Hallo Java-Gemeinde,
ich bin mal wieder bei einem Problem und hoffe, dass ihr mir vllt. dabei weiterhelfen könnt, da ich schon echt lange daran sitze und nicht weiter weiss. Es geht um ein Programm, das 3D-Figuren ein- bzw. auslesen soll (nur nebenbei als Info). Konkret geht es um Folgendes:
Wir sollen (Aufgabe aus dem Studium) die Linien eines Würfels (3D) mit Hilfe des Bresenham-Geraden-Algrithmus programmieren, ohne dazu die Java-Biblithek zu verwenden. (Würfel ist eine drehbarer Körper)
Ich denke der Algorithmus sollte soweit passen, allerdings ist das Programm durch Fehler nicht ausführbar. Ich kann allerdings mir nichts aus den Fehlermeldung reimen, was zu einer Lösung führen würde, deshalb wäre es super wenn ihr vllt. mal drüberschaut.
Zunächst einmal nur ein Codeausschnitt der entsprechenden Klasse. (Im Anhang dann das Projekt)
Die Fehlermeldung beim Ausführen der entsprechenden Klasse:
1.0Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: -1
at cog1.Raster.drawPoint(Raster.java:170)
at cog1.Raster.bresenham(Raster.java:128)
at cog1.Raster.scanlineDrawPolygon(Raster.java:235)
at cog1.Render.raster(Render.java:199)
at cog1.Render.paintComponent(Render.java:217)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JLayeredPane.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source)
at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source)
at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)
at java.awt.Container.paint(Unknown Source)
at java.awt.Window.paint(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.seqPaintDirtyRegions(Unknown Source)
at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Ich hoffe ihr könnt damit was anfangen. Bin langsam echt am verzweifeln
ich bin mal wieder bei einem Problem und hoffe, dass ihr mir vllt. dabei weiterhelfen könnt, da ich schon echt lange daran sitze und nicht weiter weiss. Es geht um ein Programm, das 3D-Figuren ein- bzw. auslesen soll (nur nebenbei als Info). Konkret geht es um Folgendes:
Wir sollen (Aufgabe aus dem Studium) die Linien eines Würfels (3D) mit Hilfe des Bresenham-Geraden-Algrithmus programmieren, ohne dazu die Java-Biblithek zu verwenden. (Würfel ist eine drehbarer Körper)
Ich denke der Algorithmus sollte soweit passen, allerdings ist das Programm durch Fehler nicht ausführbar. Ich kann allerdings mir nichts aus den Fehlermeldung reimen, was zu einer Lösung führen würde, deshalb wäre es super wenn ihr vllt. mal drüberschaut.
Zunächst einmal nur ein Codeausschnitt der entsprechenden Klasse. (Im Anhang dann das Projekt)
Java:
package cog1;
import java.awt.Color;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
// Rasterization algorithms, called by Render class.
public class Raster {
// View-port, size of window or canvas.
private int viewWidth;
private int viewHeight;
// Plane equation of polygon.
private float A;
private float B;
private float C;
private float D;
private float AdivC; // Pre-calculate for speed-up.
DecimalFormat format = new DecimalFormat("+#.##;-#.##"); // For debug.
// For each polygon we store all points from all edges
// generated by the Bresenham algorithm.
// The are use for the scan-line fill algorithm.
// After processing a polygon the data structures are reset.
// One ArrayList for every scan-line.
private ArrayList<ArrayList<Integer>> scanlineIntersection;
public Raster( final int viewWidth, final int viewHeight ) {
this.viewWidth = viewWidth;
this.viewHeight = viewHeight;
scanlineIntersection = new ArrayList<ArrayList<Integer>>();
for (int y = 0; y < viewHeight; y++) {
scanlineIntersection.add(new ArrayList<Integer>());
}
}
private void addIntersection( int x, int y ) {
if ( x >= 0 && x < viewWidth && y >= 0 && y < viewHeight ) {
//scanlineIntersection.getyes.add( new Integer(x) );
scanlineIntersection.get(y).add( x );
} else {
//System.out.println("Error in addIntersection (out of screen):"+x+","+y); //debug
}
}
private void clearIntersections() {
for (ArrayList<Integer> line : scanlineIntersection) {
line.clear();
}
}
private int abs( int val) {
return val >= 0 ? 1 : -1;
}
public void bresenham( Framebuffer framebuffer,
int startX, int startY, int endX, int endY,
final Color color, boolean toFrameBuffer ) {
final int dX = endX - startX;
final int dY = endY - startY;
final int dXAbs = Math.abs(dX);// - !!!!!!!!!!!!!!!!!
final int dYAbs = Math.abs(dY);// - !!!!!!!!!!!!!!!!!
final int dXSign = (int)abs(dX);
final int dYSign = (int)abs(dY);
final int dXAbs2 = 2 * dXAbs; // - !!!!!!!!!!!!!!!!!
final int dYAbs2 = 2 * dYAbs; // - !!!!!!!!!!!!!!!!!
final int dXdYdiff2 = 2 * (dXAbs - dYAbs); // shortcut for speedup.
final int dYdXdiff2 = 2 * (dYAbs - dXAbs); // shortcut for speedup. - Inc2
int x = startX;
int y = startY;
double e = 0.0; //Entscheidungsvariable
//Farbe festlegen
Color c = new Color(178,034,034);
// ... start here.....
