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	IsES () const
	Whether this is an ES GL variant or (if false) desktop GL.
bool	SupportsFramebufferRenderMipmap () const override
bool	SupportsTextureMaxLevel () const
	Whether GL_TEXTURE_MAX_LEVEL can be set to bound a texture's sampled mip range. Core on desktop GL and ES 3.0+; on ES 2.0 it requires the GL_APPLE_texture_max_level extension. Without it a partial mip chain cannot be made mipmap complete and samples as black.
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	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.
bool	SupportsTriangleFan () const override
	Whether the primitive type TriangleFan is supported by the backend.
bool	SupportsPrimitiveRestart () const override
	Whether primitive restart is supported.
bool	Supports32BitPrimitiveIndices () const override
	Whether 32-bit values are supported in index buffers used to draw primitives.
bool	SupportsManuallyMippedTextures () const override
	Whether a texture whose mip levels were uploaded by hand (rather than produced by BlitPass::GenerateMipmap) samples with correct per-level selection. True everywhere except OpenGL ES 2.0 without GL_APPLE_texture_max_level, where the sampled mip range cannot be bounded to the levels the texture declares.
bool	SupportsExtendedRangeFormats () const override
	Whether the XR formats are supported on this device.
bool	SupportsTextureCompression (CompressedTextureFamily family) const override
	Whether the given family of block-compressed texture formats is supported by this device. Compressed formats are sample-only and their support varies by hardware, so callers must check this before allocating a compressed texture.
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.
ISize	GetMaximumRenderPassAttachmentSize () const override
	Return the maximum size of a render pass attachment.
uint32_t	GetMaxSamplerAnisotropy () const override
	The maximum anisotropy clamp supported by device samplers.
size_t	GetMinimumUniformAlignment () const override
	The minimum alignment of uniform value offsets in bytes.
bool	NeedsPartitionedHostBuffer () const override
	Whether the host buffer should use separate device buffers for indexes from other data.
Public Member Functions inherited from impeller::Capabilities
virtual	~Capabilities ()
virtual size_t	GetMinimumStorageBufferAlignment () const
	The minimum alignment of storage buffer value offsets in bytes.

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 64 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;
  }
 
  if (desc->GetGlVersion().major_version >= 3) {
    supports_texture_to_texture_blits_ = true;
  }
 
  supports_framebuffer_fetch_ = desc->HasExtension(kFramebufferFetchExt);
 
  if (desc->HasExtension(kTextureBorderClampExt) ||
      desc->HasExtension(kNvidiaTextureBorderClampExt)) {
    supports_decal_sampler_address_mode_ = true;
  }
 
  if (desc->HasExtension(kElementIndexUintExt)) {
    supports_32bit_primitive_indices_ = true;
  }
 
  if (desc->HasExtension(kMultisampledRenderToTextureExt)) {
    supports_implicit_msaa_ = true;
 
    if (desc->HasExtension(kMultisampledRenderToTexture2Ext)) {
      // 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;
    }
  } else if (desc->GetGlVersion().major_version >= 3 && desc->IsES()) {
    GLint value = 0;
    gl.GetIntegerv(GL_MAX_SAMPLES, &value);
    supports_offscreen_msaa_ = value >= 4;
  }
  is_es_ = desc->IsES();
  is_angle_ = desc->IsANGLE();
 
  // ETC2 and EAC are mandatory in OpenGL ES 3.0. BC and ASTC are gated behind
  // extensions and are not present on most mobile or desktop GLES. The whole BC
  // family requires S3TC, RGTC, and BPTC to all be present.
  supports_texture_compression_bc_ =
      desc->HasExtension(kTextureCompressionS3TCExt) &&
      desc->HasExtension(kTextureCompressionRGTCExt) &&
      desc->HasExtension(kTextureCompressionBPTCExt);
  // Either extension is sufficient: both expose the same LDR 2D ASTC internal
  // formats this backend uses. KHR is the common one; OES is a superset that
  // also adds HDR and 3D, which are not used here.
  supports_texture_compression_astc_ =
      desc->HasExtension(kTextureCompressionAstcLdrExt) ||
      desc->HasExtension(kTextureCompressionAstcOesExt);
  // HDR reuses the same internal formats as LDR, gated by a separate extension.
  // The OES extension is a superset that also covers HDR.
  supports_texture_compression_astc_hdr_ =
      desc->HasExtension(kTextureCompressionAstcHdrExt) ||
      desc->HasExtension(kTextureCompressionAstcOesExt);
  supports_texture_compression_etc2_ =
      desc->IsES() && desc->GetGlVersion().major_version >= 3;
 
