1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/layers/Compositor.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,542 @@
1.4 +/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 +* This Source Code Form is subject to the terms of the Mozilla Public
1.6 +* License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 +* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef MOZILLA_GFX_COMPOSITOR_H
1.10 +#define MOZILLA_GFX_COMPOSITOR_H
1.11 +
1.12 +#include "Units.h" // for ScreenPoint
1.13 +#include "mozilla/Assertions.h" // for MOZ_ASSERT, etc
1.14 +#include "mozilla/RefPtr.h" // for TemporaryRef, RefCounted
1.15 +#include "mozilla/gfx/Point.h" // for IntSize, Point
1.16 +#include "mozilla/gfx/Rect.h" // for Rect, IntRect
1.17 +#include "mozilla/gfx/Types.h" // for Float
1.18 +#include "mozilla/layers/CompositorTypes.h" // for DiagnosticTypes, etc
1.19 +#include "mozilla/layers/LayersTypes.h" // for LayersBackend
1.20 +#include "nsISupportsImpl.h" // for MOZ_COUNT_CTOR, etc
1.21 +#include "nsRegion.h"
1.22 +#include <vector>
1.23 +#include "mozilla/WidgetUtils.h"
1.24 +
1.25 +/**
1.26 + * Different elements of a web pages are rendered into separate "layers" before
1.27 + * they are flattened into the final image that is brought to the screen.
1.28 + * See Layers.h for more informations about layers and why we use retained
1.29 + * structures.
1.30 + * Most of the documentation for layers is directly in the source code in the
1.31 + * form of doc comments. An overview can also be found in the the wiki:
1.32 + * https://wiki.mozilla.org/Gecko:Overview#Graphics
1.33 + *
1.34 + *
1.35 + * # Main interfaces and abstractions
1.36 + *
1.37 + * - Layer, ShadowableLayer and LayerComposite
1.38 + * (see Layers.h and ipc/ShadowLayers.h)
1.39 + * - CompositableClient and CompositableHost
1.40 + * (client/CompositableClient.h composite/CompositableHost.h)
1.41 + * - TextureClient and TextureHost
1.42 + * (client/TextureClient.h composite/TextureHost.h)
1.43 + * - TextureSource
1.44 + * (composite/TextureHost.h)
1.45 + * - Forwarders
1.46 + * (ipc/CompositableForwarder.h ipc/ShadowLayers.h)
1.47 + * - Compositor
1.48 + * (this file)
1.49 + * - IPDL protocols
1.50 + * (.ipdl files under the gfx/layers/ipc directory)
1.51 + *
1.52 + * The *Client and Shadowable* classes are always used on the content thread.
1.53 + * Forwarders are always used on the content thread.
1.54 + * The *Host and Shadow* classes are always used on the compositor thread.
1.55 + * Compositors, TextureSource, and Effects are always used on the compositor
1.56 + * thread.
1.57 + * Most enums and constants are declared in LayersTypes.h and CompositorTypes.h.
1.58 + *
1.59 + *
1.60 + * # Texture transfer
1.61 + *
1.62 + * Most layer classes own a Compositable plus some extra information like
1.63 + * transforms and clip rects. They are platform independent.
1.64 + * Compositable classes manipulate Texture objects and are reponsible for
1.65 + * things like tiling, buffer rotation or double buffering. Compositables
1.66 + * are also platform-independent. Examples of compositable classes are:
1.67 + * - ImageClient
1.68 + * - CanvasClient
1.69 + * - ContentHost
1.70 + * - etc.
1.71 + * Texture classes (TextureClient and TextureHost) are thin abstractions over
1.72 + * platform-dependent texture memory. They are maniplulated by compositables
1.73 + * and don't know about buffer rotations and such. The purposes of TextureClient
1.74 + * and TextureHost are to synchronize, serialize and deserialize texture data.
1.75 + * TextureHosts provide access to TextureSources that are views on the
1.76 + * Texture data providing the necessary api for Compositor backend to composite
1.77 + * them.
1.78 + *
1.79 + * Compositable and Texture clients and hosts are created using factory methods.
