C++ mhwrender::MDrawContext类代码示例

void ovalLocatorDrawOverride::draw (const MHWRender::MDrawContext &context, const MUserData *data) {
	MPointArray vertices =ovalLocator::vertices () ;
	// get cached data
	float color [3] ={ 0.0f, 1.0f, 0.0f } ;
	float multiplier =1.0f ;
	const ovalLocatorData *ovalData =dynamic_cast<const ovalLocatorData *>(data) ;
	if ( ovalData )
		multiplier =ovalData->multiplier ;	
	// get state data
	MStatus status ;
	const MMatrix transform =context.getMatrix (MHWRender::MDrawContext::kWorldViewMtx, &status) ;
	if ( status !=MStatus::kSuccess )
		return ;
	const MMatrix projection =context.getMatrix (MHWRender::MDrawContext::kProjectionMtx, &status) ;
	if ( status !=MStatus::kSuccess )
		return ;
	const int displayStyle =context.getDisplayStyle () ;
	// get renderer
	MHWRender::MRenderer *theRenderer =MHWRender::MRenderer::theRenderer () ;
	if ( !theRenderer )
		return ;

	// GL Draw
	if ( theRenderer->drawAPIIsOpenGL () ) {
		// set colour
		glColor3fv (color) ;
		// set world matrix
		glMatrixMode (GL_MODELVIEW) ;
		glPushMatrix () ;
		glLoadMatrixd (transform.matrix [0]) ;
		// set projection matrix
		glMatrixMode (GL_PROJECTION) ;
		glPushMatrix () ;
		glLoadMatrixd (projection.matrix [0]) ;
		if ( displayStyle & MHWRender::MDrawContext::kGouraudShaded ) {
			// See myShadedDraw
			glPushAttrib (GL_CURRENT_BIT) ;
			glBegin (GL_TRIANGLE_FAN) ;
			glVertex3f (0, 0, 0) ;
			for ( int i =0 ; i < vertices.length () ; ++i )
				glVertex3f (vertices [i].x * multiplier, vertices [i].y * multiplier, vertices [i].z * multiplier) ;
			glEnd () ;
			glPopAttrib () ;
		}
		if ( displayStyle & MHWRender::MDrawContext::kWireFrame ) {
			// See myWireFrameDraw
			glBegin (GL_LINES) ;
			for ( int i =0 ; i < vertices.length () - 1 ; ++i ) {
				glVertex3f (vertices [i].x * multiplier, vertices [i].y * multiplier, vertices [i].z * multiplier) ;
				glVertex3f (vertices [i + 1].x * multiplier, vertices [i + 1].y * multiplier, vertices [i + 1].z * multiplier) ;
			}
			glEnd () ;
		}
		glPopMatrix () ;
		glMatrixMode (GL_MODELVIEW) ;
		glPopMatrix () ;
	}
}

void arrowLocatorOverride::draw(
	const MHWRender::MDrawContext& context,
	const MUserData* data)
{
	MAngle rotationAngle;

	float color [3] ={ 0.0f, 1.0f, 0.0f } ;

	// data
	MStatus status;
	MHWRender::MStateManager* stateMgr = context.getStateManager();
	const arrowLocatorData* locatorData =
		dynamic_cast<const arrowLocatorData*>(data);
	if (!stateMgr || !locatorData) return;

	if ( locatorData )
		rotationAngle = locatorData->rotateAngle;

	// matrices
	const MMatrix transform =
		context.getMatrix(MHWRender::MFrameContext::kWorldViewMtx, &status);
	if (status != MStatus::kSuccess) return;
	const MMatrix projection =
		context.getMatrix(MHWRender::MFrameContext::kProjectionMtx, &status);
	if (status != MStatus::kSuccess) return;

	// get renderer
	MHWRender::MRenderer *theRenderer =MHWRender::MRenderer::theRenderer () ;
	if ( !theRenderer )
		return ;
	if ( theRenderer->drawAPIIsOpenGL () ) {
		
		glPushAttrib(GL_CURRENT_BIT);
		glColor4fv(color);

		glPushMatrix();
		glRotated(-rotationAngle.asDegrees(), 0.0, 1.0, 0.0);
		glBegin( GL_LINE_STRIP);
		glVertex3f(arrow[0][0],arrow[0][1],arrow[0][2]);
		glVertex3f(arrow[1][0],arrow[1][1],arrow[1][2]);
		glVertex3f(arrow[2][0],arrow[2][1],arrow[2][2]);
		glEnd();

		glBegin( GL_LINE_STRIP );
		glVertex3f(arrow[2][0],arrow[2][1],arrow[2][2]);
		glVertex3f(arrow[3][0],arrow[3][1],arrow[3][2]);
		glVertex3f(arrow[0][0],arrow[0][1],arrow[0][2]);
		glEnd();
		glPopMatrix();

	}
}

void
UsdMayaGLBatchRenderer::Draw(
    const MHWRender::MDrawContext& context,
    const MUserData *userData)
{
    // VP 2.0 Implementation
    //
    MHWRender::MRenderer* theRenderer = MHWRender::MRenderer::theRenderer();
    if( !theRenderer || !theRenderer->drawAPIIsOpenGL() )
        return;

    const _BatchDrawUserData* batchData = static_cast<const _BatchDrawUserData*>(userData);
    if( !batchData )
        return;
    
