Ant*_*zan 6 java game-engine affinetransform
假设我使用大小为8的char数组来表示图像的碰撞掩码.char的每个位代表一个像素.实际上,我将使用长[64]阵列作为64x64矩阵.
所以一个框将显示为:
00000000
01111110
01111110
01111110
01111110
01111110
01111110
00000000
45度的示例输出应该如下所示,尽管旋转可以是任何角度.这种形状对于45度旋转可能不准确,正如我手工完成的那样.
00011000
00111100
01111110
11111111
11111111
01111110
00111100
00011000
另一个示例输出向右旋转小 - 10度？这些值可能是错误的,因为在数学上我不知道它究竟会如何旋转,但我认为如果每个位的旧形状覆盖率超过50%是安全的,那么它就是1.
00000000
00111111
01111111
01111110
01111110
11111110
11111100
00000000
在没有旋转的情况下,使用此stackoverflow回复中定义的位移来快速查找这些位掩码之间的冲突:https://stackoverflow.com/a/336615/4595736
现在,在过去我使用过Path2D,Rectangles,Shapes等...并使用AffineTransform来旋转对象.Path2D是唯一提供我想要的复杂形状的类,但是用于访问每个点的"链接列表"行为并不像我希望的那样快.
在Java中旋转二进制映射的最佳方法是什么？
看起来像Matrices的Java库也不是最快的.
该解决方案基于先前的答案。它将输出点映射到输入矩阵空间中的位置，而不是将输入点映射到输出点。
在此版本中，它仅使用最接近的整数索引点的值。通过使用相邻点值的距离加权和的更复杂的值计算可能会获得更好的结果。
以下是一些结果：
Angle: 10.0 degrees
00000000 00000000
00000000 00000000
00111100 00011000
00111100 00011110
00111100 00111110
00111100 00111100
00000000 00001100
00000000 00000000
Angle: 45.0 degrees
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000001000000000
00000000000000000000 00000000011100000000
00000111111111100000 00000000111110000000
00000111111111100000 00000001111111000000
00000111111111100000 00000011111111100000
00000111111111100000 00000111111111110000
00000111111111100000 00001111111111111000
00000111111111100000 00011111111111111100
00000111111111100000 00001111111111111000
00000111111111100000 00000111111111110000
00000111111111100000 00000011111111100000
00000111111111100000 00000001111111000000
00000000000000000000 00000000111110000000
00000000000000000000 00000000011100000000
00000000000000000000 00000000001000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
Angle: 10.0 degrees
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000111111111100000 00000011111000000000
00000111111111100000 00000011111111110000
00000111111111100000 00000011111111110000
00000111111111100000 00000011111111110000
00000111111111100000 00000011111111110000
00000111111111100000 00000111111111110000
00000111111111100000 00000111111111100000
00000111111111100000 00000111111111100000
00000111111111100000 00000111111111100000
00000111111111100000 00000111111111100000
00000000000000000000 00000000001111100000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
Angle: 90.0 degrees
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000111111111100000 00000011111111110000
00000111111111100000 00000011111111110000
00000111111111100000 00000011111111110000
00000111111111100000 00000011111111110000
00000111111111100000 00000011111111110000
00000111111111100000 00000011111111110000
00000111111111100000 00000011111111110000
00000111111111100000 00000011111111110000
00000111111111100000 00000011111111110000
00000111111111100000 00000011111111110000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
00000000000000000000 00000000000000000000
测试程序：
public class Test {
public static void main(String args[]) {
int[][] input1 = { { 0, 0, 0, 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0, 0, 0, 0 },
{ 0, 0, 1, 1, 1, 1, 0, 0 }, { 0, 0, 1, 1, 1, 1, 0, 0 },
{ 0, 0, 1, 1, 1, 1, 0, 0 }, { 0, 0, 1, 1, 1, 1, 0, 0 },
{ 0, 0, 0, 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0, 0, 0, 0 } };
testit(input1, 10);
int[][] input2 = new int[20][20];
for(int i=5; i<15; i++){
for(int j = 5; j<15; j++){
input2[i][j] = 1;
}
}
testit(input2, 45);
testit(input2, 10);
testit(input2, 90);
}
private static void testit(int[][] input, double degrees) {
int[][] output = rotate(input, degrees);
System.out.println("Angle: "+degrees+" degrees");
for (int i = 0; i < input.length; i++) {
for (int j = 0; j < input[i].length; j++) {
System.out.print(input[i][j]);
}
System.out.print(" ");
for (int j = 0; j < output[i].length; j++) {
System.out.print(output[i][j]);
}
System.out.println();
}
System.out.println();
}
private static int[][] rotate(int[][] input, double degrees) {
double rad = Math.toRadians(degrees);
double sin = Math.sin(-rad);
double cos = Math.cos(-rad);
int[][] output = new int[input.length][input[0].length];
for (int i = 0; i < output.length; i++) {
double oldX = i - output.length / 2.0; // move to center
for (int j = 0; j < input[i].length; j++) {
{
double oldY = j - output[i].length / 2.0; // move to center
double x = (int) (cos * oldX + sin * oldY + input.length / 2.0);
double y = (int) (-sin * oldX + cos * oldY + input[i].length / 2.0);
output[i][j] = getNearestVal(input, x, y);
}
}
}
return output;
}
private static int getNearestVal(int[][] input, double x, double y) {
int xLow = (int) Math.floor(x);
int xHigh = (int) Math.ceil(x);
int yLow = (int) Math.floor(y);
int yHigh = (int) Math.ceil(y);
int[][] points = { { xLow, yLow }, { xLow, yHigh }, { xHigh, yLow },
{ xHigh, yHigh } };
double minDistance = Double.POSITIVE_INFINITY;
int minDistanceValue = 0;
for (int[] point : points) {
double distance = (point[0] - x) * (point[0] - x) + (point[1] - y)
* (point[1] - y);
if (distance < minDistance) {
minDistance = distance;
if (point[0] >= 0 && point[0] < input.length && point[1] >= 0
&& point[1] < input[point[0]].length) {
minDistanceValue = input[point[0]][point[1]];
} else {
minDistanceValue = 0;
}
}
}
return minDistanceValue;
}
}