public HeightmapSample[] GenerateHeightmapSamples(HeightmapDefinition definition)
{
var samples = new HeightmapSample[definition.GridSize * definition.GridSize];
for (int row = 0; row < definition.GridSize; row++)
{
for (int column = 0; column < definition.GridSize; column++)
{
var sample = GetSampleInPlanetSpace(definition, column, row);
samples[row * definition.GridSize + column] = sample;
}
}
return(samples);
}
VertexPositionNormalColor GetVertexInMeshSpace(HeightmapSample heightmapSample, int column, int row)
{
// We have two different reference frames to deal with here:
// "Planet space" coordinates which is the coordinates of the vertex in real units relative to the planet center
// "Mesh space" coordinates which is the coordinates of the vertex in real units after the center point of the mesh
// has been translated to the center of the planet
// We want to build a mesh where the center of the mesh is at 0,0 but the vertices are sphere-projected as though
// they were out in their correct place in the sphere. Then we want to keep track of the mesh's real-world location
// so we can do a camera-relative translation for rendering.
// We start with a heightmap height and vector which is in planet space. We translate the vector "downward" by the
// radius of the planet so that a zero-height point in the exact middle of the mesh surface would be at the origin.
var meshSpaceVector = ConvertToMeshSpace(heightmapSample.Vector);
var vertexColor = _terrainColorizer.GetColor(heightmapSample.Height, column, row, _gridSize, _extents);
return(new VertexPositionNormalColor {
Position = meshSpaceVector, Color = vertexColor
});
}
