/*

George Zhang

Encapsulate an image (used to get pixel values).

*/

package geetransit.minecraft05.engine;

import java.nio.ByteBuffer;

public class HeightMap implements AutoCloseable {

public static int CHANNELS = 4;

public final ByteBuffer buffer;

public final int width;

public final int length;

public HeightMap(ByteBuffer buffer, int width, int length) {

this.buffer = buffer;

this.width = width;

this.length = length;

}

public static HeightMap loadFromImage(String fileName) throws Exception {

int width[] = {0}, length[] = {0};

ByteBuffer buffer = Utils.loadImage(fileName, width, length);

return new HeightMap(buffer, width[0], length[0]);

}

@Override

public void close() {

Utils.freeImage(this.buffer);

}

// usage: compressExpand(heightAt(...), 0, MAX_COLOR, 0, 16)

public static float compressExpand(int f, float cMin, float cMax, float eMin, float eMax) {

return expand(compress(f, cMin, cMax), eMin, eMax);

}

public static float compress(int f, float min, float max) { return (f-min) / (max-min); }

public static float expand(float f, float min, float max) { return min + f*(max-min); }

public int heightAt(int x, int z) { return this.heightAt(x*CHANNELS + z*CHANNELS*this.width); }

public int heightAt(int i) {

byte r = this.buffer.get(i + 0);

byte g = this.buffer.get(i + 1);

byte b = this.buffer.get(i + 2);

byte a = this.buffer.get(i + 3);

return 0

// | ((0xFF & a) << 24) // removed cuz it turns overflows int

| ((0xFF & r) << 16)

| ((0xFF & g) << 8)

| ((0xFF & b) << 0);

}

}