impeller::Capabilities Class Reference

#include <capabilities.h>

Inheritance diagram for impeller::Capabilities:

Public Member Functions
virtual	~Capabilities ()
virtual bool	SupportsOffscreenMSAA () const =0
	Whether the context backend supports attaching offscreen MSAA color/stencil textures.
virtual bool	SupportsImplicitResolvingMSAA () const =0
	Whether the context backend supports multisampled rendering to the on-screen surface without requiring an explicit resolve of the MSAA color attachment.
virtual bool	SupportsSSBO () const =0
	Whether the context backend supports binding Shader Storage Buffer Objects (SSBOs) to pipelines.
virtual bool	SupportsBufferToTextureBlits () const =0
	Whether the context backend supports blitting from a given DeviceBuffer view to a texture region (via the relevant BlitPass::AddCopy overloads).
virtual bool	SupportsTextureToTextureBlits () const =0
	Whether the context backend supports blitting from one texture region to another texture region (via the relevant BlitPass::AddCopy overloads).
virtual bool	SupportsFramebufferFetch () const =0
	Whether the context backend is able to support pipelines with shaders that read from the framebuffer (i.e. pixels that have been written by previous draw calls in the current render pass).
virtual bool	SupportsCompute () const =0
	Whether the context backend supports ComputePass.
virtual bool	SupportsComputeSubgroups () const =0
	Whether the context backend supports configuring ComputePass command subgroups.
virtual bool	SupportsReadFromResolve () const =0
	Whether the context backend supports binding the current RenderPass attachments. This is supported if the backend can guarantee that attachment textures will not be mutated until the render pass has fully completed.
virtual bool	SupportsDecalSamplerAddressMode () const =0
	Whether the context backend supports SamplerAddressMode::Decal.
virtual bool	SupportsDeviceTransientTextures () const =0
	Whether the context backend supports allocating StorageMode::kDeviceTransient (aka "memoryless") textures, which are temporary textures kept in tile memory for the duration of the RenderPass it's attached to.
virtual PixelFormat	GetDefaultColorFormat () const =0
	Returns a supported PixelFormat for textures that store 4-channel colors (red/green/blue/alpha).
virtual PixelFormat	GetDefaultStencilFormat () const =0
	Returns a supported PixelFormat for textures that store stencil information. May include a depth channel if a stencil-only format is not available.
virtual PixelFormat	GetDefaultDepthStencilFormat () const =0
	Returns a supported PixelFormat for textures that store both a stencil and depth component. This will never return a depth-only or stencil-only texture. Returns PixelFormat::kUnknown if no suitable depth+stencil format was found.
virtual PixelFormat	GetDefaultGlyphAtlasFormat () const =0
	Returns the default pixel format for the alpha bitmap glyph atlas.

Protected Member Functions
	Capabilities ()
	Capabilities (const Capabilities &)=delete
Capabilities &	operator= (const Capabilities &)=delete

Detailed Description

Definition at line 15 of file capabilities.h.

Constructor & Destructor Documentation

~Capabilities()

impeller::Capabilities::~Capabilities ( )

virtualdefault

Capabilities() [1/2]

impeller::Capabilities::Capabilities ( )

protecteddefault

Capabilities() [2/2]

impeller::Capabilities::Capabilities ( const Capabilities &  )

protecteddelete

Member Function Documentation

GetDefaultColorFormat()

virtual PixelFormat impeller::Capabilities::GetDefaultColorFormat ( ) const

pure virtual

Returns a supported PixelFormat for textures that store 4-channel colors (red/green/blue/alpha).

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

GetDefaultDepthStencilFormat()

virtual PixelFormat impeller::Capabilities::GetDefaultDepthStencilFormat ( ) const

pure virtual

Returns a supported PixelFormat for textures that store both a stencil and depth component. This will never return a depth-only or stencil-only texture. Returns PixelFormat::kUnknown if no suitable depth+stencil format was found.

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

GetDefaultGlyphAtlasFormat()

virtual PixelFormat impeller::Capabilities::GetDefaultGlyphAtlasFormat ( ) const

pure virtual

Returns the default pixel format for the alpha bitmap glyph atlas.

