glwidget.cpp Example File
opengl/pbuffers/glwidget.cpp
/****************************************************************************
**
** Copyright (C) 2005-2005 Trolltech AS. All rights reserved.
**
** This file is part of the documentation of the Qt Toolkit.
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** and appearing in the file LICENSE.GPL included in the packaging of
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** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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****************************************************************************/
#include "glwidget.h"
#include <QtGui/QImage>
#include <math.h>
static GLint cubeArray[][3] = {
{0, 0, 0}, {0, 1, 0}, {1, 1, 0}, {1, 0, 0},
{0, 0, 1}, {1, 0, 1}, {1, 1, 1}, {0, 1, 1},
{0, 0, 0}, {1, 0, 0}, {1, 0, 1}, {0, 0, 1},
{0, 1, 0}, {0, 1, 1}, {1, 1, 1}, {1, 1, 0},
{0, 1, 0}, {0, 0, 0}, {0, 0, 1}, {0, 1, 1},
{1, 0, 0}, {1, 1, 0}, {1, 1, 1}, {1, 0, 1}
};
static GLint cubeTextureArray[][2] = {
{0, 0}, {1, 0}, {1, 1}, {0, 1},
{0, 0}, {0, 1}, {1, 1}, {1, 0},
{0, 0}, {1, 0}, {1, 1}, {0, 1},
{1, 0}, {0, 0}, {0, 1}, {1, 1},
{0, 0}, {1, 0}, {1, 1}, {0, 1},
{1, 0}, {0, 0}, {0, 1}, {1, 1}
};
static GLint faceArray[][2] = {
{1, -1}, {1, 1}, {-1, 1}, {-1, -1}
};
static GLubyte colorArray[][4] = {
{170, 202, 0, 255},
{120, 143, 0, 255},
{83, 102, 0, 255},
{120, 143, 0, 255}
};
GLWidget::GLWidget(QWidget *parent)
: QGLWidget(QGLFormat(QGL::SampleBuffers), parent)
{
// create the pbuffer
pbuffer = new QGLPixelBuffer(QSize(512, 512), format(), this);
timerId = startTimer(20);
setWindowTitle(tr("OpenGL pbuffers"));
}
GLWidget::~GLWidget()
{
pbuffer->releaseFromDynamicTexture();
glDeleteTextures(1, &dynamicTexture);
glDeleteLists(pbufferList, 1);
delete pbuffer;
}
void GLWidget::initializeGL()
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-1, 1, -1, 1, 10, 100);
glTranslatef(-0.5f, -0.5f, -0.5f);
glTranslatef(0.0f, 0.0f, -15.0f);
glMatrixMode(GL_MODELVIEW);
glEnable(GL_CULL_FACE);
initCommon();
initPbuffer();
for (int i = 0; i < 3; ++i) {
yOffs[i] = 0.0f;
xInc[i] = 0.005f;
rot[i] = 0.0f;
}
xOffs[0]= 0.0f;
xOffs[1]= 0.5f;
xOffs[2]= 1.0f;
cubeTexture = bindTexture(QImage(":res/cubelogo.png"));
}
void GLWidget::resizeGL(int w, int h)
{
glViewport(0, 0, w, h);
}
void GLWidget::paintGL()
{
// draw a spinning cube into the pbuffer..
pbuffer->makeCurrent();
glBindTexture(GL_TEXTURE_2D, cubeTexture);
glCallList(pbufferList);
glFlush();
#if defined(Q_WS_X11)
// rendering directly to a texture is not supported on X11, unfortunately
pbuffer->updateDynamicTexture(dynamicTexture);
#endif
// ..and use the pbuffer contents as a texture when rendering the
// background and the bouncing cubes
makeCurrent();
glBindTexture(GL_TEXTURE_2D, dynamicTexture);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// draw the background
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glVertexPointer(2, GL_INT, 0, faceArray);
glTranslatef(-1.2f, -0.8f, 0.0f);
glScalef(0.2f, 0.2f, 0.2f);
for (int y = 0; y < 5; ++y) {
for (int x = 0; x < 5; ++x) {
glTranslatef(2.0f, 0, 0);
glColor4f(0.5, 0.5, 0.5, 1.0);
glDrawArrays(GL_QUADS, 0, 4);
}
glTranslatef(-10.0f, 2.0f, 0);
}
glVertexPointer(3, GL_INT, 0, cubeArray);
glPopMatrix();
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
// draw the bouncing cubes
drawCube(0, 0.0f, 1.5f, 2.5f, 1.5f);
drawCube(1, 1.0f, 2.0f, 2.5f, 2.0f);
drawCube(2, 2.0f, 3.5f, 2.5f, 2.5f);
}
void GLWidget::drawCube(int i, GLfloat z, GLfloat rotation, GLfloat jmp, GLfloat amp)
{
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(xOffs[i], yOffs[i], z);
glTranslatef(0.5f, 0.5f, 0.5f);
GLfloat scale = 0.75 + i*(0.25f/2);
glScalef(scale, scale, scale);
glRotatef(rot[i], 1.0f, 1.0f, 1.0f);
glTranslatef(-0.5f, -0.5f, -0.5f);
glColor4f(1.0f, 1.0f, 1.0f, 0.8f);
glDrawArrays(GL_QUADS, 0, 24);
if (xOffs[i] > 1.0f || xOffs[i] < -1.0f) {
xInc[i] = -xInc[i];
xOffs[i] = xOffs[i] > 1.0f ? 1.0f : -1.0f;
}
xOffs[i] += xInc[i];
yOffs[i] = qAbs(cos((-3.141592f * jmp) * xOffs[i]) * amp) - 1;
rot[i] += rotation;
}
void GLWidget::initCommon()
{
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glVertexPointer(3, GL_INT, 0, cubeArray);
glTexCoordPointer(2, GL_INT, 0, cubeTextureArray);
glColorPointer(4, GL_UNSIGNED_BYTE, 0, colorArray);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
glEnable(GL_TEXTURE_2D);
glEnable(GL_DEPTH_TEST);
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
}
void GLWidget::initPbuffer()
{
// set up the pbuffer context
pbuffer->makeCurrent();
initCommon();
glViewport(0, 0, pbuffer->size().width(), pbuffer->size().height());
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-1, 1, -1, 1, -99, 99);
glTranslatef(-0.5f, -0.5f, 0.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
pbufferList = glGenLists(1);
glNewList(pbufferList, GL_COMPILE);
{
glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
// draw cube background
glPushMatrix();
glLoadIdentity();
glTranslatef(0.5f, 0.5f, -2.0f);
glDisable(GL_TEXTURE_2D);
glEnableClientState(GL_COLOR_ARRAY);
glVertexPointer(2, GL_INT, 0, faceArray);
glDrawArrays(GL_QUADS, 0, 4);
glVertexPointer(3, GL_INT, 0, cubeArray);
glDisableClientState(GL_COLOR_ARRAY);
glEnable(GL_TEXTURE_2D);
glPopMatrix();
// draw cube
glTranslatef(0.5f, 0.5f, 0.5f);
glRotatef(3.0f, 1.0f, 1.0f, 1.0f);
glTranslatef(-0.5f, -0.5f, -0.5f);
glColor4f(0.9f, 0.9f, 0.9f, 1.0f);
glDrawArrays(GL_QUADS, 0, 24);
}
glEndList();
// generate a texture that has the same size/format as the pbuffer
dynamicTexture = pbuffer->generateDynamicTexture();
// bind the dynamic texture to the pbuffer - this is a no-op under X11
pbuffer->bindToDynamicTexture(dynamicTexture);
makeCurrent();
}
