Qt下使用OpenGL（20）-根据NeHe的教程改写的

#ifndef NEHEWIDGET_H
#define NEHEWIDGET_H

#include <QtOpenGL/QGLWidget>
#include "ui_nehewidget.h"

class nehewidget : public QGLWidget
{
Q_OBJECT

public:
nehewidget(QWidget *parent = 0);
~nehewidget();

protected:
void initializeGL();
void paintGL();
void resizeGL(int w,int h);
void loadGLTextures();

bool masking;     // 是否使用“掩模”
bool scene;      // 绘制那一个场景
GLuint texture[3];     // 保存5个纹理标志
GLuint loop;      // 循环变量

GLfloat roll;      // 滚动纹理

};

#endif // NEHEWIDGET_H

#include "nehewidget.h"

nehewidget::nehewidget(QWidget *parent)
: QGLWidget(parent)
{
masking=TRUE;
roll = 0;
scene=true;
}

nehewidget::~nehewidget()
{

}

void nehewidget::initializeGL()
{
loadGLTextures();
glEnable(GL_TEXTURE_2D);

glShadeModel(GL_SMOOTH);
glClearColor(0,0,0,0);
glClearDepth(1.0);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);
}

void nehewidget::paintGL()
{
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glLoadIdentity();

glTranslatef(0.0f,0.0f,-1.0f);
glBindTexture(GL_TEXTURE_2D, texture[0]);    // 选择Logo纹理
glBegin(GL_QUADS);       // 绘制纹理四边形
glTexCoord2f(0.0f, -roll+0.0f); glVertex3f(-0.6f, -0.6f,  0.0f);
glTexCoord2f(3.0f, -roll+0.0f); glVertex3f( 0.6f, -0.6f,  0.0f);
glTexCoord2f(3.0f, -roll+3.0f); glVertex3f( 0.6f,  0.6f,  0.0f);
glTexCoord2f(0.0f, -roll+3.0f); glVertex3f(-0.6f,  0.6f,  0.0f);
glEnd();

glEnable(GL_BLEND);       // 启用混合
glDisable(GL_DEPTH_TEST);       // 禁用深度测试
if(masking) {
glBlendFunc(GL_DST_COLOR,GL_ZERO);
}
if(scene) {
glTranslatef(0.0f,0.0f,-1.0f);     // 移入屏幕一个单位
glRotatef(roll*360,0.0f,0.0f,1.0f);     // 沿Z轴旋转
if(masking) {
glBindTexture(GL_TEXTURE_2D, texture[1]);  // 选择第二个“掩模”纹理
glBegin(GL_QUADS);     // 开始绘制四边形
glTexCoord2f(0.0f, 0.0f); glVertex3f(-0.6f, -0.6f,  0.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f( 0.6f, -0.6f,  0.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 0.6f,  0.6f,  0.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f(-0.6f,  0.6f,  0.0f);
glEnd();
}
glBlendFunc(GL_ONE, GL_ONE);    // 把纹理2复制到屏幕
glBindTexture(GL_TEXTURE_2D, texture[0]);   // 选择第二个纹理
glBegin(GL_QUADS);      // 绘制四边形
glTexCoord2f(0.0f, 0.0f); glVertex3f(-0.6f, -0.6f,  0.0f);
glTexCoord2f(1.0f, 0.0f); glVertex3f( 0.6f, -0.6f,  0.0f);
glTexCoord2f(1.0f, 1.0f); glVertex3f( 0.6f,  0.6f,  0.0f);
glTexCoord2f(0.0f, 1.0f); glVertex3f(-0.6f,  0.6f,  0.0f);
glEnd();
}
else {
if(masking) {
glBindTexture(GL_TEXTURE_2D, texture[1]);  // 选择第一个“掩模”纹理
glBegin(GL_QUADS);     // 开始绘制四边形
glTexCoord2f(roll+0.0f, 0.0f); glVertex3f(-0.6f, -0.6f,  0.0f);
glTexCoord2f(roll+4.0f, 0.0f); glVertex3f( 0.6f, -0.6f,  0.0f);
glTexCoord2f(roll+4.0f, 4.0f); glVertex3f( 0.6f,  0.6f,  0.0f);
glTexCoord2f(roll+0.0f, 4.0f); glVertex3f(-0.6f,  0.6f,  0.0f);
glEnd();
}
glBlendFunc(GL_ONE, GL_ONE);     // 把纹理1复制到屏幕
glBindTexture(GL_TEXTURE_2D, texture[2]);    // 选择第一个纹理
glBegin(GL_QUADS);       // 开始绘制四边形
glTexCoord2f(roll+0.0f, 0.0f); glVertex3f(-0.6f, -0.6f,  0.0f);
glTexCoord2f(roll+4.0f, 0.0f); glVertex3f( 0.6f, -0.6f,  0.0f);
glTexCoord2f(roll+4.0f, 4.0f); glVertex3f( 0.6f,  0.6f,  0.0f);
glTexCoord2f(roll+0.0f, 4.0f); glVertex3f(-0.6f,  0.6f,  0.0f);
glEnd();

}
glEnable(GL_DEPTH_TEST);       // 启用深度测试
glDisable(GL_BLEND);       // 禁用混合
roll+=0.002f;        // 增加纹理滚动变量
if(roll>1.0f) roll-=1.0f;
}

void nehewidget::resizeGL(int w,int h)
{
if(h==0) h=1;
glViewport(0,0,(GLint)w,(GLint)h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
//下面这个函数在Qt和OpenGL新版本中都不支持了！先注释掉吧，以后不得不用时再想办法
//	gluPerspective(45.0,(GLfloat)w/(GLfloat)h,0.1,100.0);

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}

void nehewidget::loadGLTextures()
{
QImage tex,buf;
if(!buf.load("texture.bmp")) {
qWarning("Please use single-color instead");
QImage dummy(128,128,QImage::Format_RGB32);
dummy.fill(Qt::red);
buf=dummy;
}
tex=QGLWidget::convertToGLFormat(buf);
glGenTextures(3,&texture[0]);
glBindTexture(GL_TEXTURE_2D,texture[0]);
glTexImage2D(GL_TEXTURE_2D,0,3,tex.width(),tex.height(),0,GL_RGB,GL_UNSIGNED_BYTE,tex.bits());
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);

glBindTexture(GL_TEXTURE_2D,texture[1]);
glTexImage2D(GL_TEXTURE_2D,0,3,tex.width(),tex.height(),0,GL_RGB,GL_UNSIGNED_BYTE,tex.bits());
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);

glBindTexture(GL_TEXTURE_2D,texture[2]);
glTexImage2D(GL_TEXTURE_2D,0,3,tex.width(),tex.height(),0,GL_RGB,GL_UNSIGNED_BYTE,tex.bits());
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_NEAREST);

//	gluBuild2DMipmaps(GL_TEXTURE_2D,GL_RGB,tex.width(),tex.height(),GL_RGBA,GL_UNSIGNED_BYTE,tex.bits());
}