impeller::CapabilitiesGLES Class Reference

The Vulkan layers and extensions wrangler. More...

#include <capabilities_gles.h>

Inheritance diagram for impeller::CapabilitiesGLES:

Public Member Functions
	CapabilitiesGLES (const ProcTableGLES &gl)
	CapabilitiesGLES (const CapabilitiesGLES &)=delete
	CapabilitiesGLES (CapabilitiesGLES &&)=delete
CapabilitiesGLES &	operator= (const CapabilitiesGLES &)=delete
CapabilitiesGLES &	operator= (CapabilitiesGLES &&)=delete
size_t	GetMaxTextureUnits (ShaderStage stage) const
bool	IsANGLE () const
bool	SupportsOffscreenMSAA () const override
	Whether the context backend supports attaching offscreen MSAA color/stencil textures.
bool	SupportsImplicitResolvingMSAA () const override
	Whether the context backend supports multisampled rendering to the on-screen surface without requiring an explicit resolve of the MSAA color attachment.
bool	SupportsSSBO () const override
	Whether the context backend supports binding Shader Storage Buffer Objects (SSBOs) to pipelines.
bool	SupportsBufferToTextureBlits () const override
	Whether the context backend supports blitting from a given DeviceBuffer view to a texture region (via the relevant BlitPass::AddCopy overloads).
bool	SupportsTextureToTextureBlits () const override
	Whether the context backend supports blitting from one texture region to another texture region (via the relevant BlitPass::AddCopy overloads).
bool	SupportsFramebufferFetch () const override
	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).
bool	SupportsCompute () const override
	Whether the context backend supports ComputePass.
bool	SupportsComputeSubgroups () const override
	Whether the context backend supports configuring ComputePass command subgroups.
bool	SupportsReadFromResolve () const override
	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.
bool	SupportsDecalSamplerAddressMode () const override
	Whether the context backend supports SamplerAddressMode::Decal.
bool	SupportsDeviceTransientTextures () const override
	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.
PixelFormat	GetDefaultColorFormat () const override
	Returns a supported PixelFormat for textures that store 4-channel colors (red/green/blue/alpha).
PixelFormat	GetDefaultStencilFormat () const override
	Returns a supported PixelFormat for textures that store stencil information. May include a depth channel if a stencil-only format is not available.
PixelFormat	GetDefaultDepthStencilFormat () const override
	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.
PixelFormat	GetDefaultGlyphAtlasFormat () const override
	Returns the default pixel format for the alpha bitmap glyph atlas.
Public Member Functions inherited from impeller::Capabilities
virtual	~Capabilities ()

Public Attributes
size_t	max_combined_texture_image_units = 8
size_t	max_cube_map_texture_size = 16
size_t	max_fragment_uniform_vectors = 16
size_t	max_renderbuffer_size = 1
size_t	max_texture_image_units = 8
ISize	max_texture_size = ISize{64, 64}
size_t	max_varying_vectors = 8
size_t	max_vertex_attribs = 8
size_t	max_vertex_texture_image_units = 0
size_t	max_vertex_uniform_vectors = 128
ISize	max_viewport_dims
size_t	num_compressed_texture_formats = 0
size_t	num_shader_binary_formats = 0

Additional Inherited Members
Static Public Member Functions inherited from impeller::BackendCast< CapabilitiesGLES, Capabilities >
static CapabilitiesGLES &	Cast (Capabilities &base)
static const CapabilitiesGLES &	Cast (const Capabilities &base)
static CapabilitiesGLES *	Cast (Capabilities *base)
static const CapabilitiesGLES *	Cast (const Capabilities *base)
Protected Member Functions inherited from impeller::Capabilities
	Capabilities ()
	Capabilities (const Capabilities &)=delete
Capabilities &	operator= (const Capabilities &)=delete

Detailed Description

The Vulkan layers and extensions wrangler.

Definition at line 23 of file capabilities_gles.h.