//Wertevergaben der Inkremente/Dekremente für fallende und steigende Linien
final int inc_x;
final int inc_y;
if(dX > 0) // Wenn Linie nach rechts
inc_x = 1; // x inkrementieren
else // Wenn Linie nach links
inc_x = -1; // x dekrementieren
if(dY > 0) // Wenn Linie nach unten
inc_y = 1; // y inkrementieren
else // Wenn Linie nach oben
inc_y = -1; // y dekrementieren
//wenn x länger oder gleich y - langsam steigend/fallend
if(dX >= dY){
e = -Math.abs(dX);
int step = (int) (2*e);
while (x <= endX){
drawPoint(framebuffer,x,y,c);
x += inc_x;
e += dYAbs2;
if (e>0){
y += inc_y;
e += step;
}
}
}
else{ //wenn x kürzer als y - schnell steigend
e = -Math.abs(dX);
int step = (int) (2*e);
while (y <= endY){
drawPoint(framebuffer,x,y,c);
y += inc_y;
e += dXAbs2;
if (e>0){
x += inc_x;
e += step;
}
}
}
}// Ende bresenham()
//die Werte, welche mit dem Alg. erzeugt werden müssen nun in den framebuffer
private void drawPoint(Framebuffer framebuffer, int x, int y, Color c) {
if((this.viewHeight>y)&&(this.viewWidth>x)){
framebuffer.buf[x][y].color=c;
framebuffer.buf[x][y].keep=true;
framebuffer.buf[x][y].changed = false;
}
}
private int calcDerivative( final int currY, final int nextY) {
// y axis from top to bottom.
if( currY < nextY ) {
return -1;
} else if ( currY > nextY ) {
return +1;
} else {
return 0;
}
}
private void calcPlaneEquation( float[][] vertex, int[] polygon ) {
// We assume that all vertices of the polygon are in one plane.
// Two edge-vectors dim 3:
float e[][] = new float[2][3];
// Calculate two (non parallel) vectors inside the plane of the polygon.
// We assume that at least two (consecutive) vertices of a polygon
// are not on a straight line with the first vertex.
// ....
//System.out.println("Plane: A="+format.format(A)+" B="+format.format(B)+" C="+format.format(C)+" D="+format.format(D)+
// " nLength="+nLength+" A/C="+A/C); // debug
}
//Hier wird die Bresenham-Methode aufgerufen
public void scanlineDrawPolygon( Framebuffer framebuffer,
float[][] vertex, int[] polygon, final Color color, boolean fill) {
/*
// We want at least a triangle to proceed.
if( polygon.length < 3 ) { return; }
// Draw edges or register interactions.
if(fill) { clearIntersections(); }
int lastDerivative = calcDerivative(
(int)vertex[polygon[polygon.length-2]][1],
(int)vertex[polygon[polygon.length-1]][1]);
int derivative = lastDerivative;
*/
//System.out.println("______Start next Polygon_______"); //debug.
for(int v = 0; v < polygon.length - 1; v++) { // Polygon-Vertices loop.
final int currX = (int)vertex[polygon[v]][0];
final int currY = (int)vertex[polygon[v]][1];
final int nextX = (int)vertex[polygon[v+1]][0];
final int nextY = (int)vertex[polygon[v+1]][1];
bresenham( framebuffer,
(int) currX, (int) currY,
(int) nextX, (int) nextY,
color, ! fill );
// ...
}
// ...
}
private float getZ( final float x, final float y) {
// We assume that the plane equation is upto date
// with the current polygon.
return -(A*x + B*y + D)/C;
}
}Die Fehlermeldung beim Ausführen der entsprechenden Klasse:
1.0Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: -1
at cog1.Raster.drawPoint(Raster.java:170)
at cog1.Raster.bresenham(Raster.java:128)
at cog1.Raster.scanlineDrawPolygon(Raster.java:235)
at cog1.Render.raster(Render.java:199)
at cog1.Render.paintComponent(Render.java:217)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JLayeredPane.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source)
at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source)
at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)
at java.awt.Container.paint(Unknown Source)
at java.awt.Window.paint(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.seqPaintDirtyRegions(Unknown Source)
at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Ich hoffe ihr könnt damit was anfangen. Bin langsam echt am verzweifeln
