/*
* WorldEdit, a Minecraft world manipulation toolkit
* Copyright (C) sk89q <http://www.sk89q.com>
* Copyright (C) WorldEdit team and contributors
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.sk89q.worldedit.math.convolution;
import java.awt.image.Kernel;
import static com.google.common.base.Preconditions.checkNotNull;
/**
* Allows applications of Kernels onto the region's height map.
*
* <p>Only used for smoothing (with a GaussianKernel).</p>
*/
public class HeightMapFilter {
private Kernel kernel;
/**
* Construct the HeightMapFilter object.
*
* @param kernel the kernel
*/
public HeightMapFilter(Kernel kernel) {
checkNotNull(kernel);
this.kernel = kernel;
}
/**
* Construct the HeightMapFilter object.
*
* @param kernelWidth the width
* @param kernelHeight the height
* @param kernelData the data
*/
public HeightMapFilter(int kernelWidth, int kernelHeight, float[] kernelData) {
checkNotNull(kernelData);
this.kernel = new Kernel(kernelWidth, kernelHeight, kernelData);
}
/**
* @return the kernel
*/
public Kernel getKernel() {
return kernel;
}
/**
* Set Kernel
*
* @param kernel the kernel
*/
public void setKernel(Kernel kernel) {
checkNotNull(kernel);
this.kernel = kernel;
}
/**
* Filter with a 2D kernel
*
* @param inData the data
* @param width the width
* @param height the height
*
* @return the modified height map
*/
public int[] filter(int[] inData, int width, int height) {
checkNotNull(inData);
int index = 0;
float[] matrix = kernel.getKernelData(null);
int[] outData = new int[inData.length];
int kh = kernel.getHeight();
int kw = kernel.getWidth();
int kox = kernel.getXOrigin();
int koy = kernel.getYOrigin();
for (int y = 0; y < height; ++y) {
for (int x = 0; x < width; ++x) {
float z = 0;
for (int ky = 0; ky < kh; ++ky) {
int offsetY = y + ky - koy;
// Clamp coordinates inside data
if (offsetY < 0 || offsetY >= height) {
offsetY = y;
}
offsetY *= width;
int matrixOffset = ky * kw;
for (int kx = 0; kx < kw; ++kx) {
float f = matrix[matrixOffset + kx];
if (f == 0) continue;
int offsetX = x + kx - kox;
// Clamp coordinates inside data
if (offsetX < 0 || offsetX >= width) {
offsetX = x;
}
z += f * inData[offsetY + offsetX];
}
}
outData[index++] = (int) (z + 0.5);
}
}
return outData;
}
}