// Shave and a Haircut
// (c) 2019 Epic Games
// US Patent 6720962

#include <maya/MAnimControl.h>
#include <maya/MFnDependencyNode.h>
#include <maya/MGlobal.h>
#include <maya/MItDependencyNodes.h>
#include <maya/MString.h>
#include <maya/MTypeId.h>

#include "shaveConstant.h"
#include "shaveGlobals.h"
#include "shaveHairShape.h"
#include "shaveMaya.h"
#include "shaveMayaRenderer.h"
#include "shaveRenderCallback.h"
#include "shaveUtil.h"
#include "shaveVertexShader.h"


shaveMayaRenderer::shaveMayaRenderer()
:	mHaveVolumeShader(false)
,	mRenderCallback(NULL)
,	mRenderCamera("")
,	mTimeState(shaveMayaRenderer::kAwaitingNothing)
,	mWarningGivenUnsupportedHairMode(false)
,	mWarningGivenUnsupportedInstanceMode(false)
{
}


shaveMayaRenderer::~shaveMayaRenderer()
{}


void shaveMayaRenderer::frameStart(const shaveGlobals::Globals& g)
{
	shaveRenderer::frameStart(g);

	//
    // We only need the volume shader if we're doing 3D compositing or handling
    // reflections/refractions for non-geometry hair.
	//
	mHaveVolumeShader = false;

	if ((g.doCompositing && !g.composite2d)
	||	(g.visibleInReflections && (mNonGeometryNodes.length() > 0)))
	{
		//
		// If the render camera has changed, remove the volume shader from
		// the old one and add it to the new one.
		//
		MString		cameraName;
		MGlobal::executeCommand("shave_getRenderCamera()", cameraName);

		if (cameraName != mRenderCamera)
		{
			MGlobal::executeCommand("shave_cleanupVolumeShader ");

			MGlobal::executeCommand(
				MString("shave_setupVolumeShader ") + cameraName
			);

			mHaveVolumeShader = true;
			mRenderCamera = cameraName;
		}
	}

	//
	// At the moment, the Maya renderer will have us in the center of the
	// frame to rendered.  If motion blur is off, that's great.  But if
	// motion blur is on, we only care about the shutter open and close
	// times.  So we'll have to wait for them.
	//
	if (shaveMaya::doMotionBlur)
		mTimeState = kAwaitingShutterOpen;
	else
	{
		MTime	curTime = MAnimControl::currentTime();

		doShutter(curTime, shaveConstant::kShutterBoth);
		mTimeState = kAwaitingNothing;
	}
}


void shaveMayaRenderer::frameEnd(const shaveGlobals::Globals& g)
{
	mRenderCallback->disableCamRender();
	shaveRenderer::frameEnd(g);
}


float shaveMayaRenderer::getPixelAspect() const
{
	return shaveRenderer::getPixelAspect();
}


shaveConstant::RenderMode shaveMayaRenderer::getBaseRenderMode(bool* renderInstances)
		const
{
	//
	// Let the base class do its stuff first.
	//
	shaveConstant::RenderMode	hairRenderMode;

	hairRenderMode = shaveRenderer::getBaseRenderMode(renderInstances);

	//
	// The base class will have verified that the render modes are valid
	// for *some* renderer, but we must make sure that they're valid for
	// *this* renderer.
	//
	switch (hairRenderMode)
	{
		case shaveConstant::kNoRender:
		case shaveConstant::kBufferRender:
		case shaveConstant::kGeometryRender:
		break;

		default:
			if(!shaveRender::rendererIsPrMan())//not clear why for rendermane we do not have separate renderer class - dub|22Jun2012
			{
				if (!mWarningGivenUnsupportedHairMode)
				{
					MGlobal::displayWarning(
						MString("Shave: The Maya renderer does not support ")
						+ shaveRender::getRenderModeName(hairRenderMode)
						+ " hair render mode.  We'll use "
						+ shaveRender::getRenderModeName(shaveConstant::kBufferRender)
						+ " render mode instead."
					);
					mWarningGivenUnsupportedHairMode = true;
				}
			}
			hairRenderMode = shaveConstant::kBufferRender;
		break;
	}

	//
	// Return the render mode to the caller.
	//
	return hairRenderMode;
}


//
// Is this node "rendered" using normal Maya geometry?
//
bool shaveMayaRenderer::isGeomNode(const shaveHairShape* nodePtr) const
{
	//
	// Instances in Maya are always rendered using normal geometry,
	// so if instances are being rendered then this one will.
	//
	if (nodePtr->isInstanced()) return true;

	//
	// If the render mode is kGeometryRender then this node will be
	// rendered using Maya geometry, otherwise it will not.
	//
	shaveConstant::RenderMode	hairRenderMode = getRenderMode();

	return (hairRenderMode == shaveConstant::kGeometryRender);
}


bool shaveMayaRenderer::needVertexColours() const
{
	//
	// If there are any vertex shaders in the scene, then we'll need vertex
	// colour info.
	//
	MItDependencyNodes	iter(MFn::kPluginDependNode);

	for (; !iter.isDone(); iter.next())
	{
		MObject				node = iter.item();
		MFnDependencyNode	nodeFn(node);

