void BuildTerrainData(TerrainData terrainData)
{
// Define the size of the arrays that Unity's terrain will
// use internally to represent the terrain. Bigger numbers
// mean more fine details.
//if(CoRoutineShouldPause())
// yield return null;
// "Heightmap Resolution": "Pixel resolution of the terrain’s heightmap (should be a power of two plus one, eg, 513 = 512 + 1)."
// AFAIK, this defines the size of the 2-dimensional array that holds the information about the terrain (i.e. terrainData.GetHeights())
// Larger numbers lead to finer terrain details (if populated by a suitable source image heightmap).
// As for actual physical size of the terrain (in Unity world space), this is defined as:
// terrainData.Size = terrainData.heightmapScale * terrainData.heightmapResolution
terrainData.heightmapResolution = 128 + 1;
// "Base Texture Resolution": "Resolution of the composite texture used on the terrain when viewed from a distance greater than the Basemap Distance"
// AFAIK, this doesn't affect the terrain mesh -- only how the terrain texture (i.e. Splats) are rendered
terrainData.baseMapResolution = 512 + 1;
// "Detail Resolution" and "Detail Resolution Per Patch"
// (used for Details -- i.e. grass/flowers/etc...)
terrainData.SetDetailResolution(1024, 32);
// Set the Unity worldspace size of the terrain AFTER you set the resolution.
// This effectively just sets terrainData.heightmapScale for you, depending on the value of terrainData.heightmapResolution
terrainData.size = new Vector3(WorldUnitsPerChunk, TerrainHeight, WorldUnitsPerChunk);
// Get the 2-dimensional array of floats that defines the actual height data for the terrain.
// Each float has a value from 0..1, where a value of 1 means the maximum height of the terrain as defined by terrainData.size.y
//
// AFAIK, terrainData.heightmapWidth and terrainData.heightmapHeight will always be equal to terrainData.heightmapResolution
//
float[,] heights = terrainData.GetHeights(0, 0, terrainData.heightmapWidth, terrainData.heightmapHeight);
float halfDegreesPerChunk = DegreesPerChunk / 2f;
// Caching these dimensions and...
int w = terrainData.heightmapWidth;
int h = terrainData.heightmapHeight;
// Replacing loop divisions with mults cuts this function by about 10%
// -- Shout out to Karl Goodloe
float widthAdjust = 1f / (w - 1f);
float heightAdjust = 1f / (h - 1f);
// Loop through each point in the terrainData heightmap.
for (int x = 0; x < w; x++)
{
for (int y = 0; y < h; y++)
{
// Normalize x and y to a value from 0..1
// NOTE: We are INVERTING the x and y because internally Unity does this
float xPos = (float)x * widthAdjust;
float yPos = (float)y * heightAdjust;
// This converts our chunk position to a latitude/longitude,
// which we can then use to get UV coordinates from the heightmap
// FIXME: I think this is doing a pincushion effect
// Someone smarter than me will have to figure this out.
Quaternion pointRotation = ChunkRotation *
Quaternion.Euler(
xPos * DegreesPerChunk - halfDegreesPerChunk,
yPos * DegreesPerChunk - halfDegreesPerChunk,
0
);
Vector2 uv = CoordHelper.RotationToUV(pointRotation);
// Get the pixel from the heightmap image texture at the appropriate position
Color pix = HeightMapTexture.GetPixelBilinear(uv.x, uv.y);
// Update the heights array
heights[x, y] = pix.grayscale / heightMapTextureScaling;
}
}
// Update the terrain data based on our changed heights array
terrainData.SetHeights(0, 0, heights);
}
