customSpriteShader/customSpriteShader.cpp

//-
// Copyright 2016 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/MDrawContext.h>
#include <maya/MDrawRegistry.h>
#include <maya/MFnPlugin.h>
#include <maya/MFragmentManager.h>
#include <maya/MGlobal.h>
#include <maya/MPxHardwareShader.h>
#include <maya/MPxShaderOverride.h>
#include <maya/MRenderUtilities.h>
#include <maya/MShaderManager.h>
#include <maya/MStateManager.h>
#include <maya/MString.h>


//
// This plug-in implementation shows the usage of MPxShaderOverride for a Maya
// shader node which can be assigned to particle sprites for customized shading.
//
// The purpose is to demonstrate how to define, connect and debug shader fragments
// using C++ API or XML schema for shading fragments in plug-ins, and in particular
// how to define and connect a geometry shader fragment. In this case the plug-in
// will create a shader instance from a fragment graph whose connections, properties,
// values and outputs are defined in XML and connect it with a geometry shader
// fragment using MShaderInstance::addInputFragment().
//
// Because the shader instance is generated from shader fragments, the lighting
// fragments can be connected to the shader instance in order to allow the shader
// to work with maya lights. For more details please see the documentation for
// MPxSurfaceShadingNodeOverride.
//
// An implementation of color management on the input texture is also built into
// customFileTextureOutputColor.xml, which is to show how maya converts texture
// color from sRGB space to linear space. The implementation depends on input
// color space and may vary according to needs, e.g. plug-ins can also choose
// GPU linearization instead of a shader method.
//
// Transparency notification is handled by setting MPxShaderOverride::isTransparent()
// virtual method return value appropriately as needed. The support for advanced
// transparency algorithms, such as depth peeling and weighted average, are also
// handled by returning true for MPxShaderOverride::supportsAdvancedTransparency()
// and checking specific pass semantics in MPxShaderOverride::handlesDraw().
//
// The code also demonstrates handling of non-textured drawing by providing another
// MShaderInstance to be returned from MPxShaderOverride::nonTexturedShaderInstance().
// It will also handle transparency by appropriately setting the shader instance
// transparency hint using MShaderInstance::setIsTransparent().
//
// (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.
//
// For debugging shader fragments, the final effect source of the shader instance
// can be written to disk using MShaderInstance::writeEffectSourceToFile() and
// can be used to create another shader instance for being bound to a draw context.
// In case of failure, shader compilation errors can be either displayed in Script
// Editor during binding or queried from MShaderManager::getLastError() afterwards.
//
// customSpriteShader.mel is provided for easier testing, which creates some
// particle sprites with random scale and twist, and then assign them with
// customSpriteShader.
//
// 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>
//


class customSpriteShader : public MPxHardwareShader
{
public:

    ~customSpriteShader() override
    {
    }

    static void* creator()
    {
        return new customSpriteShader();
    }

    static MStatus initialize()
    {
        return MS::kSuccess;
    }

    static MTypeId id;

private:

    customSpriteShader()
    {
    }
};

MTypeId customSpriteShader::id(0x00081033);


class customSpriteShaderOverride : public MHWRender::MPxShaderOverride
{
public:

    ~customSpriteShaderOverride() override;

    static MHWRender::MPxShaderOverride* creator(const MObject& obj)
    {
        return new customSpriteShaderOverride(obj);
    }

    MHWRender::DrawAPI supportedDrawAPIs() const override
    {
        return MHWRender::kAllDevices;
    }

    MHWRender::MShaderInstance* shaderInstance(MHWRender::MDrawContext& context) const override
    {
        return fShaderInstance;
    }

    MHWRender::MShaderInstance* nonTexturedShaderInstance(bool &monitorNode) const override
    {
        monitorNode = false;
        return fNonTexturedShaderInstance;
    }

    bool isTransparent() override
    {
        return true;
    }
    
    bool supportsAdvancedTransparency() const override
    {
        return true;
    }

    MString initialize(const MInitContext& initContext, MInitFeedback& initFeedback) override;
    bool handlesDraw(MHWRender::MDrawContext& context) override;
    void activateKey(MHWRender::MDrawContext& context, const MString& key) override;
    bool draw(MHWRender::MDrawContext& context,const MHWRender::MRenderItemList& renderItemList) const override;
    void terminateKey(MHWRender::MDrawContext& context, const MString& key) override;

    static MStatus registerShadeFragments();
    static MStatus deregisterShadeFragments();
    static bool addFragmentXML(MHWRender::MFragmentManager& fragMgr, const MString& fileName, bool asGraph);

private:

    customSpriteShaderOverride(const MObject& obj);

    void createShaderInstances();

private:

