public static Vector2 GenerateUVCoord(int x, int y, int lonVertCount, int latVertCount, UVBounds uvBounds)
{
Vector2 uvScale = new Vector2(uvBounds.U2 - uvBounds.U1, uvBounds.V2 - uvBounds.V1);
Vector2 uvOffset = new Vector2(-uvBounds.U1, -uvBounds.V1);
return(MeshGenerationUtils.GenerateUVCoord(x, latVertCount - y - 1, lonVertCount, latVertCount, uvScale, uvOffset));
}
protected override void Generate()
{
int hVertCount = _sides + 1;
int vVertCount = _heightSegments + 1;
float startAngle = GetStartAngle();
float angleStep = _angleSweep / _sides;
float startHeight = GetStartY();
float heightStep = _height / _heightSegments;
Vector3[] verts = new Vector3[hVertCount * vVertCount];
Vector2[] uvs = new Vector2[hVertCount * vVertCount];
int vertexIndex = 0;
for (int x = 0; x < hVertCount; x++)
{
float angle = angleStep * x + startAngle;
Vector3 baseVertex = _radius * new Vector3(Mathf.Cos(angle), 0, Mathf.Sin(angle));
for (int y = 0; y < vVertCount; y++)
{
Vector3 vertex = baseVertex + new Vector3(0, startHeight - heightStep * y, 0);
verts[vertexIndex] = vertex;
uvs[vertexIndex] = MeshGenerationUtils.GenerateUVCoord(x, y, hVertCount, vVertCount, -Vector2.one, Vector2.one);
vertexIndex++;
}
}
_progress = 1f;
// Only one LOD is generated.
_meshData = new MeshData[] {
new MeshData()
{
Vertices = verts,
TexCoords = uvs,
Triangles = MeshGenerationUtils.GenerateTrianglesTransposed(hVertCount, vVertCount)
}
};
}
protected override TerrainMeshData GenerateForLod(IntensityImage image, int downsample = 1)
{
// Downsampling rate must be a power of 2.
if (!MathUtils.IsPowerOfTwo(downsample))
{
throw new Exception($"Downsample rate of {downsample} is not a power of 2.");
}
// Vertex count for the latitude is the same as the downsampled texture height.
// However, we need to generate an extra set of vertices in the longitude
// direction to complete the loop around. We cannot simply reuse the first
// vertices of of the loop, due to the start and end having different UV
// coordinates despite having same world coordinates.
int lonVertCount = image.Width / downsample + 1;
int latVertCount = image.Height / downsample;
Debug.Log(lonVertCount + ", " + latVertCount);
Vector3[] verts = new Vector3[lonVertCount * latVertCount];
Vector2[] uvs = new Vector2[lonVertCount * latVertCount];
// Vertex counter
int vertexIndex = 0;
// Calculate the incretmental step sizes of the latitude
// and longitude here for potential performance increase.
float latStepSize = Mathf.PI / (latVertCount - 1);
float lonStepSize = 360.0f / (lonVertCount - 1);
// Iterate through the rows of vertices.
for (int vy = 0; vy < latVertCount; vy++)
{
// The y-coordinate on the image that corresponds to the current row of vertices.
int y = vy * downsample;
// Iterate through each vertex in the row of verticies.
// Calculate the actual angle of the latitude.
float latAng = latStepSize * vy + Mathf.PI / 2;
// Create a new vertex using the latitude angle. The coordinates of this
// vertex will serve as a base for all the other vertices in this latitude.
Vector3 baseLatVertex = new Vector3(Mathf.Cos(latAng), Mathf.Sin(latAng), 0);
// Iterate through each vertex in the row of verticies.
// Traverse backwards in order to get correct orientation of texture and normals.
for (int vx = lonVertCount - 1; vx >= 0; vx--)
{
// The x-coordinate on the image that corresponds to the current vertex.
int x = vx * downsample;
// Get the raw intensity value from the image.
float value = downsample == 1 ?
image.GetPixel(x, y) :
image.GetCenteredAverage(x, y, downsample + 1);
// Scale the intensity value by the height scale, and
// then add it to the radius to get the final "height".
float height = value * _metadata.HeightScale + _metadata.Radius;
// Longitude is offset by 90 degrees so that the foward vector is at 0,0 lat and long.
verts[vertexIndex] = Quaternion.Euler(0, -90 - vx * lonStepSize, 0) * (height * baseLatVertex);
uvs[vertexIndex] = MeshGenerationUtils.GenerateUVCoord(vx, vy, lonVertCount, latVertCount);
vertexIndex++;
}
}
return(new TerrainMeshData()
{
Vertices = verts,
TexCoords = uvs,
Triangles = MeshGenerationUtils.GenerateTriangles(lonVertCount, latVertCount)
});
}