2
你好堆棧社區，鑽石廣場不當執行
我想了很長時間，很難發佈這看到因爲我不想吸引另一個「重複」線程。然而，我已經沒有想法，也不知道任何論壇或其他堆棧，我可以發佈這個來獲得一些幫助。
我寫這個應用程序作爲一個有趣的項目，試圖生成一些高度圖。然而，無論何時我嘗試一次生成多個高度圖，我的所有副本都會顯示爲黑色空洞，或者如果變量足夠低，則表示白色空洞。 （實施例16 & & 33創建白色空隙，1025創建黑）出現
我的輸出文件夾，如下所示：low value VRS higher value
這是爲什麼？我是否在凌晨3點15分失蹤，這僅僅是一種數學僥倖？ 我寫了printMap專門用於檢查地圖數據值的功能，並且它們在指定它們爲黑/白的範圍內。我認爲沒有理由在第一次迭代後持續存在。
只是爲了好玩，我打印了44張地圖，第一張以後都是黑色的，MAP_SIZE設置爲1025.隨意自己檢查一下。
我創建從這裏基於了我的閱讀我的菱形方算法：http://www.gameprogrammer.com/fractal.html#heightmaps
和約單純的噪聲地圖一箇舊的堆棧溢出線程我greyWriteImage。
編輯 感謝我能解決我的問題，原來它只是一個簡單的事實，每一個新的地圖，你試圖使用populateMap功能我忘了avgOffset重置爲1。從本質上創建問題在於你將avgOffset連續分成2個越來越小的結果，這總是會以某種方式進行。
下面我已經包含了我完成的源代碼，用於任何想要使用我的算法和輸出的人。玩的開心。
import java.awt.Color;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.imageio.ImageIO;
import java.util.concurrent.ThreadLocalRandom;
public class generateHeightMap {
// https://stackoverflow.com/questions/43179809/diamond-square-improper-implementation
private static final Random RAND = new Random();
// Size of map to generate, must be a value of (2^n+1), ie. 33, 65, 129
// 257,1025 are fun values
private static final int MAP_SIZE = 1025;
// initial seed for corners of map
private static final double SEED = ThreadLocalRandom.current().nextInt(0, 1 + 1);
// average offset of data between points
private static double avgOffSetInit = 1;
private static final String PATH = "C:\\Users\\bcm27\\Desktop\\grayScale_export";
private static String fileName = "\\grayscale_map00.PNG";
public generateHeightMap(int howManyMaps) {
System.out.printf("Seed: %s\nMap Size: %s\nAverage Offset: %s\n",
SEED, MAP_SIZE, avgOffSetInit);
System.out.println("-------------------------------------------");
for(int i = 1; i <= howManyMaps; i++){ // how many maps to generate
double[][] map = populateMap(new double[MAP_SIZE][MAP_SIZE]);
//printMap(map);
generateHeightMap.greyWriteImage(map);
fileName = "\\grayscale_map0" + i + ".PNG";
System.out.println("Output: " + PATH + fileName);
}
}
/*************************************************************************************
* @param requires a 2d map array of 0-1 values, and a valid file path
* @post creates a image file saved to path + file_name
************************************************************************************/
private static void greyWriteImage(double[][] data) {
BufferedImage image =
new BufferedImage(data.length, data[0].length, BufferedImage.TYPE_INT_RGB);
for (int y = 0; y < data[0].length; y++)
{
for (int x = 0; x < data.length; x++)
{// for each element in the data
if (data[x][y]>1){
// tells the image whether its white
data[x][y]=1;
}
if (data[x][y]<0){
// tells the image whether its black
data[x][y]=0;
}
Color col = // RBG colors
new Color((float)data[x][y],
(float)data[x][y],
(float)data[x][y]);
// sets the image pixel color equal to the RGB value
image.setRGB(x, y, col.getRGB());
}
}
try {
// retrieve image
File outputfile = new File(PATH + fileName);
outputfile.createNewFile();
ImageIO.write(image, "png", outputfile);
} catch (IOException e) {
throw new RuntimeException("I didn't handle this very well. ERROR:\n" + e);
}
}
/****************************************************************************
* @param requires map double[MAPSIZE][MAPSIZE]
* @return returns populated map
*
* [1] Taking a square of four points, generate a random value at the square
* midpoint, where the two diagonals meet. The midpoint value is calcul-
* ated by averaging the four corner values, plus a random amount. This
* gives you diamonds when you have multiple squares arranged in a grid.