  // GL_TEXTURE_MAX_LEVEL is core on desktop GL and ES 3.0+, and available on
  // ES 2.0 through GL_APPLE_texture_max_level.
  supports_texture_max_level_ = !desc->IsES() ||
                                desc->GetGlVersion().major_version >= 3 ||
                                desc->HasExtension(kAppleTextureMaxLevelExt);
 
  // Anisotropic filtering is not part of any core GL or GLES version; it is
  // always gated on GL_EXT_texture_filter_anisotropic. The query and the
  // texture parameter are applied with core ES 2.0 entry points (GetFloatv
  // and TexParameterfv), so only the extension check is needed here.
  if (desc->HasExtension(kTextureFilterAnisotropicExt)) {
    GLfloat value = 1.0f;
    gl.GetFloatv(IMPELLER_GL_MAX_TEXTURE_MAX_ANISOTROPY, &value);
    // The extension guarantees a maximum of at least 2. The limit is a float
    // but is always an integer in practice, so floor it.
    max_sampler_anisotropy_ = static_cast<uint32_t>(std::max(value, 2.0f));
  }
}

References impeller::ProcTableGLES::GetDescription(), IMPELLER_GL_MAX_TEXTURE_MAX_ANISOTROPY, impeller::kA8UNormInt, impeller::kAppleTextureMaxLevelExt, impeller::kElementIndexUintExt, impeller::kFramebufferFetchExt, impeller::kMultisampledRenderToTexture2Ext, impeller::kMultisampledRenderToTextureExt, impeller::kNvidiaTextureBorderClampExt, impeller::kR8UNormInt, impeller::kTextureBorderClampExt, impeller::kTextureCompressionAstcHdrExt, impeller::kTextureCompressionAstcLdrExt, impeller::kTextureCompressionAstcOesExt, impeller::kTextureCompressionBPTCExt, impeller::kTextureCompressionRGTCExt, impeller::kTextureCompressionS3TCExt, impeller::kTextureFilterAnisotropicExt, max_combined_texture_image_units, max_cube_map_texture_size, max_fragment_uniform_vectors, max_renderbuffer_size, max_texture_image_units, max_texture_size, max_varying_vectors, max_vertex_attribs, max_vertex_texture_image_units, max_vertex_uniform_vectors, max_viewport_dims, num_compressed_texture_formats, num_shader_binary_formats, and value.

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 298 of file capabilities_gles.cc.

                                                          {
  return PixelFormat::kR8G8B8A8UNormInt;
}

References impeller::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 306 of file capabilities_gles.cc.

                                                                 {
  return PixelFormat::kD24UnormS8Uint;
}

References impeller::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 348 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 302 of file capabilities_gles.cc.

                                                            {
  return PixelFormat::kS8UInt;
}

References impeller::kS8UInt.

GetMaximumRenderPassAttachmentSize()

ISize impeller::CapabilitiesGLES::GetMaximumRenderPassAttachmentSize ( ) const

overridevirtual

Return the maximum size of a render pass attachment.

Note that this may be smaller than the maximum allocatable texture size.

Implements impeller::Capabilities.

Definition at line 352 of file capabilities_gles.cc.

                                                                 {
  return max_texture_size;
}

References max_texture_size.

GetMaxSamplerAnisotropy()

uint32_t impeller::CapabilitiesGLES::GetMaxSamplerAnisotropy ( ) const

overridevirtual

The maximum anisotropy clamp supported by device samplers.

   A value of 1 means anisotropic filtering is not supported.
   Sampler descriptors with `max_anisotropy` greater than this value
   are clamped to it. 

Implements impeller::Capabilities.

Definition at line 356 of file capabilities_gles.cc.

                                                         {
  return max_sampler_anisotropy_;
}

GetMaxTextureUnits()

size_t impeller::CapabilitiesGLES::GetMaxTextureUnits

(

ShaderStage

stage

)

const

Definition at line 241 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();
}

References FML_UNREACHABLE, impeller::kCompute, impeller::kFragment, impeller::kUnknown, impeller::kVertex, max_texture_image_units, and max_vertex_texture_image_units.

GetMinimumUniformAlignment()

size_t impeller::CapabilitiesGLES::GetMinimumUniformAlignment ( ) const

overridevirtual

The minimum alignment of uniform value offsets in bytes.

Implements impeller::Capabilities.

Definition at line 360 of file capabilities_gles.cc.

