// This file is part of the OGRE project.

// It is subject to the license terms in the LICENSE file found in the top-level directory

// of this distribution and at https://www.ogre3d.org/licensing.

// SPDX-License-Identifier: MIT

#include "OgreStableHeaders.h"

#include "OgreShadowCameraSetup.h"

#include "OgreViewport.h"

#include "OgreHardwarePixelBuffer.h"

#include "OgreCompositorManager.h"

#include "OgreCompositor.h"

namespace Ogre {

SceneManager::TextureShadowRenderer::TextureShadowRenderer(SceneManager* owner) :

mSceneManager(owner),

mShadowCasterPlainBlackPass(0),

mShadowReceiverPass(0),

mShadowTextureCustomCasterPass(0),

mShadowTextureCustomReceiverPass(0),

mDefaultShadowFarDist(0),

mDefaultShadowFarDistSquared(0),

mShadowTextureOffset(0.6),

mShadowTextureFadeStart(0.7),

mShadowTextureFadeEnd(0.9),

mShadowTextureSelfShadow(false),

mShadowTextureConfigDirty(true),

mShadowCasterRenderBackFaces(true)

{

    // set up default shadow camera setup

    mDefaultShadowCameraSetup = DefaultShadowCameraSetup::create();

    mCullCameraSetup = DefaultShadowCameraSetup::create();

    // init shadow texture count per type.

    mShadowTextureCountPerType[Light::LT_POINT] = 1;

    mShadowTextureCountPerType[Light::LT_DIRECTIONAL] = 1;

    mShadowTextureCountPerType[Light::LT_SPOTLIGHT] = 1;

}

SceneManager::TextureShadowRenderer::~TextureShadowRenderer() {}

void SceneManager::TextureShadowRenderer::render(RenderQueueGroup* group,

                                          QueuedRenderableCollection::OrganisationMode om)

{

    // Receiver pass(es)

    if (mSceneManager->isShadowTechniqueAdditive())

    {

        // Auto-additive

        renderAdditiveTextureShadowedQueueGroupObjects(group, om);

        return;

    }

    // Modulative

    renderModulativeTextureShadowedQueueGroupObjects(group, om);

}

size_t SceneManager::TextureShadowRenderer::getShadowTexIndex(size_t startLightIndex)

{

    size_t shadowTexIndex = mShadowTextures.size();

    if (mShadowTextureIndexLightList.size() > startLightIndex)

        shadowTexIndex = mShadowTextureIndexLightList[startLightIndex];

    return shadowTexIndex;

}

//-----------------------------------------------------------------------

void SceneManager::TextureShadowRenderer::renderTextureShadowCasterQueueGroupObjects(

    RenderQueueGroup* pGroup,

    QueuedRenderableCollection::OrganisationMode om)

{

    // This is like the basic group render, except we skip all transparents

    // and we also render any non-shadowed objects

    // Note that non-shadow casters will have already been eliminated during

    // _findVisibleObjects

    // Iterate through priorities

    // Override auto param ambient to force vertex programs and fixed function to

    ColourValue currAmbient = mSceneManager->getAmbientLight();

    if (mSceneManager->isShadowTechniqueAdditive())

    {

        // Use simple black / white mask if additive

        mSceneManager->setAmbientLight(ColourValue::Black);

    }

    else

    {

        // Use shadow colour as caster colour if modulative

        mSceneManager->setAmbientLight(mSceneManager->getShadowColour());

    }

    auto visitor = mSceneManager->getQueuedRenderableVisitor();

    for (const auto& pg : pGroup->getPriorityGroups())

    {

        RenderPriorityGroup* pPriorityGrp = pg.second;

        // Sort the queue first

        pPriorityGrp->sort(mSceneManager->mCameraInProgress);

        // Do solids, override light list incase any vertex programs use them

        visitor->renderObjects(pPriorityGrp->getSolidsBasic(), om, false, false);

        visitor->renderObjects(pPriorityGrp->getSolidsNoShadowReceive(), om, false, false);

        // Do unsorted transparents that cast shadows

        visitor->renderObjects(pPriorityGrp->getTransparentsUnsorted(), om, false, false, nullptr, true);

        // Do transparents that cast shadows

        visitor->renderObjects(pPriorityGrp->getTransparents(), QueuedRenderableCollection::OM_SORT_DESCENDING, false,

                               false, nullptr, true);

    }// for each priority

    // reset ambient light

    mSceneManager->setAmbientLight(currAmbient);

}

//-----------------------------------------------------------------------

void SceneManager::TextureShadowRenderer::renderModulativeTextureShadowedQueueGroupObjects(

    RenderQueueGroup* pGroup,

    QueuedRenderableCollection::OrganisationMode om)

{

    /* For each light, we need to render all the solids from each group,

    then do the modulative shadows, then render the transparents from

    each group.

