/*
 * Copyright (c) 2008-2010, Matthias Mann
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of Matthias Mann nor the names of its contributors may
 *       be used to endorse or promote products derived from this software
 *       without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package de.matthiasmann.twl.renderer.lwjgl;

import de.matthiasmann.twl.Color;
import org.lwjgl.opengl.GL11;

/**
 * A helper class to implement tinting.
 * 
 * @author Matthias Mann
 */
public class TintStack {

    private static final float ONE_OVER_255 = 1f / 255f;

    final TintStack prev;
    TintStack next;
    float r,g,b,a;

    @SuppressWarnings("LeakingThisInConstructor")
    public TintStack() {
        this.prev = this;
        this.r = ONE_OVER_255;
        this.g = ONE_OVER_255;
        this.b = ONE_OVER_255;
        this.a = ONE_OVER_255;
    }

    private TintStack(TintStack prev) {
        this.prev = prev;
    }
    
    public TintStack pushReset() {
        if(next == null) {
            next = new TintStack(this);
        }
        next.r = ONE_OVER_255;
        next.g = ONE_OVER_255;
        next.b = ONE_OVER_255;
        next.a = ONE_OVER_255;
        return next;
    }
    
    public TintStack push(float r, float g, float b, float a) {
        if(next == null) {
            next = new TintStack(this);
        }
        next.r = this.r * r;
        next.g = this.g * g;
        next.b = this.b * b;
        next.a = this.a * a;
        return next;
    }
    
    public TintStack push(Color color) {
        return push(
                color.getRedFloat(),
                color.getGreenFloat(),
                color.getBlueFloat(),
                color.getAlphaFloat());
    }
    
    public TintStack pop() {
        return prev;
    }

    public float getR() {
        return r;
    }

    public float getG() {
        return g;
    }

    public float getB() {
        return b;
    }

    public float getA() {
        return a;
    }

    /**
     * GL11.glColor4f(color * tint);
     *
     * @param color the desired color. Will be tinted.
     */
    public void setColor(Color color) {
        GL11.glColor4f(
                r*color.getRed(),
                g*color.getGreen(),
                b*color.getBlue(),
                a*color.getAlpha());
    }
    
    /**
     * GL11.glColor4f(color * tint);
     *
     * @param r the red component 0..255
     * @param g the green component 0..255
     * @param b the blue component 0..255
     * @param a the alpha component 0..255
     */
    public void setColor(float r, float g, float b, float a) {
        GL11.glColor4f(
                this.r * r,
                this.g * g,
                this.b * b,
                this.a * a);
    }
}