                                                          {
  return 256;
}

IsANGLE()

bool impeller::CapabilitiesGLES::IsANGLE

(

)

const

Definition at line 310 of file capabilities_gles.cc.

                                     {
  return is_angle_;
}

IsES()

bool impeller::CapabilitiesGLES::IsES

(

)

const

Whether this is an ES GL variant or (if false) desktop GL.

Definition at line 223 of file capabilities_gles.cc.

                                  {
  return is_es_;
}

NeedsPartitionedHostBuffer()

bool impeller::CapabilitiesGLES::NeedsPartitionedHostBuffer ( ) const

overridevirtual

Whether the host buffer should use separate device buffers for indexes from other data.

Implements impeller::Capabilities.

Definition at line 364 of file capabilities_gles.cc.

                                                        {
#ifdef FML_OS_EMSCRIPTEN
  // WebGL has special requirements here to keep indexes and other data
  // separate. See
  // https://registry.khronos.org/webgl/specs/latest/2.0/#BUFFER_OBJECT_BINDING
  return true;
#else
  return false;
#endif
}

operator=() [1/2]

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

delete

operator=() [2/2]

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

delete

Supports32BitPrimitiveIndices()

bool impeller::CapabilitiesGLES::Supports32BitPrimitiveIndices ( ) const

overridevirtual

Whether 32-bit values are supported in index buffers used to draw primitives.

Implements impeller::Capabilities.

Definition at line 318 of file capabilities_gles.cc.

                                                           {
  return supports_32bit_primitive_indices_;
}

SupportsCompute()

bool impeller::CapabilitiesGLES::SupportsCompute ( ) const

overridevirtual

Whether the context backend supports ComputePass.

Implements impeller::Capabilities.

Definition at line 274 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 278 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 286 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 290 of file capabilities_gles.cc.

                                                             {
  return false;
}

SupportsExtendedRangeFormats()

bool impeller::CapabilitiesGLES::SupportsExtendedRangeFormats ( ) const

overridevirtual

Whether the XR formats are supported on this device.

This is only ever true for iOS and macOS devices. We may need to revisit this API when approaching wide gamut rendering for Vulkan and GLES.

Implements impeller::Capabilities.

Definition at line 329 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 270 of file capabilities_gles.cc.

                                                      {
  return supports_framebuffer_fetch_;
}

SupportsFramebufferRenderMipmap()

bool impeller::CapabilitiesGLES::SupportsFramebufferRenderMipmap ( ) const

overridevirtual

Always false. Rendering into a non-zero mip level is not yet implemented on the GLES backend; see SupportsFramebufferRenderMipmap in the .cc file.

Implements impeller::Capabilities.

Definition at line 227 of file capabilities_gles.cc.

                                                             {
  // Rendering into a non-zero mip level is not yet supported on the GLES
  // backend. The texture storage path allocates levels with mutable, lazily
  // allocated glTexImage2D storage, which yields an incomplete framebuffer
  // when a non-base mip level is attached. Until that is reworked, do not
  // advertise the capability so callers fall back instead of failing to
  // create the framebuffer. Rendering into a cube map face is unaffected.
  return false;
}

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 258 of file capabilities_gles.cc.

                                                           {
  return supports_implicit_msaa_;
}

SupportsManuallyMippedTextures()

bool impeller::CapabilitiesGLES::SupportsManuallyMippedTextures ( ) const

overridevirtual

Whether a texture whose mip levels were uploaded by hand (rather than produced by BlitPass::GenerateMipmap) samples with correct per-level selection. True everywhere except OpenGL ES 2.0 without GL_APPLE_texture_max_level, where the sampled mip range cannot be bounded to the levels the texture declares.

Implements impeller::Capabilities.

Definition at line 322 of file capabilities_gles.cc.

                                                            {
  // Without GL_TEXTURE_MAX_LEVEL the sampled mip range cannot be bounded to
  // the levels the texture declares, so a hand-uploaded chain is mipmap
  // incomplete and samples as black.
  return supports_texture_max_level_;
}

SupportsOffscreenMSAA()

bool impeller::CapabilitiesGLES::SupportsOffscreenMSAA ( ) const

overridevirtual

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

Implements impeller::Capabilities.

Definition at line 254 of file capabilities_gles.cc.

                                                   {
  return supports_offscreen_msaa_;
}

SupportsPrimitiveRestart()

bool impeller::CapabilitiesGLES::SupportsPrimitiveRestart ( ) const

overridevirtual

Whether primitive restart is supported.

Implements impeller::Capabilities.

Definition at line 314 of file capabilities_gles.cc.

