viewRenderOverride/viewRenderOverride.h

//-
// 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 <stdio.h>

#include <maya/MString.h>
#include <maya/MDrawTraversal.h>
#include <maya/MSelectionList.h>
#include <maya/M3dView.h>
#include <maya/MViewport2Renderer.h>
#include <maya/MDrawContext.h>
#include <maya/MFrameContext.h>
#include <maya/MUiMessage.h>

/*
    Sample custom render override class.

    Is responsible for setting up the render loop operations and
    updating resources for each frame render as well as any
    rendering options.

    By default the plugin will perform a number of operations
    in order to:

    1) Draw a procedurally generated background
    2) Draw the non-UI parts of the scene using internal logic.
    3) Threshold the scene
    4) Blur the thresholded output
    5) Combine the thresholded output with the original scene (resulting
       in a "glow")
    6a) Draw the UI parts of the scene using internal logic.
    6b) Perform an option custom user operation for additional UI.
    7) Draw the 2D HUD
    8) 'Present' the final output

    A number of intermediate render targets are created to hold contents
    which are passed from operation to operation.
*/
enum ETargetId // Helper to enumerate the target indexing
{
    kMyColorTarget,
    kMyDepthTarget,
    kMyBlurTarget,

    kTargetCount
};
class viewRenderOverride : public MHWRender::MRenderOverride
{
public:
    // Enumerations to identify an operation within
    // a list of operations.
    enum {
        kBackgroundBlit = 0,
        // 3d scene render to target 1
        kMaya3dSceneRender,
        // 3d opaque scene render to target 1
        kMaya3dSceneRenderOpaque,
        // 3d transparent scene render to target 1
        kMaya3dSceneRenderTransparent,
        // Brightness threshold
        kThresholdOp,
        // Down sample to target 2
        kHorizBlurOp,
        kVertBlurOp,
        // Blend target 1 and 2 back to target 1
        kBlendOp,
        // Post ops on target 1
        kPostOperation1,
        kPostOperation2,
        // Post ui draw to target 1
        kMaya3dSceneRenderUI,
        // User op draw to target 1
        kUserOpNumber,
        // Draw HUD on top
        kHUDBlit,
        // Present
        kPresentOp,
        kNumberOfOps
    };

    viewRenderOverride( const MString & name );
    ~viewRenderOverride() override;
    MHWRender::DrawAPI supportedDrawAPIs() const override;

    // Virtual overrides to return operations in this override
    bool startOperationIterator() override;
    MHWRender::MRenderOperation * renderOperation() override;
    bool nextRenderOperation() override;

    // Override setup and cleanup for this override
    //
    MStatus setup( const MString & destination ) override;
    MStatus cleanup() override;

    // Unique name for this override
    static MString gsVROName;

    const MString & panelName() const
    {
        return mPanelName;
    }
    void setSimpleRendering( bool flag )
    {
        mSimpleRendering = flag;
    }
    MString uiName() const override
    {
        return mUIName;
    }

protected:
    bool updateRenderTargets();

    // Operation lists
    MHWRender::MRenderOperation * mRenderOperations[kNumberOfOps];
    MString mRenderOperationNames[kNumberOfOps];
    int mCurrentOperation;

    // Shared render target list
    MString mTargetOverrideNames[kTargetCount];
    MHWRender::MRenderTargetDescription* mTargetDescriptions[kTargetCount];
    MHWRender::MRenderTarget* mTargets[kTargetCount];
    bool mTargetSupportsSRGBWrite[kTargetCount];

    // Override is for this panel
    MString mPanelName;

    // Split UI / nonUI draw
    bool mSplitUIDraw;

    // Simple rendering
    bool mSimpleRendering;

    // UI name which will show up in places
    // like the viewport 'Renderer' menu
    MString mUIName;

    bool mDebugOverride;

    // Callback IDs for tracking viewport changes
    MCallbackId mRendererChangeCB;
    MCallbackId mRenderOverrideChangeCB;
    static void sRendererChangeFunc(
        const MString& panelName,
        const MString& oldRenderer,
        const MString& newRenderer,
        void* clientData);
    static void sRenderOverrideChangeFunc(
        const MString& panelName,
        const MString& oldRenderer,
        const MString& newRenderer,
        void* clientData);
};

//
// Render override support classes
//
//------------------------------------------------------------------------
//  Custom present target operation
//
//  Only overrides the targets to present
//
class viewRenderPresentTarget : public MHWRender::MPresentTarget
{
public:
    viewRenderPresentTarget(const MString &name);
    ~viewRenderPresentTarget() override;

    MHWRender::MRenderTarget* const* targetOverrideList(unsigned int &listSize) override;

    void setRenderTargets(MHWRender::MRenderTarget **targets);
protected:
    // Targets used as input parameters to mShaderInstance;
    MHWRender::MRenderTarget **mTargets;
};

