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/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrBackendTextureImageGenerator_DEFINED
#define GrBackendTextureImageGenerator_DEFINED
#include "include/core/SkImageGenerator.h"
#include "include/gpu/GrBackendSurface.h"
#include "include/gpu/GrDirectContext.h"
#include "include/private/base/SkMutex.h"
#include "include/private/gpu/ganesh/GrTextureGenerator.h"
#include "src/gpu/ResourceKey.h"
#include "src/gpu/ganesh/GrSurfaceProxyView.h"
#include "src/gpu/ganesh/GrTexture.h"
class GrSemaphore;
/*
* This ImageGenerator is used to wrap a texture in one GrContext and can then be used as a source
* in another GrContext. It holds onto a semaphore which the producing GrContext will signal and the
* consuming GrContext will wait on before using the texture. Only one GrContext can ever be used
* as a consumer (this is mostly because Vulkan can't allow multiple things to wait on the same
* semaphore).
*
* In practice, this capability is used by clients to create backend-specific texture resources in
* one thread (with, say, GrContext-A) and then ship them over to another GrContext (say,
* GrContext-B) which will then use the texture as a source for draws. GrContext-A uses the
* semaphore to notify GrContext-B when the shared texture is ready to use.
*/
class GrBackendTextureImageGenerator : public GrTextureGenerator {
public:
static std::unique_ptr<GrTextureGenerator> Make(const sk_sp<GrTexture>&, GrSurfaceOrigin,
std::unique_ptr<GrSemaphore>, SkColorType,
SkAlphaType, sk_sp<SkColorSpace>);
~GrBackendTextureImageGenerator() override;
protected:
bool onIsValid(GrRecordingContext* context) const override {
if (context && context->abandoned()) {
return false;
}
return true;
}
bool onIsProtected() const override;
GrSurfaceProxyView onGenerateTexture(GrRecordingContext*,
const SkImageInfo&,
skgpu::Mipmapped mipmapped,
GrImageTexGenPolicy) override;
private:
GrBackendTextureImageGenerator(const SkColorInfo&,
const sk_sp<GrTexture>&,
GrSurfaceOrigin,
GrDirectContext::DirectContextID owningContextID,
std::unique_ptr<GrSemaphore>);
static void ReleaseRefHelper_TextureReleaseProc(void* ctx);
class RefHelper : public SkNVRefCnt<RefHelper> {
public:
RefHelper(sk_sp<GrTexture>,
GrDirectContext::DirectContextID owningContextID,
std::unique_ptr<GrSemaphore>);
~RefHelper();
sk_sp<GrTexture> fOriginalTexture;
GrDirectContext::DirectContextID fOwningContextID;
// We use this key so that we don't rewrap the GrBackendTexture in a GrTexture for each
// proxy created from this generator for a particular borrowing context.
skgpu::UniqueKey fBorrowedTextureKey;
// There is no ref associated with this pointer. We rely on our atomic bookkeeping with the
// context ID to know when this pointer is valid and safe to use. This is used to make sure
// all uses of the wrapped texture are finished on the borrowing context before we open
// this back up to other contexts. In general a ref to this release proc is owned by all
// proxies and gpu uses of the backend texture.
skgpu::RefCntedCallback* fBorrowingContextReleaseProc;
GrDirectContext::DirectContextID fBorrowingContextID;
std::unique_ptr<GrSemaphore> fSemaphore;
};
RefHelper* fRefHelper;
// This Mutex is used to guard the borrowing of the texture to one GrContext at a time as well
// as the creation of the fBorrowingContextReleaseProc. The latter happening if two threads with
// the same consuming GrContext try to generate a texture at the same time.
SkMutex fBorrowingMutex;
GrBackendTexture fBackendTexture;
GrSurfaceOrigin fSurfaceOrigin;
using INHERITED = GrTextureGenerator;
};
#endif // GrBackendTextureImageGenerator_DEFINED