blindDataShader/blindDataShaderOverride.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.
// ==========================================================================
//+
#include "blindDataShaderOverride.h"
#include <maya/MShaderManager.h>
#include <maya/MDrawContext.h>




blindDataShaderOverride::blindDataShaderOverride(const MObject& obj)
    : MHWRender::MPxShaderOverride(obj)
{
    MHWRender::MRenderer *renderer = MHWRender::MRenderer::theRenderer();
    if (!renderer)
        return;

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

    // Get a built-in shader that use vertex position and per vertex color as input.
    fCPVShaderInstance = shaderMgr->getStockShader(MHWRender::MShaderManager::k3dCPVSolidShader); 
}



blindDataShaderOverride::~blindDataShaderOverride()
{
    MHWRender::MRenderer *renderer = MHWRender::MRenderer::theRenderer();
    if (!renderer)
        return;

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

    if(fCPVShaderInstance)
        shaderMgr->releaseShader(fCPVShaderInstance);
}



MString blindDataShaderOverride::initialize(const MInitContext& initContext, MInitFeedback& initFeedback)
{
    //
    // Define the geometry requirement (Vertex shader input layout) that is required by the shader k3dCPVSolidShader.
    //
    MHWRender::MVertexBufferDescriptor positionDesc(MString(), MHWRender::MGeometry::kPosition, MHWRender::MGeometry::kFloat, 3);

    MHWRender::MVertexBufferDescriptor colorDesc(MString(), MHWRender::MGeometry::kColor, MHWRender::MGeometry::kFloat, 4);
    
    colorDesc.setSemanticName("blindDataColorStream"); // Here we set the name of the vertex buffer generator that will generate the color stream. (See initializePlugin())

    addGeometryRequirement(positionDesc);
    addGeometryRequirement(colorDesc);

    return MString("Autodesk Maya blindDataShaderOverride");
}



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



MHWRender::MShaderInstance* blindDataShaderOverride::shaderInstance(MDrawContext& /*context*/) const
{
    return fCPVShaderInstance;
}



void blindDataShaderOverride::activateKey(MDrawContext& context, const MString& key)
{
    if(fCPVShaderInstance)
        fCPVShaderInstance->bind(context);
}



void blindDataShaderOverride::terminateKey(MDrawContext& context, const MString& key)
{
    if(fCPVShaderInstance)
        fCPVShaderInstance->unbind(context);
}



bool blindDataShaderOverride::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++)
    {
        if (passSem[i] == MHWRender::MPassContext::kColorPassSemantic)
        {
            bool hasOverrideShader = passCtx.hasShaderOverride();
            if (!hasOverrideShader)
            {
                handlePass = true;
            }
        }
    }

    return handlePass;
}



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