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// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gldriver
import "image"
type bufferImpl struct {
// buf should always be equal to (i.e. the same ptr, len, cap as) rgba.Pix.
// It is a separate, redundant field in order to detect modifications to
// the rgba field that are invalid as per the screen.Buffer documentation.
buf []byte
rgba image.RGBA
size image.Point
}
func (b *bufferImpl) Release() {}
func (b *bufferImpl) Size() image.Point { return b.size }
func (b *bufferImpl) Bounds() image.Rectangle { return image.Rectangle{Max: b.size} }
func (b *bufferImpl) RGBA() *image.RGBA { return &b.rgba }
func (b *bufferImpl) preUpload() {
// Check that the program hasn't tried to modify the rgba field via the
// pointer returned by the bufferImpl.RGBA method. This check doesn't catch
// 100% of all cases; it simply tries to detect some invalid uses of a
// screen.Buffer such as:
// *buffer.RGBA() = anotherImageRGBA
if len(b.buf) != 0 && len(b.rgba.Pix) != 0 && &b.buf[0] != &b.rgba.Pix[0] {
panic("gldriver: invalid Buffer.RGBA modification")
}
}
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