH_TEST);
}
void Triangle::resizeGL(int w, int h){
core->glViewport(0, 0, w, h);
}
QVector3D cubePositions[] = { //为了省事，设为全局函数，若嫌封装性不好，改为成员变量指针，在initializeGL()重新赋值就好
QVector3D( 0.0f, 0.0f, -1.0f), //小小改动一下将z轴的0.0f变为-1.0f
QVector3D( 2.0f, 5.0f, -15.0f),
QVector3D(-1.5f, -2.2f, -2.5f),
QVector3D(-3.8f, -2.0f, -12.3f),
QVector3D( 2.4f, -0.4f, -3.5f),
QVector3D(-1.7f, 3.0f, -7.5f),
QVector3D( 1.3f, -2.0f, -2.5f),
QVector3D( 1.5f, 2.0f, -2.5f),
QVector3D( 1.5f, 0.2f, -1.5f),
QVector3D(-1.3f, 1.0f, -1.5f)
};
void Triangle::paintGL(){
core->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
core->glActiveTexture(GL_TEXTURE0);
texture1->bind();
core->glActiveTexture(GL_TEXTURE1);
texture2->bind();
ourShader->use();
QMatrix4x4 view;
GLfloat radius = 15.0f;
GLfloat camX = sin(((GLfloat)time.elapsed())/1000) * radius; //返回的毫秒太大了，除以1000小一些
GLfloat camZ = cos(((GLfloat)time.elapsed())/1000) * radius;
view.lookAt(QVector3D(camX, 0.0f, camZ), QVector3D(0.0f, 0.0f, 0.0f), QVector3D(0.0f, 1.0f, 0.0f));
ourShader->setMat4("view", view);
for(GLuint i = 0; i != 10; ++i){
QMatrix4x4 model;
model.translate(cubePositions[i]);
model.rotate(20.0f * i, cubePositions[i]);//这里角度改为固定角度
ourShader->setMat4("model", model);
core->glBindVertexArray(VAO);
core->glDrawArrays(GL_TRIANGLES, 0, 36);
}
update();
}
以下是没有改动过的函数：
widget.h
#ifndef WIDGET_H
#define WIDGET_H
#include <QOpenGLWidget>
#include <QDebug>
#include <QOpenGLFunctions_3_3_Core>
#include "shader.h"
#include <QOpenGLTexture>
#include <QTime> //增添头文件
class Triangle : public QOpenGLWidget
{
public:
Triangle();
GLuint a;
~Triangle();
protected:
virtual void initializeGL();
virtual void resizeGL(int w, int h);
virtual void paintGL();
private:
Shader *ourShader;
QOpenGLTexture *texture1;
QOpenGLTexture *texture2;
QOpenGLFunctions_3_3_Core *core;
QTime time; //增添QTime对象，替代glfwGetTime()函数
};
#endif // WIDGET_H
shader.h
#ifndef SHADER_H
#define SHADER_H
#include <QDebug>
#include <QOpenGLShader>
#include <QOpenGLShaderProgram>
#include <QString>
class Shader {
public:
Shader(const QString& vertexSourcePath, const QString& fragmentSourcePath);
~Shader();
QOpenGLShaderProgram *shaderProgram;
void use(){
shaderProgram->bind();
}
//还是把设置着色器uniform变量操作写成Shader里的inline成员函数管理，真的方便很多。
void setMat4(const QString& name, const QMatrix4x4& value){
GLuint loc = shaderProgram->uniformLocation(name);
shaderProgram->setUniformValue(loc, value);
}
void setInt(const QString& name, const GLint& value){
GLuint loc = shaderProgram->uniformLocation(name);
shaderProgram->setUniformValue(loc, value);
}
};
#endif // SHADER_H
shader.cpp
#include "shader.h"
Shader::Shader(const QString& vertexPath, const QString& fragmentPath){
QOpenGLShader vertexShader(QOpenGLShader::Vertex);
bool success = vertexShader.compileSourceFile(vertexPath);
if(!success){
qDebug() << "ERROR::SHADER::VERTEX::COMPILATION_FAILED" << endl;
qDebug() << vertexShader.log() << endl;
}
