geometryOverrideExample1/geometryOverrideExample1.cpp

//-
// ==========================================================================
// Copyright 2018 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.
// ==========================================================================
//+

//
// This plug-in shows how to use MPxGeometryOverride to render geometry with a stock shader.
// It will register a new type of node "geometryOverrideExample1_shape" that will generate 
// the geometry and connect it to a MPxGeometryOverride.
// 
// The GeometryOverrideExample1_shape class derives from MPxSurfaceShape and it is responsible 
// to generate the geometry data (Cube) and also enable the shape to be selectable in
// Viewport 2.0.
//
// The GeometryOverrideExample1 class derives from MPxGeometryOverride and shows how to
// create / update different render items and fill vertex / index buffers to render the geometry 
// of geometryOverrideExample1_shape.
//
//
// To use this plugin run the following mel commands once the plugin is loaded:
//
//  createNode geometryOverrideExample1_shape;
//
#include <maya/MFnPlugin.h>
#include <maya/MDrawRegistry.h>
#include "geometryOverrideExample1.h"
#include <maya/MShaderManager.h>
#include <maya/MSelectionMask.h>
#include <maya/MFnDependencyNode.h>
#include <maya/MGlobal.h>
#include <iostream>

static void instancingChangedCallback(MDagPath& child, MDagPath& parent, void* clientData)
{
    MGlobal::displayWarning("GeometryOverrideExample1 does't support instancing !");
}



//===========================================================================
//
//              geometryOverrideExample1_shape implementation
//
//===========================================================================

MTypeId GeometryOverrideExample1_shape::id = MTypeId(0x8003B);



GeometryOverrideExample1_shape::GeometryOverrideExample1_shape()
{
    // unit cube vertices
    fPositions.push_back(MFloatVector(-1, -1, -1));
    fPositions.push_back(MFloatVector( 1, -1, -1));
    fPositions.push_back(MFloatVector( 1, -1,  1));
    fPositions.push_back(MFloatVector(-1, -1,  1));
    fPositions.push_back(MFloatVector(-1,  1, -1));
    fPositions.push_back(MFloatVector(-1,  1,  1));
    fPositions.push_back(MFloatVector( 1,  1,  1));
    fPositions.push_back(MFloatVector( 1,  1, -1));

    const float normal_value = 0.5775f;
    fNormals.push_back(MFloatVector(-normal_value, -normal_value, -normal_value));
    fNormals.push_back(MFloatVector( normal_value, -normal_value, -normal_value));
    fNormals.push_back(MFloatVector( normal_value, -normal_value,  normal_value));
    fNormals.push_back(MFloatVector(-normal_value, -normal_value,  normal_value));
    fNormals.push_back(MFloatVector(-normal_value,  normal_value, -normal_value));
    fNormals.push_back(MFloatVector(-normal_value,  normal_value,  normal_value));
    fNormals.push_back(MFloatVector( normal_value,  normal_value,  normal_value));
    fNormals.push_back(MFloatVector( normal_value,  normal_value, -normal_value));

    fShadedIndices =
    {
        0, 1, 2, 2, 3, 0, // bottom
        4, 5, 6, 6, 7, 4, // top
        0, 3, 5, 5, 4, 0, // left
        1, 7, 6, 6, 2, 1, // right
        4, 1, 0, 4, 7, 1, // back
        5, 3, 2, 2, 6, 5, // front
    };

    fWireFrameIndices =
    {
        0, 1, 1, 2, 2, 3, 3, 0, // bottom
        4, 5, 5, 6, 6, 7, 7, 4, // top
        0, 4, 3, 5, 1, 7, 2, 6, // left / right
    };
}



GeometryOverrideExample1_shape::~GeometryOverrideExample1_shape()
{
    MMessage::removeCallback(mInstanceAddedCallbackId);
}



//  ============================================================
//
//  When instances of this node are created internally, the MObject associated
//  with the instance is not created until after the constructor of this class
//  is called. This means that no member functions of MPxSurfaceShape can
//  be called in the constructor.
//  The postConstructor solves this problem. Maya will call this function
//  after the internal object has been created.
//  As a general rule do all of your initialization in the postConstructor.
//
//  Note : For more information, see MPxSurfaceShape::postConstructor()
//
//  ============================================================
void GeometryOverrideExample1_shape::postConstructor()
{
    // This call allows the shape to have shading groups assigned
    setRenderable(true);
    
    //
    // Add a callback that will be called when instance are added.
    //
    MDagPath path;
    MDagPath::getAPathTo(thisMObject(), path);
    mInstanceAddedCallbackId = MDagMessage::addInstanceAddedDagPathCallback(const_cast<MDagPath&>(path), &instancingChangedCallback);
}