Constructor & Destructor Documentation

CapabilitiesGLES() [1/3]

impeller::CapabilitiesGLES::CapabilitiesGLES ( const ProcTableGLES &  gl )

explicit

Definition at line 25 of file capabilities_gles.cc.

                                                          {
  {
    GLint value = 0;
    gl.GetIntegerv(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS, &value);
    max_combined_texture_image_units = value;
  }
 
  {
    GLint value = 0;
    gl.GetIntegerv(GL_MAX_CUBE_MAP_TEXTURE_SIZE, &value);
    max_cube_map_texture_size = value;
  }
 
  auto const desc = gl.GetDescription();
 
  if (desc->IsES()) {
    GLint value = 0;
    gl.GetIntegerv(GL_MAX_FRAGMENT_UNIFORM_VECTORS, &value);
    max_fragment_uniform_vectors = value;
  }
 
  {
    GLint value = 0;
    gl.GetIntegerv(GL_MAX_RENDERBUFFER_SIZE, &value);
    max_renderbuffer_size = value;
  }
 
  {
    GLint value = 0;
    gl.GetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &value);
    max_texture_image_units = value;
  }
 
  {
    GLint value = 0;
    gl.GetIntegerv(GL_MAX_TEXTURE_SIZE, &value);
    max_texture_size = ISize{value, value};
  }
 
  if (desc->IsES()) {
    GLint value = 0;
    gl.GetIntegerv(GL_MAX_VARYING_VECTORS, &value);
    max_varying_vectors = value;
  }
 
  {
    GLint value = 0;
    gl.GetIntegerv(GL_MAX_VERTEX_ATTRIBS, &value);
    max_vertex_attribs = value;
  }
 
  {
    GLint value = 0;
    gl.GetIntegerv(GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS, &value);
    max_vertex_texture_image_units = value;
  }
 
  if (desc->IsES()) {
    GLint value = 0;
    gl.GetIntegerv(GL_MAX_VERTEX_UNIFORM_VECTORS, &value);
    max_vertex_uniform_vectors = value;
  }
 
  {
    GLint values[2] = {};
    gl.GetIntegerv(GL_MAX_VIEWPORT_DIMS, values);
    max_viewport_dims = ISize{values[0], values[1]};
  }
 
  {
    GLint value = 0;
    gl.GetIntegerv(GL_NUM_COMPRESSED_TEXTURE_FORMATS, &value);
    num_compressed_texture_formats = value;
  }
 
  if (desc->IsES()) {
    GLint value = 0;
    gl.GetIntegerv(GL_NUM_SHADER_BINARY_FORMATS, &value);
    num_shader_binary_formats = value;
  }
 
  if (desc->IsES()) {
    default_glyph_atlas_format_ = PixelFormat::kA8UNormInt;
  } else {
    default_glyph_atlas_format_ = PixelFormat::kR8UNormInt;
  }
 
  supports_framebuffer_fetch_ = desc->HasExtension(kFramebufferFetchExt);
 
  if (desc->HasExtension(kTextureBorderClampExt) ||
      desc->HasExtension(kNvidiaTextureBorderClampExt)) {
    supports_decal_sampler_address_mode_ = true;
  }
 
  if (desc->HasExtension(kMultisampledRenderToTextureExt)) {
    supports_implicit_msaa_ = true;
 
    // We hard-code 4x MSAA, so let's make sure it's supported.
    GLint value = 0;
    gl.GetIntegerv(GL_MAX_SAMPLES_EXT, &value);
    supports_offscreen_msaa_ = value >= 4;
  }
 
  is_angle_ = desc->IsANGLE();
}

CapabilitiesGLES() [2/3]

impeller::CapabilitiesGLES::CapabilitiesGLES ( const CapabilitiesGLES &  )

delete

CapabilitiesGLES() [3/3]

impeller::CapabilitiesGLES::CapabilitiesGLES ( CapabilitiesGLES &&  )

delete

Member Function Documentation

GetDefaultColorFormat()

PixelFormat impeller::CapabilitiesGLES::GetDefaultColorFormat ( ) const

overridevirtual

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

Implements impeller::Capabilities.