1.80 + * They should only be created by using their constructor in exceptional
1.81 + * circumstances. The factory methods are located:
1.82 + * TextureClient - CompositableClient::CreateTextureClient
1.83 + * TextureHost - TextureHost::CreateTextureHost, which calls a
1.84 + * platform-specific function, e.g., CreateTextureHostOGL
1.85 + * CompositableClient - in the appropriate subclass, e.g.,
1.86 + * CanvasClient::CreateCanvasClient
1.87 + * CompositableHost - CompositableHost::Create
1.88 + *
1.89 + *
1.90 + * # IPDL
1.91 + *
1.92 + * If off-main-thread compositing (OMTC) is enabled, compositing is performed
1.93 + * in a dedicated thread. In some setups compositing happens in a dedicated
1.94 + * process. Documentation may refer to either the compositor thread or the
1.95 + * compositor process.
1.96 + * See explanations in ShadowLayers.h.
1.97 + *
1.98 + *
1.99 + * # Backend implementations
1.100 + *
1.101 + * Compositor backends like OpenGL or flavours of D3D live in their own directory
1.102 + * under gfx/layers/. To add a new backend, implement at least the following
1.103 + * interfaces:
1.104 + * - Compositor (ex. CompositorOGL)
1.105 + * - TextureHost (ex. SharedTextureHostOGL)
1.106 + * Depending on the type of data that needs to be serialized, you may need to
1.107 + * add specific TextureClient implementations.
1.108 + */
1.109 +
1.110 +class nsIWidget;
1.111 +struct nsIntSize;
1.112 +class nsIntRegion;
1.113 +
1.114 +namespace mozilla {
1.115 +namespace gfx {
1.116 +class Matrix;
1.117 +class Matrix4x4;
1.118 +class DrawTarget;
1.119 +}
1.120 +
1.121 +namespace layers {
1.122 +
1.123 +struct Effect;
1.124 +struct EffectChain;
1.125 +class Image;
1.126 +class ISurfaceAllocator;
1.127 +class Layer;
1.128 +class NewTextureSource;
1.129 +class DataTextureSource;
1.130 +class CompositingRenderTarget;
1.131 +class PCompositorParent;
1.132 +class LayerManagerComposite;
1.133 +
1.134 +enum SurfaceInitMode
1.135 +{
1.136 + INIT_MODE_NONE,
1.137 + INIT_MODE_CLEAR
1.138 +};
1.139 +
1.140 +/**
1.141 + * A base class for a platform-dependent helper for use by TextureHost.
1.142 + */
1.143 +class CompositorBackendSpecificData
1.144 +{
1.145 + NS_INLINE_DECL_REFCOUNTING(CompositorBackendSpecificData)
1.146 +
1.147 +protected:
1.148 + virtual ~CompositorBackendSpecificData() {}
1.149 +};
1.150 +
1.151 +/**
1.152 + * Common interface for compositor backends.
1.153 + *
1.154 + * Compositor provides a cross-platform interface to a set of operations for
1.155 + * compositing quads. Compositor knows nothing about the layer tree. It must be
1.156 + * told everything about each composited quad - contents, location, transform,
1.157 + * opacity, etc.
1.158 + *
1.159 + * In theory it should be possible for different widgets to use the same
1.160 + * compositor. In practice, we use one compositor per window.
1.161 + *
1.162 + * # Usage
1.163 + *
1.164 + * For an example of a user of Compositor, see LayerManagerComposite.
1.165 + *
1.166 + * Initialization: create a Compositor object, call Initialize().
1.167 + *
1.168 + * Destruction: destroy any resources associated with the compositor, call
1.169 + * Destroy(), delete the Compositor object.
1.170 + *
1.171 + * Composition:
1.172 + * call BeginFrame,
1.173 + * for each quad to be composited:
1.174 + * call MakeCurrent if necessary (not necessary if no other context has been
1.175 + * made current),
1.176 + * take care of any texture upload required to composite the quad, this step
1.177 + * is backend-dependent,
1.178 + * construct an EffectChain for the quad,
1.179 + * call DrawQuad,
1.180 + * call EndFrame.
1.181 + * If the user has to stop compositing at any point before EndFrame, call
1.182 + * AbortFrame.
