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# brickShader.cpp

    //-
    // ==========================================================================
    // Copyright 1995,2006,2008 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.
    // ==========================================================================
    //+

    #include <math.h>

    #include <maya/MFnPlugin.h>
    #include <maya/MIOStream.h>
    #include <maya/MPxNode.h>
    #include <maya/MString.h>
    #include <maya/MTypeId.h>
    #include <maya/MPlug.h>
    #include <maya/MDataBlock.h>
    #include <maya/MDataHandle.h>
    #include <maya/MFnNumericAttribute.h>
    #include <maya/MFloatVector.h>

    class brickTextureNode : public MPxNode
    {
        public:

        brickTextureNode();
        virtual         ~brickTextureNode();

        virtual MStatus compute( const MPlug&, MDataBlock& );
        virtual void    postConstructor();

        static  void *  creator();
        static  MStatus initialize();

        //  Id tag for use with binary file format
        static  MTypeId id;

        private:

        // Input attributes
        static MObject aColor1;
        static MObject aColor2;
        static MObject aBlurFactor;
        static MObject aUVCoord;
        static MObject aFilterSize;

        // Output attributes
        static MObject aOutColor;
    };

    // static data
    MTypeId brickTextureNode::id( 0x8100d );

    // Attributes
    MObject brickTextureNode::aColor1;
    MObject brickTextureNode::aColor2;
    MObject brickTextureNode::aBlurFactor;
    MObject brickTextureNode::aUVCoord;
    MObject brickTextureNode::aFilterSize;

    MObject brickTextureNode::aOutColor;

    #define MAKE_INPUT(attr)    \
        CHECK_MSTATUS(attr.setKeyable(true) );      \
        CHECK_MSTATUS( attr.setStorable(true) );    \
        CHECK_MSTATUS( attr.setReadable(true) );    \
        CHECK_MSTATUS( attr.setWritable(true) );

    #define MAKE_OUTPUT(attr)           \
        CHECK_MSTATUS( attr.setKeyable(false) );    \
        CHECK_MSTATUS( attr.setStorable(false) );   \
        CHECK_MSTATUS( attr.setReadable(true) );    \
        CHECK_MSTATUS( attr.setWritable(false) );

    inline float step(float t, float c)
    {
        return (t < c) ? 0.0f : 1.0f;
    }

    inline float smoothstep(float t, float a, float b)
    {
        if (t < a) return 0.0;
        if (t > b) return 1.0;
        t = (t - a)/(b - a);
        return t*t*(3.0f - 2.0f*t);
    }

    inline float linearstep(float t, float a, float b)
    {
        if (t < a) return 0.0;
        if (t > b) return 1.0;
        return (t - a)/(b - a);
    }

    #if !defined(OSMac_MachO_)
    inline float MAX(float a, float b)
    {
        return (a < b) ? b : a;
    }

    inline float MIN(float a, float b)
    {
        return (a < b) ? a : b;
    }
    #endif

    void brickTextureNode::postConstructor( )
    {
        setMPSafe(true);
    }

    // DESCRIPTION:
    //
    brickTextureNode::brickTextureNode()
    {
    }

    // DESCRIPTION:
    //
    brickTextureNode::~brickTextureNode()
    {
    }

    // DESCRIPTION:
    // creates an instance of the node
    void * brickTextureNode::creator()
    {
        return new brickTextureNode();
    }

    // DESCRIPTION:
    //
    MStatus brickTextureNode::initialize()
    {
        MFnNumericAttribute nAttr;

        // Input attributes

        aColor1 = nAttr.createColor("brickColor", "bc");
        MAKE_INPUT(nAttr);
        CHECK_MSTATUS( nAttr.setDefault(.75, .3, .1) );         // Brown

        aColor2 = nAttr.createColor("jointColor", "jc");
        MAKE_INPUT(nAttr);
        CHECK_MSTATUS( nAttr.setDefault(.75, .75, .75) );       // Grey

        aBlurFactor = nAttr.create( "blurFactor", "bf", MFnNumericData::kFloat);
        MAKE_INPUT(nAttr);

        // Implicit shading network attributes

        MObject child1 = nAttr.create( "uCoord", "u", MFnNumericData::kFloat);
        MObject child2 = nAttr.create( "vCoord", "v", MFnNumericData::kFloat);
        aUVCoord = nAttr.create( "uvCoord", "uv", child1, child2);
        MAKE_INPUT(nAttr);
        CHECK_MSTATUS( nAttr.setHidden(true) );

        child1 = nAttr.create( "uvFilterSizeX", "fsx", MFnNumericData::kFloat);
        child2 = nAttr.create( "uvFilterSizeY", "fsy", MFnNumericData::kFloat);
        aFilterSize = nAttr.create("uvFilterSize", "fs", child1, child2);
        MAKE_INPUT(nAttr);
        CHECK_MSTATUS( nAttr.setHidden(true) );