QOpenGLShader fragmentShader(QOpenGLShader::Fragment);
success =fragmentShader.compileSourceFile(fragmentPath);
if(!success){
qDebug() << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED" << endl;
qDebug() << fragmentShader.log() << endl;
}
shaderProgram = new QOpenGLShaderProgram();
shaderProgram->addShader(&vertexShader);
shaderProgram->addShader(&fragmentShader);
success = shaderProgram->link();
if(!success){
qDebug() << "ERROR::SHADER::PROGRAM::LINKING_FAILED" << endl;
qDebug() << shaderProgram->log() << endl;
}
}
Shader::~Shader(){
delete shaderProgram;
}
main.cpp
#include "widget.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Triangle t;
t.show();
return a.exec();
}
vertexshadersource.vert
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec2 aTexCoord;
out vec2 TexCoord;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main(){
gl_Position = projection * view * model * vec4(aPos, 1.0f);
TexCoord = aTexCoord;
}
fragmentshadersource.frag
#version 330 core
out vec4 FragColor;
in vec2 TexCoord;
uniform sampler2D texture1;
uniform sampler2D texture2;
void main()
{
FragColor = mix(texture2D(texture1, TexCoord), texture2D(texture2, TexCoord), 0.2f);
}
（二）自由移动
初步实现，使用键盘前后左右上下控制视角的功能。如下图所示
这次仅修改widget.h与widget.cpp函数
widget.h
为封装性考虑，将Vires放在cpp文件中的全局变量cameraPos，cameraFront等变量设为了成员变量
#ifndef WIDGET_H
#define WIDGET_H
#include <QOpenGLWidget>
#include <QDebug>
#include <QOpenGLFunctions_3_3_Core>
#include "shader.h"
#include <QOpenGLTexture>
#include <QTime> //增添头文件
#include <QVector3D>
class Triangle : public QOpenGLWidget
{
public:
Triangle();
GLuint a;
~Triangle();
protected:
virtual void initializeGL();
virtual void resizeGL(int w, int h);
virtual void paintGL();
void keyPressEvent(QKeyEvent *event);
private:
Shader *ourShader;
QOpenGLTexture *texture1;
QOpenGLTexture *texture2;
QOpenGLFunctions_3_3_Core *core;
QTime time; //增添QTime对象，替代glfwGetTime()函数
QVector3D cameraPos;
QVector3D cameraFront;
QVector3D cameraUp;
GLfloat deltaTime;
GLfloat lastFrame;
};
#endif // WIDGET_H
widget.cpp
因为没有不再实现箱子的旋转动画效果了，按理说应该删除paintGL()函数里的update()刷新函数，以节省资源，可按Vries大神的思想，deltaTime，即帧与帧之间的间隔时间又必须在放循环里才能得到。参考官方给的示例，对与循环机制，是靠一个计时器timer不断调用刷新函数update()实现的，与把update()放在paintGL()里本质上没什么区别，区别就是timer是每隔20毫秒刷新一次，另一个则是取决于电脑性能本身，性能好就刷新快，差就刷新慢。所以思想上还是跟Vries看起，把update()放在paintGL()里吧。
//示例里的一段函数，每隔20秒，执行一次rotateOneStep()函数，函数里执行rotateBy()函数，而这个函数里包含有update()刷新函数。
#include "widget.h"
#include <QKeyEvent>
GLuint VBO, VAO;
Triangle::Triangle(){
this->setWindowTitle("Camera");
}
Triangle::~Triangle(){
delete ourShader;
core->glDeleteVertexArrays(1, &VAO);
core->glDeleteBuffers(1, &VBO);
texture1->destroy();
texture2->destroy();
}
void Triangle::initializeGL(){
//着色器部分
core = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_3_3_Core>();
ourShader = new Shader(":/shaders/vertexshadersource.vert", ":/shaders/fragmentshadersource.frag");
//VAO，VBO数据部分
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
