tachyon::NullGraphicsContext Class Reference

A graphics backend that draws nothing: the UI is built, laid out and recorded as usual, but no GPU is used and windows stay empty. More...

#include <gui_core/graphics/null/gui_null_graphics_context.h>

Inheritance diagram for tachyon::NullGraphicsContext:

Public Member Functions
	NullGraphicsContext ()
	~NullGraphicsContext () override
GraphicsAPI	GetAPI () const override
	The API it presents with; window backends make their windows for it.
void	SetAllocationHooks (const AllocationHooks &) override
	Host memory functions for the graphics API's allocations. Call before Initialize.
Result< void >	Initialize (IWindowBackend *windowBackend) override
	Brings the device up; GUIApplication::Initialize calls it once, before any window context.
void	Cleanup () override
	Waits for the GPU and destroys what the backend made, the renderer included.
void	BeginFrame () override
	Starts a frame's UI build: resets the renderer for new primitives (Vulkan: also frees what frame-scoped deletions held long enough).
void	EndFrame () override
	Ends the UI build, before the uploads and the window contexts' recording.
Image *	CreateImage (void *data, uint2 size, ImageFormat format, Sampler sampler, bool mipmapped=false) override
	Makes an image from size.x x size.y tightly packed pixels of format (Vulkan: data null for a cleared image); mipmapped generates its mip levels.
void	DestroyImageAtEnd (Image *img, DeviceScope scope, const std::source_location &loc=std::source_location::current()) override
	Destroys the image and deletes the object once the GPU is done with it: a few frames on for DeviceScope::Frame, at Cleanup for DeviceScope::Application.
TextAtlasManager *	CreateTextAtlasManager () override
	A new text atlas manager for the backend. The caller owns it and keeps it past Cleanup.
IWindowContext *	CreateWindowContext (void *nativeWindowHandle, OSWindowHandle osHandle, ID id, int2 size, WindowFlags windowFlags, OnGuiFunc onGui) override
	Makes the context that renders an OS window: nativeWindowHandle comes from IWindowBackend::GetNativeHandle, size is in pixels and onGui builds the window's UI.
void	DestroyWindowContext (IWindowContext *context) override
	Waits for the context's GPU work and destroys it now; its native window must still exist.
ImageSet *	GetImageSet () const override
	The images the shaders sample, by ImageIndex.
ImageIndex	RegisterImage (Image *image) override
	Adds the image to the image set; elements draw it by the returned index.
void	UnregisterImage (ImageIndex index) override
	Frees the index for reuse; the image stays (DestroyImageAtEnd destroys it).
void	PrepareFrame (StyleManager &, GradientManager &, float) override
	Uploads the styles and gradient pages for this frame's draws, after the UI build and before the window contexts record.
Public Member Functions inherited from tachyon::GraphicsContext
	GraphicsContext ()=default
virtual	~GraphicsContext ()
virtual bool	DeviceLost () const
	True once the GPU device is lost; RecreateDevice then makes a new one.
virtual Result< void >	RecreateDevice (IWindowBackend *)
	Makes a new device after DeviceLost, and everything the backend owns on it (the window contexts are the caller's to make again).
virtual float	GetLastFrameBuildSeconds () const
	Wall-clock seconds of CPU work in the last frame: from just after one present returns to just before the next, so without the vsync wait.

Additional Inherited Members
Public Attributes inherited from tachyon::GraphicsContext
GUIRenderer *	guiRenderer = nullptr
	Where the UI records its draw primitives.

Detailed Description

A graphics backend that draws nothing: the UI is built, laid out and recorded as usual, but no GPU is used and windows stay empty.

For headless runs and tests, and as the minimal example of a backend.

Constructor & Destructor Documentation

NullGraphicsContext()

tachyon::NullGraphicsContext::NullGraphicsContext

(

)

~NullGraphicsContext()

tachyon::NullGraphicsContext::~NullGraphicsContext ( )

override

Member Function Documentation

GetAPI()

GraphicsAPI tachyon::NullGraphicsContext::GetAPI ( ) const

inlineoverridevirtual

The API it presents with; window backends make their windows for it.

Implements tachyon::GraphicsContext.

SetAllocationHooks()

void tachyon::NullGraphicsContext::SetAllocationHooks ( const AllocationHooks & hooks )

inlineoverridevirtual

Host memory functions for the graphics API's allocations. Call before Initialize.

