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fd250c8d8c
There is a minimum internal image size on some system like old iOS devices. This change adds adjustment of the size. Issue: #810
47 lines
1.3 KiB
Go
47 lines
1.3 KiB
Go
// Copyright 2014 Hajime Hoshi
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package graphics
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// minInternalImageSize is the minimum size of internal images (texture/framebuffer).
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//
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// For example, the image size less than 15 is not supported on some iOS devices.
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// See also: https://stackoverflow.com/questions/15935651/certain-framebuffer-sizes-fail-on-ios-devices-gl-framebuffer-unsupported
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const minInternalImageSize = 16
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// InternalImageSize returns a nearest appropriate size as an internal image.
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func InternalImageSize(x int) int {
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if x <= 0 {
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panic("graphics: x must be positive")
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}
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if x < minInternalImageSize {
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return minInternalImageSize
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}
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r := 1
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for r < x {
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r <<= 1
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}
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return r
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}
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func isInternalImageSize(x int) bool {
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if x <= 0 {
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return false
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}
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if x < minInternalImageSize {
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return false
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}
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return (x & (x - 1)) == 0
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}
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