   Some backends may use Red channel while others use grey. This
   should not have any impact 

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

GetDefaultStencilFormat()

virtual PixelFormat impeller::Capabilities::GetDefaultStencilFormat ( ) const

pure virtual

Returns a supported PixelFormat for textures that store stencil information. May include a depth channel if a stencil-only format is not available.

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

operator=()

Capabilities & impeller::Capabilities::operator= ( const Capabilities &  )

protecteddelete

SupportsBufferToTextureBlits()

virtual bool impeller::Capabilities::SupportsBufferToTextureBlits ( ) const

pure virtual

Whether the context backend supports blitting from a given DeviceBuffer view to a texture region (via the relevant BlitPass::AddCopy overloads).

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

SupportsCompute()

virtual bool impeller::Capabilities::SupportsCompute ( ) const

pure virtual

Whether the context backend supports ComputePass.

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

SupportsComputeSubgroups()

virtual bool impeller::Capabilities::SupportsComputeSubgroups ( ) const

pure virtual

Whether the context backend supports configuring ComputePass command subgroups.

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

SupportsDecalSamplerAddressMode()

virtual bool impeller::Capabilities::SupportsDecalSamplerAddressMode ( ) const

pure virtual

Whether the context backend supports SamplerAddressMode::Decal.

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

SupportsDeviceTransientTextures()

virtual bool impeller::Capabilities::SupportsDeviceTransientTextures ( ) const

pure virtual

Whether the context backend supports allocating StorageMode::kDeviceTransient (aka "memoryless") textures, which are temporary textures kept in tile memory for the duration of the RenderPass it's attached to.

This feature is especially useful for MSAA and stencils.

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

SupportsFramebufferFetch()

virtual bool impeller::Capabilities::SupportsFramebufferFetch ( ) const

pure virtual

Whether the context backend is able to support pipelines with shaders that read from the framebuffer (i.e. pixels that have been written by previous draw calls in the current render pass).

Example of reading from the first color attachment in a GLSL shader: ``` uniform subpassInput subpass_input;

out vec4 frag_color;

void main() { vec4 color = subpassLoad(subpass_input); // Invert the colors drawn to the framebuffer. frag_color = vec4(vec3(1) - color.rgb, color.a); } ```

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

SupportsImplicitResolvingMSAA()

virtual bool impeller::Capabilities::SupportsImplicitResolvingMSAA ( ) const

pure virtual

Whether the context backend supports multisampled rendering to the on-screen surface without requiring an explicit resolve of the MSAA color attachment.

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

SupportsOffscreenMSAA()

virtual bool impeller::Capabilities::SupportsOffscreenMSAA ( ) const

pure virtual

Whether the context backend supports attaching offscreen MSAA color/stencil textures.

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

SupportsReadFromResolve()

virtual bool impeller::Capabilities::SupportsReadFromResolve ( ) const

pure virtual

Whether the context backend supports binding the current RenderPass attachments. This is supported if the backend can guarantee that attachment textures will not be mutated until the render pass has fully completed.

This is possible because many mobile graphics cards track RenderPass attachment state in intermediary tile memory prior to Storing the pass in the heap allocated attachments on DRAM. Metal's hazard tracking and Vulkan's barriers are granular enough to allow for safely accessing attachment textures prior to storage in the same RenderPass.

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

SupportsSSBO()

virtual bool impeller::Capabilities::SupportsSSBO ( ) const

pure virtual

Whether the context backend supports binding Shader Storage Buffer Objects (SSBOs) to pipelines.

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

SupportsTextureToTextureBlits()

virtual bool impeller::Capabilities::SupportsTextureToTextureBlits ( ) const

pure virtual

Whether the context backend supports blitting from one texture region to another texture region (via the relevant BlitPass::AddCopy overloads).

Implemented in impeller::CapabilitiesGLES, impeller::CapabilitiesVK, and impeller::StandardCapabilities.

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

• impeller/renderer/capabilities.h
• impeller/renderer/capabilities.cc