Method updateMeshCache

render.go:232–298

()

}

func (r *BlockRender) updateMeshCache() {
	block := NearBlock(game.camera.Pos())
	chunk := block.Chunkid()
	x, z := chunk.X, chunk.Z
	n := *renderRadius
	needed := make(map[Vec3]bool)

	for dx := -n; dx < n; dx++ {
		for dz := -n; dz < n; dz++ {
			id := Vec3{x + dx, 0, z + dz}
			if dx*dx+dz*dz > n*n {
				continue
			}
			needed[id] = true
		}
	}
	var added, removed []Vec3
	r.meshcache.Range(func(k, v interface{}) bool {
		id := k.(Vec3)
		if !needed[id] {
			removed = append(removed, id)
			return true
		}
		return true
	})

	for id := range needed {
		mesh, ok := r.meshcache.Load(id)
		// 不在cache里面的需要重新构建
		if !ok {
			added = append(added, id)
		} else {
			if mesh.(*Mesh).Dirty {
				log.Printf("update cache %v", id)
				added = append(added, id)
				removed = append(removed, id)
			}
		}
	}
	// 单次并发构造的chunk个数
	const batchBuildChunk = 4
	r.sortChunks(added)
	if len(added) > 4 {
		added = added[:batchBuildChunk]
	}

	var removedMesh []*Mesh
	for _, id := range removed {
		log.Printf("remove cache %v", id)
		mesh, _ := r.meshcache.Load(id)
		r.meshcache.Delete(id)
		removedMesh = append(removedMesh, mesh.(*Mesh))
	}

	newChunks := game.world.Chunks(added)
	for _, c := range newChunks {
		log.Printf("add cache %v", c.Id())
		r.meshcache.Store(c.Id(), r.makeChunkMesh(c, false))