Implements tachyon::GraphicsContext.

Initialize()

Result< void > tachyon::NullGraphicsContext::Initialize ( IWindowBackend * windowBackend )

overridevirtual

Brings the device up; GUIApplication::Initialize calls it once, before any window context.

It may make windows with the backend (Vulkan: a hidden one, to pick a GPU that can present to it).

Implements tachyon::GraphicsContext.

Cleanup()

void tachyon::NullGraphicsContext::Cleanup ( )

overridevirtual

Waits for the GPU and destroys what the backend made, the renderer included.

The window contexts are destroyed before it.

Implements tachyon::GraphicsContext.

BeginFrame()

void tachyon::NullGraphicsContext::BeginFrame ( )

overridevirtual

Starts a frame's UI build: resets the renderer for new primitives (Vulkan: also frees what frame-scoped deletions held long enough).

Implements tachyon::GraphicsContext.

EndFrame()

void tachyon::NullGraphicsContext::EndFrame ( )

inlineoverridevirtual

Ends the UI build, before the uploads and the window contexts' recording.

Implements tachyon::GraphicsContext.

CreateImage()

Image * tachyon::NullGraphicsContext::CreateImage ( void * data, uint2 size, ImageFormat format, Sampler sampler, bool mipmapped = false )

overridevirtual

Makes an image from size.x x size.y tightly packed pixels of format (Vulkan: data null for a cleared image); mipmapped generates its mip levels.

Doesn't wait for the GPU: the upload goes with the next frame. RegisterImage makes it drawable.

Implements tachyon::GraphicsContext.

DestroyImageAtEnd()

void tachyon::NullGraphicsContext::DestroyImageAtEnd ( Image * img, DeviceScope scope, const std::source_location & loc = std::source_location::current() )

overridevirtual

Destroys the image and deletes the object once the GPU is done with it: a few frames on for DeviceScope::Frame, at Cleanup for DeviceScope::Application.

loc is for diagnostics.

Implements tachyon::GraphicsContext.

CreateTextAtlasManager()

TextAtlasManager * tachyon::NullGraphicsContext::CreateTextAtlasManager ( )

overridevirtual

A new text atlas manager for the backend. The caller owns it and keeps it past Cleanup.

Implements tachyon::GraphicsContext.

CreateWindowContext()

IWindowContext * tachyon::NullGraphicsContext::CreateWindowContext ( void * nativeWindowHandle, OSWindowHandle osHandle, ID id, int2 size, WindowFlags windowFlags, OnGuiFunc onGui )

overridevirtual

Makes the context that renders an OS window: nativeWindowHandle comes from IWindowBackend::GetNativeHandle, size is in pixels and onGui builds the window's UI.

nullptr on failure. Destroy it with DestroyWindowContext.

Implements tachyon::GraphicsContext.

DestroyWindowContext()

void tachyon::NullGraphicsContext::DestroyWindowContext ( IWindowContext * context )

overridevirtual

Waits for the context's GPU work and destroys it now; its native window must still exist.

Implements tachyon::GraphicsContext.

GetImageSet()

ImageSet * tachyon::NullGraphicsContext::GetImageSet ( ) const

overridevirtual

The images the shaders sample, by ImageIndex.

Implements tachyon::GraphicsContext.

RegisterImage()

ImageIndex tachyon::NullGraphicsContext::RegisterImage ( Image * image )

overridevirtual

Adds the image to the image set; elements draw it by the returned index.

Implements tachyon::GraphicsContext.

UnregisterImage()

void tachyon::NullGraphicsContext::UnregisterImage ( ImageIndex index )

overridevirtual

Frees the index for reuse; the image stays (DestroyImageAtEnd destroys it).

Implements tachyon::GraphicsContext.

PrepareFrame()

void tachyon::NullGraphicsContext::PrepareFrame ( StyleManager & styleManager, GradientManager & gradientManager, float elapsedTimeSecs )

inlineoverridevirtual

Uploads the styles and gradient pages for this frame's draws, after the UI build and before the window contexts record.

elapsedTimeSecs: the frame clock's time, for shader animation.

Implements tachyon::GraphicsContext.

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The documentation for this class was generated from the following file:

• gui_core/graphics/null/gui_null_graphics_context.h