    Now, this means we are going to reorder things more, but that it required

    if the shadows are to look correct. The overall order is preserved anyway,

    it's just that all the transparents are at the end instead of them being

    interleaved as in the normal rendering loop.

    */

    // Iterate through priorities

    auto visitor = mSceneManager->getQueuedRenderableVisitor();

    for (const auto& pg : pGroup->getPriorityGroups())

    {

        RenderPriorityGroup* pPriorityGrp = pg.second;

        // Sort the queue first

        pPriorityGrp->sort(mSceneManager->mCameraInProgress);

        // Do solids

        visitor->renderObjects(pPriorityGrp->getSolidsBasic(), om, true, true);

        visitor->renderObjects(pPriorityGrp->getSolidsNoShadowReceive(), om, true, true);

    }

    // Iterate over lights, render received shadows

    // only perform this if we're in the 'normal' render stage, to avoid

    // doing it during the render to texture

    if (mSceneManager->mIlluminationStage == IRS_NONE)

    {

        mSceneManager->mIlluminationStage = IRS_RENDER_RECEIVER_PASS;

        LightList::const_iterator i, iend;

        iend = mSceneManager->_getLightsAffectingFrustum().end();

        size_t si = 0;

        for (i = mSceneManager->_getLightsAffectingFrustum().begin();

             i != iend && si < mShadowTextures.size(); ++i)

        {

            Light* l = *i;

            if (!l->getCastShadows())

                continue;

            // Get camera for current shadow texture

            Camera *cam = mShadowTextures[si]->getBuffer()->getRenderTarget()->getViewport(0)->getCamera();

            // Hook up receiver texture

            Pass* targetPass = mShadowTextureCustomReceiverPass ?

                    mShadowTextureCustomReceiverPass : mShadowReceiverPass;

            // if this light is a spotlight, we need to add the spot fader layer

            // BUT not if using a custom projection matrix, since then it will be

            // inappropriately shaped most likely

            if (l->getType() == Light::LT_SPOTLIGHT && !cam->isCustomProjectionMatrixEnabled())

            {

                // remove all TUs except 0 & 1

                // (only an issue if additive shadows have been used)

                while(targetPass->getNumTextureUnitStates() > 2)

                    targetPass->removeTextureUnitState(2);

                TextureUnitState* t = NULL;

                // Add spot fader if not present already

                if (targetPass->getNumTextureUnitStates() == 2 &&

                    targetPass->getTextureUnitState(1)->_getTexturePtr() == mSpotFadeTexture)

                {

                    // Just set

                    t = targetPass->getTextureUnitState(1);

                }

                else

                {

                    // Remove any non-conforming spot layers

                    while(targetPass->getNumTextureUnitStates() > 1)

                        targetPass->removeTextureUnitState(1);

                    t = targetPass->createTextureUnitState();

                    t->setTexture(mSpotFadeTexture);

                    t->setColourOperation(LBO_ADD);

                    t->setTextureAddressingMode(TextureUnitState::TAM_CLAMP);

                }

                t->setProjectiveTexturing(!targetPass->hasVertexProgram(), cam);

                mSceneManager->mAutoParamDataSource->setTextureProjector(cam, 1);

            }

            else

            {

                // remove all TUs except 0 including spot

                while(targetPass->getNumTextureUnitStates() > 1)

                    targetPass->removeTextureUnitState(1);

            }

            // account for the RTSS

            if (auto betterTechnique = targetPass->getParent()->getParent()->getBestTechnique())

            {

                targetPass = betterTechnique->getPass(0);