    MHWRender::MShaderInstance *fShaderInstance;
    MHWRender::MShaderInstance *fNonTexturedShaderInstance;

    static MStringArray sFragmentArray;
    static bool sDebugFragment;
};

MStringArray customSpriteShaderOverride::sFragmentArray;
bool customSpriteShaderOverride::sDebugFragment = (getenv("MAYA_CUSTOMSPRITESHADER_DEBUG_FRAGMENTS") != NULL);

customSpriteShaderOverride::customSpriteShaderOverride(const MObject& obj)
    : MHWRender::MPxShaderOverride(obj)
    , fShaderInstance(NULL)
    , fNonTexturedShaderInstance(NULL)
{
    createShaderInstances();
}

customSpriteShaderOverride::~customSpriteShaderOverride()
{
    MHWRender::MRenderer* renderer = MHWRender::MRenderer::theRenderer();
    if (renderer)
    {
        const MHWRender::MShaderManager* shaderMgr = renderer->getShaderManager();
        if (shaderMgr)
        {
            if (fShaderInstance)
            {
                shaderMgr->releaseShader(fShaderInstance);
                fShaderInstance = NULL;
            }

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

void customSpriteShaderOverride::createShaderInstances()
{
    MHWRender::MRenderer* renderer = MHWRender::MRenderer::theRenderer();
    if (renderer)
    {
        const MHWRender::MShaderManager* shaderMgr = renderer->getShaderManager();
        if (shaderMgr)
        {
            // XML-based fragment graph supports multiple connections between
            // shade fragments, while MShaderInstance::addInputFragment can only
            // support single connection between the shader instance and input
            // fragment. To see how internal fragments are implemented, use the
            // fragmentDumper plugin.
            //
            fShaderInstance = shaderMgr->getFragmentShader(
                "customFileTextureBlinnShader", "outSurfaceFinal", true);

            // Connect the custom geometry shader.
            //
            fShaderInstance->addInputFragment(
                "customPoint2ViewAlignedTexturedQuad", "GPUStage", "GPUStage");

            // Acquire and bind the snow texture.
            //
            // 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>
            //
            MString path;
            if (!MGlobal::executeCommand(MString("getModulePath -moduleName \"devkit\""), path))
            {
                path = MString(getenv("MAYA_LOCATION")) + MString("/devkit");
            }
            path += MString("/plug-ins/customSpriteShader/");
            MHWRender::MTexture* texture =
                renderer->getTextureManager()->acquireTexture(path + MString("snow.png"), "", 1);
            if (texture)
            {
                MHWRender::MTextureAssignment texResource;
                texResource.texture = texture;
                fShaderInstance->setParameter("map", texResource);
            }
            else
            {
                MString errorMsg = MString("customSpriteShader failed to acquire texture from ") + path + MString("snow.png");
                MGlobal::displayError(errorMsg);
            }

            // Acquire and bind the default texture sampler.
            //
            MHWRender::MSamplerStateDesc samplerDesc;
            const MHWRender::MSamplerState* sampler =
                MHWRender::MStateManager::acquireSamplerState(samplerDesc);
            if (sampler)
            {
                fShaderInstance->setParameter("textureSampler", *sampler);
            }

            // Particle sprites cannot directly be drawn with the default non-
            // textured shader instance which is designed for polygons, so we
            // create a non-texture shader instance as well. Note the geometry
            // shader is slightly different from the textured version.
            //
            fNonTexturedShaderInstance = shaderMgr->getFragmentShader(
                "customSolidColorBlinnShader", "outSurfaceFinal", true);
            fNonTexturedShaderInstance->addInputFragment(
                "customPoint2ViewAlignedSolidQuad", "GPUStage", "GPUStage");

            // Set color and transparency.
            float customColor[3] = {1.0, 0.0, 0.0};
            fNonTexturedShaderInstance->setParameter("customColor", customColor);

            float customTransparency[3] = { 0.0, 0.0, 0.0 };
            fNonTexturedShaderInstance->setParameter("customTransparency", customTransparency);
            fNonTexturedShaderInstance->setIsTransparent(false);

            // Dump final effect source and perform validation, for debugging the
            // custom shader fragments on all device APIs. For validation, plugin
            // can bind a temporary draw context with a shader instance generated
            // from the effect source dump. Make sure it's unbound afterwards.
            if (sDebugFragment)
            {
                MString filePath = path + MString("customSpriteShader.fx");
                fShaderInstance->writeEffectSourceToFile(filePath);