//  ============================================================
//
//  This method is overriden to support interactive object selection in Viewport 2.0
//
//  Returns The selection mask of the shaper.
//
//  Note : For more information, see MPxSurfaceShape::getShapeSelectionMask()
//
//  ============================================================
MSelectionMask  GeometryOverrideExample1_shape::getShapeSelectionMask() const
{
    MSelectionMask::SelectionType selType = MSelectionMask::kSelectMeshes;
    return MSelectionMask(selType);
}


//  ============================================================
//
//  Returns the bounding box for this object.
//  It is a good idea not to recompute here as this funcion is called often.
//
//  Note : This function is only called if MPxSurfaceShape::isBounded() return true.
//         For more information, see MPxSurfaceShape::boundingBox()
//
//  ============================================================
MBoundingBox GeometryOverrideExample1_shape::boundingBox() const
{
    MPoint corner1Point(fPositions[0].x, fPositions[0].y, fPositions[0].z); // back-left-bottom vertex position
    MPoint corner2Point(fPositions[6].x, fPositions[6].y, fPositions[6].z); // front-right-top  vertex position

    return MBoundingBox(corner1Point, corner2Point);
}




//===========================================================================
//
//              GeometryOverrideExample1 implementation
//
//===========================================================================

const char* GeometryOverrideExample1::sActiveWireframeRenderItemName  = "GeometryOverrideExample1_ActiveWireframe";
const char* GeometryOverrideExample1::sDormantWireframeRenderItemName = "GeometryOverrideExample1_DormantWireframe";
const char* GeometryOverrideExample1::sShadedRenderItemName           = "GeometryOverrideExample1_shaded";


GeometryOverrideExample1::GeometryOverrideExample1(const MObject& obj) 
    : MHWRender::MPxGeometryOverride(obj)
{
    // get the real mesh object from the MObject
    MStatus status;
    MFnDependencyNode node(obj, &status);
    if (status)
    {
        fMesh = dynamic_cast<GeometryOverrideExample1_shape*>(node.userNode());
    }
}



GeometryOverrideExample1::~GeometryOverrideExample1()
{

}


//  ============================================================
//
//  This function return draw API that is supported by this plugin.
//
//  Note : For more information, see MPxGeometryOverride::supportedDrawAPIs()
// 
//  ============================================================
MHWRender::DrawAPI GeometryOverrideExample1::supportedDrawAPIs() const
{
    return  (MHWRender::kOpenGL | MHWRender::kDirectX11 | MHWRender::kOpenGLCoreProfile);
}



//  ============================================================
//
//  Perform any work required to translate the geometry data that needs to get
//  information from the dependency graph.This should be the only place that
//  dependency graph evaluation occurs.Any data retrieved should be cached for
//  later stages.
//
//  Note : For more information, see MPxGeometryOverride::updateDG()
//
//  ============================================================
void GeometryOverrideExample1::updateDG()
{
    // In this example, there is nothing to do here
}



//  ============================================================
//
//  This method is called once during each draw-preparation phase.  If this method returns true 
//  then the associated DAG object will have a chance to update its render geometry this frame.
//  (Maya will call populateGeometry())
//
//  Note : For more information, see MPxGeometryOverride::requiresGeometryUpdate()
//
//  ============================================================
bool GeometryOverrideExample1::requiresGeometryUpdate() const
{
    // In this example, we always return false because the node doesn't have 
    // attributes that affect the geometry.
    return false;
}

//  ============================================================
//
//  If this method returns true then the MPxGeometryOverride will be considered
//  for Evaluation Manager Parallel Update.
//
//  Note : For more information, see MPxGeometryOverride::supportsEvaluationManagerParallelUpdate()
//
//  ============================================================
bool GeometryOverrideExample1::supportsEvaluationManagerParallelUpdate() const
{
    return true;
}



//  ============================================================
//
//  This method is called for each instance of the associated DAG object whenever 
//  the object changes and receive the path to the instance and the current list 
//  of render items associated with that instance. Implementations of this method 
//  may add, remove or modify items in the list. As an alternative this method 
//  can enable or disable items that must be used or not based on some properties.
//  
//  A render item represents a single renderable entity and contain many properties 
//  to let the Viewport 2.0 to know how to render the entity. By example, A render 
//  item contain a name, a type, the geometry primitive type, a set of geometry buffers
//  and a shader instance. 
//  
//  In this example, this functions will create 3 render items to render the object's 
//  geometry. The first render item will be use to display the oject with a single color 
//  only when the Viewport 2.0 is in shaded or textured mode. The second render item 
//  will be use to display the object in wireframe with a single color only when the 
//  Viewport 2.0 is in wireframe mode. The last render item will be use to render the 
//  object with a single color in wireframe only when the object is selected independing 
//  of the Viewport 2.0 display mode. Both wireframe render item will be enable or disable 
//  depending of the object selection state.
//
//  Note : For more information, see MPxGeometryOverride::updateRenderItems()
//
//  ============================================================
void GeometryOverrideExample1::updateRenderItems(const MDagPath& path, MHWRender::MRenderItemList& renderItems)
{
    if (!path.isValid())
        return;

