Qt学习笔记-OpenGL做正方体并旋转

运行截图如下图：

代码如下：

myglwidget.h

#ifndef MYGLWIDGET_H
#define MYGLWIDGET_H

#include <QOpenGLWidget>
#include <QOpenGLFunctions>
#include <QOpenGLBuffer>

class QOpenGLTexture;
class QOpenGLShaderProgram;

class MyGLWidget:public QOpenGLWidget,protected QOpenGLFunctions
{
    Q_OBJECT
public:
    MyGLWidget(QWidget *parent=0);

protected:
    void initializeGL();
    void paintGL();
    void resizeGL(int w, int h);
    void keyPressEvent(QKeyEvent *evnet);

private:
    QOpenGLShaderProgram *program;
    QOpenGLBuffer vbo;
    QOpenGLTexture *textures[6];
    GLfloat translate,xRot,yRot,zRot;
};

#endif // MYGLWIDGET_H

myglwidget.cpp

#include "myglwidget.h"
#include <QOpenGLShaderProgram>
#include <QOpenGLTexture>
#include <QDebug>
#include <QKeyEvent>

MyGLWidget::MyGLWidget(QWidget *parent)
    :QOpenGLWidget(parent)
{
    translate = -6.0;
    xRot = zRot = 0.0;
    yRot = -30.0;
}

void MyGLWidget::initializeGL(){
    initializeOpenGLFunctions();
    glEnable(GL_DEPTH_TEST);
    for(int i=0; i<6; ++i){
        textures[i] = new QOpenGLTexture(QImage(
                                             QString(":/img/side%1.png").arg(i+1)).mirrored());
    }
    QOpenGLShader *vshader = new QOpenGLShader(QOpenGLShader::Vertex,this);
    const char *vsrc =
            "#version 130\n"
            "in vec4 vPosition;                         \n"
            "in vec2 vTexCoord;                         \n"
            "out vec2 texCoord;                         \n"
            "uniform mat4 matrix;                       \n"
            "void main() {                              \n"
            "    texCoord = vTexCoord;                  \n"
            "    gl_Position = matrix * vPosition;      \n"
            "}\n";
    vshader->compileSourceCode(vsrc);
    QOpenGLShader *fshader = new QOpenGLShader(QOpenGLShader::Fragment,this);
    const char *fsrc =
                "#version 130\n"
                "uniform sampler2D tex;                     \n"
                "in vec2 texCoord;                          \n"
                "out vec4 fColor;                           \n"
                "void main() {                              \n"
                "    fColor = texture(tex, texCoord);       \n"
                "}\n";
    fshader->compileSourceCode(fsrc);

    program = new QOpenGLShaderProgram;
    program->addShader(vshader);
    program->addShader(fshader);
    program->link();
    program->bind();
}

void MyGLWidget::paintGL(){
    int w = width();
    int h = height();
    int side = qMin(w,h);
    glViewport((w-side)/2,(h-side)/2,side,side);

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    GLfloat vectices[6][4][3]=
    {
        {{1.0f,1.0f,1.0f},{1.0f,1.0f,-1.0f},{1.0f,-1.0f,-1.0f},{1.0f,-1.0f,1.0f}},
        {{-1.0f,1.0f,1.0f},{-1.0f,1.0f,-1.0f},{-1.0f,-1.0f,-1.0f},{-1.0f,-1.0f,1.0f}},
        {{1.0f,1.0f,1.0f},{-1.0f,1.0f,1.0f},{-1.0f,1.0f,-1.0f},{1.0f,1.0f,-1.0f}},
        {{1.0f,-1.0f,1.0f},{-1.0f,-1.0f,1.0f},{-1.0f,-1.0f,-1.0f},{1.0f,-1.0f,-1.0f}},
        {{1.0f,1.0f,1.0f},{1.0f,-1.0f,1.0f},{-1.0f,-1.0f,1.0f},{-1.0f,1.0f,1.0f}},
        {{1.0f,1.0f,-1.0f},{1.0f,-1.0f,-1.0f},{-1.0f,-1.0f,-1.0f},{-1.0f,1.0f,-1.0f}},
    };

    GLfloat coords[6][4][2] =
    {
        { {0.0f, 1.0f}, {0.0f, 0.0f}, {1.0f, 0.0f}, {1.0f, 1.0f} },
        { {0.0f, 1.0f}, {0.0f, 0.0f}, {1.0f, 0.0f}, {1.0f, 1.0f} },
        { {0.0f, 1.0f}, {0.0f, 0.0f}, {1.0f, 0.0f}, {1.0f, 1.0f} },
        { {0.0f, 1.0f}, {0.0f, 0.0f}, {1.0f, 0.0f}, {1.0f, 1.0f} },
        { {0.0f, 1.0f}, {0.0f, 0.0f}, {1.0f, 0.0f}, {1.0f, 1.0f} },
        { {0.0f, 1.0f}, {0.0f, 0.0f}, {1.0f, 0.0f}, {1.0f, 1.0f} },
    };

    vbo.create();
    vbo.bind();
    vbo.allocate((72+48)*sizeof(GLfloat));


    vbo.write(0,vectices,72*sizeof(GLfloat));
    GLuint vPosition = program->attributeLocation("vPosition");
    program->setAttributeBuffer(vPosition,GL_FLOAT,0,3,0);
    glEnableVertexAttribArray(vPosition);

    vbo.write(72* sizeof(GLfloat), coords, 48*sizeof(GLfloat));
    GLuint vTexCoord = program->attributeLocation("vTexCoord");
    program->setAttributeBuffer(vTexCoord, GL_FLOAT, 72* sizeof(GLfloat), 2, 0);
    glEnableVertexAttribArray(vTexCoord);
    program->setUniformValue("tex", 0);

    QMatrix4x4 matrix;
    matrix.perspective(45.0f, (GLfloat)w / (GLfloat)h, 0.1f, 100.0f);
    matrix.translate(0, 0, translate);
    matrix.rotate(xRot, 1, 0, 0);
    matrix.rotate(yRot, 0, 1, 0);
    matrix.rotate(zRot, 0, 0, 1);
    program->setUniformValue("matrix",matrix);

    for(int i=0; i<6; i++) {
            textures[i]->bind();
            glDrawArrays(GL_TRIANGLE_FAN, i*4, 4);
        }
}

void MyGLWidget::resizeGL(int w, int h){

}

void MyGLWidget::keyPressEvent(QKeyEvent *event)
{
    switch (event->key()) {
    case Qt::Key_Up:
        xRot += 10;
        break;
    case Qt::Key_Left:
        yRot += 10;
        break;
    case Qt::Key_Right:
        zRot += 10;
        break;
    case Qt::Key_Down:
        translate -= 1;
        break;
    case Qt::Key_Space:
        translate += 1;
        break;
    default:
        break;
    }
    update();
    QOpenGLWidget::keyPressEvent(event);
}

main.cpp

#include <QApplication>
#include "myglwidget.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MyGLWidget w;
    w.resize(800,600);
    w.show();

    return a.exec();
}