};
core->glGenVertexArrays(1, &VAO);//两个参数，第一个为需要创建的缓存数量。第二个为用于存储单一ID或多个ID的GLuint变量或数组的地址
core->glGenBuffers(1, &VBO);
core->glBindVertexArray(VAO);
core->glBindBuffer(GL_ARRAY_BUFFER, VBO);
core->glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
core->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
core->glEnableVertexAttribArray(0);
// texture coord attribute
core->glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
core->glEnableVertexAttribArray(1);
//纹理
//第一张箱子
texture1 = new QOpenGLTexture(QImage(":/textures/res/textures/container.jpg").mirrored(), QOpenGLTexture::GenerateMipMaps); //直接生成绑定一个2d纹理, 并生成多级纹理MipMaps
if(!texture1->isCreated()){
qDebug() << "Failed to load texture" << endl;
}
texture1->setWrapMode(QOpenGLTexture::DirectionS, QOpenGLTexture::Repeat);// 等于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
texture1->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::Repeat);// glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
texture1->setMinificationFilter(QOpenGLTexture::Linear); //等价于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
texture1->setMagnificationFilter(QOpenGLTexture::Linear); // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
//第二张笑脸
texture2 = new QOpenGLTexture(QImage(":/textures/res/textures/smile.png").mirrored(), QOpenGLTexture::GenerateMipMaps); //直接生成绑定一个2d纹理, 并生成多级纹理MipMaps
if(!texture2->isCreated()){
qDebug() << "Failed to load texture" << endl;
}
texture2->setWrapMode(QOpenGLTexture::DirectionS, QOpenGLTexture::Repeat);// 等于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
texture2->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::Repeat);// glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
texture2->setMinificationFilter(QOpenGLTexture::Linear); //等价于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
texture2->setMagnificationFilter(QOpenGLTexture::Linear); // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
//设置纹理单元编号
ourShader->use();
ourShader->setInt("texture1", 0);
ourShader->setInt("texture2", 1);
//开启计时器，返回毫秒
time.start();
//给着色器变量赋值
QMatrix4x4 projection;
projection.perspective(45.0f, (GLfloat)width()/(GLfloat)height(), 0.1f, 100.0f);
ourShader->use();
ourShader->setMat4("projection", projection);
//开启状态
core->glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
core->glEnable(GL_DEPTH_TEST);
//emmm ,本来成员变量的初始化应该放在构造函数里，不过这些变量和OpenGL相关，就放在initializeGL（）里方便管理；
cameraPos = QVector3D(0.0f, 0.0f, 3.0f);
cameraFront = QVector3D(0.0f, 0.0f, -1.0f);
cameraUp = QVector3D(0.0f, 1.0f, 0.0f);
deltaTime = 0.0f;
lastFrame = 0.0f;
}
void Triangle::resizeGL(int w, int h){
core->glViewport(0, 0, w, h);
}
QVector3D cubePositions[] = { //为了省事，设为全局函数，若嫌封装性不好，改为成员变量指针，在initializeGL()重新赋值就好
QVector3D( 0.0f, 0.0f, -1.0f), //小小改动一下将z轴的0.0f变为-1.0f
QVector3D( 2.0f, 5.0f, -15.0f),
QVector3D(-1.5f, -2.2f, -2.5f),
QVector3D(-3.8f, -2.0f, -12.3f),
QVector3D( 2.4f, -0.4f, -3.5f),
