An optional (but highly recommended) utility for creating pipelines from reflected shader information. More...

#include <pipeline_builder.h>

Public Types
using	VertexShader = VertexShader_

using	FragmentShader = FragmentShader_

Static Public Member Functions
static std::optional< PipelineDescriptor >	MakeDefaultPipelineDescriptor (const Context &context, const std::vector< Scalar > &constants={})
	Create a default pipeline descriptor using the combination reflected shader information. The descriptor can be configured further before a pipeline state object is created using it.

static bool	InitializePipelineDescriptorDefaults (const Context &context, PipelineDescriptor &desc)

Static Public Attributes
static constexpr size_t	kVertexBufferIndex

Detailed Description

template<class VertexShader_, class FragmentShader_>
struct impeller::PipelineBuilder< VertexShader_, FragmentShader_ >

An optional (but highly recommended) utility for creating pipelines from reflected shader information.

Template Parameters

VertexShader_	The reflected vertex shader information. Found in a generated header file called <shader_name>.vert.h.
FragmentShader_	The reflected fragment shader information. Found in a generated header file called <shader_name>.frag.h.

Definition at line 31 of file pipeline_builder.h.

Member Typedef Documentation

◆ FragmentShader

template<class VertexShader_ , class FragmentShader_ >

using impeller::PipelineBuilder< VertexShader_, FragmentShader_ >::FragmentShader = FragmentShader_

Definition at line 34 of file pipeline_builder.h.

◆ VertexShader

template<class VertexShader_ , class FragmentShader_ >

using impeller::PipelineBuilder< VertexShader_, FragmentShader_ >::VertexShader = VertexShader_

Definition at line 33 of file pipeline_builder.h.

Member Function Documentation

◆ InitializePipelineDescriptorDefaults()

template<class VertexShader_ , class FragmentShader_ >

static bool impeller::PipelineBuilder< VertexShader_, FragmentShader_ >::InitializePipelineDescriptorDefaults	(	const Context &	context,
		PipelineDescriptor &	desc
	)

inlinestatic

Definition at line 61 of file pipeline_builder.h.

                                {
    // Setup debug instrumentation.
    desc.SetLabel(std::format("{} Pipeline", FragmentShader::kLabel));
 
    // Resolve pipeline entrypoints.
    {
      auto vertex_function = context.GetShaderLibrary()->GetFunction(
          VertexShader::kEntrypointName, ShaderStage::kVertex);
      auto fragment_function = context.GetShaderLibrary()->GetFunction(
          FragmentShader::kEntrypointName, ShaderStage::kFragment);
 
      if (!vertex_function || !fragment_function) {
        VALIDATION_LOG << "Could not resolve pipeline entrypoint(s) '"
                       << VertexShader::kEntrypointName << "' and '"
                       << FragmentShader::kEntrypointName
                       << "' for pipeline named '" << VertexShader::kLabel
                       << "'.";
        return false;
      }
 
      desc.AddStageEntrypoint(std::move(vertex_function));
      desc.AddStageEntrypoint(std::move(fragment_function));
    }
 
    // Setup the vertex descriptor from reflected information.
    {
      auto vertex_descriptor = std::make_shared<VertexDescriptor>();
      vertex_descriptor->SetStageInputs(VertexShader::kAllShaderStageInputs,
                                        VertexShader::kInterleavedBufferLayout);
      vertex_descriptor->RegisterDescriptorSetLayouts(
          VertexShader::kDescriptorSetLayouts);
      vertex_descriptor->RegisterDescriptorSetLayouts(
          FragmentShader::kDescriptorSetLayouts);
      desc.SetVertexDescriptor(std::move(vertex_descriptor));
    }
 
    // Setup fragment shader output descriptions.
    {
      // Configure the sole color attachments pixel format. This is by
      // convention.
      ColorAttachmentDescriptor color0;
      color0.format = context.GetCapabilities()->GetDefaultColorFormat();
      color0.blending_enabled = true;
      desc.SetColorAttachmentDescriptor(0u, color0);
    }
 
    // Setup default depth buffer descriptions.
    {
      DepthAttachmentDescriptor depth0;
      depth0.depth_compare = CompareFunction::kAlways;
      desc.SetDepthStencilAttachmentDescriptor(depth0);
      desc.SetDepthPixelFormat(
          context.GetCapabilities()->GetDefaultDepthStencilFormat());
    }
 
    // Setup default stencil buffer descriptions.
    {
      StencilAttachmentDescriptor stencil0;
      stencil0.stencil_compare = CompareFunction::kEqual;
      desc.SetStencilAttachmentDescriptors(stencil0);
      desc.SetStencilPixelFormat(
          context.GetCapabilities()->GetDefaultDepthStencilFormat());
    }
 
    return true;
  }

References impeller::PipelineDescriptor::AddStageEntrypoint(), impeller::ColorAttachmentDescriptor::blending_enabled, impeller::DepthAttachmentDescriptor::depth_compare, impeller::ColorAttachmentDescriptor::format, impeller::Context::GetCapabilities(), impeller::Context::GetShaderLibrary(), impeller::kAlways, impeller::kEqual, impeller::kFragment, impeller::kVertex, impeller::PipelineDescriptor::SetColorAttachmentDescriptor(), impeller::PipelineDescriptor::SetDepthPixelFormat(), impeller::PipelineDescriptor::SetDepthStencilAttachmentDescriptor(), impeller::PipelineDescriptor::SetLabel(), impeller::PipelineDescriptor::SetStencilAttachmentDescriptors(), impeller::PipelineDescriptor::SetStencilPixelFormat(), impeller::PipelineDescriptor::SetVertexDescriptor(), impeller::StencilAttachmentDescriptor::stencil_compare, and VALIDATION_LOG.

◆ MakeDefaultPipelineDescriptor()

template<class VertexShader_ , class FragmentShader_ >

static std::optional< PipelineDescriptor > impeller::PipelineBuilder< VertexShader_, FragmentShader_ >::MakeDefaultPipelineDescriptor	(	const Context &	context,
		const std::vector< Scalar > &	constants = `{}`
	)

inlinestatic

Create a default pipeline descriptor using the combination reflected shader information. The descriptor can be configured further before a pipeline state object is created using it.

Parameters

[in] context The context

Returns: If the combination of reflected shader information is compatible and the requisite functions can be found in the context, a pipeline descriptor.

Definition at line 50 of file pipeline_builder.h.

                                           {}) {
    PipelineDescriptor desc;
    desc.SetSpecializationConstants(constants);
    if (InitializePipelineDescriptorDefaults(context, desc)) {
      return {std::move(desc)};
    }
    return std::nullopt;
  }