code: public float[] getEffectAt(float x, float y, boolean colouredLights) {
  		// first work out what propotion of the strength distance the light
  		// is from the point. This is a value from 0-1 where 1 is the centre of the
  		// light (i.e. full brightness) and 0 is the very edge (or outside) the lights
  		// range
  		float dx = (x - xpos);
  		float dy = (y - ypos);
  		float distance2 = (dx*dx)+(dy*dy);
  		float effect = 1 - (distance2 / (strength*strength));
  		
  		if (effect < 0) {
  			effect = 0;
  		}
  		
  		// if we doing coloured lights then multiple the colour of the light 
  		// by the effect. Otherwise just use the effect for all components to
  		// give white light
  		if (colouredLights) {
  			return new float[] {col.r * effect, col.g * effect, col.b * effect};
  		} else {
  			return new float[] {effect,effect,effect};
  		}
  	}
docs: Get the effect the light should apply to a given location
  
  @param x The x coordinate of the location being considered for lighting
  @param y The y coordinate of the location being considered for lighting
  @param colouredLights True if we're supporting coloured lights
  
  @return The effect on a given location of the light in terms of colour components (all
  the same if we don't support coloured lights)