    MStatus status;

    MMatrix projectionMat = context.getMatrix(MHWRender::MDrawContext::kProjectionMtx, &status);
    
    if( batchData->_bounds )
    {
        MMatrix worldViewMat = context.getMatrix(MHWRender::MDrawContext::kWorldViewMtx, &status);

        px_vp20Utils::RenderBoundingBox(*(batchData->_bounds),
                                        *(batchData->_wireframeColor),
                                        worldViewMat,
                                        projectionMat);
    }
    
    if( batchData->_drawShape && !_renderQueue.empty() )
    {
        MMatrix viewMat = context.getMatrix(MHWRender::MDrawContext::kViewMtx, &status);

        // Extract camera settings from maya view
        int viewX, viewY, viewWidth, viewHeight;
        context.getViewportDimensions(viewX, viewY, viewWidth, viewHeight);
        GfVec4d viewport(viewX, viewY, viewWidth, viewHeight);

        // Only the first call to this will do anything... After that the batch
        // queue is cleared.
        //
        _RenderBatches( &context, viewMat, projectionMat, viewport );
    }
}

MStatus PluginTestUserOperation::execute(const MHWRender::MDrawContext & drawContext)
{
	//return MStatus::kSuccess;
	M3dView view;
	if(M3dView::getM3dViewFromModelPanel(panelName, view) == MStatus::kSuccess)
	{
		// Get the current viewport and scale it relative to that
		//
		int targetW, targetH;
		drawContext.getRenderTargetSize(targetW, targetH);

		// Some user drawing of scene bounding boxes
		//
		MDagPath cameraPath;
		MFnCamera fnCamera;
		view.getCamera(cameraPath);
		MMatrix m3dViewProjection, m3dViewModelView;
		view.projectionMatrix(m3dViewProjection);
		view.modelViewMatrix(m3dViewModelView);
		MFloatMatrix m3dFloatViewProjection(m3dViewProjection.matrix);
		MFloatMatrix m3dFloatViewModelView(m3dViewModelView.matrix);
		MFloatMatrix viewProjection = m3dFloatViewModelView * m3dFloatViewProjection;
		SurfaceDrawTraversal traversal;
		traversal.enableFiltering(true);
		traversal.setFrustum(cameraPath, targetW, targetH);
		traversal.traverse();
		unsigned int numItems = traversal.numberOfItems();
		MFnMesh fnMesh;
		for (int i = 0; i < numItems; i++)
		{
			MDagPath path;
			traversal.itemPath(i, path);
			if (path.hasFn(MFn::kMesh))
			{
				fnMesh.setObject(path);
				MFloatMatrix modelWorld(path.inclusiveMatrix().matrix);
				MTransformationMatrix transformMatrix;
				MFloatMatrix modelViewProjection = modelWorld * viewProjection;
				modelViewProjection = modelViewProjection.transpose();
				MIntArray triangleCounts;
				MIntArray triangleVertices; // This is the index list for all the triangles in the mesh in one big list. Ie. first 3 are for tri 1 etc. Index into getPoints()
				fnMesh.getTriangles(triangleCounts, triangleVertices);
				//int indices[100];
				//triangleVertices.get(indices);
				MFloatPointArray vertexArray;
				//float points[1000][4];
				fnMesh.getPoints(vertexArray);
				//vertexArray.get(points);
				UserSceneRenderer::get()->render(triangleVertices, vertexArray, modelViewProjection);
			}
		}
	}
	return MStatus::kSuccess;
}

bool dx11ShaderOverride::draw(
    MHWRender::MDrawContext& context,
    const MHWRender::MRenderItemList& renderItemList) const
{
    // Get effect wrapper
    if (!fShaderNode) return false;

    // Sample code to debug pass information
    static const bool debugPassInformation = false;
    if (debugPassInformation)
    {
        const MHWRender::MPassContext & passCtx = context.getPassContext();
        const MString & passId = passCtx.passIdentifier();
        const MStringArray & passSem = passCtx.passSemantics();
        printf("dx11 shader drawing in pass[%s], semantic[", passId.asChar());
        for (unsigned int i=0; i<passSem.length(); i++)
            printf(" %s", passSem[i].asChar());
        printf("\n");
    }

    return fShaderNode->render(context, renderItemList);
}

void UsdMayaGLHdRenderer::RenderVp2(
    const RequestDataArray &requests,
    const MHWRender::MDrawContext& context,
    UsdImagingGLRenderParams params) const
{
    using namespace MHWRender;

    MStatus status;
    MHWRender::MRenderer* theRenderer = MHWRender::MRenderer::theRenderer();
    if (!theRenderer) return;

    MHWRender::MStateManager* stateMgr = context.getStateManager();
    if (!stateMgr) return;

    const int displayStyle = context.getDisplayStyle();
    if (displayStyle == 0) return;

    if (displayStyle & MDrawContext::kXray) {
        // Viewport 2.0 will call draw() twice when drawing transparent objects
        // (X-Ray mode). We skip the first draw() call.
        const MRasterizerState* rasterState = stateMgr->getRasterizerState();
        if (rasterState && rasterState->desc().cullMode == MRasterizerState::kCullFront) {
            return;
        }
    }

    if (!theRenderer->drawAPIIsOpenGL()) return;


    glPushAttrib(GL_CURRENT_BIT | GL_LIGHTING_BIT);

    const MMatrix worldView =
        context.getMatrix(MHWRender::MDrawContext::kWorldViewMtx, &status);
    GfMatrix4d modelViewMatrix(worldView.matrix);

    const MMatrix projection =
        context.getMatrix(MHWRender::MDrawContext::kProjectionMtx, &status);
    GfMatrix4d projectionMatrix(projection.matrix);