QVector3D(-1.7f, 3.0f, -7.5f),
QVector3D( 1.3f, -2.0f, -2.5f),
QVector3D( 1.5f, 2.0f, -2.5f),
QVector3D( 1.5f, 0.2f, -1.5f),
QVector3D(-1.3f, 1.0f, -1.5f)
};
void Triangle::paintGL(){
GLfloat currentFrame = (GLfloat)time.elapsed()/100;
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
core->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
core->glActiveTexture(GL_TEXTURE0);
texture1->bind();
core->glActiveTexture(GL_TEXTURE1);
texture2->bind();
ourShader->use();
QMatrix4x4 view;
view.lookAt(cameraPos, cameraPos+cameraFront, cameraUp);
ourShader->setMat4("view", view);
for(GLuint i = 0; i != 10; ++i){
QMatrix4x4 model;
model.translate(cubePositions[i]);
model.rotate(20.0f * i, cubePositions[i]);//这里角度的设置仍然为时间，如果按照Vires大神写的i*20, 箱子不会旋转
ourShader->setMat4("model", model);
core->glBindVertexArray(VAO);
core->glDrawArrays(GL_TRIANGLES, 0, 36);
}
update();
}
void Triangle::keyPressEvent(QKeyEvent *event)
{
GLfloat cameraSpeed = 2.5 * deltaTime;
if(event->key() == Qt::Key_W){
cameraPos += cameraFront * cameraSpeed;
}
if(event->key() == Qt::Key_S){
cameraPos -= cameraFront * cameraSpeed;
}
if(event->key() == Qt::Key_A){
cameraPos -= (QVector3D::crossProduct(cameraFront, cameraUp).normalized()) * cameraSpeed;
}
if(event->key() == Qt::Key_D){
cameraPos += (QVector3D::crossProduct(cameraFront, cameraUp).normalized()) * cameraSpeed;
}
if(event->key() == Qt::Key_E){ //上升
cameraPos += cameraUp * cameraSpeed;
}
if(event->key() == Qt::Key_Q){ //下降
cameraPos -= cameraUp * cameraSpeed;
}
}
（三）鼠标输入与缩放
按住鼠标左键进行视角的拖拉移动，使用鼠标滚轮放大缩小视角，emmm，还是因为没有glfw函数，无法实现Vires教程中的锁定鼠标光标功能，即下图函数。（不实现也好，这个锁定光标操作有点反人类，在（四）中，会对这个操作进行改善）
整体鼠标左键与滚轮操作，鼠标操作过程中可以同时进行键盘操作，如下图所示：
以为我们的类是继承自 Qwidget的，所以只要在proteced域内，重载mouseMoveEvent(QMouseEvent *event)即可使用鼠标事件，详见注释
widget.h
#ifndef WIDGET_H
#define WIDGET_H
#include <QOpenGLWidget>
#include <QDebug>
#include <QOpenGLFunctions_3_3_Core>
#include "shader.h"
#include <QOpenGLTexture>
#include <QTime> //增添头文件
#include <QVector3D>
class Triangle : public QOpenGLWidget
{
public:
Triangle();
GLuint a;
~Triangle();
protected:
virtual void initializeGL();
virtual void resizeGL(int w, int h);
virtual void paintGL();
void keyPressEvent(QKeyEvent *event); //键盘事件
void mouseMoveEvent(QMouseEvent *event);//鼠标事件
void wheelEvent(QWheelEvent *event); //滚轮事件
private:
Shader *ourShader;
QOpenGLTexture *texture1;
QOpenGLTexture *texture2;
QOpenGLFunctions_3_3_Core *core;
QTime time; //增添QTime对象，替代glfwGetTime()函数
QVector3D cameraPos;
QVector3D cameraFront;
QVector3D cameraUp;
GLfloat deltaTime;
GLfloat lastFrame;
GLboolean firstMouse;
GLfloat yaw;
GLfloat pitch;
GLfloat lastX;
GLfloat lastY;
GLfloat fov;
};
#endif // WIDGET_H
widget.cpp
#include "widget.h"
#include <QKeyEvent>
GLuint VBO, VAO;
Triangle::Triangle(){
this->setWindowTitle("Camera");
}
Triangle::~Triangle(){
delete ourShader;
core->glDeleteVertexArrays(1, &VAO);
core->glDeleteBuffers(1, &VBO);
texture1->destroy();
