/**
	Company:		Shout3D LLC
	Project:		Shout3D 2.0 Sample Code
	Class:			InvertSceneEffect
	Date:			March 23, 2000
	Description:	A simple example of a PostRenderEffect that makes the scene have an animated waviness run through it.
	(C) Copyright Shout3D LLC. - 1997-2001 - All rights reserved
 */

package custom_nodes;
import shout3d.core.*;
import shout3d.*;
import java.awt.Graphics;

/**
 * InvertSceneEffect
 *
 * @author Dave Westwood
 */

public class WavySceneEffect extends PostRenderEffect {

	// Amplitude of the wave in pixels
	final public IntField  waveAmplitude	= new IntField(this, "waveAmplitude", Field.ANY, 30);
	// Length of the wave in pixels
	final public IntField  waveLength	= new IntField(this, "waveLength", Field.ANY, 60);
	// Velocity of animation of the wave, in pixels per second.
	final public IntField  crawlVelocity	= new IntField(this, "crawlVelocity", Field.ANY, 10);

	/**
	 * Constructs a default InvertSceneEffect node.
	 */
	public WavySceneEffect() {}

	int[] horizOffset = null;
	double startClockT = -1;
	int oldAmplitude = -1;
	int oldWavelength = -1;
	int rowShift, toPixel, rowFirst, rowLast;

    public void filter(Graphics offScreenGraphics, int surface_pixel_bits[], float z_buffer[], int deviceWidth, int deviceHeight) {

		if (surface_pixel_bits == null)
			return;

		// Store these to avoid any nastiness happening from field values that change
		// while we are filtering.
		int curWaveAmplitude = waveAmplitude.getValue();
		int curWaveLength    = waveLength.getValue();
		int curCrawlVelocity = crawlVelocity.getValue();

		// Allocate an array of horizontal offsets for each of the rows within a waveLength's cycle
		if (horizOffset == null || oldAmplitude != curWaveAmplitude ||
			oldWavelength != curWaveLength) {

			horizOffset = new int[curWaveLength];
			for (int i = 0; i < curWaveLength; i++) {
				horizOffset[i] = (int) (curWaveAmplitude * Math.sin( 2 * 3.14159 * ((float)i) / curWaveLength));
			}
			oldAmplitude = curWaveAmplitude;
			oldWavelength =  curWaveLength;
		}

		// How much time has passed since beginning?  Need this for crawl which is
		// velocity based.
		if (startClockT == -1) {
			startClockT = getViewer().getClock().getAbsoluteTime();
		}
		double deltaT = getViewer().getClock().getAbsoluteTime() - startClockT;

		toPixel = 0;
		for (int row=0; row<deviceHeight; row++) {

			rowShift = horizOffset[ ((int)(row + (float)curCrawlVelocity * deltaT)) % curWaveLength ];

			rowFirst = toPixel;
			rowLast  = toPixel + deviceWidth - 1;
			if (rowShift > 0) {
				for (int col=0; col<deviceWidth; col++) {
					if (col + rowShift < deviceWidth) {
						surface_pixel_bits[toPixel] = surface_pixel_bits[toPixel+rowShift];
					}
					else {
						surface_pixel_bits[toPixel] = surface_pixel_bits[rowLast];
					}
					toPixel++;
				}
			}
			else if (rowShift < 0) {
				toPixel += deviceWidth - 1;
				for (int col=deviceWidth-1; col >= 0; col--) {
					if (col + rowShift >= 0){
						surface_pixel_bits[toPixel] = surface_pixel_bits[toPixel+rowShift];
					}
					else {
						surface_pixel_bits[toPixel] = surface_pixel_bits[rowFirst];
					}
					toPixel--;
				}
				toPixel += deviceWidth + 1;
			}
			else {
				// rowShift is 0, skip to next row.
				toPixel += deviceWidth;
			}
		}
    }
}