    // get root matrix
    MMatrix root = context.getMatrix(MHWRender::MDrawContext::kWorldMtx, &status);
    GfMatrix4d rootMatrix(root.matrix);

    // Extract camera settings from maya view
    int viewX, viewY, viewWidth, viewHeight;
    context.getViewportDimensions(viewX, viewY, viewWidth, viewHeight);

    GfVec4d viewport(viewX, viewY, viewWidth, viewHeight);

    M3dView::DisplayStyle viewDisplayStyle = displayStyle & MDrawContext::kWireFrame ?
        M3dView::kWireFrame : M3dView::kGouraudShaded;

    if(viewDisplayStyle == M3dView::kGouraudShaded)
    {
        px_vp20Utils::setupLightingGL(context);
        glEnable(GL_LIGHTING);
    }

    _renderer->SetCameraState(modelViewMatrix, projectionMatrix, viewport);

    _renderer->SetLightingStateFromOpenGL();


    TF_FOR_ALL(it, requests) {
        RequestData request = *it;
        if(viewDisplayStyle == M3dView::kWireFrame && request.drawRequest.displayStyle() == M3dView::kGouraudShaded) {
            request.drawRequest.setDisplayStyle(viewDisplayStyle);
        }

        switch(request.drawRequest.token()) {
        case UsdMayaGLHdRenderer::DRAW_WIREFRAME:
        case UsdMayaGLHdRenderer::DRAW_POINTS: {

            params.drawMode = request.drawRequest.token() == 
                UsdMayaGLHdRenderer::DRAW_WIREFRAME ? 
                    UsdImagingGLDrawMode::DRAW_WIREFRAME :
                    UsdImagingGLDrawMode::DRAW_POINTS;
            params.enableLighting = false;
            params.cullStyle = UsdImagingGLCullStyle::CULL_STYLE_NOTHING;

            params.overrideColor = request.fWireframeColor;

            // Get and render usdPrim
            _renderer->Render(_renderedPrim, params);

            break;
        }
        case UsdMayaGLHdRenderer::DRAW_SHADED_FLAT:
        case UsdMayaGLHdRenderer::DRAW_SHADED_SMOOTH: {


            params.drawMode = ((request.drawRequest.token() == 
                    UsdMayaGLHdRenderer::DRAW_SHADED_FLAT) ?
                        UsdImagingGLDrawMode::DRAW_GEOM_FLAT : 
                        UsdImagingGLDrawMode::DRAW_GEOM_SMOOTH);
            params.enableLighting = true;
            params.cullStyle = 
                UsdImagingGLCullStyle::CULL_STYLE_BACK_UNLESS_DOUBLE_SIDED;

            _renderer->Render(_renderedPrim, params);
//.........这里部分代码省略.........

GLuint
OpenSubdivPtexShader::bindProgram(const MHWRender::MDrawContext &     mDrawContext,
                                  OpenSubdiv::OsdGLDrawContext *osdDrawContext,
                                  const OpenSubdiv::OsdPatchArray &   patch)
{

    CHECK_GL_ERROR("bindProgram begin\n");

    // Build shader
    Effect effect;
    effect.color = _enableColor;
    effect.occlusion = _enableOcclusion;
    effect.displacement = _enableDisplacement;
    effect.normal = _enableNormal;
    EffectDesc effectDesc( patch.desc, effect );
    EffectDrawRegistry::ConfigType *
    config = effectRegistry.GetDrawConfig(effectDesc);

    // Install shader
    GLuint program = config->program;
    glUseProgram(program);

    // Update and bind transform state
    struct Transform {
        float ModelViewMatrix[16];
        float ProjectionMatrix[16];
        float ModelViewProjectionMatrix[16];
    } transformData;
    setMatrix(mDrawContext.getMatrix(MHWRender::MDrawContext::kWorldViewMtx),
              transformData.ModelViewMatrix);
    setMatrix(mDrawContext.getMatrix(MHWRender::MDrawContext::kProjectionMtx),
              transformData.ProjectionMatrix);
    setMatrix(mDrawContext.getMatrix(MHWRender::MDrawContext::kWorldViewProjMtx),
              transformData.ModelViewProjectionMatrix);

    if (!g_transformUB) {
        glGenBuffers(1, &g_transformUB);
        glBindBuffer(GL_UNIFORM_BUFFER, g_transformUB);
        glBufferData(GL_UNIFORM_BUFFER,
                     sizeof(transformData), NULL, GL_STATIC_DRAW);
    };
    glBindBuffer(GL_UNIFORM_BUFFER, g_transformUB);
    glBufferSubData(GL_UNIFORM_BUFFER,
                    0, sizeof(transformData), &transformData);
    glBindBuffer(GL_UNIFORM_BUFFER, 0);

    glBindBufferBase(GL_UNIFORM_BUFFER, g_transformBinding, g_transformUB);