Definition at line 188 of file capabilities_gles.cc.

                                                          {
  return PixelFormat::kR8G8B8A8UNormInt;
}

GetDefaultDepthStencilFormat()

PixelFormat impeller::CapabilitiesGLES::GetDefaultDepthStencilFormat ( ) const

overridevirtual

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.

Implements impeller::Capabilities.

Definition at line 196 of file capabilities_gles.cc.

                                                                 {
  return PixelFormat::kD24UnormS8Uint;
}

GetDefaultGlyphAtlasFormat()

PixelFormat impeller::CapabilitiesGLES::GetDefaultGlyphAtlasFormat ( ) const

overridevirtual

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 

Implements impeller::Capabilities.

Definition at line 204 of file capabilities_gles.cc.

                                                               {
  return default_glyph_atlas_format_;
}

GetDefaultStencilFormat()

PixelFormat impeller::CapabilitiesGLES::GetDefaultStencilFormat ( ) const

overridevirtual

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

Implements impeller::Capabilities.

Definition at line 192 of file capabilities_gles.cc.

                                                            {
  return PixelFormat::kS8UInt;
}

GetMaxTextureUnits()

size_t impeller::CapabilitiesGLES::GetMaxTextureUnits

(

ShaderStage

stage

)

const

Definition at line 131 of file capabilities_gles.cc.

                                                                   {
  switch (stage) {
    case ShaderStage::kVertex:
      return max_vertex_texture_image_units;
    case ShaderStage::kFragment:
      return max_texture_image_units;
    case ShaderStage::kUnknown:
    case ShaderStage::kCompute:
      return 0u;
  }
  FML_UNREACHABLE();
}

IsANGLE()

bool impeller::CapabilitiesGLES::IsANGLE

(

)

const

Definition at line 200 of file capabilities_gles.cc.

                                     {
  return is_angle_;
}

operator=() [1/2]

CapabilitiesGLES & impeller::CapabilitiesGLES::operator= ( CapabilitiesGLES &&  )

delete

operator=() [2/2]

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

delete

SupportsBufferToTextureBlits()

bool impeller::CapabilitiesGLES::SupportsBufferToTextureBlits ( ) const

overridevirtual

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

Implements impeller::Capabilities.

Definition at line 156 of file capabilities_gles.cc.

                                                          {
  return false;
}

SupportsCompute()

bool impeller::CapabilitiesGLES::SupportsCompute ( ) const

overridevirtual

Whether the context backend supports ComputePass.

Implements impeller::Capabilities.

Definition at line 168 of file capabilities_gles.cc.

                                             {
  return false;
}

SupportsComputeSubgroups()

bool impeller::CapabilitiesGLES::SupportsComputeSubgroups ( ) const

overridevirtual

Whether the context backend supports configuring ComputePass command subgroups.

Implements impeller::Capabilities.

Definition at line 172 of file capabilities_gles.cc.

                                                      {
  return false;
}

SupportsDecalSamplerAddressMode()

bool impeller::CapabilitiesGLES::SupportsDecalSamplerAddressMode ( ) const

overridevirtual

Whether the context backend supports SamplerAddressMode::Decal.

Implements impeller::Capabilities.

Definition at line 180 of file capabilities_gles.cc.

                                                             {
  return supports_decal_sampler_address_mode_;
}

SupportsDeviceTransientTextures()

bool impeller::CapabilitiesGLES::SupportsDeviceTransientTextures ( ) const

overridevirtual

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.

Implements impeller::Capabilities.

Definition at line 184 of file capabilities_gles.cc.

                                                             {
  return false;
}

SupportsFramebufferFetch()

bool impeller::CapabilitiesGLES::SupportsFramebufferFetch ( ) const

overridevirtual

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); } ```

Implements impeller::Capabilities.

