vp2BlinnShader/vp2BlinnShader.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.
// ==========================================================================
//+
#include <maya/MIOStream.h>
#include <math.h>
#include <cstdlib>

//#include <maya/MGlobal.h>
#include <maya/MString.h>
#include <maya/MPlug.h>
#include <maya/MFnNumericAttribute.h>
#include <maya/MFloatVector.h>
#include <maya/MFnPlugin.h>
#include <maya/MFnDependencyNode.h>
//#include <maya/MUserData.h>

//#include <maya/MHardwareRenderer.h>

// Includes for swatch rendering
#include <maya/MHWShaderSwatchGenerator.h>
#include <maya/MImage.h>
#include <maya/MRenderUtilities.h>

#include <maya/MMatrix.h>

// Viewport 2.0 includes
#include <maya/MDrawRegistry.h>
#include <maya/MPxShaderOverride.h>
#include <maya/MDrawContext.h>
#include <maya/MStateManager.h>
#include <maya/MViewport2Renderer.h>
#include <maya/MShaderManager.h>

#undef ENABLE_TRACE_API_CALLS
//#define ENABLE_TRACE_API_CALLS 1
#ifdef ENABLE_TRACE_API_CALLS
#define TRACE_API_CALLS(x) cerr <<(x)<<"\n"
#else
#define TRACE_API_CALLS(x)
#endif

#include "vp2BlinnShader.h"

// Node id
MTypeId vp2BlinnShader::id( 0x00081102 );
// Node attributes
MObject  vp2BlinnShader::aColor;
MObject  vp2BlinnShader::aTransparency;
MObject  vp2BlinnShader::aSpecularColor;
MObject  vp2BlinnShader::aNonTexturedColor;
MObject  vp2BlinnShader::aNonTexturedTransparency;

// This plug-in implementation shows the usage of an MPxShaderOverride for 
// a Maya shader node. 
//
// The purpose is to show as simple a plug-in as possible without worrying
// about the details of trying to write a shader system.
// 
// As such it attempts to (re)use as many internal VP2 API
// intterfaces and constructs as possible. 
//
// In this case the plug-in will use a stock shader instance (MShaderInstance)
// as it's single internal shader. As part of initialization it will reuse
// internal MShaderInstance utility methods to show how a DX11 shader signature
// can be set as as well as how to return the vertex requirements simply.
// As there is only one shader instance the shader key used is also simplistic
// as it can be a constant value.
//
// Transparency notificaiton is handle by setting the MPxShaderOverride::isTransparent() 
// virtual method return value appropriately based on node attribute values.
//
// The code also demonstrates handling of non-textured draw by providing another stock 
// MShaderInstance to be returned from MPxShaderOverride::nonTexturedShaderInstance()
// It will also handle transparency by appropriately updating the shader instance
// transparency hint using MShaderInstance::setIsTransparent().
//
// For update, the node attributes match a few of the MShaderInstance parameters
// to show DG update and device update. Additional attributes are added to
// show how the non-texture mode shader instance parameters can be driven
// by attribute changes.
//
// For drawing, the code reuses the internally provided binding interfaces on
// MShaderInstance as well as the utility geometry drawing method:
// MPxShaderOverride::drawGeometry().
//
// For swatch rendering the basic VP2 supplied utility 
// MRenderUtilities::renderMaterialViewerGeometry() is used.
//
// (De)registration is shown as part of plug-in (de)initialization, noting
// that the MPxShaderOverride association to the MPxNode node is achieved
// by supplying the same "drawdb/shader" classification for both registration
// interfaces.
// 

// Node methods
void * vp2BlinnShader::creator()
{
    TRACE_API_CALLS("vp2BlinnShader::creator");
    return new vp2BlinnShader();
}

vp2BlinnShader::vp2BlinnShader()
{
    TRACE_API_CALLS("vp2BlinnShader::vp2BlinnShader");
}

vp2BlinnShader::~vp2BlinnShader()
{
    TRACE_API_CALLS("vp2BlinnShader::~vp2BlinnShader");
}

MStatus vp2BlinnShader::initialize()
{
    // Shader attributes for the node
    // They have been created to match internal parameters of the
    // hardware shader instance
    //
    TRACE_API_CALLS("vp2BlinnShader::initialize");
    MFnNumericAttribute nAttr;

    // Create textured mode input attributes
    aColor = nAttr.createColor( "color", "c");
    nAttr.setStorable(true);
    nAttr.setKeyable(true);
    nAttr.setDefault(0.6f, 0.6f, 0.6f);
    nAttr.setAffectsAppearance( true );
    
    aTransparency = nAttr.create( "transparency", "tr", MFnNumericData::kFloat );
    nAttr.setStorable(true);
    nAttr.setKeyable(true);
    nAttr.setDefault(0.0f);
    nAttr.setMax(1.0f);
    nAttr.setMin(0.0f);
    nAttr.setAffectsAppearance( true );

    aSpecularColor = nAttr.createColor( "specularColor", "sc" );
    nAttr.setStorable(true);
    nAttr.setKeyable(true);
    nAttr.setDefault(1.0f, 1.0f, 1.0f);
    nAttr.setAffectsAppearance( true );

    // Create non-textured mode input attributes
    aNonTexturedColor = nAttr.createColor( "nonTexturedColor", "nc");
    nAttr.setStorable(true);
    nAttr.setKeyable(true);
    nAttr.setDefault(1.0f, 0.0f, 0.0f);
    nAttr.setAffectsAppearance( true );

    aNonTexturedTransparency = nAttr.create( "nonTexturedTransparency", "nt", MFnNumericData::kFloat );
    nAttr.setStorable(true);
    nAttr.setKeyable(true);
    nAttr.setDefault(0.0f);
    nAttr.setMax(1.0f);
    nAttr.setMin(0.0f);
    nAttr.setAffectsAppearance( true );

    // create output attributes here
    // outColor is the only output attribute and it is inherited
    // so we do not need to create or add it.
    //

    // Add the attributes to the node
    addAttribute(aColor);
    addAttribute(aTransparency);
    addAttribute(aSpecularColor);
    addAttribute(aNonTexturedColor);
    addAttribute(aNonTexturedTransparency);

    attributeAffects (aColor,           outColor);
    attributeAffects (aTransparency,    outColor);
    attributeAffects (aSpecularColor,   outColor);
    attributeAffects (aNonTexturedColor,outColor);
    attributeAffects (aNonTexturedTransparency,outColor);
    return MS::kSuccess;
}

//
// Very simplistic software compute for the Maya software renderer
// This code is not the focus of this plug-in example so just
// returns a constant color.
//
MStatus vp2BlinnShader::compute(
const MPlug&      plug,
      MDataBlock& block )
{
    TRACE_API_CALLS("vp2BlinnShader::compute");

    if ((plug != outColor) && (plug.parent() != outColor))
        return MS::kUnknownParameter;

    MFloatVector & color  = block.inputValue( aColor ).asFloatVector();

    // set output color attribute
    MDataHandle outColorHandle = block.outputValue( outColor );
    MFloatVector& outColor = outColorHandle.asFloatVector();
    outColor = color;

    outColorHandle.setClean();
    return MS::kSuccess;
}

// Swatch rendering: 
// Does not matter the mode for the viewport VP1 or VP2
// Uses material viewer utility which uses the VP2 render to draw the swatch.
MStatus vp2BlinnShader::renderSwatchImage( MImage & outImage )
{   
    if (MHWRender::MRenderer::theRenderer())
    {
        // Use some sample objects for display
        MString meshSphere("meshTeapot");
        MString meshShaderball("meshShaderball");

        unsigned int targetW, targetH;
        outImage.getSize(targetW, targetH);

        return MHWRender::MRenderUtilities::renderMaterialViewerGeometry(targetW > 128 ? meshShaderball : meshSphere, 
                                                                        thisMObject(), 
                                                                        outImage, 
                                                                        MHWRender::MRenderUtilities::kPerspectiveCamera, 
                                                                        MHWRender::MRenderUtilities::kSwatchLight);
    }
    return MS::kSuccess;
}

// Viewport 2.0 shader override implementation
class vp2BlinnShaderOverride : public MHWRender::MPxShaderOverride
{
public:
    // Static method to create a new override
    static MHWRender::MPxShaderOverride* Creator(const MObject& obj)
    {
        return new vp2BlinnShaderOverride(obj);
    }

    // Release the textured and non-textured mode shaders.
    virtual ~vp2BlinnShaderOverride()
    {
        MHWRender::MRenderer* theRenderer = MHWRender::MRenderer::theRenderer();
        if (theRenderer)
        {
            const MHWRender::MShaderManager* shaderMgr = theRenderer->getShaderManager();
            if (shaderMgr)
            {
                if (fColorShaderInstance)
                {
                    shaderMgr->releaseShader(fColorShaderInstance);
                }
                fColorShaderInstance = NULL;

                if (fNonTexturedColorShaderInstance)
                {
                    shaderMgr->releaseShader(fNonTexturedColorShaderInstance);
                }
                fColorShaderInstance = NULL;
            }
        }
        
    }

    // 1. Initialize phase
    // For this plug-in we simply set up geometry requirements
    // based on an MShaderInstance
    //
    virtual MString initialize(const MInitContext& initContext,
                                     MInitFeedback& initFeedback)
    {
        TRACE_API_CALLS("vp2BlinnShaderOverride::initialize");

        if (fColorShaderInstance)
        {
            // This plugin is using the utility method
            // MPxShaderOverride::drawGeometry(). For DX11 drawing,
            // a shader signature is required. We use
            // the signature from the same MShaderInstance used to
            // set the geometry requirements so that the signature
            // will match the requirements.
            //
            addShaderSignature( *fColorShaderInstance );
    
            // Set the geometry requirements based on the shader instance
            setGeometryRequirements( *fColorShaderInstance );
        }
        return MString("Autodesk Maya vp2 Blinn Shader Override");
    }

    // 2. Update Phase
    // Access the node attributes and cache the values to update
    // during updateDevice()
    //
    virtual void updateDG(MObject object)
    {
        TRACE_API_CALLS("vp2BlinnShaderOverride::updateDG");

        if (object == MObject::kNullObj)
            return;

        // Get the hardware shader node from the MObject.
        vp2BlinnShader *shaderNode = (vp2BlinnShader *) MPxHardwareShader::getHardwareShaderPtr( object );      
        if (!shaderNode)
            return;

        // Cache any data from the node to local data members.
        MStatus status;
        MFnDependencyNode node(object, &status);
        if (status)
        {
            node.findPlug("colorR").getValue(fDiffuse[0]);
            node.findPlug("colorG").getValue(fDiffuse[1]);
            node.findPlug("colorB").getValue(fDiffuse[2]);
            node.findPlug("transparency").getValue(fTransparency);
            fDiffuse[3] = 1.0f - fTransparency;
                    
            node.findPlug("specularColorR").getValue(fSpecular[0]);
            node.findPlug("specularColorG").getValue(fSpecular[1]);
            node.findPlug("specularColorB").getValue(fSpecular[2]);

            node.findPlug("nonTexturedColorR").getValue(fNonTextured[0]);
            node.findPlug("nonTexturedColorG").getValue(fNonTextured[1]);
            node.findPlug("nonTexturedColorB").getValue(fNonTextured[2]);
            float nonTextureTransparency = 0.0f;
            node.findPlug("nonTexturedTransparency").getValue(nonTextureTransparency);          
            fNonTextured[3] = 1.0f - nonTextureTransparency;
        }
    }

    // 2. Update Phase
    // Call into utility method to update the shader instance
    // when device level update is allowed.
    virtual void updateDevice()
    {
        updateShaderInstance();
    }

    // 2. Update Phase
    // Transparency hint
    virtual bool isTransparent()
    {
        TRACE_API_CALLS("vp2BlinnShaderOverride::isTransparent");
        return (fTransparency > 0.0f);
    }