		if (nodeFn.typeId() == shaveVertexShader::id) return true;
	}

	return false;
}


void shaveMayaRenderer::render(
		float frame, shaveConstant::ShutterState shutter, const MDagPath& camera
)
{
	if (mNonGeometryNodes.length() > 0)
	{
		//
		// If native illumination is on, the camera render will call
		// SHAVEapply_illuminationWF() which will need to sample the lights
		// in the scene.  Unfortunately, light sampling only works from
		// within an MRenderCallback.  That means that when native
		// illumination is on we cannot do the camera render here but must
		// instead do it in shaveRenderCallback.
		//
		// But wait, there's more.  Our volumetric compositing runs before
		// shaveRenderCallback is called and it needs the output from the
		// render.  So if volumetric compositing is on then we need to do
		// the render now, not later.
		//
		// That means that we cannot support both native illumination and
		// volumetric compositing at the same time.  So if they're both on
		// then volumetric compositing wins.
		//
		// That just leaves us with the case where native illumination and
		// volumetric compositing are both off. In that case we can do the
		// render either here or in the callback. We choose to do it in the
		// callback because that way we can progressively display tiles in
		// the Render View as they render.
		bool	doCamRenderNow = (doShaveCompsGlob && !doShaveComp2dGlob);

		shaveRender::bufferRender(
			shutter, camera, frame, true, true, doCamRenderNow, true
		);

		if (!doCamRenderNow
		&&	((shutter == shaveConstant::kShutterClose)
		||	 (shutter == shaveConstant::kShutterBoth)))
		{
			mRenderCallback->enableCamRender(camera);
		}

		//
		// Set up shaders on the lights to make them cast shadows for our
		// hair.
		//
		if (((shutter == shaveConstant::kShutterOpen)
				|| (shutter == shaveConstant::kShutterBoth))
		&&	(getShadowSource() == shaveConstant::kShaveShadows)
		&& !shaveShadowMatteGlob)
		{
			setupShadowShaders();
		}
	}
}


void shaveMayaRenderer::renderEnd()
{
	if (mHaveVolumeShader)
	{
		if (visibleInReflectionsGlob || !doShaveComp2dGlob)
			MGlobal::executeCommand("shave_cleanupVolumeShader");
	}

	//
	// Remove the compositing callback.
	//
	if (mRenderCallback)
	{
		MRenderCallback::removeCallback(mRenderCallback);
		delete mRenderCallback;
		mRenderCallback = NULL;
	}

	//
	// Undo the shadow matte setup.
	//
	if (shaveShadowMatteGlob
	&&	(getRenderMode() == shaveConstant::kBufferRender))
	{
		MGlobal::executeCommand("shave_cleanupShadowMatte");
	}

	//
	// Reset warning flags so that the next render will get warnings again.
	//
	mWarningGivenUnsupportedHairMode= false;
	mWarningGivenUnsupportedInstanceMode = false;

	shaveRenderer::renderEnd();
}


void shaveMayaRenderer::renderInterrupted()
{
	postCompositeCleanup();
}


void shaveMayaRenderer::renderStart()
{
	mTimeState = kAwaitingNothing;
	shaveRenderer::renderStart();

	//
	// A shadow matte pass is only useful when there is buffered hair in
	// the scene.  If that's the case, and a shadow matte pass has been
	// requested, then set it up.
	//
	if (shaveShadowMatteGlob
	&&	(getRenderMode() == shaveConstant::kBufferRender))
	{
		MGlobal::executeCommand("shave_setupShadowMatte");
	}

	//
	// Set up a render callback to handle compositing buffer renders onto
	// the final image.
	//
	// NOTE:	There's a bug in Maya: it will crash if you reuse an
	//			instance of a render callback object.  So we have to
	//			allocate a fresh one each time.
	//
	mRenderCallback = new shaveRenderCallback(this);

	MRenderCallback::addCallback(mRenderCallback, 255);
}


void shaveMayaRenderer::timeChange(const MTime& newTime)
{
	switch (mTimeState)
	{
		case kAwaitingShutterOpen:
			doShutter(newTime, shaveConstant::kShutterOpen);

			if (shaveRenderCancelled)
				mTimeState = kAwaitingNothing;
			else
				mTimeState = kAwaitingCenterFrame;
		break;

		case kAwaitingCenterFrame:
			mTimeState = kAwaitingShutterClose;
		break;

		case kAwaitingShutterClose:
			doShutter(newTime, shaveConstant::kShutterClose);

			mTimeState = kAwaitingNothing;
		break;

		default:
		break;
	}
}


//************************************************
//
//		Helper Methods
//
//************************************************

void shaveMayaRenderer::postCompositeCleanup()
{
	//
	// Remove any shadow shaders we may have created.
	//
	if (!shaveShadowMatteGlob
	&&	(getShadowSource() == shaveConstant::kShaveShadows))
	{
		MGlobal::executeCommand("shave_disconnectShadowShaders()");
	}

	//
	// It's now safe to free up Shave's render buffers.
	//
	shaveRender::bufferRenderCleanup();
}


//
// Hook up shadow handler nodes to the lights.
//
void shaveMayaRenderer::setupShadowShaders()
{
	unsigned int	i;
	unsigned int	numLights = (unsigned int)shaveUtil::globalLightList.size();


	for (i = 0; i < numLights; i++)
	{
	    MDagPath	lightPath = shaveUtil::globalLightList[i].path;
		MString		cmd = "shave_connectShadowShader "
						+ lightPath.fullPathName() + " ";

		//
		//  MString supplies a '+=' operator for ints, but not a '+' operator.
		//
		cmd += (int)i;
		MGlobal::executeCommand(cmd);
	}
}