java triangle interpolation how to aka rgb test image

Question

So what i wanted to do is interpolate a triangle in java without any external libraries for a challenge, just using swing to display the image. I searched all over the web and i couldn't find anything. Thats why i'm making this.

Answer 1

The solution: Weighted averages!

private int interpolate(int x, int y, int v1, int v2, int v3) {
    // these are my triangle corners

    Vector p1v = new Vector(p1.x, p1.y);
    Vector p2v = new Vector(p2.x, p2.y);
    Vector p3v = new Vector(p3.x, p3.y);

    // current point
    Vector f = new Vector(x, y);

    // calculate weighted average

    double a1 = triangleArea(f, p2v, p3v);
    double a2 = triangleArea(f, p1v, p3v);
    double a3 = triangleArea(f, p1v, p2v);

    return (int) ((a1 * v1 + a2 * v2 + a3 * v3) / (a1 + a2 + a3));

}

Usage - put in double for loop for x and y values:

int red = interpolate((int) x, y, p1red, p2red, p3red);
int green = interpolate((int) x, y, p1green, p2green, p3green);
int blue = interpolate((int) x, y, p1blue, p2blue, p3blue);

//System.out.println("xyrgb: " + (int)x + ", " + y + ", " + red + ", " + green + ", " + blue);

bI.setRGB((int)x, y, new Color(red, green, blue).getRGB());

You can find more of the code on my github: here

Screenie: