gecko-dev/gfx/layers/Compositor.h

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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/. */
#ifndef MOZILLA_GFX_COMPOSITOR_H
#define MOZILLA_GFX_COMPOSITOR_H
#include "Units.h" // for ScreenPoint
#include "mozilla/Assertions.h" // for MOZ_ASSERT, etc
#include "mozilla/RefPtr.h" // for already_AddRefed, RefCounted
#include "mozilla/gfx/2D.h" // for DrawTarget
#include "mozilla/gfx/MatrixFwd.h" // for Matrix, Matrix4x4
#include "mozilla/gfx/Point.h" // for IntSize, Point
#include "mozilla/gfx/Polygon.h" // for Polygon
#include "mozilla/gfx/Rect.h" // for Rect, IntRect
#include "mozilla/gfx/Types.h" // for Float
#include "mozilla/gfx/Triangle.h" // for Triangle, TexturedTriangle
#include "mozilla/layers/CompositorTypes.h" // for DiagnosticTypes, etc
#include "mozilla/layers/LayersTypes.h" // for LayersBackend
#include "mozilla/layers/TextureSourceProvider.h"
#include "mozilla/widget/CompositorWidget.h"
#include "nsISupportsImpl.h" // for MOZ_COUNT_CTOR, etc
#include "nsRegion.h"
#include <vector>
#include "mozilla/WidgetUtils.h"
/**
* Different elements of a web pages are rendered into separate "layers" before
* they are flattened into the final image that is brought to the screen.
* See Layers.h for more informations about layers and why we use retained
* structures.
* Most of the documentation for layers is directly in the source code in the
* form of doc comments. An overview can also be found in the the wiki:
* https://wiki.mozilla.org/Gecko:Overview#Graphics
*
*
* # Main interfaces and abstractions
*
* - Layer, ShadowableLayer and LayerComposite
* (see Layers.h and ipc/ShadowLayers.h)
* - CompositableClient and CompositableHost
* (client/CompositableClient.h composite/CompositableHost.h)
* - TextureClient and TextureHost
* (client/TextureClient.h composite/TextureHost.h)
* - TextureSource
* (composite/TextureHost.h)
* - Forwarders
* (ipc/CompositableForwarder.h ipc/ShadowLayers.h)
* - Compositor
* (this file)
* - IPDL protocols
* (.ipdl files under the gfx/layers/ipc directory)
*
* The *Client and Shadowable* classes are always used on the content thread.
* Forwarders are always used on the content thread.
* The *Host and Shadow* classes are always used on the compositor thread.
* Compositors, TextureSource, and Effects are always used on the compositor
* thread.
* Most enums and constants are declared in LayersTypes.h and CompositorTypes.h.
*
*
* # Texture transfer
*
* Most layer classes own a Compositable plus some extra information like
* transforms and clip rects. They are platform independent.
* Compositable classes manipulate Texture objects and are reponsible for
* things like tiling, buffer rotation or double buffering. Compositables
* are also platform-independent. Examples of compositable classes are:
* - ImageClient
* - CanvasClient
* - ContentHost
* - etc.
* Texture classes (TextureClient and TextureHost) are thin abstractions over
* platform-dependent texture memory. They are maniplulated by compositables
* and don't know about buffer rotations and such. The purposes of TextureClient
* and TextureHost are to synchronize, serialize and deserialize texture data.
* TextureHosts provide access to TextureSources that are views on the
* Texture data providing the necessary api for Compositor backend to composite
* them.
*
* Compositable and Texture clients and hosts are created using factory methods.
* They should only be created by using their constructor in exceptional
* circumstances. The factory methods are located:
* TextureClient - CompositableClient::CreateTextureClient
* TextureHost - TextureHost::CreateTextureHost, which calls a
* platform-specific function, e.g., CreateTextureHostOGL
* CompositableClient - in the appropriate subclass, e.g.,
* CanvasClient::CreateCanvasClient
* CompositableHost - CompositableHost::Create
*
*
* # IPDL
*
* If off-main-thread compositing (OMTC) is enabled, compositing is performed
* in a dedicated thread. In some setups compositing happens in a dedicated
* process. Documentation may refer to either the compositor thread or the
* compositor process.
* See explanations in ShadowLayers.h.
*
*
* # Backend implementations
*
* Compositor backends like OpenGL or flavours of D3D live in their own directory
* under gfx/layers/. To add a new backend, implement at least the following
* interfaces:
* - Compositor (ex. CompositorOGL)
* - TextureHost (ex. SurfaceTextureHost)
* Depending on the type of data that needs to be serialized, you may need to
* add specific TextureClient implementations.
*/
class nsIWidget;
namespace mozilla {
namespace gfx {
class DrawTarget;
class DataSourceSurface;
} // namespace gfx
namespace layers {
struct Effect;
struct EffectChain;
class Image;
class Layer;
class TextureSource;
class DataTextureSource;
class CompositingRenderTarget;
class CompositorBridgeParent;
class LayerManagerComposite;
class CompositorOGL;
class CompositorD3D11;
class BasicCompositor;
class TextureReadLock;
struct GPUStats;
class AsyncReadbackBuffer;
enum SurfaceInitMode
{
INIT_MODE_NONE,
INIT_MODE_CLEAR
};
/**
* Common interface for compositor backends.
*
* Compositor provides a cross-platform interface to a set of operations for
* compositing quads. Compositor knows nothing about the layer tree. It must be
* told everything about each composited quad - contents, location, transform,
* opacity, etc.
*
* In theory it should be possible for different widgets to use the same
* compositor. In practice, we use one compositor per window.
*
* # Usage
*
* For an example of a user of Compositor, see LayerManagerComposite.
*
* Initialization: create a Compositor object, call Initialize().
*
* Destruction: destroy any resources associated with the compositor, call
* Destroy(), delete the Compositor object.
*
* Composition:
* call BeginFrame,
* for each quad to be composited:
* call MakeCurrent if necessary (not necessary if no other context has been
* made current),
* take care of any texture upload required to composite the quad, this step
* is backend-dependent,
* construct an EffectChain for the quad,
* call DrawQuad,
* call EndFrame.
*
* By default, the compositor will render to the screen, to render to a target,
* call SetTargetContext or SetRenderTarget, the latter with a target created
* by CreateRenderTarget or CreateRenderTargetFromSource.
*
* The target and viewport methods can be called before any DrawQuad call and
* affect any subsequent DrawQuad calls.
*/
class Compositor : public TextureSourceProvider
{
protected:
virtual ~Compositor();
public:
explicit Compositor(widget::CompositorWidget* aWidget,
CompositorBridgeParent* aParent = nullptr);
virtual bool Initialize(nsCString* const out_failureReason) = 0;
virtual void Destroy() override;
bool IsDestroyed() const { return mIsDestroyed; }
virtual void DetachWidget() { mWidget = nullptr; }
/**
* Request a texture host identifier that may be used for creating textures
* across process or thread boundaries that are compatible with this
* compositor.
*/
virtual TextureFactoryIdentifier GetTextureFactoryIdentifier() = 0;
/**
* Properties of the compositor.
*/
virtual bool CanUseCanvasLayerForSize(const gfx::IntSize& aSize) = 0;
/**
* Set the target for rendering. Results will have been written to aTarget by
* the time that EndFrame returns.
*
* If this method is not used, or we pass in nullptr, we target the compositor's
* usual swap chain and render to the screen.
*/
void SetTargetContext(gfx::DrawTarget* aTarget, const gfx::IntRect& aRect)
{
mTarget = aTarget;
mTargetBounds = aRect;
}
gfx::DrawTarget* GetTargetContext() const
{
return mTarget;
}
void ClearTargetContext()
{
mTarget = nullptr;
}
typedef uint32_t MakeCurrentFlags;
static const MakeCurrentFlags ForceMakeCurrent = 0x1;
/**
* Make this compositor's rendering context the current context for the
* underlying graphics API. This may be a global operation, depending on the
* API. Our context will remain the current one until someone else changes it.
*
* Clients of the compositor should call this at the start of the compositing
* process, it might be required by texture uploads etc.
*
* If aFlags == ForceMakeCurrent then we will (re-)set our context on the
* underlying API even if it is already the current context.
*/
virtual void MakeCurrent(MakeCurrentFlags aFlags = 0) = 0;
/**
* Creates a Surface that can be used as a rendering target by this
* compositor.
*/
virtual already_AddRefed<CompositingRenderTarget>
CreateRenderTarget(const gfx::IntRect& aRect, SurfaceInitMode aInit) = 0;
/**
* Creates a Surface that can be used as a rendering target by this
* compositor, and initializes the surface by copying from aSource.
* If aSource is null, then the current screen buffer is used as source.
*
* aSourcePoint specifies the point in aSource to copy data from.
*/
virtual already_AddRefed<CompositingRenderTarget>
CreateRenderTargetFromSource(const gfx::IntRect& aRect,
const CompositingRenderTarget* aSource,
const gfx::IntPoint& aSourcePoint) = 0;
/**
* Grab a snapshot of aSource and store it in aDest, so that the pixels can
* be read on the CPU by mapping aDest at some point in the future.
* aSource and aDest must have the same size.
* If this is a GPU compositor, this call must not block on the GPU.
* Returns whether the operation was successful.
*/
virtual bool
ReadbackRenderTarget(CompositingRenderTarget* aSource,
AsyncReadbackBuffer* aDest) { return false; }
/**
* Create an AsyncReadbackBuffer of the specified size. Can return null.
*/
virtual already_AddRefed<AsyncReadbackBuffer>
CreateAsyncReadbackBuffer(const gfx::IntSize& aSize) { return nullptr; }
/**
* Draw a part of aSource into the current render target.
* Scaling is done with linear filtering.
* Returns whether the operation was successful.
*/
virtual bool
BlitRenderTarget(CompositingRenderTarget* aSource,
const gfx::IntSize& aSourceSize,
const gfx::IntSize& aDestSize) { return false; }
/**
* Sets the given surface as the target for subsequent calls to DrawQuad.
* Passing null as aSurface sets the screen as the target.
*/
virtual void SetRenderTarget(CompositingRenderTarget* aSurface) = 0;
/**
* Returns the current target for rendering. Will return null if we are
* rendering to the screen.
*/
virtual CompositingRenderTarget* GetCurrentRenderTarget() const = 0;
/**
* Returns a render target which contains the entire window's drawing.
* On platforms where no such render target is used during compositing (e.g.
* with buffered BasicCompositor, where only the invalid area is drawn to a
* render target), this will return null.
*/
virtual CompositingRenderTarget* GetWindowRenderTarget() const { return nullptr; }
/**
* Mostly the compositor will pull the size from a widget and this method will
* be ignored, but compositor implementations are free to use it if they like.
*/
virtual void SetDestinationSurfaceSize(const gfx::IntSize& aSize) = 0;
/**
* Declare an offset to use when rendering layers. This will be ignored when
* rendering to a target instead of the screen.
*/
virtual void SetScreenRenderOffset(const ScreenPoint& aOffset) = 0;
void DrawGeometry(const gfx::Rect& aRect,
const gfx::IntRect& aClipRect,
const EffectChain &aEffectChain,
gfx::Float aOpacity,
const gfx::Matrix4x4& aTransform,
const gfx::Rect& aVisibleRect,
const Maybe<gfx::Polygon>& aGeometry);
void DrawGeometry(const gfx::Rect& aRect,
const gfx::IntRect& aClipRect,
const EffectChain &aEffectChain,
gfx::Float aOpacity,
const gfx::Matrix4x4& aTransform,
const Maybe<gfx::Polygon>& aGeometry)
{
DrawGeometry(aRect, aClipRect, aEffectChain, aOpacity,
aTransform, aRect, aGeometry);
}
/**
* Tell the compositor to draw a quad. What to do draw and how it is
* drawn is specified by aEffectChain. aRect is the quad to draw, in user space.
* aTransform transforms from user space to screen space. If texture coords are
* required, these will be in the primary effect in the effect chain.
* aVisibleRect is used to determine which edges should be antialiased,
* without applying the effect to the inner edges of a tiled layer.
*/
virtual void DrawQuad(const gfx::Rect& aRect, const gfx::IntRect& aClipRect,
const EffectChain& aEffectChain,
gfx::Float aOpacity, const gfx::Matrix4x4& aTransform,
const gfx::Rect& aVisibleRect) = 0;
/**
* Overload of DrawQuad, with aVisibleRect defaulted to the value of aRect.
* Use this when you are drawing a single quad that is not part of a tiled
* layer.
*/
void DrawQuad(const gfx::Rect& aRect, const gfx::IntRect& aClipRect,
const EffectChain& aEffectChain,
gfx::Float aOpacity, const gfx::Matrix4x4& aTransform) {
DrawQuad(aRect, aClipRect, aEffectChain, aOpacity, aTransform, aRect);
}
virtual void DrawTriangle(const gfx::TexturedTriangle& aTriangle,
const gfx::IntRect& aClipRect,
const EffectChain& aEffectChain,
gfx::Float aOpacity,
const gfx::Matrix4x4& aTransform,
const gfx::Rect& aVisibleRect)
{
MOZ_CRASH("Compositor::DrawTriangle is not implemented for the current platform!");
}
virtual bool SupportsLayerGeometry() const
{
return false;
}
/**
* Draw an unfilled solid color rect. Typically used for debugging overlays.
*/
void SlowDrawRect(const gfx::Rect& aRect, const gfx::Color& color,
const gfx::IntRect& aClipRect = gfx::IntRect(),
const gfx::Matrix4x4& aTransform = gfx::Matrix4x4(),
int aStrokeWidth = 1);
/**
* Draw a solid color filled rect. This is a simple DrawQuad helper.
*/
void FillRect(const gfx::Rect& aRect, const gfx::Color& color,
const gfx::IntRect& aClipRect = gfx::IntRect(),
const gfx::Matrix4x4& aTransform = gfx::Matrix4x4());
void SetClearColor(const gfx::Color& aColor) {
mClearColor = aColor;
}
void SetDefaultClearColor(const gfx::Color& aColor) {
mDefaultClearColor = aColor;
}
void SetClearColorToDefault() {
mClearColor = mDefaultClearColor;
}
/*
* Clear aRect on current render target.
*/
virtual void ClearRect(const gfx::Rect& aRect) = 0;
/**
* Start a new frame.
*
* aInvalidRect is the invalid region of the screen; it can be ignored for
* compositors where the performance for compositing the entire window is
* sufficient.
*
* aClipRectIn is the clip rect for the window in window space (optional).
* aTransform is the transform from user space to window space.
* aRenderBounds bounding rect for rendering, in user space.
*
* If aClipRectIn is null, this method sets *aClipRectOut to the clip rect
* actually used for rendering (if aClipRectIn is non-null, we will use that
* for the clip rect).
*
* If aRenderBoundsOut is non-null, it will be set to the render bounds
* actually used by the compositor in window space. If aRenderBoundsOut
* is returned empty, composition should be aborted.
*
* If aOpaque is true, then all of aInvalidRegion will be drawn to with
* opaque content.
*/
virtual void BeginFrame(const nsIntRegion& aInvalidRegion,
const gfx::IntRect* aClipRectIn,
const gfx::IntRect& aRenderBounds,
const nsIntRegion& aOpaqueRegion,
gfx::IntRect* aClipRectOut = nullptr,
gfx::IntRect* aRenderBoundsOut = nullptr) = 0;
/**
* Notification that we've finished issuing draw commands for normal
* layers (as opposed to the diagnostic overlay which comes after).
*/
virtual void NormalDrawingDone() {}
/**
* Flush the current frame to the screen and tidy up.
*
* Derived class overriding this should call Compositor::EndFrame.
*/
virtual void EndFrame();
virtual void CancelFrame(bool aNeedFlush = true) { ReadUnlockTextures(); }
/**
* Whether textures created by this compositor can receive partial updates.
*/
virtual bool SupportsPartialTextureUpdate() = 0;
void SetDiagnosticTypes(DiagnosticTypes aDiagnostics)
{
mDiagnosticTypes = aDiagnostics;
}
DiagnosticTypes GetDiagnosticTypes() const
{
return mDiagnosticTypes;
}
void DrawDiagnostics(DiagnosticFlags aFlags,
const gfx::Rect& visibleRect,
const gfx::IntRect& aClipRect,
const gfx::Matrix4x4& transform,
uint32_t aFlashCounter = DIAGNOSTIC_FLASH_COUNTER_MAX);
void DrawDiagnostics(DiagnosticFlags aFlags,
const nsIntRegion& visibleRegion,
const gfx::IntRect& aClipRect,
const gfx::Matrix4x4& transform,
uint32_t aFlashCounter = DIAGNOSTIC_FLASH_COUNTER_MAX);
#ifdef MOZ_DUMP_PAINTING
virtual const char* Name() const = 0;
#endif // MOZ_DUMP_PAINTING
virtual LayersBackend GetBackendType() const = 0;
virtual CompositorOGL* AsCompositorOGL() { return nullptr; }
virtual CompositorD3D11* AsCompositorD3D11() { return nullptr; }
virtual BasicCompositor* AsBasicCompositor() { return nullptr; }
virtual Compositor* AsCompositor() override {
return this;
}
TimeStamp GetLastCompositionEndTime() const override {
return mLastCompositionEndTime;
}
void UnlockAfterComposition(TextureHost* aTexture) override;
bool NotifyNotUsedAfterComposition(TextureHost* aTextureHost) override;
/**
* Notify the compositor that composition is being paused. This allows the
* compositor to temporarily release any resources.
* Between calling Pause and Resume, compositing may fail.
*/
virtual void Pause() {}
/**
* Notify the compositor that composition is being resumed. The compositor
* regain any resources it requires for compositing.
* Returns true if succeeded.
*/
virtual bool Resume() { return true; }
/**
* Call before rendering begins to ensure the compositor is ready to
* composite. Returns false if rendering should be aborted.
*/
virtual bool Ready() { return true; }
virtual void ForcePresent() { }
virtual bool IsPendingComposite() { return false; }
virtual void FinishPendingComposite() {}
widget::CompositorWidget* GetWidget() const { return mWidget; }
// Return statistics for the most recent frame we computed statistics for.
virtual void GetFrameStats(GPUStats* aStats);
ScreenRotation GetScreenRotation() const {
return mScreenRotation;
}
void SetScreenRotation(ScreenRotation aRotation) {
mScreenRotation = aRotation;
}
// A stale Compositor has no CompositorBridgeParent; it will not process
// frames and should not be used.
void SetInvalid();
virtual bool IsValid() const override;
CompositorBridgeParent* GetCompositorBridgeParent() const {
return mParent;
}
protected:
void DrawDiagnosticsInternal(DiagnosticFlags aFlags,
const gfx::Rect& aVisibleRect,
const gfx::IntRect& aClipRect,
const gfx::Matrix4x4& transform,
uint32_t aFlashCounter);
bool ShouldDrawDiagnostics(DiagnosticFlags);
/**
* Given a layer rect, clip, and transform, compute the area of the backdrop that
* needs to be copied for mix-blending. The output transform translates from 0..1
* space into the backdrop rect space.
*
* The transformed layer quad is also optionally returned - this is the same as
* the result rect, before rounding.
