0

我已经实现了一个在 openGL 中翻译、旋转和 scle 二维纹理的程序。这 3 个转换单独工作得很好，但是当我把翻译和其他人一起扔时，事情就变得古怪了。

对于缩放，当比例高于 1.0 时，一切似乎都很好，但是一旦我低于，纹理就会离开屏幕。轮换的同样悲伤的故事。当角度很小，但超过20°或什么时，没有明显的问题，在两边，事情变得奇怪了。

这是我的代码。有趣的功能在最后。

#include "glwidget.h"

#include <GL/glu.h>
#include <QMouseEvent>
#include <QKeyEvent>
#include <tgmath.h>
#include <QtDebug>
#ifdef WIN32
    #include <GL/glext.h>
       PFNGLACTIVETEXTUREPROC pGlActiveTexture = NULL;
    #define glActiveTexture pGlActiveTexture
#endif //WIN32

GlWidget::GlWidget(QWidget *parent) :
    QGLWidget(QGLFormat(), parent),
    scale(0.5),
    angle(0),
    translate{0,0,0},
    keyLock(false)
{
}

GlWidget::~GlWidget(){}

QSize GlWidget::sizeHint() const
{
    return QSize(640,480);
}

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

    h = (h<=0?1:h);

    pMatrix.setToIdentity();
    pMatrix.perspective(60.0,(float)w /(float)h,2,5);

    glViewport(0,0,w,h);
    glScissor(w*0.8,0,w,h);
    glDisable(GL_SCISSOR_TEST);
}

void GlWidget::initializeGL(){

    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    #ifdef WIN32
        glActiveTexture = (PFNGLACTIVETEXTUREPROC) wglGetProcAddress((LPCSTR) "glActiveTexture");
    #endif

    glEnable(GL_DEPTH_TEST);
    glEnable(GL_CULL_FACE);

    qglClearColor(QColor(Qt::black));


    shaderProgram.addShaderFromSourceFile(QGLShader::Vertex, ":/vertexShader.vsh");
    shaderProgram.addShaderFromSourceFile(QGLShader::Fragment, ":/fragmentShader.fsh");
    shaderProgram.link();

    vertices << QVector3D(-1,-1,-2) << QVector3D(1,-1,-2) << QVector3D(-1,1,-2)
             << QVector3D(-1,1,-2) << QVector3D(1,-1,-2) << QVector3D(1,1,-2);

    textureCoordinates << QVector2D(0, 0) << QVector2D(1, 0) << QVector2D(0, 1)
                       << QVector2D(0, 1) << QVector2D(1, 0) << QVector2D(1, 1);

    texture = bindTexture(QPixmap(":/icone.png"));
    //mMatrix.setToIdentity();
    mMatrix.scale(scale,scale);


}

void GlWidget::paintGL(){

    qglClearColor(QColor(Qt::white));
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    QMatrix4x4 vMatrix;
    shaderProgram.bind();
    shaderProgram.setUniformValue("mvpMatrix", pMatrix*vMatrix*mMatrix);
    shaderProgram.setUniformValue("texture", 0);

    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texture);
    glActiveTexture(0);

    shaderProgram.setAttributeArray("vertex", vertices.constData());
    shaderProgram.enableAttributeArray("vertex");
    shaderProgram.setAttributeArray("textureCoordinate", textureCoordinates.constData());
    shaderProgram.enableAttributeArray("textureCoordinate");

    glEnable(GL_BLEND);

    glDrawArrays(GL_TRIANGLES,0,vertices.size());

    glDisable(GL_BLEND);

    shaderProgram.disableAttributeArray("vertex");
    shaderProgram.disableAttributeArray("textureCoordinate");
    shaderProgram.release();

    qglClearColor(QColor(Qt::black));
    glEnable(GL_SCISSOR_TEST);
    glClear(GL_COLOR_BUFFER_BIT);
    glDisable(GL_SCISSOR_TEST);

}

void GlWidget::mousePressEvent(QMouseEvent *event){
    if(event->button()==Qt::LeftButton){
        lastPosF = QVector3D(event->pos().x(),event->pos().y(),0);
        lastPos = getModelCoordinates(event->pos());
        //keyLock=true;
    }
    event->accept();
    //update();
}

void GlWidget::mouseMoveEvent(QMouseEvent *event){
    if(!event->buttons().testFlag(Qt::LeftButton)) return;
    currentPosF = QVector3D(event->pos().x(),event->pos().y(),0);
    QVector3D currentPos(getModelCoordinates(event->pos()));

    //qDebug()<<currentPos;

    if(keysPressed.contains(Qt::Key_Control) && !keysPressed.contains(Qt::Key_Shift)){
        resizeTexture(currentPos);
    }
    else if(!keysPressed.contains(Qt::Key_Control) && keysPressed.contains(Qt::Key_Shift)){
        rotateTexture(currentPos);
    }
    else if(!keysPressed.contains(Qt::Key_Control) && !keysPressed.contains(Qt::Key_Shift)){
        dragTexture(currentPos);
    }

    mMatrix.setToIdentity();
    mMatrix.translate(translate);
    mMatrix.scale(scale,scale);
    mMatrix.rotate(angle,0,0,1);

    //lastPos = currentPos;
    update();

}

void GlWidget::mouseReleaseEvent(QMouseEvent *event)
{
    if(event->button()==Qt::LeftButton)
        keyLock=false;

}

void GlWidget::keyPressEvent(QKeyEvent *event){
    if(!keyLock) keysPressed.append(event->key());

