Question

我已经能够在另一个程序中的编号数组中成功实现中点位移，所以我试图在3D世界中实现它以创建地形但是算法的结果不是我的意思预期

void MidPointDisplacement(float grid[][WIDTH], int left, int right, int top, int bottom, int row, int col)
{
  int centreX = (left + right) / 2;     //Get the centre of the row
  int centreY = (top + bottom) / 2;     //Get the centre of the column

  if (centreX == left)
  {
    return;
  }
  if (centreY == bottom)
  {
    return;
  }

  grid[top][centreX] = ((grid[top][left] + grid[top][right]) / 2) + jitter;     //define top
  grid[bottom][centreX] = ((grid[bottom][left] + grid[bottom][right]) / 2) + jitter; //define bottom
  grid[centreY][left] = ((grid[top][left] + grid[bottom][left]) / 2) + jitter; //define left
  grid[centreY][right] = ((grid[top][right] + grid[bottom][right]) / 2) + jitter;  //define right

  grid[centreX][centreY] = ((grid[centreY][left] + grid[centreY][right] +     grid[top][centreX] + grid[bottom][centreX]) / 4) + jitter; //Get centre

 //decreased the random values
 RANDMAX / 2;
 RANDMIN / 2;

 MidPointDisplacement(grid, centreX, right, centreY, bottom, row, col);
 MidPointDisplacement(grid, left, centreX, top, centreY, row, col);
 MidPointDisplacement(grid, centreX, right, top, centreY, row, col);
 MidPointDisplacement(grid, left, centreX, centreY, bottom, row, col);
}

以上结果如下： 3D Midpoint Displacement

但是我期待这样的地形：

What I expected

这有什么原因可能吗？我最初认为它可能是抖动但是降低初始值并不能解决这个问题。

float jitter = rand() % (int)(RANDMAX - RANDMIN + 1) + RANDMIN;

抖动是一个全局浮点数，它在RANDMAX（初始值为5.0f）和RANDMIN（初始值为-5.0f）之间取一个随机值。

解决方案：

为了解决上述错误，我删除了我在程序中创建的抖动，而是使抖动成为1的浮点变量。

在MidpointDisplacement函数中，我改变了这个：

  grid[top][centreX] = ((grid[top][left] + grid[top][right]) / 2) + jitter;     //define top
  grid[bottom][centreX] = ((grid[bottom][left] + grid[bottom][right]) / 2) + jitter; //define bottom
  grid[centreY][left] = ((grid[top][left] + grid[bottom][left]) / 2) + jitter; //define left
  grid[centreY][right] = ((grid[top][right] + grid[bottom][right]) / 2) + jitter;  //define right

  grid[centreX][centreY] = ((grid[centreY][left] + grid[centreY][right] +     grid[top][centreX] + grid[bottom][centreX]) / 4) + jitter; //Get centre

对此：

  grid[top][centreX] = ((grid[top][left] + grid[top][right]) / 2) + ((rand() % 256) - 128) / 128.0F * JITTER_RANGE * jitter;  //define top
  grid[bottom][centreX] = ((grid[bottom][left] + grid[bottom][right]) / 2) + ((rand() % 256) - 128) / 128.0F * JITTER_RANGE * jitter; //define bottom
  grid[centreY][left] = ((grid[top][left] + grid[bottom][left]) / 2) + ((rand() % 256) - 128) / 128.0F * JITTER_RANGE * jitter; //define left
  grid[centreY][right] = ((grid[top][right] + grid[bottom][right]) / 2) + ((rand() % 256) - 128) / 128.0F * JITTER_RANGE * jitter;  //define right

  grid[centreY][centreX] = ((grid[centreY][left] + grid[centreY][right] + grid[top][centreX] + grid[bottom][centreX]) / 4) + ((rand() % 256) - 128) / 128.0F * JITTER_RANGE * jitter; //Get centre

然后我再次调用该函数，但是这次我将抖动除以2。

另外，我发现我愚蠢地将centreX和centreY错误地放在了一行（这里没有改变）：

  grid[centreX][centreY] = ((grid[centreY][left] + grid[centreY][right] +     grid[top][centreX] + grid[bottom][centreX]) / 4) + jitter; //Get centre

实施中点位移

0 个答案: