checkerShader/checkerShader.cpp

//-
// ===========================================================================
// 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.
// ===========================================================================
//+

//
// DESCRIPTION: A simple example of a programmable checker texture.
// 
// This example produces a dependency graph node CheckerNode.
//
// This node is an example of evaluating texture UV coordinates and producing
// a checkerboard pattern. It also can take advantage of the 2d texture placement
// node for transforming UV coordinates with a manipulator.
//
// Inputs:
//
//  BiasU, BiasV: Control for the center of the checker.
//  Color1, Color2: the 2 colors for the checker.
//  UV: UV coordinates that are being evaluated.
//
// Output:
//
//  outColor: the result color.
//  It is a 3 float value that represents the resulting color derived from the
//  object's UV texture coordinates. 
//
// Before using the shader, enter the following commands:
//
//  shadingNode -asTexture checkerTexture;
//  shadingNode -asUtility place2dTexture;
//  connectAttr place2dTexture1.outUV checkerTexture1.uvCoord;
//
// You can now connect the outColor output to an input of a surface/shader node
// such as Color.
//
// The plugin assumes that the devkit location follows "Setting up your build
// environment" at Maya Developer Help; otherwise, shaders/textures cannot be
// located. In this case create a mod (module description file) as below in a
// suitable modules folder (getenv "MAYA_MODULE_PATH") and restart Maya.
//
//   + devkit 1.0 <local devkit path>
//

#include <math.h>
#include <cstdlib>

#include <maya/MPxNode.h>
#include <maya/MIOStream.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>
#include <maya/MFnPlugin.h>
#include <maya/MDrawRegistry.h>
#include <maya/MPxShadingNodeOverride.h>
#include <maya/MViewport2Renderer.h>
#include <maya/MFragmentManager.h>
#include <maya/MGlobal.h>

//
// Node declaration
class CheckerNode : public MPxNode
{
    public:
                    CheckerNode();
            ~CheckerNode() override;

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

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

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

    private:

    // Input attributes
    static MObject aColor1;
    static MObject aColor2;
    static MObject aBias;
    static MObject aUVCoord;

    // Output attributes
    static MObject aOutColor;
    static MObject aOutAlpha;
};

//
// Override declaration
class CheckerNodeOverride : public MHWRender::MPxShadingNodeOverride
{
public:
    static MHWRender::MPxShadingNodeOverride* creator(const MObject& obj);

    ~CheckerNodeOverride() override;

    MHWRender::DrawAPI supportedDrawAPIs() const override;

    MString fragmentName() const override;

private:
    CheckerNodeOverride(const MObject& obj);

    MString fFragmentName;
};

//
// Node definition
// static data
const MTypeId CheckerNode::id( 0x81006 );

// Attributes
MObject  CheckerNode::aColor1;
MObject  CheckerNode::aColor2;
MObject  CheckerNode::aBias;
MObject  CheckerNode::aUVCoord;

MObject  CheckerNode::aOutColor;
MObject  CheckerNode::aOutAlpha;

#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) );

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


CheckerNode::CheckerNode()
{
}

CheckerNode::~CheckerNode()
{
}

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

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

    // Input attributes

    aColor1 = nAttr.createColor("color1", "c1");
    MAKE_INPUT(nAttr);
    CHECK_MSTATUS(nAttr.setDefault(0., .58824, .644) );     // Light blue

    aColor2 = nAttr.createColor("color2", "c2");
    MAKE_INPUT(nAttr);
    CHECK_MSTATUS(nAttr.setDefault(1., 1., 1.) );           // White

    aBias = nAttr.create( "bias", "b", MFnNumericData::k2Float);
    MAKE_INPUT(nAttr);
    CHECK_MSTATUS(nAttr.setMin(0.0f, 0.0f) );
    CHECK_MSTATUS(nAttr.setMax(1.0f, 1.0f) );
    CHECK_MSTATUS(nAttr.setDefault(0.5f, 0.5f) );

    // 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) );

    // Output attributes

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

    aOutAlpha = nAttr.create( "outAlpha", "oa", MFnNumericData::kFloat);
    MAKE_OUTPUT(nAttr);

    // Add attributes to the node database.

    CHECK_MSTATUS(addAttribute(aColor1));
    CHECK_MSTATUS(addAttribute(aColor2));
    CHECK_MSTATUS(addAttribute(aBias));
    CHECK_MSTATUS(addAttribute(aUVCoord));

    CHECK_MSTATUS(addAttribute(aOutColor));
    CHECK_MSTATUS(addAttribute(aOutAlpha));

    // All input affect the output color and alpha
    CHECK_MSTATUS(attributeAffects (aColor1,  aOutColor));
    CHECK_MSTATUS(attributeAffects(aColor1, aOutAlpha));

    CHECK_MSTATUS(attributeAffects (aColor2,  aOutColor));
    CHECK_MSTATUS(attributeAffects(aColor2, aOutAlpha));

    CHECK_MSTATUS(attributeAffects(aBias, aOutColor));
    CHECK_MSTATUS(attributeAffects(aBias, aOutAlpha));

    CHECK_MSTATUS(attributeAffects (aUVCoord, aOutColor));
    CHECK_MSTATUS(attributeAffects(aUVCoord, aOutAlpha));

    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/alpha of our checker for a given UV coordinate.
// Put the result into the output plug.

MStatus CheckerNode::compute(
const MPlug&      plug,
      MDataBlock& block )
{
    // outColor or individial R, G, B channel, or alpha
    if((plug != aOutColor) && (plug.parent() != aOutColor) &&
       (plug != aOutAlpha))
        return MS::kUnknownParameter;

    MFloatVector resultColor;
    float2 & uv = block.inputValue( aUVCoord ).asFloat2();
    float2 & bias = block.inputValue( aBias ).asFloat2();

    int count = 0;
    if (uv[0] - floorf(uv[0]) < bias[0]) count++;
    if (uv[1] - floorf(uv[1]) < bias[1]) count++;

    if (count & 1)
        resultColor = block.inputValue( aColor2 ).asFloatVector();
    else
        resultColor = block.inputValue( aColor1 ).asFloatVector();

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

    // Set ouput alpha attribute
    MDataHandle outAlphaHandle = block.outputValue( aOutAlpha );
    float& outAlpha = outAlphaHandle.asFloat();
    outAlpha = (count & 1) ? 1.f : 0.f;
    outAlphaHandle.setClean();

    return MS::kSuccess;
}

//
// Override definition
MHWRender::MPxShadingNodeOverride* CheckerNodeOverride::creator(
    const MObject& obj)
{
    return new CheckerNodeOverride(obj);
}

CheckerNodeOverride::CheckerNodeOverride(const MObject& obj)
: MPxShadingNodeOverride(obj)
, fFragmentName("")
{
    // Fragments are defined in separate XML files, add the checker node
    // directory to the search path and load from the files.
    static const MString sFragmentName("checkerNodePluginFragment");
    static const MString sFragmentOutputName("checkerNodePluginFragmentOutput");
    static const MString sFragmentGraphName("checkerNodePluginGraph");
    MHWRender::MRenderer* theRenderer = MHWRender::MRenderer::theRenderer();
    if (theRenderer)
    {
        MHWRender::MFragmentManager* fragmentMgr =
            theRenderer->getFragmentManager();
        if (fragmentMgr)
        {
            // Add search path (once only)
            //
            // The plugin assumes that the devkit location follows "Setting up your build
            // environment" at Maya Developer Help; otherwise, shaders/textures cannot be
            // located. In this case create a mod (module description file) as below in a
            // suitable modules folder (getenv "MAYA_MODULE_PATH") and restart Maya.
            //
            //   + devkit 1.0 <local devkit path>
            //
            static bool sAdded = false;
            if (!sAdded)
            {
                MString location;
                if( ! MGlobal::executeCommand(MString("getModulePath -moduleName \"devkit\""), location, false) ) {
                    location = MString(getenv("MAYA_LOCATION")) + MString("/devkit");
                } 
                location += "/plug-ins/checkerShader";
                fragmentMgr->addFragmentPath(location);
                sAdded = true;
            }

            // Add fragments if needed
            bool fragAdded = fragmentMgr->hasFragment(sFragmentName);
            bool structAdded = fragmentMgr->hasFragment(sFragmentOutputName);
            bool graphAdded = fragmentMgr->hasFragment(sFragmentGraphName);
            if (!fragAdded)
            {
                fragAdded = (sFragmentName == fragmentMgr->addShadeFragmentFromFile(sFragmentName + ".xml", false));
            }
            if (!structAdded)
            {
                structAdded = (sFragmentOutputName == fragmentMgr->addShadeFragmentFromFile(sFragmentOutputName + ".xml", false));
            }
            if (!graphAdded)
            {
                graphAdded = (sFragmentGraphName == fragmentMgr->addFragmentGraphFromFile(sFragmentGraphName + ".xml"));
            }

            // If we have them all, use the final graph for the override
            if (fragAdded && structAdded && graphAdded)
            {
                fFragmentName = sFragmentGraphName;
            }
        }
    }
}

CheckerNodeOverride::~CheckerNodeOverride()
{
}

MHWRender::DrawAPI CheckerNodeOverride::supportedDrawAPIs() const
{
    return MHWRender::kOpenGL | MHWRender::kDirectX11 | MHWRender::kOpenGLCoreProfile;
}

MString CheckerNodeOverride::fragmentName() const
{
    return fFragmentName;
}

static const MString sRegistrantId("checkerTexturePlugin");

//
// Plugin setup
MStatus initializePlugin( MObject obj )
{
    const MString UserClassify( "texture/2d:drawdb/shader/texture/2d/checkerTexture" );

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

    CHECK_MSTATUS(
        MHWRender::MDrawRegistry::registerShadingNodeOverrideCreator(
            "drawdb/shader/texture/2d/checkerTexture",
            sRegistrantId,
            CheckerNodeOverride::creator));

    return MS::kSuccess;
}

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

    CHECK_MSTATUS(
        MHWRender::MDrawRegistry::deregisterShadingNodeOverrideCreator(
            "drawdb/shader/texture/2d/checkerTexture",
            sRegistrantId));

    return MS::kSuccess;
}