devicescale.go (882B)
1 // Copyright 2018 The Ebiten Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package devicescale 16 17 import ( 18 "sync" 19 ) 20 21 type pos struct { 22 x, y int 23 } 24 25 var ( 26 m sync.Mutex 27 cache = map[pos]float64{} 28 ) 29 30 func GetAt(x, y int) float64 { 31 m.Lock() 32 defer m.Unlock() 33 if s, ok := cache[pos{x, y}]; ok { 34 return s 35 } 36 s := impl(x, y) 37 cache[pos{x, y}] = s 38 return s 39 }