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@ClickerMonkey
Created October 29, 2014 15:09
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Collision resolution visualization
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.event.KeyEvent;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import java.util.Arrays;
import java.util.List;
import com.gameprogblog.engine.Play;
import com.gameprogblog.engine.PlayLoop;
import com.gameprogblog.engine.PlayLoopVariable;
import com.gameprogblog.engine.PlayScreen;
import com.gameprogblog.engine.PlayState;
import com.gameprogblog.engine.Scene;
import com.gameprogblog.engine.Vector;
import com.gameprogblog.engine.input.PlayInput;
public class CollisionResolution implements Play
{
public static void main( String[] args )
{
Play game = new CollisionResolution();
PlayLoop loop = new PlayLoopVariable( 0.1f );
PlayScreen screen = new PlayScreen( 640, 480, Color.black, true, loop, game );
PlayScreen.showWindow( screen, "CollisionResolution" );
}
public static final Font FONT = new Font( "Monospaced", Font.PLAIN, 12 );
private float draggableRadius = 8.0f;
private List<Vector> draggables;
private int draggingIndex = -1;
private Vector pos0, pos1, velp0, velp1, normalp;
private boolean playing = false;
private float mass0, mass1, restitution0, restitution1, friction0, friction1;
@Override
public void start( Scene scene )
{
pos0 = new Vector( 300, 300 );
pos1 = new Vector( 400, 400 );
velp0 = new Vector( 400, 300 );
velp1 = new Vector( 300, 400 );
normalp = new Vector( 320, 320 );
draggables = Arrays.asList( pos0, pos1, velp0, velp1, normalp );
mass0 = 1.0f;
mass1 = 1.0f;
restitution0 = 1.0f;
restitution1 = 1.0f;
friction0 = 0.0f;
friction1 = 0.0f;
playing = true;
}
@Override
public void input( PlayInput input )
{
if (input.keyDown[KeyEvent.VK_ESCAPE])
{
playing = false;
}
if (input.keyUp[KeyEvent.VK_Q]) mass0 -= 0.01f;
if (input.keyUp[KeyEvent.VK_W]) mass0 += 0.01f;
if (input.keyUp[KeyEvent.VK_A]) mass1 -= 0.01f;
if (input.keyUp[KeyEvent.VK_S]) mass1 += 0.01f;
if (input.keyUp[KeyEvent.VK_E]) restitution0 -= 0.01f;
if (input.keyUp[KeyEvent.VK_R]) restitution0 += 0.01f;
if (input.keyUp[KeyEvent.VK_D]) restitution1 -= 0.01f;
if (input.keyUp[KeyEvent.VK_F]) restitution1 += 0.01f;
if (input.keyUp[KeyEvent.VK_T]) friction0 -= 0.01f;
if (input.keyUp[KeyEvent.VK_Y]) friction0 += 0.01f;
if (input.keyUp[KeyEvent.VK_G]) friction1 -= 0.01f;
if (input.keyUp[KeyEvent.VK_H]) friction1 += 0.01f;
Vector mouse = new Vector( input.mouseX, input.mouseY );
if (draggingIndex != -1 && !input.mouseDragging)
{
draggingIndex = -1;
}
if (draggingIndex == -1 && input.mouseDragging)
{
for (int i = 0; i < draggables.size(); i++)
{
if (mouse.distance( draggables.get( i ) ) < draggableRadius)
{
draggingIndex = i;
}
}
}
if (draggingIndex != -1)
{
draggables.get( draggingIndex ).set( mouse );
}
}
@Override
public void update( PlayState state, Scene scene )
{
}
@Override
public void draw( PlayState state, Graphics2D gr, Scene scene )
{