texture2->destroy();
}
void Triangle::initializeGL(){
//着色器部分
core = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_3_3_Core>();
ourShader = new Shader(":/shaders/vertexshadersource.vert", ":/shaders/fragmentshadersource.frag");
//VAO，VBO数据部分
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
};
core->glGenVertexArrays(1, &VAO);//两个参数，第一个为需要创建的缓存数量。第二个为用于存储单一ID或多个ID的GLuint变量或数组的地址
core->glGenBuffers(1, &VBO);
core->glBindVertexArray(VAO);
core->glBindBuffer(GL_ARRAY_BUFFER, VBO);
core->glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
core->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
core->glEnableVertexAttribArray(0);
// texture coord attribute
core->glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
core->glEnableVertexAttribArray(1);
//纹理
//第一张箱子
texture1 = new QOpenGLTexture(QImage(":/textures/res/textures/container.jpg").mirrored(), QOpenGLTexture::GenerateMipMaps); //直接生成绑定一个2d纹理, 并生成多级纹理MipMaps
if(!texture1->isCreated()){
qDebug() << "Failed to load texture" << endl;
}
texture1->setWrapMode(QOpenGLTexture::DirectionS, QOpenGLTexture::Repeat);// 等于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
texture1->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::Repeat);// glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
texture1->setMinificationFilter(QOpenGLTexture::Linear); //等价于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
texture1->setMagnificationFilter(QOpenGLTexture::Linear); // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
//第二张笑脸
texture2 = new QOpenGLTexture(QImage(":/textures/res/textures/smile.png").mirrored(), QOpenGLTexture::GenerateMipMaps); //直接生成绑定一个2d纹理, 并生成多级纹理MipMaps
if(!texture2->isCreated()){
qDebug() << "Failed to load texture" << endl;
}
texture2->setWrapMode(QOpenGLTexture::DirectionS, QOpenGLTexture::Repeat);// 等于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
texture2->setWrapMode(QOpenGLTexture::DirectionT, QOpenGLTexture::Repeat);// glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
texture2->setMinificationFilter(QOpenGLTexture::Linear); //等价于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
texture2->setMagnificationFilter(QOpenGLTexture::Linear); // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
//设置纹理单元编号
ourShader->use();
ourShader->setInt("texture1", 0);
ourShader->setInt("texture2", 1);
//开启计时器，返回毫秒
time.start();
//开启状态
core->glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
core->glEnable(GL_DEPTH_TEST);
//emmm ,本来成员变量的初始化应该放在构造函数里，不过这些变量和OpenGL相关，就放在initializeGL（）里方便管理；
cameraPos = QVector3D(0.0f, 0.0f, 3.0f);
cameraFront = QVector3D(0.0f, 0.0f, -1.0f);
cameraUp = QVector3D(0.0f, 1.0f, 0.0f);
deltaTime = 0.0f;
lastFrame = 0.0f;
//与鼠标相关的摄像机变量初始化
firstMouse = true;
yaw = -90.0f; // 偏航角如果是0.0f,指向的是 x轴正方向，即右方向，所以向里转90度，初始方向指向z轴负方向
pitch = 0.0f;
lastX = 800.0f / 2.0;
lastY = 600.0 / 2.0;
fov = 45.0f;
}
void Triangle::resizeGL(int w, int h){
