hwUnlitShader/ShadingConnection.h

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#ifndef MAYA_ShadingConnection
#define MAYA_ShadingConnection

// ShadingConnection.h

// DESCRIPTION:  This class stores useful information about
//               a shader's attribute, including what's connected upstream of it.
//               It also automatically passes through shader switches.
//
// The ShadingConnection is a helper class that stores useful information 
// about a shader's attribute, including what's connected upstream of it.
//
// It can:
//      Traverse upstream until it finds if the connection is ultimately 
// on a constant color, or a shading object. This process goes through 
// shading switches if it encounters some. The object/color found is called
// the "target".
//
// At the end of this process, the following information is stored:
// 1. Target type: whether or not the connection ends up on a shading 
//                 object (for example: file texture), or a constant 
//                 color (ex: bright red).
// 2. Target identity: either the color, or the target object itself. Note
//                     that the caller is responsible to first check the type
//                     before calling color() or object().
// 3. Directness: Whether or not the connection was direct (ie: there was
//                no shading switch in between the source and the target)
//                or indirect (ie: there were shading switches in between.)
//
// In order to traverse the shading network, we need the name of the shape.
//
// AUTHOR: Christian Laforte
//

#include <maya/MColor.h>

class ShadingConnection
{
public:
    enum TYPE
    {
        CONSTANT_COLOR, 
        TEXTURE
    };

    ShadingConnection(MObject shaderObj, MString shapeName, MString attribute = "");

    TYPE traverseAttribute(MString attributeName);
    
    TYPE analyzePlug(MPlug plug);
    
    TYPE traverseTripleShadingSwitch(MObject connectedObject);

    TYPE type();

    MColor constantColor();

    MObject texture();

    MObject shaderObj();

    MString shaderName();

    MString attributeName();

    MString shapeName();

    TYPE setConstantColor(MColor col);
    TYPE setTexture(MObject texture);

    bool isDirectConnection();

    
private:
    // Input
    MObject m_shaderObj;
    MString m_attributeName;
    MString m_shapeName;

    // Output   
    TYPE m_type;
    MColor m_constantColor;
    MObject m_texture;
    bool m_directConnection;


};


#endif // MAYA_ShadingConnection