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; }