            }

            TextureUnitState* texUnit = targetPass->getTextureUnitState(0);

            // clamp to border colour in case this is a custom material

            texUnit->setSampler(mBorderSampler);

            resolveShadowTexture(texUnit, si, 0);

            // Set lighting / blending modes

            targetPass->setSceneBlending(SBF_DEST_COLOUR, SBF_ZERO);

            targetPass->setLightingEnabled(false);

            targetPass->_load();

            // Fire pre-receiver event

            fireShadowTexturesPreReceiver(l, cam);

            renderTextureShadowReceiverQueueGroupObjects(pGroup, om);

            ++si;

        } // for each light

        mSceneManager->mIlluminationStage = IRS_NONE;

    }

}

//-----------------------------------------------------------------------

void SceneManager::TextureShadowRenderer::renderAdditiveTextureShadowedQueueGroupObjects(

    RenderQueueGroup* pGroup,

    QueuedRenderableCollection::OrganisationMode om)

{

    LightList lightList(1);

    auto visitor = mSceneManager->getQueuedRenderableVisitor();

    for (const auto& pg : pGroup->getPriorityGroups())

    {

        RenderPriorityGroup* pPriorityGrp = pg.second;

        // Sort the queue first

        pPriorityGrp->sort(mSceneManager->mCameraInProgress);

        // Render all the ambient passes first, no light iteration, no lights

        visitor->renderObjects(pPriorityGrp->getSolidsBasic(), om, false, false);

        // Also render any objects which have receive shadows disabled

        visitor->renderObjects(pPriorityGrp->getSolidsNoShadowReceive(), om, true, true);

        // only perform this next part if we're in the 'normal' render stage, to avoid

        // doing it during the render to texture

        if (mSceneManager->mIlluminationStage == IRS_NONE)

        {

            // Iterate over lights, render masked

            size_t si = 0;

            for (Light* l : mSceneManager->_getLightsAffectingFrustum())

            {

                if (l->getCastShadows() && si < mShadowTextures.size())

                {

                    // Hook up receiver texture

                    Pass* targetPass = mShadowTextureCustomReceiverPass ?

                        mShadowTextureCustomReceiverPass : mShadowReceiverPass;

                    // account for the RTSS

                    if (auto betterTechnique = targetPass->getParent()->getParent()->getBestTechnique())

                    {

                        targetPass = betterTechnique->getPass(0);

                    }

                    TextureUnitState* texUnit = targetPass->getTextureUnitState(0);

                    // clamp to border colour in case this is a custom material

                    texUnit->setSampler(mBorderSampler);

                    resolveShadowTexture(texUnit, si, 0);

                    // Remove any spot fader layer

                    if (targetPass->getNumTextureUnitStates() > 1 &&

                        targetPass->getTextureUnitState(1)->getTextureName() == "spot_shadow_fade.dds")

                    {

                        // remove spot fader layer (should only be there if

                        // we previously used modulative shadows)

                        targetPass->removeTextureUnitState(1);

                    }

                    // Set lighting / blending modes

                    targetPass->setSceneBlending(SBF_ONE, SBF_ONE);

                    targetPass->setLightingEnabled(true);

                    targetPass->_load();

                    // increment shadow texture since used

                    ++si;

                    mSceneManager->mIlluminationStage = IRS_RENDER_RECEIVER_PASS;

                }

                else

                {

                    mSceneManager->mIlluminationStage = IRS_NONE;

                }

                // render lighting passes for this light

                lightList[0] = l;

                // set up light scissoring, always useful in additive modes

                ClipResult scissored = mSceneManager->buildAndSetScissor(lightList, mSceneManager->mCameraInProgress);

                ClipResult clipped = CLIPPED_NONE;

                if(mSceneManager->getShadowUseLightClipPlanes())

                    clipped = mSceneManager->buildAndSetLightClip(lightList);

                // skip if entirely clipped

                if(scissored == CLIPPED_ALL || clipped == CLIPPED_ALL)

                    continue;

                visitor->renderObjects(pPriorityGrp->getSolidsDiffuseSpecular(), om, false, false, &lightList);

                if (scissored == CLIPPED_SOME)

                    mSceneManager->resetScissor();

                if (clipped == CLIPPED_SOME)

                    mSceneManager->resetLightClip();

            }// for each light

            mSceneManager->mIlluminationStage = IRS_NONE;

            // Now render decal passes, no need to set lights as lighting will be disabled

            visitor->renderObjects(pPriorityGrp->getSolidsDecal(), om, false, false);

        }

    }// for each priority

}

//-----------------------------------------------------------------------

void SceneManager::TextureShadowRenderer::renderTextureShadowReceiverQueueGroupObjects(

    RenderQueueGroup* pGroup,

    QueuedRenderableCollection::OrganisationMode om)

{

    // Iterate through priorities

    // Override auto param ambient to force vertex programs to go full-bright

    ColourValue currAmbient = mSceneManager->getAmbientLight();

    mSceneManager->setAmbientLight(ColourValue::White);

    auto visitor = mSceneManager->getQueuedRenderableVisitor();

    for (const auto& pg : pGroup->getPriorityGroups())

    {

        RenderPriorityGroup* pPriorityGrp = pg.second;

        // Do solids, override light list incase any vertex programs use them

        visitor->renderObjects(pPriorityGrp->getSolidsBasic(), om, false, false);

        // Don't render transparents or passes which have shadow receipt disabled

    }// for each priority

    // reset ambient

    mSceneManager->setAmbientLight(currAmbient);

}

//---------------------------------------------------------------------

void SceneManager::TextureShadowRenderer::setupRenderTarget(const String& camName, RenderTarget* rendTarget,

                                                            uint16 depthBufferId)

{

    if (rendTarget->getDepthBufferPool() != RBP_NONE)

    {

        rendTarget->setDepthBufferPool(depthBufferId);

    }

    // Don't update automatically - we'll do it when required

    rendTarget->setAutoUpdated(false);

    float aspectRatio = (Real)rendTarget->getWidth() / (Real)rendTarget->getHeight();

    // Create camera for this texture, but note that we have to rebind

    // in prepareShadowTextures to coexist with multiple SMs

    Camera* cam = mSceneManager->createCamera(camName);

    cam->setAspectRatio(aspectRatio);

    auto camNode = mSceneManager->getRootSceneNode()->createChildSceneNode();

    camNode->attachObject(cam);

    mShadowTextureCameras.push_back(cam);

    // insert dummy camera-light combination

    mShadowCamLightMapping[cam] = NULL;

    // use separate culling camera, in case a focused shadow setup is used

    // in which case we want to keep the original light frustum for culling

    Camera* cullCam = mSceneManager->createCamera(camName+"/Cull");

    cullCam->setAspectRatio(aspectRatio);

    cam->setCullingFrustum(cullCam);

    camNode->attachObject(cullCam);

    // Create a viewport, if not there already

    if (rendTarget->getNumViewports() != 0)

        return;

    // Note camera assignment is transient when multiple SMs

    Viewport *v = rendTarget->addViewport(NULL);

    v->setClearEveryFrame(true);

    v->setOverlaysEnabled(false);

    v->setBackgroundColour(ColourValue::White);

}

void SceneManager::TextureShadowRenderer::ensureShadowTexturesCreated()

{

    if(!mBorderSampler)

    {

        mBorderSampler = TextureManager::getSingleton().createSampler();

        mBorderSampler->setAddressingMode(TAM_BORDER);

        mBorderSampler->setBorderColour(ColourValue::White);

        mBorderSampler->setFiltering(FT_MIP, FO_NONE); // we do not have mips. GLES2 is particularly picky here.

    }

    if (mShadowTextureConfigDirty)

    {

        destroyShadowTextures();

        ShadowTextureManager::getSingleton().getShadowTextures(mShadowTextureConfigList, mShadowTextures);

        // clear shadow cam - light mapping

        mShadowCamLightMapping.clear();

        //Used to get the depth buffer ID setting for each RTT

        size_t __i = 0;

        // Recreate shadow textures

        for (auto& shadowTex : mShadowTextures)

        {

            uint16 depthBufferId = mShadowTextureConfigList[__i].depthBufferPoolId;

            for(uint32 i = 0; i < shadowTex->getNumLayers(); i++)