    // Update and bind tessellation state
    struct Tessellation {
        float TessLevel;
        int GregoryQuadOffsetBase;
        int PrimitiveIdBase;
    } tessellationData;

    tessellationData.TessLevel = static_cast<float>(1 << _tessFactor);
    tessellationData.GregoryQuadOffsetBase = patch.GetQuadOffsetBase;
    tessellationData.PrimitiveIdBase = patch.GetPatchIndex();;

    if (!g_tessellationUB) {
        glGenBuffers(1, &g_tessellationUB);
        glBindBuffer(GL_UNIFORM_BUFFER, g_tessellationUB);
        glBufferData(GL_UNIFORM_BUFFER,
                     sizeof(tessellationData), NULL, GL_STATIC_DRAW);
    };
    glBindBuffer(GL_UNIFORM_BUFFER, g_tessellationUB);
    glBufferSubData(GL_UNIFORM_BUFFER,
                    0, sizeof(tessellationData), &tessellationData);
    glBindBuffer(GL_UNIFORM_BUFFER, 0);

    glBindBufferBase(GL_UNIFORM_BUFFER,
                     g_tessellationBinding,
                     g_tessellationUB);


#ifdef USE_NON_IMAGE_BASED_LIGHTING
    // Update and bind lighting state
    int numLights = mDrawContext.numberOfActiveLights();
    struct Lighting {
        struct Light {
            float position[4];
            float diffuse[4];
            float ambient[4];
            float specular[4];
        } lightSource[2];
    } lightingData;
    memset(&lightingData, 0, sizeof(lightingData));

    for (int i = 0; i < numLights && i < 1; ++i) {
        MFloatPointArray positions;
        MFloatVector direction;
        float intensity;
        MColor color;
        bool hasDirection, hasPosition;
        mDrawContext.getLightInformation(i, positions, direction, intensity,
                                         color, hasDirection, hasPosition);

        Lighting::Light &light = lightingData.lightSource[i];
        if (hasDirection) {
            light.position[0] = -direction[0];
//.........这里部分代码省略.........

void OpenSubdivDrawOverride::draw(const MHWRender::MDrawContext& context, const MUserData* data)
{
    // get cached data
    bool isSelected = false;
    SubdivUserData* mesh = const_cast<SubdivUserData*>(dynamic_cast<const SubdivUserData*>(data));
    if (mesh)
    {
        isSelected = mesh->fIsSelected;
    }

    // set colour
    static const float colorData[] = {1.0f, 0.0f, 0.0f};
    static const float selectedColorData[] = {0.0f, 1.0f, 0.0f};
    if(isSelected)
        glColor3fv(selectedColorData);
    else
        glColor3fv(colorData);
    MStatus status;

    // set world matrix
    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    MMatrix transform =
        context.getMatrix(MHWRender::MDrawContext::kWorldViewMtx, &status);
    if (status)
    {
        glLoadMatrixd(transform.matrix[0]);
    }

    // set projection matrix
    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
    MMatrix projection =
        context.getMatrix(MHWRender::MDrawContext::kProjectionMtx, &status);
    if (status)
    {
        glLoadMatrixd(projection.matrix[0]);
    }


    const int displayStyle = context.getDisplayStyle();
    glPushAttrib( GL_CURRENT_BIT );
    glPushAttrib( GL_ENABLE_BIT);

    if(displayStyle & MHWRender::MDrawContext::kGouraudShaded) {
        glEnable(GL_LIGHTING);
        glEnable(GL_LIGHT0);
        glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
    }else if(displayStyle & MHWRender::MDrawContext::kWireFrame){
        glDisable(GL_LIGHTING);
        glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    }

    {
        int vertexStride = mesh->GetVertexStride();
//        int varyingStride = mesh->GetVaryingStride();
        //printf("Draw. stride = %d\n", stride);
        glBindBuffer(GL_ARRAY_BUFFER, mesh->GetVertexBuffer());
        glVertexPointer(3, GL_FLOAT, vertexStride, ((char*)(0)));
        glEnableClientState(GL_VERTEX_ARRAY);

        glBindBuffer(GL_ARRAY_BUFFER, mesh->GetVertexBuffer());
        glNormalPointer(GL_FLOAT, vertexStride, ((char*)(12)));
//        glBindBuffer(GL_ARRAY_BUFFER, mesh->GetVaryingBuffer());
//        glNormalPointer(GL_FLOAT, varyingStride, ((char*)(0)));
        glEnableClientState(GL_NORMAL_ARRAY);

        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mesh->GetElementBuffer());
        glDrawElements(mesh->GetPrimType(), mesh->GetNumIndices(), GL_UNSIGNED_INT, NULL);

        glBindBuffer(GL_ARRAY_BUFFER, 0);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
    }

    glPopAttrib();
    glPopAttrib();

    glPopMatrix();

    glMatrixMode(GL_MODELVIEW);
    glPopMatrix();

    glColor3f(1, 1, 1);
}

/*
	From the draw context, get the list of lights and queue the ones we are interested in
	into the "desired list"
*/
MStatus shadowPrepass::execute( const MHWRender::MDrawContext & context )
{
	MHWRender::MRenderer* theRenderer = MHWRender::MRenderer::theRenderer();
	if (!theRenderer)
		return MStatus::kSuccess;

