Slick2D Radial Gradient

Engines, Libraries and Tools
#1

Hello,
With apologies, I think that I originally posted this under the wrong section, so I moved my question here. I am having difficulty creating a lighting system for my game. The way I plan to render lighting is like this:

  • Create a lighting map by using additive blending and radial gradients from all of the lightsources
  • Combine the lightmap with the rendered game using multiplicative blending

The issue with my code so far is creating a radial gradient class. I am using Slick2D, which doesn’t include a radial gradient class that implements ShapeFill, the interface used to fill shapes. I decided to create one myself, which looks like this:
`import org.newdawn.slick.;
import org.newdawn.slick.geom.;
import org.newdawn.slick.svg.*;

public class RadialFill implements ShapeFill {
Color start;
Color end;
float centerX;
float centerY;

public RadialFill(Color s, Color e){
	start = s;
	end = e;
}

@Override
public Color colorAt(Shape shape, float x, float y) {
	float e = (float) (Math.sqrt((x - centerX) * (x - centerX) + (y - centerY) * (y - centerY))) / ((shape.getHeight() > shape.getWidth() ? shape.getHeight() : shape.getWidth()) / 2 );
	float s = 1 - e;
	Color col = new Color(1,1,1,1);
	col.r = (e * end.r) + (s * start.r);
	col.b = (e * end.b) + (s * start.b);
	col.g = (e * end.g) + (s * start.g);
	col.a = (e * end.a) + (s * start.a);
	return col;
}

public void setCenter(float x, float y){
	centerX = x;
	centerY = y;
}

public float getCenterX(){
	return centerX;
}

public float getCenterY(){
	return centerY;
}

public void setStartColor(Color s){
	start = s;
}

public Color getStartColor(){
	return start;
}

public void setEndColor(Color e){
	end = e;
}

public Color getEndColor(){
	return end;
}

@Override
public Vector2f getOffsetAt(Shape shape, float x, float y) {
	// TODO Auto-generated method stub
	return new Vector2f(0,0);
}

}
Here is the test code that I made:import org.newdawn.slick.;
import org.newdawn.slick.fills.;
import org.newdawn.slick.geom.;
import org.newdawn.slick.state.;
import org.newdawn.slick.svg.*;

public class LightTestState extends BasicGameState {

Input input;
GradientFill grad;
RadialFill gradFill;
Ellipse mouseLight;
int mouseX;
int mouseY;
boolean ready = false;

@Override
public void init(GameContainer container, StateBasedGame game)
		throws SlickException {
	input = container.getInput();
	grad = new GradientFill(0, 0, Color.yellow, 100, 100, Color.black, false);
	gradFill = new RadialFill(Color.yellow, Color.black);
	ready = true;
}

@Override
public void render(GameContainer container, StateBasedGame game, Graphics g)
		throws SlickException {
	if (ready){
		g.setAntiAlias(true);
		g.setDrawMode(Graphics.MODE_ADD);
		mouseLight = new Ellipse(mouseX, mouseY, 100, 100);
		gradFill.setCenter(mouseX, mouseY);
		g.fill(mouseLight, grad);
	}
}

@Override
public void update(GameContainer container, StateBasedGame game, int delta)
		throws SlickException {
	mouseX = input.getMouseX();
	mouseY = input.getMouseY();
}

@Override
public int getID() {
	// TODO Auto-generated method stub
	return 1;
}

} import org.newdawn.slick.AppGameContainer;
import org.newdawn.slick.GameContainer;
import org.newdawn.slick.SlickException;
import org.newdawn.slick.state.StateBasedGame;
import org.newdawn.slick.tests.*;

public class Noteblock extends StateBasedGame {

public Noteblock(){
	super("Noteblock");
}

@Override
public void initStatesList(GameContainer container) throws SlickException {
	// TODO Auto-generated method stub
	container.setShowFPS(false);
	addState(new LightTestState());
}

/**
 * @param args
 */
public static void main(String[] args) {
	//GradientTest.main(null);
	try {
		AppGameContainer container = new AppGameContainer(new Noteblock());
		container.setDisplayMode(800,600,false);
		container.start();
	} catch (SlickException e) {
		e.printStackTrace();
	}
}

}
`
However, when I try to create a radial gradient with this code, it doesn’t work. At best, it can only make a fill of one color. ??? Any ideas? Any help would be appreciated.