    MRenderer* renderer = MRenderer::theRenderer();
    if (!renderer)
        return;
    
    const MShaderManager* shaderManager = renderer->getShaderManager();
    if (!shaderManager)
        return;


    //
    // Create a render item that will render geometry with a single color 
    // if it didn't already exist.
    //
    // This render item will be used only in shaded and textured mode.
    //
    auto renderItemIndex = renderItems.indexOf(sShadedRenderItemName);
    if (renderItemIndex < 0)
    {
        // Create the new render item with the given name.
        // We designate this item as a UI Material.
        // The "topology" for the render item is a triangle list.
        MHWRender::MRenderItem* shadedRenderItem = 
            MHWRender::MRenderItem::Create(sShadedRenderItemName,
                                           MHWRender::MRenderItem::MaterialSceneItem,
                                           MHWRender::MGeometry::kTriangles);

        // We want this render item to only show up when in shaded or textured mode
        shadedRenderItem->setDrawMode((MHWRender::MGeometry::DrawMode)(MHWRender::MGeometry::kShaded | 
                                                                      MHWRender::MGeometry::kTextured));
        
        // The the depth priority of this render item to sDormantFilledDepthPriority (The default value).
        // Depth priority is usefull when an object is displayed with many render items.
        // Viewport 2.0 will use the depth priority to know which render item must be draw on top
        // of others.
        shadedRenderItem->depthPriority(MHWRender::MRenderItem::sDormantFilledDepthPriority);

        // Enable the render item so it will be use for rendering
        shadedRenderItem->enable(true);

        // Get an instance of a 3dSolidShader from the shader manager.
        // The shader tells the graphics hardware how to draw the geometry. 
        // The MShaderInstance is a reference to a shader along with the values for the shader parameters.
        MShaderInstance* shader = shaderManager->getStockShader(MShaderManager::k3dSolidShader);
        if (shader)
        {
            // Set the shader color parameter
            const float blueColor[] = { 0.0f, 0.0f, 1.0f, 1.0f };
            shader->setParameter("solidColor", blueColor);

            // Assign the shader to the render item. This adds a reference to that
            // shader.
            shadedRenderItem->setShader(shader);

            // Once assigned, no need to hold on to shader instance
            shaderManager->releaseShader(shader);
        }

        // The item must be added to the persistent list to be considered
        // for update / rendering
        renderItems.append(shadedRenderItem);
    }


    // Get the inherited DAG display properties.
    auto wireframeColor = MHWRender::MGeometryUtilities::wireframeColor(path);
    auto displayStatus = MHWRender::MGeometryUtilities::displayStatus(path);

    // Update the wireframe render item used when the object will be selected
    bool isWireFrameRenderItemEnabled = displayStatus == MHWRender::kLead || displayStatus == MHWRender::kActive;
    updateWireframeItems(sActiveWireframeRenderItemName,
                          MHWRender::MGeometry::kAll, 
                          MHWRender::MRenderItem::sSelectionDepthPriority,
                          wireframeColor,
                          isWireFrameRenderItemEnabled,
                          renderItems, 
                          *shaderManager);

    // Update the wireframe render item used when the object will not be selected
    isWireFrameRenderItemEnabled = displayStatus == MHWRender::kDormant;
    updateWireframeItems(sDormantWireframeRenderItemName,
                          MHWRender::MGeometry::kWireframe, 
                          MHWRender::MRenderItem::sDormantWireDepthPriority,
                          wireframeColor,
                          isWireFrameRenderItemEnabled,
                          renderItems,
                          *shaderManager);
}