            {

                String camName = StringUtil::format("%sCam%d", shadowTex->getName().c_str(), i);

                auto rtidx = shadowTex->getUsage() & TU_TARGET_ALL_LAYERS ? 0 : i;

                setupRenderTarget(camName, shadowTex->getRenderTarget(rtidx), depthBufferId);

            }

            ++__i;

        }

        // Assume first one is representative

        if (!mShadowTextureConfigList.empty())

            mNoShadowTexture =

                ShadowTextureManager::getSingleton().getNoShadowTexture(mShadowTextureConfigList[0].format);

        mShadowTextureConfigDirty = false;

    }

}

//---------------------------------------------------------------------

void SceneManager::TextureShadowRenderer::destroyShadowTextures(void)

{

    for (auto cam : mShadowTextureCameras)

    {

        mSceneManager->getRootSceneNode()->removeAndDestroyChild(cam->getParentSceneNode());

        // Always destroy camera since they are local to this SM

        if(auto cullcam = dynamic_cast<Camera*>(cam->getCullingFrustum()))

            mSceneManager->destroyCamera(cullcam);

        mSceneManager->destroyCamera(cam);

    }

    mShadowTextures.clear();

    mShadowTextureCameras.clear();

    // set by render*TextureShadowedQueueGroupObjects

    mSceneManager->mAutoParamDataSource->setTextureProjector(NULL, 0);

    // Will destroy if no other scene managers referencing

    ShadowTextureManager::getSingleton().clearUnused();

    mShadowTextureConfigDirty = true;

}

//---------------------------------------------------------------------

void SceneManager::TextureShadowRenderer::prepareTexCam(Camera* texCam, Camera* cam, Viewport* vp, Light* light,

                                                        size_t j)

{

    // Associate main view camera as LOD camera

    texCam->setLodCamera(cam);

    // set base

    if (light->getType() != Light::LT_POINT)

    {

#ifdef OGRE_NODELESS_POSITIONING

        texCam->getParentSceneNode()->setDirection(light->getDerivedDirection(), Node::TS_WORLD);

#else

        texCam->getParentSceneNode()->setOrientation(light->getParentNode()->_getDerivedOrientation());

#endif

    }

    if (light->getType() != Light::LT_DIRECTIONAL)

        texCam->getParentSceneNode()->setPosition(light->getDerivedPosition());

    // update shadow cam - light mapping

    ShadowCamLightMapping::iterator camLightIt = mShadowCamLightMapping.find(texCam);

    assert(camLightIt != mShadowCamLightMapping.end());

    camLightIt->second = light;

    if (!light->getCustomShadowCameraSetup())

        mDefaultShadowCameraSetup->getShadowCamera(mSceneManager, cam, vp, light, texCam, j);

    else

        light->getCustomShadowCameraSetup()->getShadowCamera(mSceneManager, cam, vp, light, texCam, j);

    // Fire shadow caster update, callee can alter camera settings

    fireShadowTexturesPreCaster(light, texCam, j);

}

void SceneManager::TextureShadowRenderer::updateShadowTextures(Camera* cam, Viewport* vp, const LightList* lightList)

{

    // Determine far shadow distance

    Real shadowDist = mDefaultShadowFarDist;

    if (!shadowDist)

    {

        // need a shadow distance, make one up

        shadowDist = cam->getNearClipDistance() * 300;

    }

    Real shadowOffset = shadowDist * mShadowTextureOffset;

    // Precalculate fading info

    Real shadowEnd = shadowDist + shadowOffset;

    Real fadeStart = shadowEnd * mShadowTextureFadeStart;

    Real fadeEnd = shadowEnd * mShadowTextureFadeEnd;

    // Additive lighting should not use fogging, since it will overbrighten; use border clamp

    if (!mSceneManager->isShadowTechniqueAdditive())

    {

        // set fogging to hide the shadow edge

        mShadowReceiverPass->setFog(true, FOG_LINEAR, ColourValue::White, 0, fadeStart, fadeEnd);

    }

    else

    {

        // disable fogging explicitly

        mShadowReceiverPass->setFog(true, FOG_NONE);

    }

    // Iterate over the lights we've found, max out at the limit of light textures

    // Note that the light sorting must now place shadow casting lights at the

    // start of the light list, therefore we do not need to deal with potential

    // mismatches in the light<->shadow texture list any more

    LightList::const_iterator i, iend;

