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UnrealEngine/Engine/Source/ThirdParty/MaterialX/MaterialX-1.38.10/source/MaterialXGenShader/ShaderNodeImpl.h
2025-05-18 13:04:45 +08:00

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//
// Copyright Contributors to the MaterialX Project
// SPDX-License-Identifier: Apache-2.0
//
#ifndef MATERIALX_SHADERNODEIMPL_H
#define MATERIALX_SHADERNODEIMPL_H
/// @file
/// Base class for shader node implementations
#include <MaterialXGenShader/Library.h>
#include <MaterialXGenShader/Export.h>
#include <MaterialXCore/Util.h>
MATERIALX_NAMESPACE_BEGIN
class InterfaceElement;
class Node;
using ShaderGraphInputSocket = ShaderOutput;
/// Shared pointer to a ShaderNodeImpl
using ShaderNodeImplPtr = shared_ptr<class ShaderNodeImpl>;
/// @class ShaderNodeImpl
/// Class handling the shader generation implementation for a node.
/// Responsible for emitting the function definition and function call
/// that is the node implementation.
class MX_GENSHADER_API ShaderNodeImpl
{
public:
virtual ~ShaderNodeImpl() { }
/// Return an identifier for the target used by this implementation.
/// By default an empty string is returned, representing all targets.
/// Only override this method if your derived node implementation class
/// is for a specific target.
virtual const string& getTarget() const { return EMPTY_STRING; }
/// Initialize with the given implementation element.
/// Initialization must set the name and hash for the implementation,
/// as well as any other data needed to emit code for the node.
virtual void initialize(const InterfaceElement& element, GenContext& context);
/// Return the name of this implementation.
const string& getName() const
{
return _name;
}
/// Return a hash for this implementation.
/// The hash should correspond to the function signature generated for the node,
/// and can be used to compare implementations, e.g. to query if an identical
/// function has already been emitted during shader generation.
size_t getHash() const
{
return _hash;
}
/// Add additional inputs on a node.
virtual void addInputs(ShaderNode& node, GenContext& context) const;
/// Set values for additional inputs on a node.
virtual void setValues(const Node& node, ShaderNode& shaderNode, GenContext& context) const;
/// Add additional classifications on a node.
virtual void addClassification(ShaderNode& node) const;
/// Create shader variables needed for the implementation of this node (e.g. uniforms, inputs and outputs).
/// Used if the node requires input data from the application.
virtual void createVariables(const ShaderNode& node, GenContext& context, Shader& shader) const;
/// Emit function definition for the given node instance.
virtual void emitFunctionDefinition(const ShaderNode& node, GenContext& context, ShaderStage& stage) const;
/// Emit the function call or inline source code for given node instance in the given context.
virtual void emitFunctionCall(const ShaderNode& node, GenContext& context, ShaderStage& stage) const;
/// Emit declaration and initialization of output variables to use in a function call.
virtual void emitOutputVariables(const ShaderNode& node, GenContext& context, ShaderStage& stage) const;
/// Return a pointer to the graph if this implementation is using a graph,
/// or returns nullptr otherwise.
virtual ShaderGraph* getGraph() const;
/// Returns true if an input is editable by users.
/// Editable inputs are allowed to be published as shader uniforms
/// and hence must be presentable in a user interface.
/// By default all inputs are considered to be editable.
virtual bool isEditable(const ShaderInput& /*input*/) const
{
return true;
}
/// Returns true if a graph input is accessible by users.
/// Accessible inputs are allowed to be published as shader uniforms
/// and hence must be presentable in a user interface.
/// By default all graph inputs are considered to be acessible.
virtual bool isEditable(const ShaderGraphInputSocket& /*input*/) const
{
return true;
}
protected:
/// Protected constructor
ShaderNodeImpl();
protected:
string _name;
size_t _hash;
};
/// A no operation node, to be used for organizational nodes that has no code to execute.
class MX_GENSHADER_API NopNode : public ShaderNodeImpl
{
public:
static ShaderNodeImplPtr create();
};
MATERIALX_NAMESPACE_END
#endif