Compiler:

tetrahedron.cpp: In function "void berechne_eckpunkte(float, float, float)":
tetrahedron.cpp:39: error: "hinten" was not declared in this scope
tetrahedron.cpp:43: error: "vorne_links" was not declared in this scope
tetrahedron.cpp:47: error: "vorne_rechts" was not declared in this scope
tetrahedron.cpp:51: error: "oben" was not declared in this scope

Aber in der Headerdatei steht es doch unter public Zeile 11!!!!!!!
Also was zum Teufel geht hier ab?!

Tetrahedron.h:

#ifndef TETRAHEDRON_H
#define TETRAHEDRON_H

#include <QGLWidget>

class Tetrahedron : public QGLWidget
{
	Q_OBJECT
	public:
		Tetrahedron(QWidget *parent = 0);
		float hinten[3], vorne_links[3], vorne_rechts[3], oben[3];
		void berechne_eckpunkte(float ursprungX, float ursprungY, float ursprungZ);

	protected:
		void initializeGL();
		void resizeGL(int width, int height);
		void paintGL();
		void mousePressEvent(QMouseEvent *event);
		void mouseMoveEvent(QMouseEvent *event);
		void mouseDoubleClickEvent(QMouseEvent *event);

	private:
		void draw();
		int faceAtPosition(const QPoint &pos);
		GLfloat rotationX;
		GLfloat rotationY;
		GLfloat rotationZ;
		QColor faceColors[4];
		QPoint lastPos;
};

#endif

Tetrahedron.cpp:

#include <QtGui>
#include <QtOpenGL>
#include <cmath>

#include "tetrahedron.h"

Tetrahedron::Tetrahedron(QWidget *parent)
	: QGLWidget(parent)
{
	setFormat(QGLFormat(QGL::DoubleBuffer | QGL::DepthBuffer));
}

void Tetrahedron::initializeGL()
{
	qglClearColor(Qt::black);
	glShadeModel(GL_FLAT);
	glEnable(GL_DEPTH_TEST);
	glEnable(GL_CULL_FACE);
}

void Tetrahedron::resizeGL(int width, int height)
{
	glViewport(0, 0, width, height);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	GLfloat x = GLfloat(width) / height;
	glFrustum(-x, x, -1.0, 1.0, 4.0, 15.0);
	glMatrixMode(GL_MODELVIEW);
}

void Tetrahedron::paintGL()
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	draw();
}

void berechne_eckpunkte(float ursprungX, float ursprungY, float ursprungZ)
{
	hinten[0] = ursprungX;
	hinten[1] = ursprungY;
	hinten[2] = ursprungZ;

	vorne_links[0] = ursprungX - 0.5;
	vorne_links[1] = ursprungY;
	vorne_links[2] = ursprungZ + (sqrt(3.0)/2.0);

	vorne_rechts[0] = ursprungX + 0.5;
	vorne_rechts[1] = ursprungY;
	vorne_rechts[2] = ursprungZ + (sqrt(3.0)/2.0);

	oben[0] = ursprungX;
	oben[1] = ursprungY + (sqrt(6.0)/3.0);
	oben[2] = ursprungZ + (sqrt(3.0)/3.0);
}

void Tetrahedron::draw()
{
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	berechne_eckpunkte(0.0, 0.0, 0.0);
	glBegin(GL_POLYGON);

	glVertex3f(hinten[0],hinten[1],hinten[2]);
	glVertex3f(vorne_links[0],vorne_links[1],vorne_links[2]);
	glVertex3f(oben[0],oben[1],oben[2]);

	glVertex3f(vorne_links[0],vorne_links[1],vorne_links[2]);
	glVertex3f(vorne_rechts[0],vorne_rechts[1],vorne_rechts[2]);
	glVertex3f(oben[0],oben[1],oben[2]);

	glVertex3f(vorne_rechts[0],vorne_rechts[1],vorne_rechts[2]);
	glVertex3f(hinten[0],hinten[1],hinten[2]);
	glVertex3f(oben[0],oben[1],oben[2]);

	glVertex3f(hinten[0],hinten[1],hinten[2]);
	glVertex3f(vorne_links[0],vorne_links[1],vorne_links[2]);
	glVertex3f(vorne_rechts[0],vorne_rechts[1],vorne_rechts[2]);

	glEnd();
}

void Tetrahedron::mousePressEvent(QMouseEvent *event)
{
	lastPos = event->pos();
}

void Tetrahedron::mouseMoveEvent(QMouseEvent *event)
{
	GLfloat dx = GLfloat(event->x() - lastPos.x()) / width();
	GLfloat dy = GLfloat(event->y() - lastPos.y()) / height();

	if (event->buttons() & Qt::LeftButton)
	{
		rotationX += 180*dy;
		rotationY += 180*dx;
		updateGL();
	}
	else
	{
		if (event->buttons() & Qt::RightButton)
		{
			rotationX += 180*dy;
			rotationZ += 180*dx;
			updateGL();
		}
	}
	lastPos = event->pos();
}

void Tetrahedron::mouseDoubleClickEvent(QMouseEvent *event)
{
	int face = faceAtPosition(event->pos());
	if (face != -1)
	{
		QColor color = QColorDialog::getColor(faceColors[face], this);
		if (color.isValid())
		{
			faceColors[face] = color;
			updateGL();
		}
	}
}

int Tetrahedron::faceAtPosition(const QPoint &pos)
{
	const int MaxSize = 512;
	GLuint buffer[MaxSize];
	GLint viewport[4];

	makeCurrent();

	glGetIntegerv(GL_VIEWPORT, viewport);
	glSelectBuffer(MaxSize, buffer);
	glRenderMode(GL_SELECT);

	glInitNames();
	glPushName(0);

	glMatrixMode(GL_PROJECTION);
	glPushMatrix();
	glLoadIdentity();
	gluPickMatrix(GLdouble(pos.x()), GLdouble(viewport[3] - pos.y()), 5.0, 5.0, viewport);
	GLfloat x = GLfloat(width()) / height();
	glFrustum(-x, x, -1.0, 1.0, 4.0, 15.0);
	draw();
	glMatrixMode(GL_PROJECTION);
	glPopMatrix();

	if (!glRenderMode(GL_RENDER))
	{
		return -1;
	}
	return buffer[3];
}

Main.cpp:

#include <QApplication>
#include <iostream>

#include "tetrahedron.h"

int main(int argc, char *argv[])
{
	QApplication app(argc, argv);

	if (!QGLFormat::hasOpenGL())
	{
		std::cerr << "Geht nicht" << std::endl;
		return 1;
	}

	Tetrahedron tetrahedron;
	tetrahedron.setWindowTitle("Tetrahedron");
	tetrahedron.resize(300, 300);
	tetrahedron.show();

	return app.exec();
}

Danke an alle, die versuchen mir zu helfen und sorry für so viel Code!

=>

void Tetrahedron::berechne_eckpunkte(float ursprungX, float ursprungY, float ursprungZ)

DANKE!