*
* [2] Taking each diamond of four points, generate a random value at the
* center of the diamond. Calculate the midpoint value by averaging the
* corner values, plus a random amount generated in the same range as
* used for the diamond step. This gives you squares again.
*
* '*' equals a new value
* '=' equals a old value
*
* * - - - * = - - - = = - * - = = - = - = = * = * =
* - - - - - - - - - - - - - - - - * - * - * = * = *
* - - - - - - - * - - * - = - * = - = - = = * = * =
* - - - - - - - - - - - - - - - - * - * - * = * = *
* * - - - * = - - - = = - * - = = - = - = = * = * =
* A B C D E
*
* A: Seed corners
* B: Randomized center value
* C: Diamond step
* D: Repeated square step
* E: Inner diamond step
*
* Rinse and repeat C->D->E until data map is filled
*
***************************************************************************/
private static double[][] populateMap(double[][] map) {
// assures us we have a fresh map each time
double avgOffSet = avgOffSetInit;
// assigns the corners of the map values to SEED
map[0][0] =
map[0][MAP_SIZE-1] =
map[MAP_SIZE-1][0] =
map[MAP_SIZE-1][MAP_SIZE-1] = SEED;
// square and diamond loop start
for(int sideLength = MAP_SIZE-1; sideLength >= 2; sideLength /=2,avgOffSet/= 2.0) {
int halfSide = sideLength/2;
double avgOfPoints;
/********************************************************************
* [1] SQUARE FRACTAL [1]
*********************************************************************/
// loops through x & y values of the height map
for(int x = 0; x < MAP_SIZE-1; x += sideLength) {
for(int y = 0; y <MAP_SIZE-1; y += sideLength) {
avgOfPoints = map[x][y] + //top left point
map[x + sideLength][y] + //top right point
map[x][y + sideLength] + //lower left point
map[x + sideLength][y + sideLength];//lower right point
// average of surrounding points
avgOfPoints /= 4.0;
// random value of 2*offset subtracted
// by offset for range of +/- the average
map[x+halfSide][y+halfSide] = avgOfPoints +
(RAND.nextDouble()*2*avgOffSet) - avgOffSet;
}
}
/********************************************************************
* [2] DIAMOND FRACTAL [2]
*********************************************************************/
for(int x=0; x < MAP_SIZE-1; x += halfSide) {
for(int y = (x + halfSide) % sideLength; y < MAP_SIZE-1;
y += sideLength) {
avgOfPoints =
map[(x - halfSide + MAP_SIZE) % MAP_SIZE][y] +//left of center
map[(x + halfSide) % MAP_SIZE][y] + //right of center
map[x][(y + halfSide) % MAP_SIZE] + //below center
map[x][(y - halfSide + MAP_SIZE) % MAP_SIZE]; //above center
// average of surrounding values
avgOfPoints /= 4.0;
// in range of +/- offset
avgOfPoints += (RAND.nextDouble()*2*avgOffSet) - avgOffSet;
//update value for center of diamond
map[x][y] = avgOfPoints;
// comment out for non wrapping values
if(x == 0) map[MAP_SIZE-1][y] = avgOfPoints;
if(y == 0) map[x][MAP_SIZE-1] = avgOfPoints;
} // end y
} // end x
} // end of diamond
return map;
} // end of populateMap
/*************************************************************************************
* @param requires a 2d map array to print the values of at +/-0.00
************************************************************************************/
@SuppressWarnings("unused")
private static void printMap(double[][] map) {
System.out.println("---------------------------------------------");
for (int x = 0; x < map.length; x++) {
for (int y = 0; y < map[x].length; y++) {
System.out.printf("%+.2f ", map[x][y]);
}
System.out.println();
}
}
} // end of class
如果您好奇，我添加了算法的說明。我想我的錯誤純粹是數學的，可能等到我睡了之後再發布。 – bcm27
@ bcm27謝謝，我必須*用*算法有時[:-) –
沒問題，我甚至更新了我的源代碼給你。乾杯 – bcm27