	// Skip lighting modes where there are no lights which can
	// cast shadows
	MHWRender::MDrawContext::LightingMode lightingMode = context.getLightingMode();
	if (lightingMode != MHWRender::MDrawContext::kSelectedLights &&
		lightingMode != MHWRender::MDrawContext::kSceneLights)
	{
		return MStatus::kSuccess;
	}

	MHWRender::MDrawContext::LightFilter lightFilter = 
		MHWRender::MDrawContext::kFilteredIgnoreLightLimit;
	unsigned int nbSceneLights = context.numberOfActiveLights(lightFilter);

	for (unsigned int i=0; i<nbSceneLights; i++)
	{
		MHWRender::MLightParameterInformation* lightInfo = 
			context.getLightParameterInformation( i, lightFilter );
		if (!lightInfo)
			continue;

		// Get the actually Maya light node
		MStatus status = MStatus::kFailure;
		MDagPath lightPath = lightInfo->lightPath(&status);
		if (status != MStatus::kSuccess || !lightPath.isValid())
			continue;

		// Would be good to have an API method here to indicate if it
		// casts shadows
		MIntArray intVals;

		// Check if light is enabled, and emits any lighting
		MHWRender::MLightParameterInformation::StockParameterSemantic semantic =
			MHWRender::MLightParameterInformation::kLightEnabled;
		if (MStatus::kSuccess == lightInfo->getParameter( semantic, intVals ))
		{
			if (intVals.length())
			{
				if (intVals[0] == 0)
					continue;
			}
		}

		semantic = MHWRender::MLightParameterInformation::kEmitsDiffuse;
		if (MStatus::kSuccess == lightInfo->getParameter( semantic, intVals ))
		{
			if (intVals.length())
			{
				if (intVals[0] == 0)
					continue;
			}
		}

		semantic = MHWRender::MLightParameterInformation::kEmitsSpecular;
		if (MStatus::kSuccess == lightInfo->getParameter( semantic, intVals ))
		{
			if (intVals.length())
			{
				if (intVals[0] == 0)
					continue;
			}
		}

		// Check if local shadows are enabled.
		semantic = MHWRender::MLightParameterInformation::kShadowOn;
		if (MStatus::kSuccess == lightInfo->getParameter( semantic, intVals ))
		{
			if (intVals.length())
			{
				if (intVals[0] == 0)
					continue;
			}
		}

		// Check if the shadow is "dirty"
		bool shadowIsDirty = false;
		semantic = MHWRender::MLightParameterInformation::kShadowDirty;
		if (MStatus::kSuccess == lightInfo->getParameter( semantic, intVals ))
		{
			if (intVals.length())
			{
				if (intVals[0] == 0)
				//	continue;

				shadowIsDirty = intVals[0] != 0 ? true : false ;
			}
		}

		// Check the light list to prune, if not already pruned
		bool prune = false;
		if (lightingMode != MHWRender::MDrawContext::kSelectedLights)
//.........这里部分代码省略.........

/*
	Utility method to update shader parameters based on available
	lighting information.
*/
static void updateLightShader( MHWRender::MShaderInstance *shaderInstance,
						const MHWRender::MDrawContext & context,
						const MSelectionList * lightList )
{
	if (!shaderInstance)
		return;

	// Check pass context information to see if we are in a shadow 
	// map update pass. If so do nothing.
	//
	const MHWRender::MPassContext & passCtx = context.getPassContext();
	const MStringArray & passSem = passCtx.passSemantics();
	bool handlePass = true;
	for (unsigned int i=0; i<passSem.length() && handlePass; i++)
	{
		// Handle special pass drawing.
		//
		if (passSem[i] == MHWRender::MPassContext::kShadowPassSemantic)
		{
			handlePass = false;
		}
	}
	if (!handlePass) return;

	//
	// Perform light shader update with lighting information
	// If the light list is not empty then use that light's information.
	// Otherwise choose the first appropriate light which can cast shadows.
	//

	// Defaults in case there are no lights
	//
	bool globalShadowsOn = false;
	bool localShadowsOn = false;
	bool shadowDirty = false;
	MFloatVector direction(0.0f, 0.0f, 1.0f);
	float lightIntensity = 0.0f; // If no lights then black out the light
	float lightColor[3] = { 0.0f, 0.0f, 0.0f };

	MStatus status;

	// Scan to find the first N lights that has a direction component in it
	// It's possible we find no lights.
	//
	MHWRender::MDrawContext::LightFilter considerAllSceneLights = MHWRender::MDrawContext::kFilteredIgnoreLightLimit;
	unsigned int lightCount = context.numberOfActiveLights(considerAllSceneLights);
	if (lightCount)
	{
		MFloatArray floatVals;
		MIntArray intVals;
		MHWRender::MTextureAssignment shadowResource;
		shadowResource.texture = NULL;
		MHWRender::MSamplerStateDesc samplerDesc;
		MMatrix shadowViewProj;
		float shadowColor[3] = { 0.0f, 0.0f, 0.0f };

		unsigned int i=0;
		bool foundDirectional = false;
		for (i=0; i<lightCount && !foundDirectional ; i++)
		{
			MHWRender::MLightParameterInformation *lightParam = context.getLightParameterInformation( i, considerAllSceneLights );
			if (lightParam)
			{
				// Prune against light list if any.
				if (lightList && lightList->length())
				{
					if (!lightList->hasItem(lightParam->lightPath()))
						continue;
				}

				MStringArray params;
				lightParam->parameterList(params);
				for (unsigned int p=0; p<params.length(); p++)
				{
					MString pname = params[p];

