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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "DrawTargetWebglInternal.h"
#include "SourceSurfaceWebgl.h"
namespace mozilla::gfx {
SourceSurfaceWebgl::SourceSurfaceWebgl(DrawTargetWebgl* aDT)
: mFormat(aDT->GetFormat()),
mSize(aDT->GetSize()),
mDT(aDT),
mSharedContext(aDT->mSharedContext) {}
SourceSurfaceWebgl::SourceSurfaceWebgl(
const RefPtr<TextureHandle>& aHandle,
const RefPtr<DrawTargetWebgl::SharedContext>& aSharedContext)
: mFormat(aHandle->GetFormat()),
mSize(aHandle->GetSize()),
mSharedContext(aSharedContext),
mHandle(aHandle) {
mHandle->SetSurface(this);
}
SourceSurfaceWebgl::~SourceSurfaceWebgl() {
if (mHandle) {
// Signal that the texture handle is not being used now.
mHandle->SetSurface(nullptr);
}
}
// Read back the contents of the target or texture handle for data use.
inline bool SourceSurfaceWebgl::EnsureData() {
if (mData) {
return true;
}
if (!mDT) {
// Assume that the target changed, so there should be a texture handle
// holding a copy. Try to read data from the copy since we can't read
// from the target.
if (!mHandle || !mSharedContext) {
return false;
}
mData = mSharedContext->ReadSnapshot(mHandle);
} else {
mData = mDT->ReadSnapshot();
}
return !!mData;
}
uint8_t* SourceSurfaceWebgl::GetData() {
if (!EnsureData()) {
return nullptr;
}
return mData->GetData();
}
int32_t SourceSurfaceWebgl::Stride() {
if (!EnsureData()) {
return 0;
}
return mData->Stride();
}
bool SourceSurfaceWebgl::Map(MapType aType, MappedSurface* aMappedSurface) {
if (!EnsureData()) {
return false;
}
return mData->Map(aType, aMappedSurface);
}
void SourceSurfaceWebgl::Unmap() {
if (mData) {
mData->Unmap();
}
}
// Handler for when the owner DrawTargetWebgl is about to modify its internal
// framebuffer, and so this snapshot must be copied into a new texture, if
// possible, or read back into data, if necessary, to preserve this particular
// version of the framebuffer.
void SourceSurfaceWebgl::DrawTargetWillChange(bool aNeedHandle) {
MOZ_ASSERT(mDT);
// Only try to copy into a new texture handle if we don't already have data.
// However, we still might need to immediately draw this snapshot to a WebGL
// target, which would require a subsequent upload, so also copy into a new
// handle even if we already have data in that case since it is faster than
// uploading.
if ((!mData || aNeedHandle) && !mHandle) {
// Prefer copying the framebuffer to a texture if possible.
mHandle = mDT->CopySnapshot();
if (mHandle) {
// Link this surface to the handle.
mHandle->SetSurface(this);
} else {
// If that fails, then try to just read the data to a surface.
EnsureData();
}
}
mDT = nullptr;
}
// Handler for when the owner DrawTargetWebgl is itself being destroyed and
// needs to transfer ownership of its internal backing texture to the snapshot.
void SourceSurfaceWebgl::GiveTexture(RefPtr<TextureHandle> aHandle) {
// If we get here, then the target still points to this surface as its
// snapshot and needs to hand off its backing texture before it is destroyed.
MOZ_ASSERT(mDT);
MOZ_ASSERT(!mHandle);
mHandle = aHandle.forget();
mHandle->SetSurface(this);
mDT = nullptr;
}
// Handler for when the owner DrawTargetWebgl is destroying the cached texture
// handle that has been allocated for this snapshot.
void SourceSurfaceWebgl::OnUnlinkTexture(
DrawTargetWebgl::SharedContext* aContext) {
// If we get here, then we must have copied a snapshot, which only happens
// if the target changed.
MOZ_ASSERT(!mDT);
// If the snapshot was mapped before the target changed, we may have read
// data instead of holding a copied texture handle. If subsequently we then
// try to draw with this snapshot, we might have allocated an external texture
// handle in the texture cache that still links to this snapshot and can cause
// us to end up here inside OnUnlinkTexture.
MOZ_ASSERT(mHandle || mData);
if (!mData) {
mData = aContext->ReadSnapshot(mHandle);
}
mHandle = nullptr;
}
already_AddRefed<SourceSurface> SourceSurfaceWebgl::ExtractSubrect(
const IntRect& aRect) {
// Ensure we have a texture source available to extract from.
if (!(mDT || (mHandle && mSharedContext)) || aRect.IsEmpty() ||
!GetRect().Contains(aRect)) {
return nullptr;
}
RefPtr<TextureHandle> subHandle;
RefPtr<DrawTargetWebgl::SharedContext> sharedContext;
if (mDT) {
// If this is still a snapshot linked to a target, then copy from the
// target.
subHandle = mDT->CopySnapshot(aRect);
if (!subHandle) {
return nullptr;
}
sharedContext = mDT->mSharedContext;
} else {
// Otherwise, we have a handle, but we need to verify it is still linked to
// a valid context.
sharedContext = mSharedContext;
if (!sharedContext) {
return nullptr;
}
// Try to copy directly from the handle using the context.
subHandle = sharedContext->CopySnapshot(aRect, mHandle);
if (!subHandle) {
return nullptr;
}
}
RefPtr<SourceSurface> surface =
new SourceSurfaceWebgl(subHandle, sharedContext);
return surface.forget();
}
} // namespace mozilla::gfx
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