//  ============================================================
//
//  Fill in data and index streams based on the requirements passed in.
//  Associate indexing with the render items passed in.
//
//  Note : For more information, see MPxGeometryOverride::populateGeometry()
//
//  ============================================================
void GeometryOverrideExample1::populateGeometry(const MHWRender::MGeometryRequirements& requirements, const MHWRender::MRenderItemList& renderItems, MHWRender::MGeometry& data)
{
    if (!fMesh)
        return;
    
    const MVertexBufferDescriptorList&  vertexBufferDescriptorList = requirements.vertexRequirements();
    for (int i = 0; i < vertexBufferDescriptorList.length(); i++)
    {
        MVertexBufferDescriptor desc{};
        if (!vertexBufferDescriptorList.getDescriptor(i, desc))
            continue;

        switch (desc.semantic())
        {
        case MGeometry::kPosition:
        {
            //
            // Create and fill the vertex position buffer
            //
            MHWRender::MVertexBuffer* positionBuffer = data.createVertexBuffer(desc);

            if (positionBuffer)
            {
                GeometryOverrideExample1_shape::PositionList positions = fMesh->getPositions();
                
                void* buffer = positionBuffer->acquire(positions.size(), true /*writeOnly */);
                if(buffer)
                {
                    const std::size_t bufferSizeInByte = 
                        sizeof(GeometryOverrideExample1_shape::PositionList::value_type) * positions.size();

                    memcpy(buffer, positions.data(), bufferSizeInByte);

                    // Transfer from CPU to GPU memory.
                    positionBuffer->commit(buffer);
                }
            }
        }
            break;
        case MGeometry::kNormal:
        {
            //
            // Create and fill the vertex normal buffer
            //
            MHWRender::MVertexBuffer* normalsBuffer = data.createVertexBuffer(desc);

            if (normalsBuffer)
            {
                GeometryOverrideExample1_shape::NormalList normals = fMesh->getNormals();

                void* buffer = normalsBuffer->acquire(normals.size(), true /*writeOnly*/);
                if(buffer)
                {
                    const std::size_t bufferSizeInByte =
                        sizeof(GeometryOverrideExample1_shape::NormalList::value_type) * normals.size();

                    memcpy(buffer, normals.data(), bufferSizeInByte);

                    // Transfer from CPU to GPU memory.
                    normalsBuffer->commit(buffer);
                }
            }
        }
                break;
        case MGeometry::kTexture:
        case MGeometry::kColor:
        case MGeometry::kTangent:
        case MGeometry::kBitangent:
        case MGeometry::kTangentWithSign:
        case MGeometry::kInvalidSemantic:   // avoid compiling error
            //
            // In this example, we don't need to used those vertex informantions.
            //
            break;
        }
    }


    //   Update indexing data for all appropriate render items
    const int numItems = renderItems.length();
    for (int i = 0; i < numItems; i++)
    {
        const MHWRender::MRenderItem* item = renderItems.itemAt(i);
        if (!item)
            continue;
        
        if (item->primitive() == MHWRender::MGeometry::kTriangles)
        {
            //
            // Create and fill the index buffer used to render triangles
            //
            MHWRender::MIndexBuffer* indexBuffer = data.createIndexBuffer(MHWRender::MGeometry::kUnsignedInt32);
            if (indexBuffer)
            {
                GeometryOverrideExample1_shape::IndexList indices = fMesh->getShadedIndices();
                void* buffer = indexBuffer->acquire(indices.size(), true /*writeOnly*/);
                if (buffer)
                {
                    const std::size_t bufferSizeInByte =
                        sizeof(GeometryOverrideExample1_shape::IndexList::value_type) * indices.size();

                    memcpy(buffer, indices.data(), bufferSizeInByte);

                    // Transfer from CPU to GPU memory.
                    indexBuffer->commit(buffer);

                    // Associate index buffer with render item
                    item->associateWithIndexBuffer(indexBuffer);
                }
            }
        }
        else if(item->primitive() == MHWRender::MGeometry::kLines)
        {           
            //
            // Create and fill the index buffer used to render lines (Wireframe)
            //
            MHWRender::MIndexBuffer* indexBuffer = data.createIndexBuffer(MHWRender::MGeometry::kUnsignedInt32);
            if (indexBuffer)
            {
                GeometryOverrideExample1_shape::IndexList indices = fMesh->getWireFrameIndices();

                void* buffer = indexBuffer->acquire(indices.size(), true /*writeOnly*/);
                if (buffer)
                {
                    const std::size_t bufferSizeInByte =
                        sizeof(GeometryOverrideExample1_shape::IndexList::value_type) * indices.size();

                    memcpy(buffer, indices.data(), bufferSizeInByte);

                    // Transfer from CPU to GPU memory.
                    indexBuffer->commit(buffer);

                    // Associate index buffer with render item
                    item->associateWithIndexBuffer(indexBuffer);
                }
            }
        }
    }
}