					MHWRender::MLightParameterInformation::StockParameterSemantic semantic = lightParam->parameterSemantic( pname );
					switch (semantic)
					{
						// Pick a few light parameters to pick up as an example
					case MHWRender::MLightParameterInformation::kWorldDirection:
						lightParam->getParameter( pname, floatVals );
						direction = MFloatVector( floatVals[0], floatVals[1], floatVals[2] );
						foundDirectional = true;
						break;
					case MHWRender::MLightParameterInformation::kIntensity:
						lightParam->getParameter( pname, floatVals );
						lightIntensity = floatVals[0];
						break;
					case MHWRender::MLightParameterInformation::kColor:
						lightParam->getParameter( pname, floatVals );
						lightColor[0] = floatVals[0];
						lightColor[1] = floatVals[1];
						lightColor[2] = floatVals[2];
						break;

//.........这里部分代码省略.........

MStatus viewRenderUserOperation::execute( const MHWRender::MDrawContext & drawContext )
{
	// Sample code to debug pass information
	static const bool debugPassInformation = false;
	if (debugPassInformation)
	{
		const MHWRender::MPassContext & passCtx = drawContext.getPassContext();
		const MString & passId = passCtx.passIdentifier();
		const MStringArray & passSem = passCtx.passSemantics();
		printf("viewRenderUserOperation: drawing in pass[%s], semantic[", passId.asChar());
		for (unsigned int i=0; i<passSem.length(); i++)
			printf(" %s", passSem[i].asChar());
		printf("\n");
	}

	// Example code to find the active override.
	// This is not necessary if the operations just keep a reference
	// to the override, but this demonstrates how this
	// contextual information can be extracted.
	//
	MHWRender::MRenderer *theRenderer = MHWRender::MRenderer::theRenderer();
	const MHWRender::MRenderOverride *overridePtr = NULL;
	if (theRenderer)
	{
		const MString & overrideName = theRenderer->activeRenderOverride();
		overridePtr = theRenderer->findRenderOverride( overrideName );
	}

	// Some sample code to debug lighting information in the MDrawContext
	//
	if (fDebugLightingInfo)
	{
		viewRenderOverrideUtilities::printDrawContextLightInfo( drawContext );
	}

	// Some sample code to debug other MDrawContext information
	//
	if (fDebugDrawContext)
	{
		MStatus status;
		MMatrix matrix = drawContext.getMatrix(MHWRender::MFrameContext::kWorldMtx, &status);
		double dest[4][4];
		status = matrix.get(dest);
		printf("World matrix is:\n");
		printf("\t%f, %f, %f, %f\n", dest[0][0], dest[0][1], dest[0][2], dest[0][3]);
		printf("\t%f, %f, %f, %f\n", dest[1][0], dest[1][1], dest[1][2], dest[1][3]);
		printf("\t%f, %f, %f, %f\n", dest[2][0], dest[2][1], dest[2][2], dest[2][3]);
		printf("\t%f, %f, %f, %f\n", dest[3][0], dest[3][1], dest[3][2], dest[3][3]);

		MDoubleArray viewDirection = drawContext.getTuple(MHWRender::MFrameContext::kViewDirection, &status);
		printf("Viewdirection is: %f, %f, %f\n", viewDirection[0], viewDirection[1], viewDirection[2]);

		MBoundingBox box = drawContext.getSceneBox(&status);
		printf("Screen box is:\n");
		printf("\twidth=%f, height=%f, depth=%f\n", box.width(), box.height(), box.depth());
		float center[4];
		box.center().get(center);
		printf("\tcenter=(%f, %f, %f, %f)\n", center[0], center[1], center[2], center[3]);


		int originX, originY, width, height;
		status = drawContext.getViewportDimensions(originX, originY, width, height);
		printf("Viewport dimension: center(%d, %d), width=%d, heigh=%d\n", originX, originY, width, height);
	}

	//  Draw some addition things for scene draw
	//
	M3dView mView;
	if (mPanelName.length() &&
		(M3dView::getM3dViewFromModelPanel(mPanelName, mView) == MStatus::kSuccess))
	{
		// Get the current viewport and scale it relative to that
		//
		int targetW, targetH;
		drawContext.getRenderTargetSize( targetW, targetH );

		if (fDrawLabel)
		{
			MString testString("Drawing with override: ");
			testString += overridePtr->name();
			MPoint pos(0.0,0.0,0.0);
			glColor3f( 1.0f, 1.0f, 1.0f );
			mView.drawText( testString, pos);
		}

		// Some user drawing of scene bounding boxes
		//
		if (fDrawBoundingBoxes)
		{
			MDagPath cameraPath;
			mView.getCamera( cameraPath);
			MCustomSceneDraw userDraw;
			userDraw.draw( cameraPath, targetW, targetH );
		}
	}
	return MStatus::kSuccess;
}