1.183 + * If the compositor is usually used for compositing but compositing is
1.184 + * temporarily done without the compositor, call EndFrameForExternalComposition
1.185 + * after compositing each frame so the compositor can remain internally
1.186 + * consistent.
1.187 + *
1.188 + * By default, the compositor will render to the screen, to render to a target,
1.189 + * call SetTargetContext or SetRenderTarget, the latter with a target created
1.190 + * by CreateRenderTarget or CreateRenderTargetFromSource.
1.191 + *
1.192 + * The target and viewport methods can be called before any DrawQuad call and
1.193 + * affect any subsequent DrawQuad calls.
1.194 + */
1.195 +class Compositor
1.196 +{
1.197 +protected:
1.198 + virtual ~Compositor() {}
1.199 +
1.200 +public:
1.201 + NS_INLINE_DECL_REFCOUNTING(Compositor)
1.202 +
1.203 + Compositor(PCompositorParent* aParent = nullptr)
1.204 + : mCompositorID(0)
1.205 + , mDiagnosticTypes(DIAGNOSTIC_NONE)
1.206 + , mParent(aParent)
1.207 + , mScreenRotation(ROTATION_0)
1.208 + {
1.209 + }
1.210 +
1.211 + virtual TemporaryRef<DataTextureSource> CreateDataTextureSource(TextureFlags aFlags = 0) = 0;
1.212 + virtual bool Initialize() = 0;
1.213 + virtual void Destroy() = 0;
1.214 +
1.215 + /**
1.216 + * Return true if the effect type is supported.
1.217 + *
1.218 + * By default Compositor implementations should support all effects but in
1.219 + * some rare cases it is not possible to support an effect efficiently.
1.220 + * This is the case for BasicCompositor with EffectYCbCr.
1.221 + */
1.222 + virtual bool SupportsEffect(EffectTypes aEffect) { return true; }
1.223 +
1.224 + /**
1.225 + * Request a texture host identifier that may be used for creating textures
1.226 + * across process or thread boundaries that are compatible with this
1.227 + * compositor.
1.228 + */
1.229 + virtual TextureFactoryIdentifier GetTextureFactoryIdentifier() = 0;
1.230 +
1.231 + /**
1.232 + * Properties of the compositor.
1.233 + */
1.234 + virtual bool CanUseCanvasLayerForSize(const gfx::IntSize& aSize) = 0;
1.235 + virtual int32_t GetMaxTextureSize() const = 0;
1.236 +
1.237 + /**
1.238 + * Set the target for rendering. Results will have been written to aTarget by
1.239 + * the time that EndFrame returns.
1.240 + *
1.241 + * If this method is not used, or we pass in nullptr, we target the compositor's
1.242 + * usual swap chain and render to the screen.
1.243 + */
1.244 + virtual void SetTargetContext(gfx::DrawTarget* aTarget) = 0;
1.245 +
1.246 + typedef uint32_t MakeCurrentFlags;
1.247 + static const MakeCurrentFlags ForceMakeCurrent = 0x1;
1.248 + /**
1.249 + * Make this compositor's rendering context the current context for the
1.250 + * underlying graphics API. This may be a global operation, depending on the
1.251 + * API. Our context will remain the current one until someone else changes it.
1.252 + *
1.253 + * Clients of the compositor should call this at the start of the compositing
1.254 + * process, it might be required by texture uploads etc.
1.255 + *
1.256 + * If aFlags == ForceMakeCurrent then we will (re-)set our context on the
1.257 + * underlying API even if it is already the current context.
1.258 + */
1.259 + virtual void MakeCurrent(MakeCurrentFlags aFlags = 0) = 0;
1.260 +
1.261 + /**
1.262 + * Creates a Surface that can be used as a rendering target by this
1.263 + * compositor.
1.264 + */
1.265 + virtual TemporaryRef<CompositingRenderTarget>
1.266 + CreateRenderTarget(const gfx::IntRect& aRect, SurfaceInitMode aInit) = 0;
1.267 +
1.268 + /**
1.269 + * Creates a Surface that can be used as a rendering target by this
1.270 + * compositor, and initializes the surface by copying from aSource.
1.271 + * If aSource is null, then the current screen buffer is used as source.
