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. More...

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;
   }