//------------------------------------------------------------------------
// Custom quad operation
//
//  General quad operation which can be instantiated with a few
//  different shaders.
//
class viewRenderQuadRender : public MHWRender::MQuadRender
{
public:
    // Shader list
    typedef enum {
        kEffectNone,
        kPost_EffectMonochrome, // Mono color shader
        kPost_EffectEdgeDetect, // Edge detect shader
        kPost_EffectInvert,     // Invert color shader
        kScene_Threshold,       // Color threshold shader
        kScene_BlurHoriz,       // Horizontal blur shader
        kScene_BlurVert,        // Vertical blur shader
        kSceneBlur_Blend,       // Blend shader
        kPre_MandelBrot,        // Mandelbrot shader
    } MQuadShader ;

    viewRenderQuadRender(const MString &name);
    ~viewRenderQuadRender() override;

    const MHWRender::MShaderInstance * shader() override;
    MHWRender::MRenderTarget* const* targetOverrideList(unsigned int &listSize) override;
    MHWRender::MClearOperation & clearOperation() override;

    void setRenderTargets(MHWRender::MRenderTarget **targets)
    {
        mTargets = targets;
    }
    void setShader( MQuadShader shader )
    {
        mShader = shader;
    }
    MQuadShader shader() const
    {
        return mShader;
    }
    const MFloatPoint & viewRectangle() const
    {
        return mViewRectangle;
    }
    void setViewRectangle(const MFloatPoint & rect)
    {
        mViewRectangle = rect;
    }

protected:
    // Shader to use for the quad render
    MHWRender::MShaderInstance *mShaderInstance;
    // Targets used as input parameters to mShaderInstance;
    MHWRender::MRenderTarget** mTargets;
    // View rectangle
    MFloatPoint mViewRectangle;

    // Shader to use for quad rendering
    MQuadShader mShader;
};

//------------------------------------------------------------------------
// Custom hud operation
//
class viewRenderHUDOperation : public MHWRender::MHUDRender
{
public:
    viewRenderHUDOperation()
    {
        mTargets = NULL;
    }

    // Target override
    MHWRender::MRenderTarget* const* targetOverrideList(unsigned int &listSize) override
    {
        if (mTargets)
        {
            listSize = 2;
            return &mTargets[0];
        }
        listSize = 0;
        return NULL;
    }

    bool hasUIDrawables() const override
    {
        return true;
    }

    void addUIDrawables( MHWRender::MUIDrawManager& drawManager2D, const MHWRender::MFrameContext& frameContext ) override;

    void setRenderTargets(MHWRender::MRenderTarget **targets)
    {
        mTargets = targets;
    }

    ~viewRenderHUDOperation() override
    {
        mTargets = NULL;
    }

protected:
    MHWRender::MRenderTarget** mTargets;
};


//------------------------------------------------------------------------
//
// Simple scene operation that just overrides the clear operation
// and the viewport rectange.
//
class simpleViewRenderSceneRender : public MHWRender::MSceneRender
{
public:
    simpleViewRenderSceneRender(const MString &name);
    const MFloatPoint * viewportRectangleOverride() override;
    MHWRender::MClearOperation & clearOperation() override;

    MFloatPoint mViewRectangle;
};

//------------------------------------------------------------------------
/* Custom scene operation

    A scene render which is reused as necessary with different
    override parameters
*/
class viewRenderSceneRender : public MHWRender::MSceneRender
{
public:
    viewRenderSceneRender(
        const MString &name,
        MHWRender::MSceneRender::MSceneFilterOption sceneFilter,
        unsigned int clearMask);
    ~viewRenderSceneRender() override;

    void setRenderTargets(MHWRender::MRenderTarget **targets);

    MHWRender::MRenderTarget* const* targetOverrideList(unsigned int &listSize) override;
    bool enableSRGBWrite() override;
    const MHWRender::MCameraOverride * cameraOverride() override;
    MHWRender::MSceneRender::MSceneFilterOption renderFilterOverride() override;
    MHWRender::MSceneRender::MDisplayMode displayModeOverride() override;
    MHWRender::MSceneRender::MLightingMode lightModeOverride() override;
    const bool* shadowEnableOverride() override;
    MHWRender::MSceneRender::MCullingOption cullingOverride() override;

    void preRender() override;
    void postRender() override;
    MUint64 getObjectTypeExclusions() override;
    const MSelectionList * objectSetOverride() override;
    MHWRender::MClearOperation & clearOperation() override;
    const MHWRender::MShaderInstance* shaderOverride() override;
    bool hasUIDrawables() const override
    {
        return true;
    }

    void addPreUIDrawables( MHWRender::MUIDrawManager& drawManager, const MHWRender::MFrameContext& frameContext ) override;
    void addPostUIDrawables( MHWRender::MUIDrawManager& drawManager, const MHWRender::MFrameContext& frameContext ) override;

    const MString & panelName() const
    {
        return mPanelName;
    }
    void setPanelName( const MString & name )
    {
        mPanelName.set( name.asChar() );
    }
    const MFloatPoint & viewRectangle() const
    {
        return mViewRectangle;
    }
    void setViewRectangle(const MFloatPoint & rect)
    {
        mViewRectangle = rect;
    }