    // 2. Update Phase
    // There is nothing to do at the end of update.
    // Method is included for debug tracing only.
    virtual void endUpdate()
    {
        TRACE_API_CALLS("vp2BlinnShaderOverride::endUpdate");
    }

    // 3. Draw Phase
    // Return the shader instance used for rendering
    virtual MHWRender::MShaderInstance* shaderInstance() const
    {
        TRACE_API_CALLS("vp2BlinnShaderOverride::shaderInstance");
        return fColorShaderInstance;
    }

    // 3. Draw Phase
    // Bind the shader on activateKey() and
    // the termination occur in terminateKey().
    virtual void activateKey(MHWRender::MDrawContext& context, const MString& key)
    {
        MString out("vp2BlinnShaderOverride::activateKey[");
        out += key;
        out += "]";
        TRACE_API_CALLS(out.asChar());

        fColorShaderInstance->bind( context );
    }

    // 3. Draw Phase
    // Use custom shader instance
    //
    virtual bool draw(MHWRender::MDrawContext& context,
                 const MHWRender::MRenderItemList& renderItemList) const
    {
        MString out("vp2BlinnShaderOverride::draw[Count=");
        out += renderItemList.length();
        out += "]";
        TRACE_API_CALLS(out);

        // Activate all the shader passes and draw using internal draw methods.
        unsigned int passCount = fColorShaderInstance->getPassCount( context );
        for (unsigned int i=0; i<passCount; i++)
        {
            fColorShaderInstance->activatePass( context, i );
            MHWRender::MPxShaderOverride::drawGeometry(context);
        }

        return true;
    }

    // 3. Draw Phase
    // Unbind / terminate the shader instance here.
    virtual void terminateKey(MHWRender::MDrawContext& context, const MString& key)
    {
        MString out("vp2BlinnShaderOverride::terminateKey[");
        out += key;
        out += "]";
        TRACE_API_CALLS(out.asChar());

        // Unbind the shader
        fColorShaderInstance->unbind( context );
    }

    
    // We are using an internal resources so we support all draw APIs
    // automatically.
    virtual MHWRender::DrawAPI supportedDrawAPIs() const
    {
        return (MHWRender::kOpenGL | MHWRender::kDirectX11 | MHWRender::kOpenGLCoreProfile);
    }

    // Supply a shader instance to be used when in non-textured mode. This
    // allows for identification of objects using the "non-textured" mode color.
    //
    virtual MHWRender::MShaderInstance* nonTexturedShaderInstance(bool &monitor) const
    {
        TRACE_API_CALLS("vp2BlinnShaderOverride::nonTexturedShaderInstance");
        if (fNonTexturedColorShaderInstance)
        {
            monitor = true;
            // Mark whether the shader is transparent or not
            fNonTexturedColorShaderInstance->setIsTransparent( fNonTextured[3] != 1.0f );
            return fNonTexturedColorShaderInstance;
        }
        return NULL;
    }

protected:
    //
    // Update the shader using the values cached during DG evaluation
    // Called from updateDevice() during update phase.
    //
    void updateShaderInstance()
    {
        TRACE_API_CALLS("vp2BlinnShaderOverride::updateShaderInstance");
        
        if (fColorShaderInstance)
        {
            // Update shader to mark it as drawing with transparency or not.
            fColorShaderInstance->setIsTransparent( isTransparent() );
            fColorShaderInstance->setParameter("diffuseColor", &fDiffuse[0] );
            fColorShaderInstance->setParameter("specularColor", &fSpecular[0] );
        }
        if (fNonTexturedColorShaderInstance)
        {
            fNonTexturedColorShaderInstance->setParameter("diffuseColor", &fNonTextured[0]);
            fNonTexturedColorShaderInstance->setIsTransparent( fNonTextured[3] != 1.0f );
        }
    }

    // Code to create MShaderInstances using a stock internal Blinn shader
    // Create one shader for textured mode and one for non-textured mode.
    // 
    void createShaderInstance()
    {
        TRACE_API_CALLS("vp2BlinnShaderOverride::createShaderInstance");