1.272 + *
1.273 + * aSourcePoint specifies the point in aSource to copy data from.
1.274 + */
1.275 + virtual TemporaryRef<CompositingRenderTarget>
1.276 + CreateRenderTargetFromSource(const gfx::IntRect& aRect,
1.277 + const CompositingRenderTarget* aSource,
1.278 + const gfx::IntPoint& aSourcePoint) = 0;
1.279 +
1.280 + /**
1.281 + * Sets the given surface as the target for subsequent calls to DrawQuad.
1.282 + * Passing null as aSurface sets the screen as the target.
1.283 + */
1.284 + virtual void SetRenderTarget(CompositingRenderTarget* aSurface) = 0;
1.285 +
1.286 + /**
1.287 + * Returns the current target for rendering. Will return null if we are
1.288 + * rendering to the screen.
1.289 + */
1.290 + virtual CompositingRenderTarget* GetCurrentRenderTarget() const = 0;
1.291 +
1.292 + /**
1.293 + * Mostly the compositor will pull the size from a widget and this method will
1.294 + * be ignored, but compositor implementations are free to use it if they like.
1.295 + */
1.296 + virtual void SetDestinationSurfaceSize(const gfx::IntSize& aSize) = 0;
1.297 +
1.298 + /**
1.299 + * Declare an offset to use when rendering layers. This will be ignored when
1.300 + * rendering to a target instead of the screen.
1.301 + */
1.302 + virtual void SetScreenRenderOffset(const ScreenPoint& aOffset) = 0;
1.303 +
1.304 + /**
1.305 + * Tell the compositor to draw a quad. What to do draw and how it is
1.306 + * drawn is specified by aEffectChain. aRect is the quad to draw, in user space.
1.307 + * aTransform transforms from user space to screen space. If texture coords are
1.308 + * required, these will be in the primary effect in the effect chain.
1.309 + */
1.310 + virtual void DrawQuad(const gfx::Rect& aRect, const gfx::Rect& aClipRect,
1.311 + const EffectChain& aEffectChain,
1.312 + gfx::Float aOpacity, const gfx::Matrix4x4 &aTransform) = 0;
1.313 +
1.314 + /**
1.315 + * Tell the compositor to draw lines connecting the points. Behaves like
1.316 + * DrawQuad.
1.317 + */
1.318 + virtual void DrawLines(const std::vector<gfx::Point>& aLines, const gfx::Rect& aClipRect,
1.319 + const gfx::Color& aColor,
1.320 + gfx::Float aOpacity, const gfx::Matrix4x4 &aTransform)
1.321 + { /* Should turn into pure virtual once implemented in D3D */ }
1.322 +
1.323 + /*
1.324 + * Clear aRect on current render target.
1.325 + */
1.326 + virtual void ClearRect(const gfx::Rect& aRect) { }
1.327 +
1.328 + /**
1.329 + * Start a new frame.
1.330 + *
1.331 + * aInvalidRect is the invalid region of the screen; it can be ignored for
1.332 + * compositors where the performance for compositing the entire window is
1.333 + * sufficient.
1.334 + *
1.335 + * aClipRectIn is the clip rect for the window in window space (optional).
1.336 + * aTransform is the transform from user space to window space.
1.337 + * aRenderBounds bounding rect for rendering, in user space.
1.338 + *
1.339 + * If aClipRectIn is null, this method sets *aClipRectOut to the clip rect
1.340 + * actually used for rendering (if aClipRectIn is non-null, we will use that
1.341 + * for the clip rect).
1.342 + *
1.343 + * If aRenderBoundsOut is non-null, it will be set to the render bounds
1.344 + * actually used by the compositor in window space. If aRenderBoundsOut
1.345 + * is returned empty, composition should be aborted.
1.346 + */
1.347 + virtual void BeginFrame(const nsIntRegion& aInvalidRegion,
1.348 + const gfx::Rect* aClipRectIn,
1.349 + const gfx::Matrix& aTransform,
1.350 + const gfx::Rect& aRenderBounds,
1.351 + gfx::Rect* aClipRectOut = nullptr,
1.352 + gfx::Rect* aRenderBoundsOut = nullptr) = 0;
1.353 +
1.354 + /**
1.355 + * Flush the current frame to the screen and tidy up.