                MHWRender::MDrawContext* dc =
                    MHWRender::MRenderUtilities::acquireSwatchDrawContext();
                MHWRender::MShaderInstance* shaderInstance =
                    shaderMgr->getEffectsFileShader(filePath, "");

                if (dc && shaderInstance)
                {
                    if (!shaderInstance->bind(*dc))
                    {
                        MString errorMsg = filePath +
                            MString(":\n") +
                            MHWRender::MShaderManager::getLastError() +
                            MHWRender::MShaderManager::getLastErrorSource(true, true, 2);
                        MGlobal::displayError(errorMsg);
                    }

                    shaderInstance->unbind(*dc);
                }

                shaderMgr->releaseShader(shaderInstance);
                MHWRender::MRenderUtilities::releaseDrawContext(dc);
            }
        }
    }
}

MString customSpriteShaderOverride::initialize(const MInitContext&, MInitFeedback&)
{
    MString empty;

    MHWRender::MVertexBufferDescriptor positionDesc(
        empty,
        MHWRender::MGeometry::kPosition,
        MHWRender::MGeometry::kFloat,
        3);

    MHWRender::MVertexBufferDescriptor normalDesc(
        empty,
        MHWRender::MGeometry::kNormal,
        MHWRender::MGeometry::kFloat,
        3);

    MString spritePP("spritePP");
    MHWRender::MVertexBufferDescriptor spriteDesc(
        spritePP,
        MHWRender::MGeometry::kTexture,
        spritePP,
        MHWRender::MGeometry::kFloat,
        4);

    MHWRender::MVertexBufferDescriptor uvDesc(
        empty,
        MHWRender::MGeometry::kTexture,
        MHWRender::MGeometry::kFloat,
        2);

    addGeometryRequirement(positionDesc);
    addGeometryRequirement(normalDesc);
    addGeometryRequirement(spriteDesc);
    addGeometryRequirement(uvDesc);

    if (fShaderInstance)
    {
        addShaderSignature(*fShaderInstance);
    }

    return MString("customSpriteShaderOverride");
}

bool customSpriteShaderOverride::handlesDraw(MHWRender::MDrawContext& context)
{
    const MHWRender::MPassContext& passCtx = context.getPassContext();
    const MStringArray& passSem = passCtx.passSemantics();

    bool handlePass = false;
    for (unsigned int i=0; i<passSem.length(); i++)
    {
        const MString& pass = passSem[i];

        // For color passes, only handle if there isn't already a global override.
        // This is the same as the default logic for this method in MPxShaderOverride
        if (pass == MHWRender::MPassContext::kColorPassSemantic)
        {
            if (!passCtx.hasShaderOverride())
            {
                handlePass = true;
            }
        }
        // Advanced transparency algorithms are supported.
        else if (pass == MHWRender::MPassContext::kTransparentPeelSemantic ||
                 pass == MHWRender::MPassContext::kTransparentPeelAndAvgSemantic ||
                 pass == MHWRender::MPassContext::kTransparentWeightedAvgSemantic)
        {
            handlePass = true;
        }
        // If these semantics are specified then they override the color pass
        // semantic handling.
        else if (pass == MHWRender::MPassContext::kDepthPassSemantic ||
                 pass == MHWRender::MPassContext::kNormalDepthPassSemantic)
        {
            handlePass = false;
        }
    }

    return handlePass;
}

void customSpriteShaderOverride::activateKey(MHWRender::MDrawContext& context, const MString& key)
{
    if (fShaderInstance)
    {
        fShaderInstance->bind(context);
    }
}

bool customSpriteShaderOverride::draw(MHWRender::MDrawContext& context, const MHWRender::MRenderItemList& renderItemList) const
{
    if (fShaderInstance)
    {
        unsigned int passCount = fShaderInstance->getPassCount(context);
        if (passCount)
        {
            for (unsigned int i = 0; i < passCount; i++)
            {
                fShaderInstance->activatePass(context, i);
                MHWRender::MPxShaderOverride::drawGeometry(context);
            }
        }
    }

    return true;
}

void customSpriteShaderOverride::terminateKey(MHWRender::MDrawContext& context, const MString& key)
{
    if (fShaderInstance)
    {
        fShaderInstance->unbind(context);
    }
}

bool customSpriteShaderOverride::addFragmentXML(MHWRender::MFragmentManager& fragMgr,
                                                const MString& fileName,
                                                bool asGraph)
{
    MString fragName = asGraph ? fragMgr.addFragmentGraphFromFile( fileName ) :
                                 fragMgr.addShadeFragmentFromFile( fileName, false );

    if (fragName.length() == 0)
    {
        MString errorMsg = MString("customSpriteShader failed to add fragment from ") + fileName;
        MGlobal::displayError(errorMsg);
        return false;
    }