//
// #### Override draw method.  
//
// Setup draw state and call osdMeshData methods to setup 
// and refine geometry.  Call to shader to do actual drawing.
//
bool
OpenSubdivShaderOverride::draw(
    MHWRender::MDrawContext &context,
    const MHWRender::MRenderItemList &renderItemList) const
{
    {
        MHWRender::MStateManager *stateMgr = context.getStateManager();
        static const MDepthStencilState * depthState = NULL;
        if (!depthState) {
            MDepthStencilStateDesc desc;
            depthState = stateMgr->acquireDepthStencilState(desc);
        }
        static const MBlendState *blendState = NULL;
        if (!blendState) {
            MBlendStateDesc desc;

            int ntargets = desc.independentBlendEnable ?
                MHWRender::MBlendState::kMaxTargets : 1;

            for (int i = 0; i < ntargets; ++i) {
                desc.targetBlends[i].blendEnable = false;
            }
            blendState = stateMgr->acquireBlendState(desc);
        }

        stateMgr->setDepthStencilState(depthState);
        stateMgr->setBlendState(blendState);
    }

    for (int i = 0; i < renderItemList.length(); i++) 
    {
        const MHWRender::MRenderItem *renderItem = renderItemList.itemAt(i);
        OsdMeshData *data =
            static_cast<OsdMeshData*>(renderItem->customData());
        if (data == NULL) {
            return false;
        }

        // If attributes or topology have changed which affect 
        // the HBR mesh it will be regenerated here.
        data->rebuildHbrMeshIfNeeded(_shader);

        const MHWRender::MVertexBuffer *position = NULL;
        {
            const MHWRender::MGeometry *geometry = renderItem->geometry();
            for (int i = 0; i < geometry->vertexBufferCount(); i++) {
                const MHWRender::MVertexBuffer *vb = geometry->vertexBuffer(i);
                const MHWRender::MVertexBufferDescriptor &vdesc = vb->descriptor();

                if (vdesc.name() == "osdPosition")
                    position = vb;
            }
        }

        // If HBR mesh was regenerated, rebuild FAR mesh factory
        // and recreate OSD draw context
        data->prepare();

        // Refine geometry
        data->updateGeometry(position);

        // Draw patches
        _shader->draw(context, data);
    }

    return true;
}

bool
OpenSubdivShaderOverride::draw(MHWRender::MDrawContext &context, const MHWRender::MRenderItemList &renderItemList) const
{
	using namespace MHWRender;
    {
        MHWRender::MStateManager *stateMgr = context.getStateManager();
        static const MDepthStencilState * depthState = NULL;
        if (!depthState) {
            MDepthStencilStateDesc desc;
            depthState = stateMgr->acquireDepthStencilState(desc);
        }
        static const MBlendState *blendState = NULL;
        if (!blendState) {
            MBlendStateDesc desc;

            for(int i = 0; i < (desc.independentBlendEnable ? MHWRender::MBlendState::kMaxTargets : 1); ++i) 
            {    
                desc.targetBlends[i].blendEnable = false;
            }
            blendState = stateMgr->acquireBlendState(desc);
        }

        stateMgr->setDepthStencilState(depthState);
        stateMgr->setBlendState(blendState);
    }

    for(int i=0; i< renderItemList.length(); i++){
        const MHWRender::MRenderItem *renderItem = renderItemList.itemAt(i);
        OsdMeshData *data = (OsdMeshData*)(renderItem->customData());
        if (data == NULL) {
            return false;
        }
        
        data->populateIfNeeded(_shader->getLevel(), _shader->getScheme(), _shader->getKernel());

        const MHWRender::MVertexBuffer *position = NULL, *normal = NULL;
        {
            const MHWRender::MGeometry *geometry = renderItem->geometry();
            for(int i = 0; i < geometry->vertexBufferCount(); i++){
                const MHWRender::MVertexBuffer *vb = geometry->vertexBuffer(i);
                const MHWRender::MVertexBufferDescriptor &vdesc = vb->descriptor();
                if (vdesc.name() == "osdPosition")
                    position = vb;
                if (vdesc.name() == "osdNormal")
                    normal = vb;
            }
        }

        float diffuse[4] = {1, 1, 1, 1};
        float ambient[4] = {0.1f, 0.1f, 0.1f, 0.1f};
        float specular[4] = {1, 1, 1, 1};
        glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse);
        glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
        glLightfv(GL_LIGHT0, GL_SPECULAR, specular);

        glPushAttrib(GL_POLYGON_BIT);
        glPushAttrib(GL_ENABLE_BIT);

        if (_shader->isWireframe()) {
            glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
            glDisable(GL_LIGHTING);
            glDisable(GL_LIGHT0);
        } else {
            glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
            glEnable(GL_LIGHTING);
            glEnable(GL_LIGHT0);
        }

        // draw meshdata
        data->prepare();

        data->updateGeometry(position, normal);

        data->draw();

        glPopAttrib();
        glPopAttrib();
    }
    return true;
}

// #### bindProgram
//
//      Do all the work to build and install shader including
//      set up buffer blocks for uniform variables, set up
//      default lighting parameters, pass material uniforms
//      and bind texture buffers used by texture maps and by
//      OpenSubdiv's built-in shading code.
//
GLuint
OpenSubdivShader::bindProgram(const MHWRender::MDrawContext &     mDrawContext,
                                    OpenSubdiv::OsdGLDrawContext *osdDrawContext,
                              const OpenSubdiv::OsdDrawContext::PatchArray &   patch)
{

    CHECK_GL_ERROR("bindProgram begin\n");

    // Primitives are triangles for Loop subdivision, quads otherwise
    Effect effect = kFill;
    EffectDesc effectDesc( patch.GetDescriptor(), effect );

