原始链接：

https://www.jianshu.com/p/273b7f960f3d

简介

要学习OpenGL的话，强烈安利这个教程JoeyDeVries的learnopengl，这里是中文翻译好的版本。教程中使用OpenGL是通过GLFW这个库，而在Qt中对OpenGL封装得很好，并且和GUI以及IO相关的处理Qt更便捷，学习起来更轻松。这里就对每篇教程，在Qt在分别直接使用OpenGL的函数和Qt封装好的类以作对比。
教程中使用的OpenGL版本为3.3，在Qt中需要使用此版本的OpenGL只需要继承类QOpenGLFunctions_3_3_Core即可。如果为了在不同设备上都能用OpenGL的话，Qt提供了类QOpenGLFunctions，这个类包含了大部分公共的函数，可能会有个别函数不能用。

对比说明

教程地址

原教程地址，相关知识可以点击链接学习。
我的工程地址，准备后期每篇教程一个commit，可以切换着看，查看本篇代码 git checkout v1.3，喜欢就点个Star吧~

不同点 (仅列出新增)

  1. Qt提供了QOpenGLTexture类来处理OpenGL中的Texture，并且创建的时候可以直接传递一个QImage给纹理对象，如果使用gl相关函数还要读取图片数据的data再设置，比较麻烦。

运行结果

 
运行结果

使用OpenGL函数版

CoreFunctionWidget.h

#ifndef COREFUNCTIONWIDGET_H

#define COREFUNCTIONWIDGET_H



#include <QOpenGLWidget>

#include <QOpenGLExtraFunctions>

#include <QOpenGLFunctions_3_3_Core>

#include <QOpenGLShader>

#include <QOpenGLShaderProgram>



class CoreFunctionWidget : public QOpenGLWidget

                           , protected /*QOpenGLExtraFunctions*/QOpenGLFunctions_3_3_Core

{

    Q_OBJECT

public:

    explicit CoreFunctionWidget(QWidget *parent = nullptr);

    ~CoreFunctionWidget();



protected:

    virtual void initializeGL();

    virtual void resizeGL(int w, int h);

    virtual void paintGL();



private:

    QOpenGLShaderProgram shaderProgram;



//    QTimer* m_pTimer = nullptr;

//    float m_uniformValue = 0.0f;

};



#endif // COREFUNCTIONWIDGET_H

CoreFunctionWidget.cpp

#include "CoreFunctionWidget.h"

#include <QDebug>

#include <QTimer>



static GLuint VBO, VAO, EBO, texture1, texture2;



CoreFunctionWidget::CoreFunctionWidget(QWidget *parent) : QOpenGLWidget(parent)

{

//    m_pTimer = new QTimer(this);

//    m_pTimer->setInterval(200);



//    connect(m_pTimer, &QTimer::timeout, this, [=]{

//        m_uniformValue += 0.1f;



//        if (m_uniformValue > 1.5f) {

//            m_uniformValue = -1.5f;

//        }



//        update();

//    });



//    m_pTimer->start();

}



CoreFunctionWidget::~CoreFunctionWidget()

{

    glDeleteVertexArrays(1, &VAO);

    glDeleteBuffers(1, &VBO);

    glDeleteBuffers(1, &EBO);

}



void CoreFunctionWidget::initializeGL(){

    this->initializeOpenGLFunctions();



    bool success = shaderProgram.addShaderFromSourceFile(QOpenGLShader::Vertex, ":/textures.vert");

    if (!success) {

        qDebug() << "shaderProgram addShaderFromSourceFile failed!" << shaderProgram.log();

        return;

    }



    success = shaderProgram.addShaderFromSourceFile(QOpenGLShader::Fragment, ":/textures.frag");

    if (!success) {

        qDebug() << "shaderProgram addShaderFromSourceFile failed!" << shaderProgram.log();

        return;

    }



    success = shaderProgram.link();

    if(!success) {

        qDebug() << "shaderProgram link failed!" << shaderProgram.log();

    }



    //VAO，VBO data

    float vertices[] = {

        // positions          // colors           // texture coords

         0.5f,  0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // top right

         0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // bottom right

        -0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left

        -0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // top left

    };

    unsigned int indices[] = {  // note that we start from 0!