                                                      {
  return false;
}

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 282 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 262 of file capabilities_gles.cc.

                                          {
  return false;
}

SupportsTextureCompression()

bool impeller::CapabilitiesGLES::SupportsTextureCompression ( CompressedTextureFamily  family ) const

overridevirtual

Whether the given family of block-compressed texture formats is supported by this device. Compressed formats are sample-only and their support varies by hardware, so callers must check this before allocating a compressed texture.

Implements impeller::Capabilities.

Definition at line 333 of file capabilities_gles.cc.

                                          {
  switch (family) {
    case CompressedTextureFamily::kBC:
      return supports_texture_compression_bc_;
    case CompressedTextureFamily::kETC2:
      return supports_texture_compression_etc2_;
    case CompressedTextureFamily::kASTC:
      return supports_texture_compression_astc_;
    case CompressedTextureFamily::kASTCHDR:
      return supports_texture_compression_astc_hdr_;
  }
  return false;
}

References impeller::kASTC, impeller::kASTCHDR, impeller::kBC, and impeller::kETC2.

SupportsTextureMaxLevel()

bool impeller::CapabilitiesGLES::SupportsTextureMaxLevel

(

)

const

Whether GL_TEXTURE_MAX_LEVEL can be set to bound a texture's sampled mip range. Core on desktop GL and ES 3.0+; on ES 2.0 it requires the GL_APPLE_texture_max_level extension. Without it a partial mip chain cannot be made mipmap complete and samples as black.

Definition at line 237 of file capabilities_gles.cc.

                                                     {
  return supports_texture_max_level_;
}

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 266 of file capabilities_gles.cc.

                                                           {
  return supports_texture_to_texture_blits_;
}

SupportsTriangleFan()

bool impeller::CapabilitiesGLES::SupportsTriangleFan ( ) const

overridevirtual

Whether the primitive type TriangleFan is supported by the backend.

Implements impeller::Capabilities.

Definition at line 294 of file capabilities_gles.cc.

                                                 {
  return true;
}

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.

Referenced by CapabilitiesGLES().

max_cube_map_texture_size

size_t impeller::CapabilitiesGLES::max_cube_map_texture_size = 16

Definition at line 41 of file capabilities_gles.h.

Referenced by CapabilitiesGLES().

max_fragment_uniform_vectors

size_t impeller::CapabilitiesGLES::max_fragment_uniform_vectors = 16

Definition at line 44 of file capabilities_gles.h.

Referenced by CapabilitiesGLES().

max_renderbuffer_size

size_t impeller::CapabilitiesGLES::max_renderbuffer_size = 1

Definition at line 47 of file capabilities_gles.h.

Referenced by CapabilitiesGLES().

max_texture_image_units

size_t impeller::CapabilitiesGLES::max_texture_image_units = 8

Definition at line 50 of file capabilities_gles.h.

Referenced by CapabilitiesGLES(), and GetMaxTextureUnits().

max_texture_size

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

Definition at line 53 of file capabilities_gles.h.

{64, 64};

Referenced by CapabilitiesGLES(), and GetMaximumRenderPassAttachmentSize().

max_varying_vectors

size_t impeller::CapabilitiesGLES::max_varying_vectors = 8

Definition at line 56 of file capabilities_gles.h.

Referenced by CapabilitiesGLES().

max_vertex_attribs

size_t impeller::CapabilitiesGLES::max_vertex_attribs = 8

Definition at line 59 of file capabilities_gles.h.

Referenced by CapabilitiesGLES().

max_vertex_texture_image_units

size_t impeller::CapabilitiesGLES::max_vertex_texture_image_units = 0

Definition at line 62 of file capabilities_gles.h.

Referenced by CapabilitiesGLES(), and GetMaxTextureUnits().

max_vertex_uniform_vectors

size_t impeller::CapabilitiesGLES::max_vertex_uniform_vectors = 128

Definition at line 65 of file capabilities_gles.h.

Referenced by CapabilitiesGLES().

max_viewport_dims

ISize impeller::CapabilitiesGLES::max_viewport_dims

Definition at line 68 of file capabilities_gles.h.

Referenced by CapabilitiesGLES().

num_compressed_texture_formats

size_t impeller::CapabilitiesGLES::num_compressed_texture_formats = 0

Definition at line 71 of file capabilities_gles.h.

Referenced by CapabilitiesGLES().

num_shader_binary_formats

size_t impeller::CapabilitiesGLES::num_shader_binary_formats = 0

Definition at line 74 of file capabilities_gles.h.

Referenced by CapabilitiesGLES().

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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