glwidget.cpp Example File opengl/samplebuffers/glwidget.cpp
#include "glwidget.h"
#include <math.h>
#ifndef GL_MULTISAMPLE
#define GL_MULTISAMPLE 0x809D
#endif
GLWidget::GLWidget(QWidget *parent)
: QGLWidget(QGLFormat(QGL::SampleBuffers), parent)
{
startTimer(40);
setWindowTitle(tr("Sample Buffers"));
}
void GLWidget::initializeGL()
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-.5, .5, .5, -.5, -1000, 1000);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
makeObject();
}
void GLWidget::resizeGL(int w, int h)
{
glViewport(0, 0, w, h);
}
void GLWidget::paintGL()
{
static float rot = 0.0;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glEnable(GL_MULTISAMPLE);
glTranslatef(-0.25f, -0.10f, 0.0f);
glScalef(0.75f, 1.15f, 0.0f);
glRotatef(rot, 0.0f, 0.f, 1.0f);
glCallList(list);
glPopMatrix();
glPushMatrix();
glDisable(GL_MULTISAMPLE);
glTranslatef(0.25f, -0.10f, 0.0f);
glScalef(0.75f, 1.15f, 0.0f);
glRotatef(rot, 0.0f, 0.0f, 1.0f);
glCallList(list);
glPopMatrix();
rot += 0.2f;
qglColor(Qt::black);
renderText(-0.35, 0.4, 0.0, "Multisampling enabled");
renderText(0.15, 0.4, 0.0, "Multisampling disabled");
}
void GLWidget::timerEvent(QTimerEvent *)
{
update();
}
void GLWidget::makeObject()
{
QColor trolltechGreen(QColor::fromCmykF(0.40, 0.0, 1.0, 0.0));
const double Pi = 3.14159265358979323846;
const int NumSectors = 15;
GLdouble x1 = +0.06;
GLdouble y1 = -0.14;
GLdouble x2 = +0.14;
GLdouble y2 = -0.06;
GLdouble x3 = +0.08;
GLdouble y3 = +0.00;
GLdouble x4 = +0.30;
GLdouble y4 = +0.22;
list = glGenLists(1);
glNewList(list, GL_COMPILE);
{
for (int i = 0; i < NumSectors; ++i) {
double angle1 = (i * 2 * Pi) / NumSectors;
GLdouble x5 = 0.30 * sin(angle1);
GLdouble y5 = 0.30 * cos(angle1);
GLdouble x6 = 0.20 * sin(angle1);
GLdouble y6 = 0.20 * cos(angle1);
double angle2 = ((i + 1) * 2 * Pi) / NumSectors;
GLdouble x7 = 0.20 * sin(angle2);
GLdouble y7 = 0.20 * cos(angle2);
GLdouble x8 = 0.30 * sin(angle2);
GLdouble y8 = 0.30 * cos(angle2);
qglColor(trolltechGreen);
quad(GL_QUADS, x5, y5, x6, y6, x7, y7, x8, y8);
qglColor(Qt::black);
quad(GL_LINE_LOOP, x5, y5, x6, y6, x7, y7, x8, y8);
}
qglColor(trolltechGreen);
quad(GL_QUADS, x1, y1, x2, y2, y2, x2, y1, x1);
quad(GL_QUADS, x3, y3, x4, y4, y4, x4, y3, x3);
qglColor(Qt::black);
quad(GL_LINE_LOOP, x1, y1, x2, y2, y2, x2, y1, x1);
quad(GL_LINE_LOOP, x3, y3, x4, y4, y4, x4, y3, x3);
}
glEndList();
}
void GLWidget::quad(GLenum primitive, GLdouble x1, GLdouble y1, GLdouble x2, GLdouble y2,
GLdouble x3, GLdouble y3, GLdouble x4, GLdouble y4)
{
glBegin(primitive);
{
glVertex2d(x1, y1);
glVertex2d(x2, y2);
glVertex2d(x3, y3);
glVertex2d(x4, y4);
}
glEnd();
}
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