/*
 * Copyright (c) 2009-2010 jMonkeyEngine
 * 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 'jMonkeyEngine' 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 com.jme3.post.filters;

import com.jme3.asset.AssetManager;
import com.jme3.post.Filter;
import com.jme3.material.Material;
import com.jme3.renderer.RenderManager;
import com.jme3.renderer.ViewPort;

/**
 *  A post-processing filter that performs a depth range
 *  blur using a scaled convolution filter.
 *
 *  @version   $Revision: 779 $
 *  @author    Paul Speed
 */
public class DepthOfFieldFilter extends Filter {

    private float focusDistance = 50f;
    private float focusRange = 10f;
    private float blurScale = 1f;
    // These values are set internally based on the
    // viewport size.
    private float xScale;
    private float yScale;

    /**
     * Creates a DepthOfField filter
     */
    public DepthOfFieldFilter() {
        super("Depth Of Field");
    }

    @Override
    protected boolean isRequiresDepthTexture() {
        return true;
    }

    @Override
    protected Material getMaterial() {

        return material;
    }

    @Override
    protected void initFilter(AssetManager assets, RenderManager renderManager,
            ViewPort vp, int w, int h) {
        material = new Material(assets, "Common/MatDefs/Post/DepthOfField.j3md");
        material.setFloat("FocusDistance", focusDistance);
        material.setFloat("FocusRange", focusRange);


        xScale = 1.0f / w;
        yScale = 1.0f / h;

        material.setFloat("XScale", blurScale * xScale);
        material.setFloat("YScale", blurScale * yScale);
    }

    /**
     *  Sets the distance at which objects are purely in focus.
     */
    public void setFocusDistance(float f) {

        this.focusDistance = f;
        if (material != null) {
            material.setFloat("FocusDistance", focusDistance);
        }

    }

    /**
     * returns the focus distance
     * @return 
     */
    public float getFocusDistance() {
        return focusDistance;
    }

    /**
     *  Sets the range to either side of focusDistance where the
     *  objects go gradually out of focus.  Less than focusDistance - focusRange
     *  and greater than focusDistance + focusRange, objects are maximally "blurred".
     */
    public void setFocusRange(float f) {
        this.focusRange = f;
        if (material != null) {
            material.setFloat("FocusRange", focusRange);
        }

    }

    /**
     * returns the focus range
     * @return 
     */
    public float getFocusRange() {
        return focusRange;
    }

    /**
     *  Sets the blur amount by scaling the convolution filter up or
     *  down.  A value of 1 (the default) performs a sparse 5x5 evenly
     *  distribubted convolution at pixel level accuracy.  Higher values skip
     *  more pixels, and so on until you are no longer blurring the image
     *  but simply hashing it.
     *
     *  The sparse convolution is as follows:
     *%MINIFYHTMLc3d0cd9fab65de6875a381fd3f83e1b338%*
     *  Where 'x' is the texel being modified.  Setting blur scale higher
     *  than 1 spaces the samples out.
     */
    public void setBlurScale(float f) {
        this.blurScale = f;
        if (material != null) {
            material.setFloat("XScale", blurScale * xScale);
            material.setFloat("YScale", blurScale * yScale);
        }
    }

    /**
     * returns the blur scale
     * @return 
     */
    public float getBlurScale() {
        return blurScale;
    }
}