1.356 + */
1.357 + virtual void EndFrame() = 0;
1.358 +
1.359 + virtual void SetFBAcquireFence(Layer* aLayer) {}
1.360 +
1.361 + /**
1.362 + * Post-rendering stuff if the rendering is done outside of this Compositor
1.363 + * e.g., by Composer2D.
1.364 + * aTransform is the transform from user space to window space.
1.365 + */
1.366 + virtual void EndFrameForExternalComposition(const gfx::Matrix& aTransform) = 0;
1.367 +
1.368 + /**
1.369 + * Tidy up if BeginFrame has been called, but EndFrame won't be.
1.370 + */
1.371 + virtual void AbortFrame() = 0;
1.372 +
1.373 + /**
1.374 + * Setup the viewport and projection matrix for rendering to a target of the
1.375 + * given dimensions. The size and transform here will override those set in
1.376 + * BeginFrame. BeginFrame sets a size and transform for the default render
1.377 + * target, usually the screen. Calling this method prepares the compositor to
1.378 + * render using a different viewport (that is, size and transform), usually
1.379 + * associated with a new render target.
1.380 + * aWorldTransform is the transform from user space to the new viewport's
1.381 + * coordinate space.
1.382 + */
1.383 + virtual void PrepareViewport(const gfx::IntSize& aSize,
1.384 + const gfx::Matrix& aWorldTransform) = 0;
1.385 +
1.386 + /**
1.387 + * Whether textures created by this compositor can receive partial updates.
1.388 + */
1.389 + virtual bool SupportsPartialTextureUpdate() = 0;
1.390 +
1.391 + void SetDiagnosticTypes(DiagnosticTypes aDiagnostics)
1.392 + {
1.393 + mDiagnosticTypes = aDiagnostics;
1.394 + }
1.395 +
1.396 + DiagnosticTypes GetDiagnosticTypes() const
1.397 + {
1.398 + return mDiagnosticTypes;
1.399 + }
1.400 +
1.401 + void DrawDiagnostics(DiagnosticFlags aFlags,
1.402 + const gfx::Rect& visibleRect,
1.403 + const gfx::Rect& aClipRect,
1.404 + const gfx::Matrix4x4& transform,
1.405 + uint32_t aFlashCounter = DIAGNOSTIC_FLASH_COUNTER_MAX);
1.406 +
1.407 + void DrawDiagnostics(DiagnosticFlags aFlags,
1.408 + const nsIntRegion& visibleRegion,
1.409 + const gfx::Rect& aClipRect,
1.410 + const gfx::Matrix4x4& transform,
1.411 + uint32_t aFlashCounter = DIAGNOSTIC_FLASH_COUNTER_MAX);
1.412 +
1.413 +#ifdef MOZ_DUMP_PAINTING
1.414 + virtual const char* Name() const = 0;
1.415 +#endif // MOZ_DUMP_PAINTING
1.416 +
1.417 + virtual LayersBackend GetBackendType() const = 0;
1.418 +
1.419 + /**
1.420 + * Each Compositor has a unique ID.
1.421 + * This ID is used to keep references to each Compositor in a map accessed
1.422 + * from the compositor thread only, so that async compositables can find
1.423 + * the right compositor parent and schedule compositing even if the compositor
1.424 + * changed.
1.425 + */
1.426 + uint32_t GetCompositorID() const
1.427 + {
1.428 + return mCompositorID;
1.429 + }
1.430 + void SetCompositorID(uint32_t aID)
1.431 + {
1.432 + MOZ_ASSERT(mCompositorID == 0, "The compositor ID must be set only once.");
1.433 + mCompositorID = aID;
1.434 + }
1.435 +
1.436 + /**
1.437 + * Notify the compositor that composition is being paused. This allows the
1.438 + * compositor to temporarily release any resources.
1.439 + * Between calling Pause and Resume, compositing may fail.
1.440 + */
1.441 + virtual void Pause() {}
1.442 + /**
1.443 + * Notify the compositor that composition is being resumed. The compositor
1.444 + * regain any resources it requires for compositing.
1.445 + * Returns true if succeeded.