//  ============================================================
//
//  Clean up any cached data stored from the updateDG() phase.
//
//  Note : For more information, see MPxGeometryOverride::cleanUp()
//
//  ============================================================
void GeometryOverrideExample1::cleanUp()
{
    // Nothing here because the plugin doesn't keep any temporary data.
}



//  ============================================================
//
//  Update the wireframe render item named 'renderItemName' or create it
//  if it doesn't exists.
//
//  Note : Arguments drawMode and depthPriority are only used for creation of 
//         the render item.
//
//  ============================================================
void GeometryOverrideExample1::updateWireframeItems(const char* renderItemName, MGeometry::DrawMode drawMode, 
                                                    unsigned int depthPriority, MColor color, bool isEnable,
                                                    MHWRender::MRenderItemList& renderItemList, 
                                                    const MHWRender::MShaderManager& shaderManager)
{

    MHWRender::MRenderItem* renderItem = nullptr;

    // Try to find the active wireframe render item.
    // If the returning index is smaller than 0, that means 
    // the render item does't exists yet. So, create it.
    auto renderItemIndex = renderItemList.indexOf(renderItemName);
    if (renderItemIndex < 0)
    {
        // Create the new render item with the given name.
        // We designate this item as a UI "decoration" and will not be
        // involved in rendering aspects such as casting shadows
        // The "topology" for the render item is a line list.
        renderItem = MHWRender::MRenderItem::Create(renderItemName,
                                                    MHWRender::MRenderItem::DecorationItem,
                                                    MHWRender::MGeometry::kLines);

        // We want this render item to show up when in all mode ( Wireframe, Shaded, Textured and BoundingBox)
        renderItem->setDrawMode(drawMode);

        // Set selection priority: on top of everything
        renderItem->depthPriority(depthPriority);

        // Get an instance of a 3dSolidShader from the shader manager.
        // The shader tells the graphics hardware how to draw the geometry. 
        // The MShaderInstance is a reference to a shader along with the values for the shader parameters.
        MShaderInstance* shader = shaderManager.getStockShader(MShaderManager::k3dSolidShader);
        if (shader)
        {
            // Assign the shader to the render item. This adds a reference to that
            // shader.
            renderItem->setShader(shader);

            // Once assigned, no need to hold on to shader instance
            shaderManager.releaseShader(shader);
        }

        // The item must be added to the persistent list to be considered
        // for update / rendering
        renderItemList.append(renderItem);
    }
    else
    {
        renderItem = renderItemList.itemAt(renderItemIndex);
    }

    if(renderItem)
    {
        MHWRender::MShaderInstance* shader = renderItem->getShader();
        if (shader)
        {
            // Set the shader color parameter
            shader->setParameter("solidColor", &color.r);
        }

        renderItem->enable(isEnable);
    }
}



//===========================================================================
//
//              initialize / uninitialize plugin
//
//===========================================================================



namespace
{
    MString sDrawDbClassification("drawdb/geometry/geometryOverrideExample1");
    MString sDrawRegistrantId("geometryOverrideExample1Plugin");
}




MStatus initializePlugin(MObject obj)
{
    MFnPlugin plugin(obj, PLUGIN_COMPANY, "3.0", "Any");
    MStatus status;

    status = plugin.registerShape("geometryOverrideExample1_shape",             // the name of the new type of user defined shape node
                                GeometryOverrideExample1_shape::id,             // a unique id that identifies this node
                                &GeometryOverrideExample1_shape::creator,       // function that will return a pointer to a new instance of the class 
                                                                                // (derived from MPxSurfaceNode) that implements the new shape node type
                                &GeometryOverrideExample1_shape::initialize,    // function that will initialize all the attributes of the new shape node type
                                nullptr,
                                &sDrawDbClassification);
    if (!status)
    {
        std::cerr << "Failed to register geometryOverrideExample1_shape." << std::endl;
        return status;
    }


    status = MHWRender::MDrawRegistry::registerGeometryOverrideCreator(sDrawDbClassification,
                                                                        sDrawRegistrantId,
                                                                        GeometryOverrideExample1::Creator);
    if (!status)
    {
        std::cerr << "Failed to register Viewport 2.0 geometry override." << std::endl;
        return status;
    }

    return status;

}

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

    status = MHWRender::MDrawRegistry::deregisterGeometryOverrideCreator(sDrawDbClassification, sDrawRegistrantId);
    if (!status)
    {
        std::cerr << "Failed to deregister geometry override." << std::endl;
    }

    status = plugin.deregisterNode(GeometryOverrideExample1_shape::id);
    if (!status) 
    {
        std::cerr << "Failed to deregister GeometryOverrideExample1_shape." << std::endl;
    }

    return status;
}