/* -*- coding: utf-8 -*- */
/**
 * Example code for the course "Tietokonegrafiikan perusteet" 2012.
 * Exercise 6: preliminary rendering library "draft" combining the
 * classes from previous exercises.
 */
package demo1;
/**
 * Example code for the course "Tietokonegrafiikan perusteet" 2012
 * and 2013. Likely not useful for "production use".
 * 
 * Exercise 1: preliminary vector, matrix, and image classes.
 * 
 * @author Paavo Nieminen
 * 
 */

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;

import javax.imageio.ImageIO;

/** My own image class.
 */
public class PixelImageRGB {
    private int width;
    private int height;
    private float[] red;
    private float[] green;
    private float[] blue;

    /* Black by default. */
    public PixelImageRGB(int width, int height) {
        this.width = width;
        this.height = height;
        int arrsz = width * height;
        red = new float[arrsz];
        green = new float[arrsz];
        blue = new float[arrsz];
    }

    /** Just a test image for debugging. */
    public void testImage() {
        float r, g, b;
        for (int y = 0; y < height; y++) {
            for (int x = 0; x < width; x++) {
                r = -(width / 2) + x;
                g = (float) x * y / (width * height);
                b = (float) y / height;
                setPixel(x, y, r, g, b);
            }
        }
    };

    /** Set a pixel at (x,y) to floating point RGB value. 
     * FIXME: Z-buffering could be here, when implemented; needs z as parameter.
     * TODO: Could also do alpha blending; needs alpha as parameter in that case.
     */
    public void setPixel(int x, int y, float r, float g, float b) {
        int loc = y * width + x;
        red[loc] = r;
        green[loc] = g;
        blue[loc] = b;
    }

    /** Return a copy of the image as a Java BufferedImage object. */
    public BufferedImage asBufferedImage() {
        BufferedImage bim = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);
        for (int y = 0; y < height; y++) {
            for (int x = 0; x < width; x++) {
                bim.setRGB(x, y, rgbAt(x, y));
            }
        }
        return bim;
    }

    /** Returns a color value compatible with BufferedImage.TYPE_INT_RGB */
    private int rgbAt(int x, int y) {
        int rgb = 0;
        int loc = y * width + x;

        rgb += 0xff * clamp(red[loc]);
        rgb <<= 8;
        rgb += 0xff * clamp(green[loc]);
        rgb <<= 8;
        rgb += 0xff * clamp(blue[loc]);
        return rgb;
    }

    /** Clamp a float to [0,1] */
    private static float clamp(float value) {
        return value > 1.f ? 1.f : (value < 0.f ? 0.f : value);
    }

    /** Save as PNG. */
    public void saveAsPng(String fname) throws IOException {
        File file = new File(fname);
        ImageIO.write(asBufferedImage(), "png", file);
    }

    /** Reset to black. */
    public void clear() {
        for(int i=0;i<red.length;i++){
            red[i] = 0; green[i]=0; blue[i]=0;
        }
    }
}