1.446 + */
1.447 + virtual bool Resume() { return true; }
1.448 +
1.449 + /**
1.450 + * Call before rendering begins to ensure the compositor is ready to
1.451 + * composite. Returns false if rendering should be aborted.
1.452 + */
1.453 + virtual bool Ready() { return true; }
1.454 +
1.455 + // XXX I expect we will want to move mWidget into this class and implement
1.456 + // these methods properly.
1.457 + virtual nsIWidget* GetWidget() const { return nullptr; }
1.458 +
1.459 + /**
1.460 + * Debug-build assertion that can be called to ensure code is running on the
1.461 + * compositor thread.
1.462 + */
1.463 + static void AssertOnCompositorThread();
1.464 +
1.465 + /**
1.466 + * We enforce that there can only be one Compositor backend type off the main
1.467 + * thread at the same time. The backend type in use can be checked with this
1.468 + * static method. We need this for creating texture clients/hosts etc. when we
1.469 + * don't have a reference to a Compositor.
1.470 + *
1.471 + * This can only be used from the compositor thread!
1.472 + */
1.473 + static LayersBackend GetBackend();
1.474 +
1.475 + size_t GetFillRatio() {
1.476 + float fillRatio = 0;
1.477 + if (mPixelsFilled > 0 && mPixelsPerFrame > 0) {
1.478 + fillRatio = 100.0f * float(mPixelsFilled) / float(mPixelsPerFrame);
1.479 + if (fillRatio > 999.0f) {
1.480 + fillRatio = 999.0f;
1.481 + }
1.482 + }
1.483 + return fillRatio;
1.484 + }
1.485 +
1.486 + virtual CompositorBackendSpecificData* GetCompositorBackendSpecificData() {
1.487 + return nullptr;
1.488 + }
1.489 +
1.490 + ScreenRotation GetScreenRotation() const {
1.491 + return mScreenRotation;
1.492 + }
1.493 +
1.494 + void SetScreenRotation(ScreenRotation aRotation) {
1.495 + mScreenRotation = aRotation;
1.496 + }
1.497 +
1.498 + // On b2g the clip rect is in the coordinate space of the physical screen
1.499 + // independently of its rotation, while the coordinate space of the layers,
1.500 + // on the other hand, depends on the screen orientation.
1.501 + // This only applies to b2g as with other platforms, orientation is handled
1.502 + // at the OS level rather than in Gecko.
1.503 + // In addition, the clip rect needs to be offset by the rendering origin.
1.504 + // This becomes important if intermediate surfaces are used.
1.505 + gfx::Rect ClipRectInLayersCoordinates(gfx::Rect aClip) const;
1.506 +
1.507 +protected:
1.508 + void DrawDiagnosticsInternal(DiagnosticFlags aFlags,
1.509 + const gfx::Rect& aVisibleRect,
1.510 + const gfx::Rect& aClipRect,
1.511 + const gfx::Matrix4x4& transform,
1.512 + uint32_t aFlashCounter);
1.513 +
1.514 + bool ShouldDrawDiagnostics(DiagnosticFlags);
1.515 +
1.516 + /**
1.517 + * Set the global Compositor backend, checking that one isn't already set.
1.518 + */
1.519 + static void SetBackend(LayersBackend backend);
1.520 +
1.521 + uint32_t mCompositorID;
1.522 + DiagnosticTypes mDiagnosticTypes;
1.523 + PCompositorParent* mParent;
1.524 +
1.525 + /**
1.526 + * We keep track of the total number of pixels filled as we composite the
1.527 + * current frame. This value is an approximation and is not accurate,
1.528 + * especially in the presence of transforms.
1.529 + */
1.530 + size_t mPixelsPerFrame;
1.531 + size_t mPixelsFilled;
1.532 +
1.533 + ScreenRotation mScreenRotation;
1.534 +
1.535 + virtual gfx::IntSize GetWidgetSize() const = 0;
1.536 +
1.537 +private:
1.538 + static LayersBackend sBackend;
1.539 +
1.540 +};
1.541 +
1.542 +} // namespace layers
1.543 +} // namespace mozilla
1.544 +
1.545 +#endif /* MOZILLA_GFX_COMPOSITOR_H */