        0, 1, 3,  // first Triangle

        1, 2, 3   // second Triangle

    };



    glGenVertexArrays(1, &VAO);

    glGenBuffers(1, &VBO);

    glGenBuffers(1, &EBO);

    // bind the Vertex Array Object first, then bind and set vertex buffer(s), and then configure vertex attributes(s).

    glBindVertexArray(VAO);



    glBindBuffer(GL_ARRAY_BUFFER, VBO);

    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);



    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);

    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);



    // position attribute

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);

    glEnableVertexAttribArray(0);

    // color attribute

    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));

    glEnableVertexAttribArray(1);

    // texture coord attribute

    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));

    glEnableVertexAttribArray(2);



    // texture 1

    // ---------

    glGenTextures(1, &texture1);

    glBindTexture(GL_TEXTURE_2D, texture1);

     // set the texture wrapping parameters

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);   // set texture wrapping to GL_REPEAT (default wrapping method)

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

    // set texture filtering parameters

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    // load image, create texture and generate mipmaps

    QImage img1 = QImage(":/container.jpg").convertToFormat(QImage::Format_RGB888);

    if (!img1.isNull()) {

        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, img1.width(), img1.height(), 0, GL_RGB, GL_UNSIGNED_BYTE, img1.bits());

        glGenerateMipmap(GL_TEXTURE_2D);

    }



    // texture 2// ---------glGenTextures(1,&texture2);glBindTexture(GL_TEXTURE_2D, texture2);// set the texture wrapping parametersglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);// set texture wrapping to GL_REPEAT (default wrapping method)glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);// set texture filtering parametersglTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);// load image, create texture and generate mipmaps

    QImage img2=QImage(":/awesomeface.png").convertToFormat(QImage::Format_RGBA8888).mirrored(true,true);if(!img2.isNull()){// note that the awesomeface.png has transparency and thus an alpha channel, so make sure to tell OpenGL the data type is of GL_RGBAglTexImage2D(GL_TEXTURE_2D,0, GL_RGBA, img2.width(), img2.height(),0, GL_RGBA, GL_UNSIGNED_BYTE, img2.bits());glGenerateMipmap(GL_TEXTURE_2D);}// tell opengl for each sampler to which texture unit it belongs to (only has to be done once)

    shaderProgram.bind();// don't forget to activate/use the shader before setting uniforms!glUniform1i(shaderProgram.uniformLocation("texture1"),0);glUniform1i(shaderProgram.uniformLocation("texture2"),1);

    shaderProgram.release();//    glBindBuffer(GL_ARRAY_BUFFER, 0);//取消VBO的绑定//    remember: do NOT unbind the EBO while a VAO is active as the bound element buffer object IS stored in the VAO; keep the EBO bound.//    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);//    You can unbind the VAO afterwards so other VAO calls won't accidentally modify this VAO, but this rarely happens. Modifying other//    VAOs requires a call to glBindVertexArray anyways so we generally don't unbind VAOs (nor VBOs) when it's not directly necessary.//    glBindVertexArray(0);   //取消VAO绑定//线框模式，QOpenGLExtraFunctions没这函数, 3_3_Core有//    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);}void CoreFunctionWidget::resizeGL(int w,int h){glViewport(0,0, w, h);}void CoreFunctionWidget::paintGL(){glClearColor(0.2f,0.3f,0.3f,1.0f);glClear(GL_COLOR_BUFFER_BIT);



    shaderProgram.bind();{// bind textures on corresponding texture unitsglActiveTexture(GL_TEXTURE0);glBindTexture(GL_TEXTURE_2D, texture1);glActiveTexture(GL_TEXTURE1);glBindTexture(GL_TEXTURE_2D, texture2);// render containerglBindVertexArray(VAO);glDrawElements(GL_TRIANGLES,6, GL_UNSIGNED_INT,0);}

    shaderProgram.release();}

使用Qt相关函数版

QtFunctionWidget.h

#ifndef QTFUNCTIONWIDGET_H

#define QTFUNCTIONWIDGET_H



#include <QOpenGLWidget>





#include <QOpenGLWidget>

#include <QOpenGLShader>

#include <QOpenGLShaderProgram>

#include <QOpenGLFunctions>

#include <QOpenGLVertexArrayObject>

#include <QOpenGLBuffer>

#include <QOpenGLTexture>



class QtFunctionWidget : public QOpenGLWidget, protected QOpenGLFunctions

{

public:

    QtFunctionWidget(QWidget *parent = nullptr);

    ~QtFunctionWidget() Q_DECL_OVERRIDE;



protected:

    virtual void initializeGL() Q_DECL_OVERRIDE;

    virtual void resizeGL(int w, int h) Q_DECL_OVERRIDE;

    virtual void paintGL() Q_DECL_OVERRIDE;



private:

    QOpenGLShaderProgram shaderProgram;

    QOpenGLBuffer vbo, ebo;

    QOpenGLVertexArrayObject vao;

    QOpenGLTexture *texture1 = nullptr;

    QOpenGLTexture *texture2 = nullptr;



//    QTimer* m_pTimer = nullptr;

//    float m_uniformValue = 0.0f;

};



#endif // QTFUNCTIONWIDGET_H

QtFunctionWidget.cpp

#include "QtFunctionWidget.h"

