Util.h

//
// TM & (c) 2017 Lucasfilm Entertainment Company Ltd. and Lucasfilm Ltd.
// All rights reserved.  See LICENSE.txt for license.
//

#ifndef MATERIALX_SHADERGEN_UTIL_H
#define MATERIALX_SHADERGEN_UTIL_H

/// @file
/// Shader generation utility methods

#include <MaterialXGenShader/Export.h>

#include <MaterialXCore/Document.h>

#include <unordered_set>

MATERIALX_NAMESPACE_BEGIN

class ShaderGenerator;

/// Returns true if the given element is a surface shader with the potential
/// of being transparent. This can be used by HW shader generators to determine
/// if a shader will require transparency handling.
///
/// Note: This function will check some common cases for how a surface
/// shader can be transparent. It is not covering all possible cases for
/// how transparency can be done and target applications might need to do
/// additional checks to track transparency correctly. For example, custom
/// surface shader nodes implemented in source code will not be tracked by this
/// function and transprency for such nodes must be tracked separately by the
/// target application.
///
MX_GENSHADER_API bool isTransparentSurface(ElementPtr element, const string& target = EMPTY_STRING);

/// Maps a value to a four channel color if it is of the appropriate type.
/// Supported types include float, Vector2, Vector3, Vector4,
/// and Color4. If not mapping is possible the color value is
/// set to opaque black.
MX_GENSHADER_API void mapValueToColor(ConstValuePtr value, Color4& color);

/// Return whether a nodedef requires an implementation
MX_GENSHADER_API bool requiresImplementation(ConstNodeDefPtr nodeDef);

/// Determine if a given element requires shading / lighting for rendering
MX_GENSHADER_API bool elementRequiresShading(ConstTypedElementPtr element);

/// Find any material node elements which are renderable (have input shaders)
/// @param doc Document to examine
/// @param elements List of renderable elements (returned)
/// @param includeReferencedGraphs Whether to check for outputs on referenced graphs
/// @param processedSources List of elements examined. 
MX_GENSHADER_API void findRenderableMaterialNodes(ConstDocumentPtr doc,
                                                  vector<TypedElementPtr>& elements, 
                                                  bool includeReferencedGraphs,
                                                  std::unordered_set<ElementPtr>& processedSources);

/// Find any elements which may be renderable from within a document.
/// This includes all outputs on node graphs and shader references which are not
/// part of any included library. Light shaders are not considered to be renderable.
/// The option to include node graphs referened by shader references is disabled by default.
MX_GENSHADER_API void findRenderableElements(ConstDocumentPtr doc, vector<TypedElementPtr>& elements,
                                             bool includeReferencedGraphs = false);

/// Given a node input, return the corresponding input within its matching nodedef.
/// The optional target string can be used to guide the selection of nodedef declarations.
MX_GENSHADER_API InputPtr getNodeDefInput(InputPtr nodeInput, const string& target);

/// Perform token substitutions on the given source string, using the given substituation map.
/// Tokens are required to start with '$' and can only consist of alphanumeric characters.
/// The full token name, including '$' and all following alphanumeric character, will be replaced
/// by the corresponding string in the substitution map, if the token exists in the map.
MX_GENSHADER_API void tokenSubstitution(const StringMap& substitutions, string& source);

/// Compute the UDIM coordinates for a set of UDIM identifiers
/// @return List of UDIM coordinates
MX_GENSHADER_API vector<Vector2> getUdimCoordinates(const StringVec& udimIdentifiers);

/// Get the UV scale and offset to transform uv coordinates from UDIM uv space to
/// 0..1 space.
MX_GENSHADER_API void getUdimScaleAndOffset(const vector<Vector2>& udimCoordinates, Vector2& scaleUV, Vector2& offsetUV);

/// Determine whether the given output is directly connected to a node that
/// generates world-space coordinates (e.g. the "normalmap" node).
/// @param output Output to check
/// @return Return the node if found.
MX_GENSHADER_API NodePtr connectsToWorldSpaceNode(OutputPtr output);

/// Returns true if there is are any value elements with a given set of attributes either on the
/// starting node or any graph upsstream of that node.
/// @param output Starting node 
/// @param attributes Attributes to test for
MX_GENSHADER_API bool hasElementAttributes(OutputPtr output, const StringVec& attributes);

MATERIALX_NAMESPACE_END

#endif