zorldo

Goofing around with Ebiten
git clone git://bsandro.tech/zorldo
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math.go (1155B)


      1 // Copyright 2014 Hajime Hoshi
      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 graphics
     16 
     17 // InternalImageSize returns a nearest appropriate size as an internal image.
     18 func InternalImageSize(x int) int {
     19 	// minInternalImageSize is the minimum size of internal images (texture/framebuffer).
     20 	//
     21 	// For example, the image size less than 15 is not supported on some iOS devices.
     22 	// See also: https://stackoverflow.com/questions/15935651
     23 	const minInternalImageSize = 16
     24 
     25 	if x <= 0 {
     26 		panic("graphics: x must be positive")
     27 	}
     28 	if x < minInternalImageSize {
     29 		return minInternalImageSize
     30 	}
     31 	r := 1
     32 	for r < x {
     33 		r <<= 1
     34 	}
     35 	return r
     36 }