    ShadowTextureList::iterator si, siend;

    CameraList::iterator ci;

    iend = lightList->end();

    siend = mShadowTextures.end();

    ci = mShadowTextureCameras.begin();

    mShadowTextureIndexLightList.clear();

    size_t shadowTextureIndex = 0;

    for (i = lightList->begin(), si = mShadowTextures.begin(); i != iend && si != siend; ++i)

    {

        Light* light = *i;

        // skip light if shadows are disabled

        if (!light->getCastShadows())

            continue;

        mDestRenderSystem->_setDepthClamp(light->getType() == Light::LT_DIRECTIONAL);

        // texture iteration per light.

        size_t textureCountPerLight = mShadowTextureCountPerType[light->getType()];

        for (size_t j = 0; j < textureCountPerLight && si != siend; ++j)

        {

            TexturePtr &shadowTex = *si;

            size_t layer = j < shadowTex->getDepth() ? j : 0;

            size_t face = j < shadowTex->getNumFaces() ? j : 0;

            RenderTarget *shadowRTT = shadowTex->getBuffer(face)->getRenderTarget(layer);

            Viewport *shadowView = shadowRTT->getViewport(0);

            Camera *texCam = *ci;

            // rebind camera, incase another SM in use which has switched to its cam

            shadowView->setCamera(texCam);

            // also update culling camera

            auto cullCam = dynamic_cast<Camera*>(texCam->getCullingFrustum());

            cullCam->_notifyViewport(shadowView);

            mCullCameraSetup->getShadowCamera(mSceneManager, cam, vp, light, cullCam, j);

            // Use the material scheme of the main viewport

            // This is required to pick up the correct shadow_caster_material and similar properties.

            shadowView->setMaterialScheme(vp->getMaterialScheme());

            // Set the viewport visibility flags

            shadowView->setVisibilityMask(light->getLightMask() & vp->getVisibilityMask());

            bool allLayers = shadowTex->getUsage() & TU_TARGET_ALL_LAYERS;

            size_t layers = std::max(shadowTex->getDepth(), shadowTex->getNumFaces());

            prepareTexCam(texCam, cam, vp, light, j);

            if(allLayers && layers <= textureCountPerLight)

            {

                std::vector<const Camera*> cams = {texCam};

                j++;

                for(; j < layers; ++j)

                {

                    texCam = *(++ci); // next camera

                    texCam->_notifyViewport(shadowView);

                    prepareTexCam(texCam, cam, vp, light, j);

                    cams.push_back(texCam);

                }

                mSceneManager->setVPRTCameras(cams);

            }

            // Update target

            shadowRTT->update();

            if((j + 1) >= layers)

                ++si; // next shadow texture

            ++ci; // next camera

        }

        mDestRenderSystem->_setDepthClamp(false);

        // set the first shadow texture index for this light.

        mShadowTextureIndexLightList.push_back(shadowTextureIndex);

        shadowTextureIndex += textureCountPerLight;

    }

    fireShadowTexturesUpdated(std::min(lightList->size(), mShadowTextures.size()));

    ShadowTextureManager::getSingleton().clearUnused();

}

void SceneManager::TextureShadowRenderer::setShadowTextureCasterMaterial(const MaterialPtr& mat)

{

    if(!mat) {

        mShadowTextureCustomCasterPass = 0;

        return;

    }

    mat->load();

    if (!mat->getBestTechnique())

    {

        // unsupported

        mShadowTextureCustomCasterPass = 0;

    }

    else

    {

        OgreAssert(!mat->getTechnique(0)->getPasses().empty(), "technique 0 has no passes");

        mShadowTextureCustomCasterPass = mat->getTechnique(0)->getPass(0);

    }

}

//---------------------------------------------------------------------

void SceneManager::TextureShadowRenderer::setShadowTextureReceiverMaterial(const MaterialPtr& mat)

{

    if(!mat) {

        mShadowTextureCustomReceiverPass = 0;

        return;

    }

    mat->load();

    if (!mat->getBestTechnique())

    {

        // unsupported

        mShadowTextureCustomReceiverPass = 0;