#include <QDebug>

#include <QTimer>



QtFunctionWidget::QtFunctionWidget(QWidget *parent) : QOpenGLWidget (parent),

    vbo(QOpenGLBuffer::VertexBuffer),

    ebo(QOpenGLBuffer::IndexBuffer)

{

//    m_pTimer = new QTimer(this);

//    m_pTimer->setInterval(200);



//    connect(m_pTimer, &QTimer::timeout, this, [=]{

//        m_uniformValue += 0.1f;



//        if (m_uniformValue > 1.5f) {

//            m_uniformValue = -1.5f;

//        }



//        update();

//    });



//    m_pTimer->start();

}



QtFunctionWidget::~QtFunctionWidget(){

    makeCurrent();



    vbo.destroy();

    ebo.destroy();

    vao.destroy();



    delete texture1;

    delete texture2;



    doneCurrent();

}



void QtFunctionWidget::initializeGL(){

    this->initializeOpenGLFunctions();



    bool success = shaderProgram.addShaderFromSourceFile(QOpenGLShader::Vertex, ":/textures.vert");

    if (!success) {

        qDebug() << "shaderProgram addShaderFromSourceFile failed!" << shaderProgram.log();

        return;

    }



    success = shaderProgram.addShaderFromSourceFile(QOpenGLShader::Fragment, ":/textures.frag");

    if (!success) {

        qDebug() << "shaderProgram addShaderFromSourceFile failed!" << shaderProgram.log();

        return;

    }



    success = shaderProgram.link();

    if(!success) {

        qDebug() << "shaderProgram link failed!" << shaderProgram.log();

    }



    //VAO，VBO data

    float vertices[] = {

        // positions          // colors           // texture coords

         0.5f,  0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // top right

         0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // bottom right

        -0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left

        -0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // top left

    };

    unsigned int indices[] = {  // note that we start from 0!

        0, 1, 3,  // first Triangle

        1, 2, 3   // second Triangle

    };



    QOpenGLVertexArrayObject::Binder vaoBind(&vao);



    vbo.create();

    vbo.bind();

    vbo.allocate(vertices, sizeof(vertices));



    ebo.create();

    ebo.bind();

    ebo.allocate(indices, sizeof(indices));



    // position attribute

    int attr = -1;

    attr = shaderProgram.attributeLocation("aPos");

    shaderProgram.setAttributeBuffer(attr, GL_FLOAT, 0, 3, sizeof(GLfloat) * 8);

    shaderProgram.enableAttributeArray(attr);

    // color attribute

    attr = shaderProgram.attributeLocation("aColor");

    shaderProgram.setAttributeBuffer(attr, GL_FLOAT, sizeof(GLfloat) * 3, 3, sizeof(GLfloat) * 8);

    shaderProgram.enableAttributeArray(attr);

    // texture coord attribute

    attr = shaderProgram.attributeLocation("aTexCoord");

    shaderProgram.setAttributeBuffer(attr, GL_FLOAT, sizeof(GLfloat) * 6, 2, sizeof(GLfloat) * 8);

    shaderProgram.enableAttributeArray(attr);



    // texture 1

    // ---------

    texture1 = new QOpenGLTexture(QImage(":/container.jpg"), 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";

    }

    // set the texture wrapping parameters

    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);

    // set texture filtering parameters

    texture1->setMinificationFilter(QOpenGLTexture::Linear);   //等价于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    texture1->setMagnificationFilter(QOpenGLTexture::Linear);



    // texture 2

    // ---------

    texture2 = new QOpenGLTexture(QImage(":/awesomeface.png").mirrored(true,true), QOpenGLTexture::GenerateMipMaps);//直接生成绑定一个2d纹理, 并生成多级纹理MipMapsif(!texture2->isCreated()){qDebug()<<"Failed to load texture";}// set the texture wrapping parameters

    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);// set texture filtering parameters

    texture2->setMinificationFilter(QOpenGLTexture::Linear);//等价于glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    texture1->setMagnificationFilter(QOpenGLTexture::Linear);// tell opengl for each sampler to which texture unit it belongs to (only has to be done once)

    shaderProgram.bind();// don't forget to activate/use the shader before setting uniforms!

    shaderProgram.setUniformValue("texture1",0);

    shaderProgram.setUniformValue("texture2",1);

    shaderProgram.release();



    vbo.release();//    remember: do NOT unbind the EBO while a VAO is active as the bound element buffer object IS stored in the VAO; keep the EBO bound.//    ebo.release();}



void QtFunctionWidget::resizeGL(int w, int h){glViewport(0,0, w, h);}



void QtFunctionWidget::paintGL(){glClearColor(0.2f,0.3f,0.3f,1.0f);glClear(GL_COLOR_BUFFER_BIT);



    shaderProgram.bind();{glActiveTexture(GL_TEXTURE0);

        texture1->bind();//        glBindTexture(GL_TEXTURE_2D, texture1->textureId());glActiveTexture(GL_TEXTURE1);

        texture2->bind();//        glBindTexture(GL_TEXTURE_2D, texture2->textureId());// render container