}

void GlWidget::keyReleaseEvent(QKeyEvent *event){
    if(!keyLock) keysPressed.remove(keysPressed.lastIndexOf(event->key()));
}

QVector3D GlWidget::getModelCoordinates(QPoint mousePos){
    QVector3D modelPos;

    double X,Y,Z;
    GLdouble modelMat[16],projMat[16];
    GLint viewport[4]={0,0,this->width(),this->height()};
    //glGetDoublev(GL_MODELVIEW_MATRIX ,modelMat);
    //glGetDoublev(GL_PROJECTION_MATRIX,projMat);
    //glGetIntegerv(GL_VIEWPORT,viewport);
    for(int i=0; i<4;i++){
        modelMat[i*4]=(double)mMatrix.column(i).x();
        modelMat[1+i*4]=(double)mMatrix.column(i).y();
        modelMat[2+i*4]=(double)mMatrix.column(i).z();
        modelMat[3+i*4]=(double)mMatrix.column(i).w();
    }
    for(int i=0; i<4;i++){
        projMat[i*4]=(double)pMatrix.column(i).x();
        projMat[1+i*4]=(double)pMatrix.column(i).y();
        projMat[2+i*4]=(double)pMatrix.column(i).z();
        projMat[3+i*4]=(double)pMatrix.column(i).w();
    }
    //GLdouble z;

    gluUnProject((double)mousePos.x(),(double)viewport[3]-(double)mousePos.y(),0,modelMat,projMat,viewport,&X,&Y,&Z);
    modelPos.setX(fabs(X)<1e-8?1e-8:static_cast<float>(X));
    modelPos.setY(static_cast<float>(Y));
    modelPos.setZ(static_cast<float>(Z));

    qDebug();
    qDebug()<<"first :"<<lastPos<<" - Now :"<<modelPos;


    return modelPos;
}

void GlWidget::resizeTexture(QVector3D currentPos)
{
    float diff = sqrt(pow(currentPos.x(),2)+pow(currentPos.y(),2)) / sqrt(pow(lastPos.x(),2)+pow(lastPos.y(),2));
    //diff=diff>1?1:diff;
    //diff /= sqrt(pow(lastPos.x(),2)+pow(lastPos.y(),2));
    scale*= diff;
    scale=scale<0?-scale:scale;
    qDebug()<<"diff : "<<diff<<"  - scale : "<<scale;
    /*mMatrix.setToIdentity();
    mMatrix.scale(scale,scale);
    mMatrix.rotate(angle,0,0,1);*/
}

void GlWidget::rotateTexture(QVector3D currentPos)
{
    float angle1 = atan((float)currentPos.y()/(float)currentPos.x());
    float angle2 = atan((float)lastPos.y()/(float)lastPos.x());
    float delta =angle1-angle2*(angle1*angle2>=0?1:-1);
    delta*=180/M_PI;
    angle+=delta;
    while(angle>360|| angle < 0){
        angle = (angle>360?angle-360:angle);
        angle = (angle<0?angle+360:angle);
    }
    qDebug()<<"angle 1 : "<<atan((float)lastPos.y()/(float)lastPos.x())
           << "angle 2 : "<<atan((float)currentPos.y()/(float)currentPos.x());
    qDebug()<<"delta : "<<delta<<" - Angle : "<<angle;
    //qDebug()<<angle;
    /*mMatrix.setToIdentity();
    mMatrix.scale(scale,scale);
    mMatrix.rotate(angle,0,0,1);*/
    //lastPos = currentPos;
}

void GlWidget::dragTexture(QVector3D currentPos)
{
    if(lastPos.x() > 1.0 || lastPos.x() < -1.0 || lastPos.y() > 1.0 || lastPos.y() < -1.0)
        return;
    translate += (currentPos-lastPos);
    /*mMatrix.setToIdentity();
    mMatrix.translate(translate);*/
    //translate += currentPosF-lastPosF;
    lastPosF=currentPosF;
    qDebug()<<translate;
}

这是我的顶点和片段着色器：

#version 330

uniform mat4 mvpMatrix;

in vec4 vertex;
in vec2 textureCoordinate;

out vec2 varyingTextureCoordinate;

void main(void)
{
    varyingTextureCoordinate = textureCoordinate;
    gl_Position = mvpMatrix * vertex;
}


#version 330

uniform sampler2D texture;

in vec2 varyingTextureCoordinate;

out vec4 fragColor;

void main(void)
{
    fragColor = texture2D(texture, varyingTextureCoordinate);
}

感谢您的回答。

4

1 回答 1

0

对于围绕 z 轴旋转 15 度，您的旋转矩阵应该是：

0.965926, -0.258819, 0.0, 0.0
0.258819, 0.965926, 0.0, 0.0
0.0, 0.0, 1.0, 0.0
0.0, 0.0, 0.0, 1.0

这些矩阵都是 4 X 4 矩阵。翻译矩阵如下所示：

1.0, 0.0, 0.0, transX
0.0, 1.0, 0.0, transY
0.0, 0.0, 1.0, transZ
0.0, 0.0, 0.0, 1.0

比例矩阵如下所示：

scaleX, 0.0, 0.0, 0.0
0.0, scaleY, 0.0, 0.0
0.0, 0.0, scaleZ, 0.0
0.0, 0.0, 0.0, 1.0

按顺序将这些矩阵相乘，以获得您想要的效果，但请记住顺序很重要。

于 2015-01-18T15:47:06.227 回答