    sFragmentArray.append(fragName);
    return true;
}

MStatus customSpriteShaderOverride::registerShadeFragments()
{
    MHWRender::MRenderer* renderer = MHWRender::MRenderer::theRenderer();
    if (renderer)
    {
        MHWRender::MFragmentManager* fragMgr = renderer->getFragmentManager();
        if (fragMgr)
        {
            // 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>
            //
            MString path;
            if (!MGlobal::executeCommand(MString("getModulePath -moduleName \"devkit\""), path, false))
            {
                path = MString(getenv("MAYA_LOCATION")) + MString("/devkit");
            }
            path += "/plug-ins/customSpriteShader";
            fragMgr->addFragmentPath(path);

            MString info = MString("customSpriteShader added a fragment search path: ") + path;
            MGlobal::displayInfo(info);

            // Fragment graphs are registered after shader fragments because of dependency.
            if (addFragmentXML(*fragMgr, "customFileTextureOutputColor.xml", false) &&
                addFragmentXML(*fragMgr, "customFileTextureOutputTransparency.xml", false) &&
                addFragmentXML(*fragMgr, "customPoint2ViewAlignedSolidQuad.xml", false) &&
                addFragmentXML(*fragMgr, "customPoint2ViewAlignedTexturedQuad.xml", false) &&
                addFragmentXML(*fragMgr, "customFileTextureBlinnShader.xml", true) &&
                addFragmentXML(*fragMgr, "customSolidColorBlinnShader.xml", true))
            {
                return MS::kSuccess;
            }
        }
    }

    return MS::kFailure;
}

MStatus customSpriteShaderOverride::deregisterShadeFragments()
{
    bool success = false;

    MHWRender::MRenderer* renderer = MHWRender::MRenderer::theRenderer();
    if (renderer)
    {
        MHWRender::MFragmentManager* fragMgr = renderer->getFragmentManager();
        if (fragMgr)
        {
            success = true;

            for (unsigned int i = 0; i < sFragmentArray.length(); i++)
            {
                MString fragName = sFragmentArray[i];
                if (fragMgr->hasFragment(fragName) && !fragMgr->removeFragment(fragName))
                {
                    success = false;

                    MString errorMsg = MString("customSpriteShader failed to remove fragment ") + sFragmentArray[i];
                    MGlobal::displayError(errorMsg);
                }
            }
        }
    }

    sFragmentArray.clear();
    return success ? MS::kSuccess : MS::kFailure;
}


static MString sCustomSpriteShaderRegistrantId("customSpriteShaderRegistrantId");
static MString sCustomSpriteShaderDrawdbClassification("drawdb/shader/surface/customSpriteShader");

MStatus initializePlugin( MObject obj )
{
    MStatus status = customSpriteShaderOverride::registerShadeFragments();
    if (status != MS::kSuccess)
    {
        status.perror("registerShadeFragments");
        return status;
    }

    MFnPlugin plugin(obj, "Autodesk", "1.0", "Any");

    MString UserClassification("shader/surface/:");
    UserClassification += sCustomSpriteShaderDrawdbClassification;

    status = plugin.registerNode(
        "customSpriteShader",
        customSpriteShader::id,
        customSpriteShader::creator,
        customSpriteShader::initialize,
        MPxNode::kHardwareShader,
        &UserClassification);
    if (status != MS::kSuccess)
    {
        status.perror("registerNode");
        return status;
    }

    status = MHWRender::MDrawRegistry::registerShaderOverrideCreator(
        sCustomSpriteShaderDrawdbClassification,
        sCustomSpriteShaderRegistrantId,
        customSpriteShaderOverride::creator);
    if (status != MS::kSuccess)
    {
        status.perror("registerShaderOverrideCreator");
        return status;
    }

    return status;
}

MStatus uninitializePlugin( MObject obj )
{
    MFnPlugin plugin(obj);

    MStatus status = plugin.deregisterNode(customSpriteShader::id);
    if (status != MS::kSuccess)
    {
        status.perror("deregisterNode");
        return status;
    }

    status = MHWRender::MDrawRegistry::deregisterShaderOverrideCreator(
        sCustomSpriteShaderDrawdbClassification,
        sCustomSpriteShaderRegistrantId);
    if (status != MS::kSuccess)
    {
        status.perror("deregisterShaderOverrideCreator");
        return status;
    }

    status = customSpriteShaderOverride::deregisterShadeFragments();
    if (status != MS::kSuccess)
    {
        status.perror("deregisterShadeFragments");
        return status;
    }

    return status;
}