        QOpenGLVertexArrayObject::BindervaoBind(&vao);glDrawElements(GL_TRIANGLES,6,GL_UNSIGNED_INT, nullptr);



        texture1->release();

        texture2->release();}

    shaderProgram.release();}

GLSL

textures.vert

#version 330 core

layout (location = 0) in vec3 aPos;

layout (location = 1) in vec3 aColor;

layout (location = 2) in vec2 aTexCoord;



out vec3 ourColor;

out vec2 TexCoord;



void main()

{

    gl_Position = vec4(aPos, 1.0);

    ourColor = aColor;

    TexCoord = aTexCoord;

}

textures.frag

#version 330 core

out vec4 FragColor;



in vec3 ourColor;

in vec2 TexCoord;



uniform sampler2D texture1;

uniform sampler2D texture2;



void main()

{

    //FragColor = texture(texture1, TexCoord) * vec4(ourColor, 1.0);

    FragColor = mix(texture(texture1, TexCoord), texture(texture2, TexCoord), 0.2);

}

main.cpp

#include <QApplication>

#include "MainWindow.h"

#include "QtFunctionWidget.h"

#include "CoreFunctionWidget.h"



int main(int argc, char *argv[])

{

    QApplication a(argc, argv);



//    MainWindow w;

    QtFunctionWidget w1;

    CoreFunctionWidget w2;



    w1.setWindowTitle(QObject::tr("QtFunction"));

    w2.setWindowTitle(QObject::tr("CoreFunction"));



    w1.show();

    w2.show();



    return a.exec();

}
 
 

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OpenGL

 
 
"小礼物走一走，来简书关注我"

 

资源ID管理插件

https://www.codeproject.com/Articles/1244/Resource-ID-Organiser-Add-In-for-Visual-C-5-0-6-0

 

新版本：

https://www.riverblade.co/products/resorg/downloads/

GTK For Windows下界面美化调优

1.安装相应的界面引擎：

mingw-w64-x86_64-gtk-engine-murrine

mingw-w64-x86_64-gtk-engines

mingw-w64-i686-gtk-engine-murrine

mingw-w64-i686-gtk-engines

2.安装一个Windows10的界面优化包，需要手工安装，下载地址：

https://github.com/B00merang-Project/Windows-10

将其中的gtk-2.0、gtk-3.0、gtk-3.20都拷贝到share/themes/Windows10目录下，Windows10目录需要自己建立

3.修改etc/gtk-2.0、etc/gtk-3.0，放入一个settings.ini文件，内容如下：

[Settings]gtk-theme-name=Windows10

gtk-font-name=Segoe UI 9

mingw-w64及w32均有etc，都需要放一份

再启动GTK的程序，就能够看到界面已经漂亮多了

VC的编译器下，有好几个OS子系统宏，分别是：

WIN32/_WIN32/WIN64/_WIN64

其中WIN32是在windows.h中定义的

WIN64/_WIN64宏通常是通过工程文件配置预定义宏开关完成

其中_WIN32这个宏最特殊，属于没有定义会被强制定义，所有32位系统、64位系统下均有此宏定义

比如64位工程，编译时指定了WIN64/_WIN64，其实编译时会有三个宏

_WIN32/WIN64/_WIN64

因此，在区分OS类别时，则通常应该如此定义：

#if (defined _WIN64 || defined WIN64 || defined _WIN32 || defined WIN32 || defined WINCE)

#elif (defined ANDROID)

#else

#endif

区分64位的WINDOWS与32位，只能如此定义：

#if (defined _WIN64 || defined WIN64)

#elif (defined _WIN32 || defined WIN32)

#else

#endif

极容易踩到这个坑，定义这样：

#if (defined _WIN32 || defined WIN32)

#elif (defined _WIN64 || defined WIN64)

#else

#endif

 

CMakeLists.txt中可以指定多个目标，比如编译两个库：

add_library(xxx SHARED ............

add_library(yyy SHARED ............

 

而希望分别指定不同的编译开关，应在之前保存好相应的编译开关参数，比如：

set(CMAKE_xxx_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DONLY_SDK -std=c++11")
set(CMAKE_yyy_CXX_FLAGS "${CMAKE_CXX_FLAGS}  -Dyyy_SDK -DONLY_SDK -std=c++11")

然后在add_library之后，使用set_target_properties修改目标的编译参数

set_target_properties(xxx PROPERTIES COMPILE_FLAGS ${CMAKE_xxx_CXX_FLAGS})

set_target_properties(yyy PROPERTIES COMPILE_FLAGS ${CMAKE_yyy_CXX_FLAGS})

 

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