*/
gfx::IntRect ComputeBackdropCopyRect(const gfx::Rect& aRect,
const gfx::IntRect& aClipRect,
const gfx::Matrix4x4& aTransform,
gfx::Matrix4x4* aOutTransform,
gfx::Rect* aOutLayerQuad = nullptr);
gfx::IntRect ComputeBackdropCopyRect(const gfx::Triangle& aTriangle,
const gfx::IntRect& aClipRect,
const gfx::Matrix4x4& aTransform,
gfx::Matrix4x4* aOutTransform,
gfx::Rect* aOutLayerQuad = nullptr);
virtual void DrawTriangles(const nsTArray<gfx::TexturedTriangle>& aTriangles,
const gfx::Rect& aRect,
const gfx::IntRect& aClipRect,
const EffectChain& aEffectChain,
gfx::Float aOpacity,
const gfx::Matrix4x4& aTransform,
const gfx::Rect& aVisibleRect);
virtual void DrawPolygon(const gfx::Polygon& aPolygon,
const gfx::Rect& aRect,
const gfx::IntRect& aClipRect,
const EffectChain& aEffectChain,
gfx::Float aOpacity,
const gfx::Matrix4x4& aTransform,
const gfx::Rect& aVisibleRect);
/**
* Last Composition end time.
*/
TimeStamp mLastCompositionEndTime;
DiagnosticTypes mDiagnosticTypes;
CompositorBridgeParent* mParent;
/**
* We keep track of the total number of pixels filled as we composite the
* current frame. This value is an approximation and is not accurate,
* especially in the presence of transforms.
*/
size_t mPixelsPerFrame;
size_t mPixelsFilled;
ScreenRotation mScreenRotation;
RefPtr<gfx::DrawTarget> mTarget;
gfx::IntRect mTargetBounds;
widget::CompositorWidget* mWidget;
bool mIsDestroyed;
gfx::Color mClearColor;
gfx::Color mDefaultClearColor;
private:
static LayersBackend sBackend;
};
// Returns the number of rects. (Up to 4)
typedef gfx::Rect decomposedRectArrayT[4];
size_t DecomposeIntoNoRepeatRects(const gfx::Rect& aRect,
const gfx::Rect& aTexCoordRect,
decomposedRectArrayT* aLayerRects,
decomposedRectArrayT* aTextureRects);
static inline bool
BlendOpIsMixBlendMode(gfx::CompositionOp aOp)
{
switch (aOp) {
case gfx::CompositionOp::OP_MULTIPLY:
case gfx::CompositionOp::OP_SCREEN:
case gfx::CompositionOp::OP_OVERLAY:
case gfx::CompositionOp::OP_DARKEN:
case gfx::CompositionOp::OP_LIGHTEN:
case gfx::CompositionOp::OP_COLOR_DODGE:
case gfx::CompositionOp::OP_COLOR_BURN:
case gfx::CompositionOp::OP_HARD_LIGHT:
case gfx::CompositionOp::OP_SOFT_LIGHT:
case gfx::CompositionOp::OP_DIFFERENCE:
case gfx::CompositionOp::OP_EXCLUSION:
case gfx::CompositionOp::OP_HUE:
case gfx::CompositionOp::OP_SATURATION:
case gfx::CompositionOp::OP_COLOR:
case gfx::CompositionOp::OP_LUMINOSITY:
return true;
default:
return false;
}
}
class AsyncReadbackBuffer
{
public:
NS_INLINE_DECL_REFCOUNTING(AsyncReadbackBuffer)
gfx::IntSize GetSize() const { return mSize; }
virtual bool MapAndCopyInto(gfx::DataSourceSurface* aSurface,
const gfx::IntSize& aReadSize) const=0;
protected:
explicit AsyncReadbackBuffer(const gfx::IntSize& aSize) : mSize(aSize) {}
virtual ~AsyncReadbackBuffer() {}
gfx::IntSize mSize;
};
struct TexturedVertex
{
float position[2];
float texCoords[2];
};
nsTArray<TexturedVertex>
TexturedTrianglesToVertexArray(const nsTArray<gfx::TexturedTriangle>& aTriangles);
} // namespace layers
} // namespace mozilla
#endif /* MOZILLA_GFX_COMPOSITOR_H */