        // Output attributes
        aOutColor = nAttr.createColor("outColor", "oc");
        MAKE_OUTPUT(nAttr);

        // Add attributes to the node database.
        CHECK_MSTATUS( addAttribute(aColor1) );
        CHECK_MSTATUS( addAttribute(aColor2) );
        CHECK_MSTATUS( addAttribute(aBlurFactor) );
        CHECK_MSTATUS( addAttribute(aFilterSize) );
        CHECK_MSTATUS( addAttribute(aUVCoord) );

        CHECK_MSTATUS( addAttribute(aOutColor) );

        // All input affect the output color
        CHECK_MSTATUS( attributeAffects(aColor1,        aOutColor) );
        CHECK_MSTATUS( attributeAffects(aColor2,        aOutColor) );
        CHECK_MSTATUS( attributeAffects(aBlurFactor,    aOutColor) );
        CHECK_MSTATUS( attributeAffects(aFilterSize,    aOutColor) );
        CHECK_MSTATUS( attributeAffects(aUVCoord,       aOutColor) );

        return MS::kSuccess;
    }

    // DESCRIPTION:
    // This function gets called by Maya to evaluate the texture.
    //
    // Get color1 and color2 from the input block.
    // Get UV coordinates from the input block.
    // Compute the color of our brick for a given UV coordinate.
    // Put the result into the output plug.
    MStatus brickTextureNode::compute(const MPlug& plug, MDataBlock& block)
    {
        // outColor or individial R, G, B channel
        if((plug != aOutColor) && (plug.parent() != aOutColor))
            return MS::kUnknownParameter;

        MFloatVector resultColor;
        float2 & uv = block.inputValue( aUVCoord ).asFloat2();
        MFloatVector& surfaceColor1 = block.inputValue( aColor1 ).asFloatVector();
        MFloatVector& surfaceColor2 = block.inputValue( aColor2 ).asFloatVector();

        // normalize the UV coords
        uv[0] -= floorf(uv[0]);
        uv[1] -= floorf(uv[1]);

        float borderWidth = 0.1f;
        float brickHeight = 0.4f;
        float brickWidth  = 0.9f;
        float & blur = block.inputValue( aBlurFactor ).asFloat();

        float v1 = borderWidth/2;
        float v2 = v1 + brickHeight;
        float v3 = v2 + borderWidth;
        float v4 = v3 + brickHeight;
        float u1 = borderWidth/2;
        float u2 = brickWidth/2;
        float u3 = u2 + borderWidth;
        float u4 = u1 + brickWidth;

        float2& fs = block.inputValue( aFilterSize ).asFloat2();
        float du = blur*fs[0]/2.0f;
        float dv = blur*fs[1]/2.0f;

        float t = MAX(MIN(linearstep(uv[1], v1 - dv, v1 + dv) -
                          linearstep(uv[1], v2 - dv, v2 + dv),
                          MAX(linearstep(uv[0], u3 - du, u3 + du),
                              1 - linearstep(uv[0], u2 - du, u2 + du))),
                      MIN(linearstep(uv[1], v3 - dv, v3 + dv) -
                          linearstep(uv[1], v4 - dv, v4 + dv),
                          linearstep(uv[0], u1 - du, u1 + du) -
                          linearstep(uv[0], u4 - du, u4 + du)));

        resultColor = t*surfaceColor1 + (1.0f - t)*surfaceColor2;

        // set ouput color attribute
        MDataHandle outColorHandle = block.outputValue( aOutColor );
        MFloatVector& outColor = outColorHandle.asFloatVector();
        outColor = resultColor;
        outColorHandle.setClean();

        return MS::kSuccess;
    }

    MStatus initializePlugin( MObject obj )
    {
        const MString UserClassify( "texture/2d" );

        MFnPlugin plugin(obj, PLUGIN_COMPANY, "4.5", "Any");
        CHECK_MSTATUS( plugin.registerNode("brickTexture", brickTextureNode::id,
                            &brickTextureNode::creator,
                            &brickTextureNode::initialize,
                            MPxNode::kDependNode,
                            &UserClassify ) );

        return MS::kSuccess;
    }

    MStatus uninitializePlugin( MObject obj )
    {
        MFnPlugin plugin( obj );
        CHECK_MSTATUS( plugin.deregisterNode( brickTextureNode::id ) );

        return MS::kSuccess;
    }