    // Build shader
    EffectDrawRegistry::ConfigType *
        config = g_effectRegistry.GetDrawConfig(effectDesc);

    // Install shader
    GLuint program = config->program;
    glUseProgram(program);

    // Update and bind transform state
    struct Transform {
        float ModelViewMatrix[16];
        float ProjectionMatrix[16];
        float ModelViewProjectionMatrix[16];
    } transformData;
    setMatrix(mDrawContext.getMatrix(MHWRender::MDrawContext::kWorldViewMtx),
              transformData.ModelViewMatrix);
    setMatrix(mDrawContext.getMatrix(MHWRender::MDrawContext::kProjectionMtx),
              transformData.ProjectionMatrix);
    setMatrix(mDrawContext.getMatrix(MHWRender::MDrawContext::kWorldViewProjMtx),
              transformData.ModelViewProjectionMatrix);

    if (!g_transformUB) {
        glGenBuffers(1, &g_transformUB);
        glBindBuffer(GL_UNIFORM_BUFFER, g_transformUB);
        glBufferData(GL_UNIFORM_BUFFER,
                sizeof(transformData), NULL, GL_STATIC_DRAW);
    };
    glBindBuffer(GL_UNIFORM_BUFFER, g_transformUB);
    glBufferSubData(GL_UNIFORM_BUFFER,
                0, sizeof(transformData), &transformData);
    glBindBuffer(GL_UNIFORM_BUFFER, 0);

    glBindBufferBase(GL_UNIFORM_BUFFER, g_transformBinding, g_transformUB);

    // Update and bind tessellation state
    struct Tessellation {
        float TessLevel;
    } tessellationData;

    tessellationData.TessLevel = static_cast<float>(1 << _tessFactor);

    if (!g_tessellationUB) {
        glGenBuffers(1, &g_tessellationUB);
        glBindBuffer(GL_UNIFORM_BUFFER, g_tessellationUB);
        glBufferData(GL_UNIFORM_BUFFER,
                sizeof(tessellationData), NULL, GL_STATIC_DRAW);
    };
    glBindBuffer(GL_UNIFORM_BUFFER, g_tessellationUB);
    glBufferSubData(GL_UNIFORM_BUFFER,
                0, sizeof(tessellationData), &tessellationData);
    glBindBuffer(GL_UNIFORM_BUFFER, 0);

    glBindBufferBase(GL_UNIFORM_BUFFER,
                     g_tessellationBinding,
                     g_tessellationUB);


    // Update and bind lighting state
    int numLights = mDrawContext.numberOfActiveLights();
    struct Lighting {
        struct Light {
            float position[4];
            float diffuse[4];
            float ambient[4];
            float specular[4];
        } lightSource[2];
    } lightingData;
    memset(&lightingData, 0, sizeof(lightingData));

    for (int i = 0; i < numLights && i < 2; ++i) {
        MFloatPointArray positions;
        MFloatVector direction;
        float intensity;
        MColor color;
        bool hasDirection, hasPosition;
        mDrawContext.getLightInformation(i, positions, direction, intensity,
                                    color, hasDirection, hasPosition);

        MMatrix modelView = mDrawContext.getMatrix(MHWRender::MDrawContext::kWorldViewMtx);
        direction = MVector(direction) * modelView;
//.........这里部分代码省略.........

bool
OpenSubdivPtexShaderOverride::draw(
    MHWRender::MDrawContext &context,
    const MHWRender::MRenderItemList &renderItemList) const
{
    {
        MHWRender::MStateManager *stateMgr = context.getStateManager();
        static const MDepthStencilState * depthState = NULL;
        if (!depthState) {
            MDepthStencilStateDesc desc;
            depthState = stateMgr->acquireDepthStencilState(desc);
        }
        static const MBlendState *blendState = NULL;
        if (!blendState) {
            MBlendStateDesc desc;

            int ntargets = desc.independentBlendEnable ?
                MHWRender::MBlendState::kMaxTargets : 1;

            for (int i = 0; i < ntargets; ++i) {
                desc.targetBlends[i].blendEnable = false;
            }
            blendState = stateMgr->acquireBlendState(desc);
        }

        stateMgr->setDepthStencilState(depthState);
        stateMgr->setBlendState(blendState);
    }

    for (int i = 0; i < renderItemList.length(); i++) 
    {
        const MHWRender::MRenderItem *renderItem = renderItemList.itemAt(i);
        OsdPtexMeshData *data =
            static_cast<OsdPtexMeshData*>(renderItem->customData());
        if (data == NULL) {
            return false;
        }

        // pass attribute values into osdPtexMeshData
        data->rebuildHbrMeshIfNeeded(_shader);

        const MHWRender::MVertexBuffer *position = NULL, *normal = NULL;
        {
            const MHWRender::MGeometry *geometry = renderItem->geometry();
            for (int i = 0; i < geometry->vertexBufferCount(); i++) {
                const MHWRender::MVertexBuffer *vb = geometry->vertexBuffer(i);
                const MHWRender::MVertexBufferDescriptor &vdesc = vb->descriptor();

                if (vdesc.name() == "osdPosition")
                    position = vb;
                else if (vdesc.name() == "osdNormal")
                    normal = vb;
            }
        }

        // draw meshdata
        data->prepare();

        data->updateGeometry(position, normal);

        _shader->draw(context, data);
    }

    return true;
}