func drawChunk(chunkX, chunkY int64) {
chunk := terrain.GetChunkAt(chunkX, chunkY)
if chunk.DisplayList == 0 {
chunk.DisplayList = gl.GenLists(1)
gl.NewList(chunk.DisplayList, gl.COMPILE)
for x := 0; x < config.ChunkArraySize()-1; x++ {
for y := 0; y < config.ChunkArraySize()-1; y++ {
gl.Normal3d(chunk.Normals.Get(x, y))
gl.Vertex3d(chunk.Vertices.Get(x, y))
x++
gl.Normal3d(chunk.Normals.Get(x, y))
gl.Vertex3d(chunk.Vertices.Get(x, y))
y++
gl.Normal3d(chunk.Normals.Get(x, y))
gl.Vertex3d(chunk.Vertices.Get(x, y))
x--
gl.Normal3d(chunk.Normals.Get(x, y))
gl.Vertex3d(chunk.Vertices.Get(x, y))
y--
}
}
gl.EndList()
}
gl.CallList(chunk.DisplayList)
}
func generateChunk(chunkCoord ChunkCoordinate) *Chunk {
startX, startY := float64(chunkCoord.X<<config.ChunkShift), float64(chunkCoord.Y<<config.ChunkShift)
coord := func(i, j int) (x, y float64) {
return startX + float64(i)/float64(config.TerrainSubdivisions()), startY + float64(j)/float64(config.TerrainSubdivisions())
}
// Optimization: Pre-generate the noise values we'll be using instead of generating them repeatedly
heightCount := config.ChunkArraySize() + config.TerrainSubdivisions()
heights := make([][]float64, heightCount)
for i := range heights {
heights[i] = make([]float64, heightCount)
for j := range heights[i] {
x, y := coord(i, j)
heights[i][j] = terrainHeight(x, y, config.TerrainDetail())
}
}
chunk := new(Chunk)
chunk.Vertices = make(Vec3Array, config.ChunkArraySize()*config.ChunkArraySize()*3)
chunk.Normals = make(Vec3Array, config.ChunkArraySize()*config.ChunkArraySize()*3)
for i := 0; i < config.ChunkArraySize(); i++ {
for j := 0; j < config.ChunkArraySize(); j++ {
x, y := coord(i, j)
// Normal
current, right, top := heights[i][j], heights[i+config.TerrainSubdivisions()][j], heights[i][j+config.TerrainSubdivisions()]
v := vector.Vec3(current-right, current-top, scaleVertical/2)
v.Normalize()
chunk.Normals.Set(i, j, v[0], v[1], v[2])
// Position
chunk.Vertices.Set(i, j, x, y, current)
}
}
chunk.markGet()
return chunk
}