core->glViewport(0, 0, w, h);
}
QVector3D cubePositions[] = { //为了省事，设为全局函数，若嫌封装性不好，改为成员变量指针，在initializeGL()重新赋值就好
QVector3D( 0.0f, 0.0f, -1.0f), //小小改动一下将z轴的0.0f变为-1.0f
QVector3D( 2.0f, 5.0f, -15.0f),
QVector3D(-1.5f, -2.2f, -2.5f),
QVector3D(-3.8f, -2.0f, -12.3f),
QVector3D( 2.4f, -0.4f, -3.5f),
QVector3D(-1.7f, 3.0f, -7.5f),
QVector3D( 1.3f, -2.0f, -2.5f),
QVector3D( 1.5f, 2.0f, -2.5f),
QVector3D( 1.5f, 0.2f, -1.5f),
QVector3D(-1.3f, 1.0f, -1.5f)
};
void Triangle::paintGL(){
GLfloat currentFrame = (GLfloat)time.elapsed()/100;
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
core->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
core->glActiveTexture(GL_TEXTURE0);
texture1->bind();
core->glActiveTexture(GL_TEXTURE1);
texture2->bind();
ourShader->use();
QMatrix4x4 projection;
projection.perspective(fov, (GLfloat)width()/(GLfloat)height(), 0.1f, 100.f);
ourShader->setMat4("projection", projection);
QMatrix4x4 view;
view.lookAt(cameraPos, cameraPos+cameraFront, cameraUp);
ourShader->setMat4("view", view);
for(GLuint i = 0; i != 10; ++i){
QMatrix4x4 model;
model.translate(cubePositions[i]);
model.rotate(20.0f * i, cubePositions[i]);//这里角度的设置仍然为时间，如果按照Vires大神写的i*20, 箱子不会旋转
ourShader->setMat4("model", model);
core->glBindVertexArray(VAO);
core->glDrawArrays(GL_TRIANGLES, 0, 36);
}
update();
}
void Triangle::keyPressEvent(QKeyEvent *event)
{
GLfloat cameraSpeed = 2.5 * deltaTime;
if(event->key() == Qt::Key_W){
cameraPos += cameraFront * cameraSpeed;
}
if(event->key() == Qt::Key_S){
cameraPos -= cameraFront * cameraSpeed;
}
if(event->key() == Qt::Key_A){
cameraPos -= (QVector3D::crossProduct(cameraFront, cameraUp).normalized()) * cameraSpeed;
}
if(event->key() == Qt::Key_D){
cameraPos += (QVector3D::crossProduct(cameraFront, cameraUp).normalized()) * cameraSpeed;
}
if(event->key() == Qt::Key_E){ //上升
cameraPos += cameraUp * cameraSpeed;
}
if(event->key() == Qt::Key_Q){ //下降
cameraPos -= cameraUp * cameraSpeed;
}
}
void Triangle::mouseMoveEvent(QMouseEvent *event)
{
GLfloat xpos = event->pos().x();
GLfloat ypos = event->pos().y();
if (firstMouse)
{
lastX = event->pos().x();
lastY = event->pos().y();
firstMouse = false;
}
GLfloat xoffset = xpos - lastX;
GLfloat yoffset = lastY - ypos; // reversed since y-coordinates go from bottom to top
lastX = xpos;
lastY = ypos;
GLfloat sensitivity = 0.01f; // change this value to your liking
xoffset *= sensitivity;
yoffset *= sensitivity;
yaw += xoffset;
pitch += yoffset;
// make sure that when pitch is out of bounds, screen doesn't get flipped
if (pitch > 89.0f)
pitch = 89.0f;
if (pitch < -89.0f)
pitch = -89.0f;
QVector3D front(cos(yaw) * cos(pitch), sin(pitch), sin(yaw) * cos(pitch));
cameraFront = front.normalized();
}
void Triangle::wheelEvent(QWheelEvent *event)
{
QPoint offset = event->angleDelta();
if(fov >= 1.0f && fov <=45.0f)
fov -= ((GLfloat)offset.y())/20;
if(fov < 1.0f)
fov = 1.0f;
if(fov > 45.0f)
fov = 45.0f;
}