    MHWRender::MRenderTarget* colorTarget() const
    {
        return mTargets ? mTargets[kMyColorTarget] : NULL;
    }
    MHWRender::MRenderTarget* depthTarget() const
    {
        return mTargets ? mTargets[kMyDepthTarget] : NULL;
    }
    void setEnableSRGBWriteFlag( bool val )
    {
        mEnableSRGBWrite = val;
    }
    bool enableSRGBWriteFlag() const
    {
        return mEnableSRGBWrite;
    }

protected:
    MSelectionList mSelectionList;

    // 3D viewport panel name, if available
    MString mPanelName;
    // Camera override
    MHWRender::MCameraOverride mCameraOverride;
    // Viewport rectangle override
    MFloatPoint mViewRectangle;
    // Available render targets
    MHWRender::MRenderTarget** mTargets;
    // Shader override for surfaces
    MHWRender::MShaderInstance *mShaderOverride;
    // Scene draw filter override
    MHWRender::MSceneRender::MSceneFilterOption mSceneFilter;
    // Mask for clear override
    unsigned int mClearMask;

    // Some sample override flags
    bool    mUseShaderOverride;
    bool    mUseStockShaderOverride;
    bool    mAttachPrePostShaderCallback;
    bool    mUseShadowShader;
    bool    mOverrideDisplayMode;
    bool    mOverrideDisplayModeFlatActive;
    bool    mOverrideLightingMode;
    bool    mOverrideCullingMode;
    bool    mDebugTargetResourceHandle;
    bool    mOverrrideM3dViewDisplayMode;
    M3dView::DisplayStyle mPrevDisplayStyle; // Track previous display style of override set
    bool    mFilterDrawNothing;
    bool    mFilterDrawSelected;
    bool    mEnableSRGBWrite;
};

//------------------------------------------------------------------------
/*
    Custom user operation. One approach to adding a pre and
    post scene callback. In this approach only 1 operation
    is reused twice with internal state as to when it is being
    used. Another approach which may be more suitable for when
    global state is changed is to create 2 instances of this
    operation and keep global state on the override instead of
    locally here.

    The cost of an override is very small so creating more instances
    can provide a clearer and cleaner render loop logic.
*/
class viewRenderUserOperation : public MHWRender::MUserRenderOperation
{
public:
    viewRenderUserOperation(const MString &name);
    ~viewRenderUserOperation() override;

    MStatus execute( const MHWRender::MDrawContext & drawContext ) override;
    const MHWRender::MCameraOverride * cameraOverride() override;
    MHWRender::MRenderTarget* const* targetOverrideList(unsigned int &listSize) override;
    bool enableSRGBWrite() override;
    bool hasUIDrawables() const override;
    void addUIDrawables(
        MHWRender::MUIDrawManager& drawManager,
        const MHWRender::MFrameContext& frameContext ) override;

    void setRenderTargets(MHWRender::MRenderTarget **targets)
    {
        mTargets = targets;
    }
    void setEnableSRGBWriteFlag( bool val )
    {
        fEnableSRGBWriteFlag = val;
    }

    const MString & panelName() const
    {
        return mPanelName;
    }
    void setPanelName( const MString & name )
    {
        mPanelName.set( name.asChar() );
    }
    const MFloatPoint & viewRectangle() const
    {
        return mViewRectangle;
    }
    void setViewRectangle(const MFloatPoint & rect)
    {
        mViewRectangle = rect;
    }

protected:
    // 3D viewport panel name, if any
    MString mPanelName;
    // Camera override
    MHWRender::MCameraOverride mCameraOverride;
    // Viewport rectangle override
    MFloatPoint mViewRectangle;
    // Available targets
    MHWRender::MRenderTarget** mTargets;
    // sRGB write flag
    bool fEnableSRGBWriteFlag;
    // Draw an extra label
    bool fDrawLabel;
    // Use camera override
    bool fUserCameraOverride;
    // Draw colored bounding boxes
    bool fDrawBoundingBoxes;
    // Debugging flags
    bool fDebugDrawContext;
    bool fDebugLightingInfo;
};

/*
    Draw traversal utility used by
    the custom user operation (viewRenderUserOperation)
*/
class MSurfaceDrawTraversal : public MDrawTraversal
{
    // Override to filter out some node types.
    bool filterNode( const MDagPath &traversalItem ) override;
};

/*
    A very simplistic custom scene draw example which just draws
    coloured bounding boxes for surface types.

    This code is similiar to the example code found in the
    plugin examples OpenGLViewportRenderer and DX11ViewportRenderer
    found in earlier versions of Mayaw hich just traverse the scene
    to perform a draw.

    Used by the custom user operation (viewRenderUserOperation)
*/
class MCustomSceneDraw
{
public:
    MCustomSceneDraw();
    ~MCustomSceneDraw();

    // Draw a bounding box
    void drawBounds( const MDagPath &dagPath,
                     const MBoundingBox &box);

    // Draw a scene full of bounding boxes
    bool draw(MDagPath &cameraPath, unsigned int width, unsigned int height);
};




/*
    Some utility routines
*/
class viewRenderOverrideUtilities
{
public:
    static void printDrawContextLightInfo( const MHWRender::MDrawContext & drawContext );
};