Golang EntityDB.Has方法代碼示例

/*
HelperMove validates an entity's attempt to move and sets the entity's
movement component appropriately.  Returns true if the entity could move
*/
func HelperMove(db *engine.EntityDB, eid engine.Entity, dx, dy, dz int64) bool {
	if !db.Has(eid, "movement", "position") {
		return false
	}

	pos := db.Get(eid, "position").(*Position)
	emap := db.Get(pos.R, "map").(*EntityMap)
	mov := db.Get(eid, "movement").(*Movement)

	// TODO: fix layer system and make it real.
	// Check the entities in the layer beneath the move target
	// to see if the entity is a wall (with art symbol '#')
	target := emap.Get(pos.X+dx, pos.Y+dy, pos.Z+dz-1)
	if db.Has(target, "art") && db.Get(target, "art").(*Art).Symbol == '#' {
		mov.Dx = 0
		mov.Dy = 0
		mov.Dz = 0
		return false
	}

	// Move can be done!
	mov.Dx = dx
	mov.Dy = dy
	mov.Dz = dz
	return true
}

/*
RenderMapAt draws a portion of the map centered at the given entity
*/
func RenderMapAt(db *engine.EntityDB, eid engine.Entity) {
	width, height := termbox.Size()

	pos := db.Get(eid, "position").(*base.Position)
	emap := db.Get(pos.R, "map").(*base.EntityMap)

	for y := 0; y < height; y++ {
		py := pos.Y + int64(y-height/2)
		for x := 0; x < width; x++ {
			px := pos.X + int64(x-width/2)

			// Search for the highest entity on the map in the same general layer
			//  as the passed entity that can be drawn.  This will need to be more
			//  formal in the future (not hardcoded knowing the player is on z level
			//  1, tiles are on z level 0, and the bat at z level 2)
			topArt := &base.Art{}
			for i := int64(1); i >= -1; i-- {
				entity := emap.Get(px, py, pos.Z+i)
				if db.Has(entity, "art") {
					topArt = db.Get(entity, "art").(*base.Art)
					break
				}
			}

			// And draw the found art, which will be an empty black square
			//  if nothing was found
			Draw(x, height-1-y, topArt.Symbol, topArt.Fg, topArt.Bg)
		}
	}
	termbox.Flush()
}

/*
HelperPlace puts an entity on to the map at a particular position
*/
func HelperPlace(db *engine.EntityDB, eid engine.Entity, r engine.Entity, x, y, z int64) {
	if !db.Has(r, "map") {
		return
	}

	db.Get(r, "map").(*EntityMap).Set(x, y, z, eid)
	pos := db.Create(eid, "position").(*Position)
	pos.R, pos.X, pos.Y, pos.Z = r, x, y, z
}