xgenMR/XgHairUtil.h

// Copyright 2015 Autodesk, Inc.  All rights reserved.
//
// Use of this software is subject to the terms of the Autodesk 
// license agreement provided at the time of installation or download, 
// or which otherwise accompanies this software in either electronic 
// or hard copy form.

#ifndef __XGENHAIRUTIL_H__
#define __XGENHAIRUTIL_H__

#include <vector>
#include <shader.h>

namespace XGenMR
{

// All user data descriptions
// This is used at shader execution to query the index of a particular user data.
struct UserDataFormat
{
public:

    // Single User data definition
    struct Entry
    {
        Entry();
        Entry( const std::string& str, unsigned int offset, unsigned int numScalars );

        // Checks if name and size are valid.
        bool isValid() const;

        // We'll persist all the hair layout information in a custom user data, on the hair object
        void toString( std::string& out_str ) const;

        std::string m_name;
        unsigned int m_offset;
        unsigned int m_numScalars;
    };

    UserDataFormat();
    UserDataFormat( const char* str, size_t size );

    enum EType
    {
        eInvalid,
        eTexList,
        eInplace,
    };
    EType getType() const { return m_type; }
    void setType( EType t ) { m_type = t; }

    // We'll persist all the hair layout information in a custom user data, on the hair object
    void toString( std::string& out_str ) const;

    // register a user data to the list, the map is filled later on by buildMap()
    void registerUserData( const std::string& str, unsigned int numScalars, int perPoint );

    // build the map from the list of registered user data.
    // It builds the offsets correctly
    void buildMap();

    // Add a user data to the map. The offset must be known.
    bool addUserData( const std::string& str, unsigned int offset, unsigned int numScalars );

    Entry* find( const std::string& str );

    Entry* getEntry( size_t i );
    const Entry* getEntry( size_t i ) const;

    size_t getEntryCount() const;

    size_t getOffsetScalars( ) const { return m_offsetScalars;}

private:
    EType m_type;
    std::map<std::string,Entry> m_map;
    std::vector<Entry> m_list; // temp list used by register and build map.
    size_t m_offsetScalars; // inplace user data scalars
};

// hair util shader class. 
// Will deprecate it soon. The seexpr shader does much more and better. 
class HairUtil
{
public:
    // mental ray input parameters
    struct Params
    {
        miTag format;
    };

    void init( miState* state, Params* paras );

    // calls getField for the 3 components, based on the what init() picked.
    miBoolean execute( miVector* result, miState* state, Params* paras );

    static const char* Names[43];

    // What data to retreive on the miState
    enum Field
    {
        no_field, bary, point, normal, normal_geom, direction, tex,
        derivs0, derivs1, derivs2, derivs3, derivs4, derivs5, derivs6, derivs7, derivs8, derivs9, 
        scalars0, scalars1, scalars2, scalars3, scalars4, scalars5, scalars6, scalars7, scalars8, scalars9, 
        hair_min_raster_size, hair_raster_area,
        hair_min_pixel_size, hair_pixel_area,
        tex_list0, tex_list1, tex_list2, tex_list3, tex_list4, tex_list5, tex_list6, tex_list7, tex_list8, tex_list9, 
    };

    // A component of the Vector3
    enum Comp
    {
        no_comp, x, y, z
    };

    // Return the data from the miState
    static float getField( miState* state, Field field, Comp component );

private:
    // Texture Helper
    static bool getTextures( miState *state, int& max_tex, miVector** out_textures );
    static bool getHairScalars( miState *state, int& max_scalars, std::vector<miScalar>& out_scalars );

    

    // Data for the shader instance, initialized in init()
    std::string m_format;
    Field m_fields[3];
    Comp m_components[3];
};

}
#endif