TextureColor.A32B32G32R32F[][] FixupHeightmap(Texture t, int level, int levelSize, TextureColor.A32B32G32R32F[][][] olddata)
{
/* Ok so we want to store extra "blending" information
* The mipmaps are already calculated
* In the R channel we store the heightmap
* In the B channel we store the next level blend
*
* IMPORTANT: Last row and last column are unhandled!
* */
TextureColor.A32B32G32R32F[][] data = olddata[level];
for (int y = 0; y < levelSize - 2; y += 2)
{
for (int x = 0; x < levelSize - 2; x += 2)
{
TextureColor.A32B32G32R32F cur = olddata[level + 1][y / 2][x / 2];
TextureColor.A32B32G32R32F bottom = olddata[level + 1][y / 2 + 1][x / 2];
TextureColor.A32B32G32R32F right = olddata[level + 1][y / 2][x / 2 + 1];
TextureColor.A32B32G32R32F bottomright = olddata[level + 1][y / 2 + 1][x / 2 + 1];
data[y][x].G = cur.G;
data[y][x + 1].G = (cur.G + right.G) / 2;
data[y + 1][x].G = (cur.G + bottom.G) / 2;
data[y + 1][x + 1].G = (cur.G + bottomright.G) / 2;
}
}
DataRectangle r = t.LockRectangle(level, LockFlags.Discard);
for (int y = 0; y < levelSize; y++)
{
r.Data.WriteRange(data[y]);
}
t.UnlockRectangle(level);
return(data);
}
void FixupHeightmap(Texture t, int textureSize)
{
int levels = (int)Math.Log(textureSize, 2);
TextureColor.A32B32G32R32F[][][] data = new TextureColor.A32B32G32R32F[levels][][];
DataRectangle r = t.LockRectangle(0, LockFlags.ReadOnly);
data[0] = TextureUtil.ReadTexture <TextureColor.A32B32G32R32F>(r, textureSize);
t.UnlockRectangle(0);
for (int i = 1; i < levels; i++)
{
int levelSize = (int)Math.Pow(2, levels - i);
data[i] = new TextureColor.A32B32G32R32F[levelSize][];
for (int y = 0; y < levelSize; y++)
{
data[i][y] = new TextureColor.A32B32G32R32F[levelSize];
for (int x = 0; x < levelSize; x++)
{
data[i][y][x] =
(data[i - 1][y * 2][x * 2] +
data[i - 1][y * 2][x * 2 + 1] +
data[i - 1][y * 2 + 1][x * 2] +
data[i - 1][y * 2 + 1][x * 2 + 1]) / 4f;
}
}
}
for (int i = 0; i < levels; i++)
{
FixupHeightmap(t, i, (int)Math.Pow(2, levels - i), data);
}
}