        MHWRender::MRenderer *renderer = MHWRender::MRenderer::theRenderer();
        const MHWRender::MShaderManager* shaderMgr = renderer ? renderer->getShaderManager() : NULL;
        if (!shaderMgr)
            return;

        if (!fColorShaderInstance)
        {
            fColorShaderInstance = shaderMgr->getStockShader( MHWRender::MShaderManager::k3dBlinnShader );
        }
        if (!fNonTexturedColorShaderInstance)
        {
            fNonTexturedColorShaderInstance = shaderMgr->getStockShader( MHWRender::MShaderManager::k3dBlinnShader );
            if (fNonTexturedColorShaderInstance)
            {
                fNonTexturedColorShaderInstance->setParameter("diffuseColor", &fNonTextured[0]);
            }
        }
    }

    //
    // Constructor. Simply initialize shader instances for usage.
    // 
    vp2BlinnShaderOverride(const MObject& obj)
    : MHWRender::MPxShaderOverride(obj)
    , fColorShaderInstance(NULL)
    , fNonTexturedColorShaderInstance(NULL)
    , fTransparency(0.0f)
    {       
        fDiffuse[0] = fDiffuse[1] = fDiffuse[2] = fDiffuse[3] = 0.0f;
        fSpecular[0] = fSpecular[1] = fSpecular[2] = 0.0f;
        fNonTextured[0] = 1.0; fNonTextured[1] = fNonTextured[2] = 0.0f;
        fNonTextured[3] = 1.0f;

        // Create a shader instance to use for drawing
        //
        createShaderInstance();
    }

    // Cached shader inputs values
    float fTransparency;
    float fDiffuse[4];
    float fSpecular[3];
    float fShininess[3];
    float fNonTextured[4];

    // Shader to use to draw with
    MHWRender::MShaderInstance *fColorShaderInstance;
    // Shader to use to draw non-textured with
    MHWRender::MShaderInstance *fNonTexturedColorShaderInstance;
};

// Plug-in handling
static const MString svp2BlinnShaderRegistrantId("vp2BlinnShaderRegistrantId");

// Note that we use the same drawdb classification for both registerNode()
// and registerShaderOverrideCreator() to associate the override with the Maya node.
//
MStatus initializePlugin( MObject obj )
{
    TRACE_API_CALLS("initializePlugin");
    MStatus   status;

    const MString& swatchName = MHWShaderSwatchGenerator::initialize();
    const MString UserClassify( "shader/surface/utility/:drawdb/shader/surface/vp2BlinnShader:swatch/"+swatchName);

    MFnPlugin plugin( obj, PLUGIN_COMPANY, "1.0", "Any");
    status = plugin.registerNode( "vp2BlinnShader", vp2BlinnShader::id,
                                  vp2BlinnShader::creator, vp2BlinnShader::initialize,
                                  MPxNode::kHardwareShader, &UserClassify );
    if (!status) {
        status.perror("registerNode");
        return status;
    }

    // Register a shader override for this node
    MHWRender::MDrawRegistry::registerShaderOverrideCreator(
        "drawdb/shader/surface/vp2BlinnShader",
        svp2BlinnShaderRegistrantId,
        vp2BlinnShaderOverride::Creator);
    if (status != MS::kSuccess) return status;

    return MS::kSuccess;
}

MStatus uninitializePlugin( MObject obj )
{
    TRACE_API_CALLS("uninitializePlugin");
    MStatus   status;

    MFnPlugin plugin( obj );

    // Unregister the shader node
    plugin.deregisterNode( vp2BlinnShader::id );
    if (!status) {
        status.perror("deregisterNode");
        return status;
    }

    // Deregister the shader override
    status = MHWRender::MDrawRegistry::deregisterShaderOverrideCreator(
        "drawdb/shader/surface/vp2BlinnShader", svp2BlinnShaderRegistrantId);
    if (status != MS::kSuccess) return status;

    return MS::kSuccess;
}