Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
//License from project: LGPL 

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.IntBuffer;
import java.util.ArrayList;

public class Main {
    private static IntBuffer[] generateMipmaps(int[] rgb, int width, int height, int mipmaps) {
        if (rgb == null) {
            return null;
        } else {
            ArrayList mipmapData = new ArrayList();
            IntBuffer buffer = newIntBuffer(width * height * 4);
            buffer.put(rgb).position(0);
            int level = 0;

            while (true) {
                mipmapData.add(buffer);

                if (width <= 0 || height <= 0 || level >= mipmaps) {
                    return (IntBuffer[]) mipmapData.toArray(new IntBuffer[mipmapData.size()]);
                }

                IntBuffer newBuffer = newIntBuffer(width * height);
                scaleHalf(buffer, width, height, newBuffer, 0);
                buffer = newBuffer;
                ++level;
                width >>= 1;
                height >>= 1;
            }
        }
    }

    private static IntBuffer newIntBuffer(int size) {
        ByteBuffer buffer = ByteBuffer.allocateDirect(size);
        buffer.order(ByteOrder.LITTLE_ENDIAN);
        return buffer.asIntBuffer();
    }

    static void scaleHalf(IntBuffer in, int w, int h, IntBuffer out, int rotate) {
        for (int i = 0; i < w / 2; ++i) {
            for (int j = 0; j < h / 2; ++j) {
                int k = w * 2 * j + 2 * i;
                int pixel00 = in.get(k);
                int pixel01 = in.get(k + 1);
                int pixel10 = in.get(k + w);
                int pixel11 = in.get(k + w + 1);

                if (rotate != 0) {
                    pixel00 = Integer.rotateLeft(pixel00, rotate);
                    pixel01 = Integer.rotateLeft(pixel01, rotate);
                    pixel10 = Integer.rotateLeft(pixel10, rotate);
                    pixel11 = Integer.rotateLeft(pixel11, rotate);
                }

                int pixel = average4RGBA(pixel00, pixel01, pixel10, pixel11);

                if (rotate != 0) {
                    pixel = Integer.rotateRight(pixel, rotate);
                }

                out.put(w / 2 * j + i, pixel);
            }
        }
    }

    private static int average4RGBA(int pixel00, int pixel01, int pixel10, int pixel11) {
        int a00 = pixel00 & 255;
        int a01 = pixel01 & 255;
        int a10 = pixel10 & 255;
        int a11 = pixel11 & 255;

        switch (a00 << 24 | a01 << 16 | a10 << 8 | a11) {
        case -16777216:
            return pixel00;

        case -16776961:
            return average2RGBA(pixel00, pixel11);

        case -16711936:
            return average2RGBA(pixel00, pixel10);

        case -65536:
            return average2RGBA(pixel00, pixel01);

        case -1:
        case 0:
            return average2RGBA(average2RGBA(pixel00, pixel11), average2RGBA(pixel01, pixel10));

        case 255:
            return pixel11;

        case 65280:
            return pixel10;

        case 65535:
            return average2RGBA(pixel10, pixel11);

        case 16711680:
            return pixel01;

        case 16711935:
            return average2RGBA(pixel01, pixel11);

        case 16776960:
            return average2RGBA(pixel01, pixel10);

        default:
            int a = a00 + a01 + a10 + a11;
            int pixel = a >> 2;

            for (int i = 8; i < 32; i += 8) {
                int average = (a00 * (pixel00 >> i & 255) + a01 * (pixel01 >> i & 255) + a10 * (pixel10 >> i & 255)
                        + a11 * (pixel11 >> i & 255)) / a;
                pixel |= average << i;
            }

            return pixel;
        }
    }

    private static int average2RGBA(int a, int b) {
        return ((a & -16843010) >>> 1) + ((b & -16843010) >>> 1) | a & b & 16843009;
    }
}