gr.setColor( Color.blue );
for (Vector d : draggables)
{
gr.draw( new Ellipse2D.Float( d.x - draggableRadius, d.y - draggableRadius, draggableRadius * 2, draggableRadius * 2 ) );
}
gr.setColor( Color.cyan );
drawVector( gr, pos0.x, pos0.y, velp0.x, velp0.y );
drawVector( gr, pos1.x, pos1.y, velp1.x, velp1.y );
drawVector( gr, (pos0.x + pos1.x) * 0.5f, (pos0.y + pos1.y) * 0.5f, normalp.x, normalp.y );
Vector contact = pos0.add( pos1 ).muli( 0.5f );
Vector vel0 = velp0.sub( pos0 );
Vector vel1 = velp1.sub( pos1 );
Vector normal = normalp.sub( contact ).normali();
float friction = Math.max( friction0, friction1 );
float restitution = (restitution0 * restitution1) * 0.5f + 0.5f;
float radius = pos0.distance( pos1 ) * 0.5f;
float masssum = 2.0f / (mass0 + mass1);
gr.setColor( Color.gray );
gr.draw( new Ellipse2D.Float( contact.x - 3, contact.y - 3, 3 * 2, 3 * 2 ) );
gr.draw( new Ellipse2D.Float( pos0.x - radius, pos0.y - radius, radius * 2, radius * 2 ) );
gr.draw( new Ellipse2D.Float( pos1.x - radius, pos1.y - radius, radius * 2, radius * 2 ) );
int textY = 8;
gr.setColor( Color.white );
gr.setFont( FONT );
gr.drawString( "vel0: " + vel0, 8, textY += 16 );
gr.drawString( "vel1: " + vel1, 8, textY += 16 );
gr.drawString( "normal: " + normal, 8, textY += 16 );
gr.drawString( "mass0[q/w]: " + mass0, 8, textY += 16 );
gr.drawString( "mass1[a/s]: " + mass1, 8, textY += 16 );
gr.drawString( "restitution0[e/r]: " + restitution0, 8, textY += 16 );
gr.drawString( "restitution1[d/f]: " + restitution1, 8, textY += 16 );
gr.drawString( "friction0[t/y]: " + friction0, 8, textY += 16 );
gr.drawString( "friction1[g/h]: " + friction1, 8, textY += 16 );
gr.drawString( "friction: " + friction, 8, textY += 16 );
gr.drawString( "restitution: " + restitution, 8, textY += 16 );
Vector V = vel0.sub( vel1 );
Vector Vn = normal.mul( V.dot( normal ) );
Vector Vt = V.sub( Vn );
Vector Vprime = Vn.mul( restitution ).addsi( Vt, friction );
vel0.addsi( Vprime, -1 );
vel0.muli( mass1 * masssum );
vel1.addsi( Vprime, +1 );
vel1.muli( mass0 * masssum );
gr.setColor( Color.orange );
drawVector( gr, contact.x, contact.y, contact.x + Vn.x, contact.y + Vn.y );
gr.setColor( Color.pink );
drawVector( gr, contact.x, contact.y, contact.x + Vt.x, contact.y + Vt.y );
gr.setColor( Color.red );
drawVector( gr, pos0.x, pos0.y, pos0.x + vel0.x, pos0.y + vel0.y );
drawVector( gr, pos1.x, pos1.y, pos1.x + vel1.x, pos1.y + vel1.y );
}
private void drawVector( Graphics2D gr, float x0, float y0, float x1, float y1 )
{
Vector v = new Vector( x1 - x0, y1 - y0 );
Vector v0 = v.rotate( 0.3f ).normali().muli( draggableRadius * 2 );
Vector v1 = v.rotate( -0.3f ).normali().muli( draggableRadius * 2 );
gr.draw( new Line2D.Float( x0, y0, x1, y1 ) );
gr.draw( new Line2D.Float( x1, y1, x1 - v0.x, y1 - v0.y ) );
gr.draw( new Line2D.Float( x1, y1, x1 - v1.x, y1 - v1.y ) );
}
@Override
public void destroy()
{
}
@Override
public boolean isPlaying()
{
return playing;
}
}
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