    }

    else

    {

        OgreAssert(!mat->getTechnique(0)->getPasses().empty(), "technique 0 has no passes");

        mShadowTextureCustomReceiverPass = mat->getTechnique(0)->getPass(0);

    }

}

//---------------------------------------------------------------------

void SceneManager::TextureShadowRenderer::setShadowTechnique(ShadowTechnique technique)

{

    if (mSceneManager->getShadowTechnique() == SHADOWTYPE_TEXTURE_MODULATIVE && !mSpotFadeTexture)

        mSpotFadeTexture = TextureManager::getSingleton().load("spot_shadow_fade.dds", RGN_INTERNAL);

    if (!mSceneManager->isShadowTechniqueTextureBased())

    {

        // Destroy shadow textures to optimise resource usage

        destroyShadowTextures();

        mSpotFadeTexture.reset();

    }

    else

    {

        // assure no custom shadow matrix is used accidentally in case we switch

        // from a custom shadow mapping type to a non-custom (uniform shadow mapping)

        for ( Camera* texCam : mShadowTextureCameras)

        {

            texCam->setCustomViewMatrix(false);

            texCam->setCustomProjectionMatrix(false);

        }

    }

    if(!mSceneManager->getShadowTechnique())

        return;

    // init shadow caster material for texture shadows

    if (!mShadowCasterPlainBlackPass)

    {

        MaterialPtr matPlainBlack = MaterialManager::getSingleton().getByName("Ogre/TextureShadowCaster");

        matPlainBlack->load();

        mShadowCasterPlainBlackPass = matPlainBlack->getTechnique(0)->getPass(0);

    }

    if (!mShadowReceiverPass)

    {

        MaterialPtr matShadRec = MaterialManager::getSingleton().getByName("Ogre/TextureShadowReceiver", RGN_INTERNAL);

        if (!matShadRec)

        {

            matShadRec = MaterialManager::getSingleton().create("Ogre/TextureShadowReceiver", RGN_INTERNAL);

            mShadowReceiverPass = matShadRec->getTechnique(0)->getPass(0);

            // Don't set lighting and blending modes here, depends on additive / modulative

            TextureUnitState* t = mShadowReceiverPass->createTextureUnitState();

            t->setProjectiveTexturing(true, NULL); // will be set later, but the RTSS needs to know about this

        }

        else

        {

            mShadowReceiverPass = matShadRec->getTechnique(0)->getPass(0);

        }

    }

}

const Pass* SceneManager::TextureShadowRenderer::deriveShadowCasterPass(const Pass* pass)

{

    Pass* retPass;

    if (pass->getParent()->getShadowCasterMaterial())

    {

        auto bestTech = pass->getParent()->getShadowCasterMaterial()->getBestTechnique();

        if (bestTech && bestTech->getNumPasses() > 0) {

            return bestTech->getPass(0);

        }

    }

    retPass = mShadowTextureCustomCasterPass ?

        mShadowTextureCustomCasterPass : mShadowCasterPlainBlackPass;

    // Special case alpha-blended passes

    if ((pass->getSourceBlendFactor() == SBF_SOURCE_ALPHA &&

        pass->getDestBlendFactor() == SBF_ONE_MINUS_SOURCE_ALPHA)

        || pass->getAlphaRejectFunction() != CMPF_ALWAYS_PASS)

    {

        // Alpha blended passes must retain their transparency

        retPass->setAlphaRejectSettings(pass->getAlphaRejectFunction(),

            pass->getAlphaRejectValue());

        retPass->setSceneBlending(pass->getSourceBlendFactor(), pass->getDestBlendFactor());

        retPass->getParent()->getParent()->setTransparencyCastsShadows(true);

        // So we allow the texture units, but override the colour functions

        // Copy texture state, shift up one since 0 is shadow texture

        unsigned short origPassTUCount = pass->getNumTextureUnitStates();

        for (unsigned short t = 0; t < origPassTUCount; ++t)

        {

            TextureUnitState* tex;

            if (retPass->getNumTextureUnitStates() <= t)

            {

                tex = retPass->createTextureUnitState();

            }

            else

            {

                tex = retPass->getTextureUnitState(t);

            }

            // copy base state

            (*tex) = *(pass->getTextureUnitState(t));