Definition at line 164 of file capabilities_gles.cc.

                                                      {
  return supports_framebuffer_fetch_;
}

SupportsImplicitResolvingMSAA()

bool impeller::CapabilitiesGLES::SupportsImplicitResolvingMSAA ( ) const

overridevirtual

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

Implements impeller::Capabilities.

Definition at line 148 of file capabilities_gles.cc.

                                                           {
  return supports_implicit_msaa_;
}

SupportsOffscreenMSAA()

bool impeller::CapabilitiesGLES::SupportsOffscreenMSAA ( ) const

overridevirtual

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

Implements impeller::Capabilities.

Definition at line 144 of file capabilities_gles.cc.

                                                   {
  return supports_offscreen_msaa_;
}

SupportsReadFromResolve()

bool impeller::CapabilitiesGLES::SupportsReadFromResolve ( ) const

overridevirtual

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.

Implements impeller::Capabilities.

Definition at line 176 of file capabilities_gles.cc.

                                                     {
  return false;
}

SupportsSSBO()

bool impeller::CapabilitiesGLES::SupportsSSBO ( ) const

overridevirtual

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

Implements impeller::Capabilities.

Definition at line 152 of file capabilities_gles.cc.

                                          {
  return false;
}

SupportsTextureToTextureBlits()

bool impeller::CapabilitiesGLES::SupportsTextureToTextureBlits ( ) const

overridevirtual

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

Implements impeller::Capabilities.

Definition at line 160 of file capabilities_gles.cc.

                                                           {
  return false;
}

Member Data Documentation

max_combined_texture_image_units

size_t impeller::CapabilitiesGLES::max_combined_texture_image_units = 8

Definition at line 38 of file capabilities_gles.h.

max_cube_map_texture_size

size_t impeller::CapabilitiesGLES::max_cube_map_texture_size = 16

Definition at line 41 of file capabilities_gles.h.

max_fragment_uniform_vectors

size_t impeller::CapabilitiesGLES::max_fragment_uniform_vectors = 16

Definition at line 44 of file capabilities_gles.h.

max_renderbuffer_size

size_t impeller::CapabilitiesGLES::max_renderbuffer_size = 1

Definition at line 47 of file capabilities_gles.h.

max_texture_image_units

size_t impeller::CapabilitiesGLES::max_texture_image_units = 8

Definition at line 50 of file capabilities_gles.h.

max_texture_size

ISize impeller::CapabilitiesGLES::max_texture_size = ISize{64, 64}

Definition at line 53 of file capabilities_gles.h.

{64, 64};

max_varying_vectors

size_t impeller::CapabilitiesGLES::max_varying_vectors = 8

Definition at line 56 of file capabilities_gles.h.

max_vertex_attribs

size_t impeller::CapabilitiesGLES::max_vertex_attribs = 8

Definition at line 59 of file capabilities_gles.h.

max_vertex_texture_image_units

size_t impeller::CapabilitiesGLES::max_vertex_texture_image_units = 0

Definition at line 62 of file capabilities_gles.h.

max_vertex_uniform_vectors

size_t impeller::CapabilitiesGLES::max_vertex_uniform_vectors = 128

Definition at line 65 of file capabilities_gles.h.

max_viewport_dims

ISize impeller::CapabilitiesGLES::max_viewport_dims

Definition at line 68 of file capabilities_gles.h.

num_compressed_texture_formats

size_t impeller::CapabilitiesGLES::num_compressed_texture_formats = 0

Definition at line 71 of file capabilities_gles.h.

num_shader_binary_formats

size_t impeller::CapabilitiesGLES::num_shader_binary_formats = 0

Definition at line 74 of file capabilities_gles.h.

---

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

• impeller/renderer/backend/gles/capabilities_gles.h
• impeller/renderer/backend/gles/capabilities_gles.cc