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math.go
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/
math.go
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// Copyright 2014 Hajime Hoshi
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package graphics
// InternalImageSize returns a nearest appropriate size as an internal image.
func InternalImageSize(x int) int {
// minInternalImageSize is the minimum size of internal images (texture/framebuffer).
//
// For example, the image size less than 15 is not supported on some iOS devices.
// See also: https://stackoverflow.com/questions/15935651
const minInternalImageSize = 16
if x <= 0 {
panic("graphics: x must be positive")
}
if x < minInternalImageSize {
return minInternalImageSize
}
r := 1
for r < x {
r <<= 1
}
return r
}