/**
	Company:		Shout3D LLC
	Project:		Shout3D 2.0 Sample Code
	Class:			GradientTexture
	Date:			July 12, 2000
	Description:	A subclass of PixelBasedTexture that generates a texture algorithmically.
	(C) Copyright Shout3D LLC. - 1997-2001 - All rights reserved
 */

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

/**
 * GradientTexture
 *
 * A subclass of PixelBasedTexture that generates a texture algorithmically.
 *
 * Demonstrates how to subclass from PixelBasedTexture and use its
 * API to create a procedurally generated texture.
 *
 * @author Paul Isaacs
 */

public class GradientTexture extends PixelBasedTexture implements FieldObserver {

	final public IntField  width	= new IntField(this, "width", Field.NON_NEGATIVE_INT, 2);
	final public IntField  height	= new IntField(this, "height", Field.NON_NEGATIVE_INT, 128);
	final public FloatArrayField  gradientColors	= new FloatArrayField(this, "gradientColors", Field.COLOR_ARRAY, null );

	/**
	 * Constructs a default GradientTexture node.
	 */
	public GradientTexture() {
		width.addFieldObserver(this,null);
		height.addFieldObserver(this,null);
		gradientColors.addFieldObserver(this,null);
	}

	public void finalize() throws Throwable {
		width.removeFieldObserver(this);
		height.removeFieldObserver(this);
		gradientColors.removeFieldObserver(this);
		// Must call this or super classes will not properly finalize.
		super.finalize();
	}

	public void onFieldChange(Field theField, Object userData) {
		// When the fields change, update the pixels.
		if (theField == width || theField == height || theField == gradientColors)
			updateCustomPixels();
	}

	/**
	 * Generates a texture that is a gradient of colors based on those
	 * in the gradientColors field.
	 */
	public void updateCustomPixels() {
		if (width.getValue() <= 0 || height.getValue() <= 0 ||
			gradientColors.getValue() == null ||
			gradientColors.getValue().length < 3) {
			// fuggedaboudit.
			setCustomPixels(0,0,null,null,null,null);
		}
		else {
			// Generate the texture based on the fields.
			byte[][] myRed = new byte[height.getValue()][width.getValue()];
			byte[][] myGreen = new byte[height.getValue()][width.getValue()];
			byte[][] myBlue = new byte[height.getValue()][width.getValue()];

			int numColors = gradientColors.getValue().length / 3;
			byte r, g, b;
			float rowFraction, prevAmount, nextAmount;
			int   prevColor, nextColor;
			float[] gradColors = gradientColors.getValue();

			// For each row of the texture
			for (int i = 0; i < height.getValue(); i++) {
				// set rowFraction to a value between 0..1 expressing how far towards maximum height this row is.
				rowFraction = (float)i/(float)(height.getValue()-1);
				// find colors before (or at) and after (or at) this row
				prevColor = (int) (rowFraction * (numColors-1));
				nextColor = (prevColor == numColors-1) ? prevColor : prevColor + 1;
				// Amounts of each to mix to ramp smoothly from prevColor to nextColor
				prevAmount = nextColor - rowFraction*(numColors-1);
				nextAmount = (prevColor==nextColor) ? 1 : rowFraction*(numColors-1) - prevColor;

				// Mix some of each color to get the gradient color
				// Color values in the pixel array need to be bytes ranging 0-255
				r = (byte)(255* (gradColors[3*prevColor]   * prevAmount + gradColors[3*nextColor]   * nextAmount));
				g = (byte)(255* (gradColors[3*prevColor+1] * prevAmount + gradColors[3*nextColor+1] * nextAmount));
				b = (byte)(255* (gradColors[3*prevColor+2] * prevAmount + gradColors[3*nextColor+2] * nextAmount));
				// Set all pixels in the row to this color.
				for (int j = 0; j < width.getValue(); j++){
					// Color values are bytes ranging 0-255
					myRed[i][j]   = r;
					myGreen[i][j] = g;
					myBlue[i][j]  = b;
				}
			}
			// Set the pixels, alpha channel is null.
			setCustomPixels(width.getValue(), height.getValue(),
							myRed, myGreen, myBlue, null);
		}
	}
}