            // override colour function

            tex->setColourOperationEx(LBX_SOURCE1, LBS_MANUAL, LBS_CURRENT,

                                      mSceneManager->isShadowTechniqueAdditive() ? ColourValue::Black : mSceneManager->getShadowColour());

        }

        // Remove any extras

        while (retPass->getNumTextureUnitStates() > origPassTUCount)

        {

            retPass->removeTextureUnitState(origPassTUCount);

        }

    }

    else

    {

        // reset

        retPass->setSceneBlending(SBT_REPLACE);

        retPass->setAlphaRejectFunction(CMPF_ALWAYS_PASS);

        while (retPass->getNumTextureUnitStates() > 0)

        {

            retPass->removeTextureUnitState(0);

        }

    }

    // give the RTSS a chance to generate a better technique

    retPass->getParent()->getParent()->load();

    Technique* btech = retPass->getParent()->getParent()->getBestTechnique();

    if( btech )

    {

        retPass = btech->getPass(0);

    }

    // Propagate culling modes

    retPass->setCullingMode(pass->getCullingMode());

    retPass->setManualCullingMode(pass->getManualCullingMode());

    return retPass;

}

//---------------------------------------------------------------------

const Pass* SceneManager::TextureShadowRenderer::deriveShadowReceiverPass(const Pass* pass)

{

    if (pass->getParent()->getShadowReceiverMaterial())

    {

        return pass->getParent()->getShadowReceiverMaterial()->getBestTechnique()->getPass(0);

    }

    Pass* retPass = mShadowTextureCustomReceiverPass ? mShadowTextureCustomReceiverPass : mShadowReceiverPass;

    unsigned short keepTUCount;

    // If additive, need lighting parameters & standard programs

    if (mSceneManager->isShadowTechniqueAdditive())

    {

        retPass->setLightingEnabled(true);

        retPass->setAmbient(pass->getAmbient());

        retPass->setSelfIllumination(pass->getSelfIllumination());

        retPass->setDiffuse(pass->getDiffuse());

        retPass->setSpecular(pass->getSpecular());

        retPass->setShininess(pass->getShininess());

        retPass->setLightMask(pass->getLightMask());

        // We need to keep alpha rejection settings

        retPass->setAlphaRejectSettings(pass->getAlphaRejectFunction(),

            pass->getAlphaRejectValue());

        // Copy texture state, shift up one since 0 is shadow texture

        unsigned short origPassTUCount = pass->getNumTextureUnitStates();

        for (unsigned short t = 0; t < origPassTUCount; ++t)

        {

            unsigned short targetIndex = t+1;

            TextureUnitState* tex;

            if (retPass->getNumTextureUnitStates() <= targetIndex)

            {

                tex = retPass->createTextureUnitState();

            }

            else

            {

                tex = retPass->getTextureUnitState(targetIndex);

            }

            (*tex) = *(pass->getTextureUnitState(t));

            // If programmable, have to adjust the texcoord sets too

            // D3D insists that texcoordsets match tex unit in programmable mode

            if (retPass->hasVertexProgram())

                tex->setTextureCoordSet(targetIndex);

        }

        keepTUCount = origPassTUCount + 1;

    }// additive lighting

    else

    {

        // need to keep spotlight fade etc

        keepTUCount = retPass->getNumTextureUnitStates();

    }

    // re-/set light iteration settings

    retPass->setIteratePerLight(pass->getIteratePerLight(), pass->getRunOnlyForOneLightType(),

                                pass->getOnlyLightType());

    // Remove any extra texture units

    while (retPass->getNumTextureUnitStates() > keepTUCount)

    {

        retPass->removeTextureUnitState(keepTUCount);

    }

    // give the RTSS a chance to generate a better technique

    retPass->getParent()->getParent()->load();

    Technique* btech = retPass->getParent()->getParent()->getBestTechnique();

    if( btech )

    {

        retPass = btech->getPass(0);

    }

    return retPass;

}

const Pass* SceneManager::TextureShadowRenderer::deriveTextureShadowPass(const Pass* pass)

{

    if (mSceneManager->_getCurrentRenderStage() == IRS_RENDER_TO_TEXTURE)

    {

        // Derive a special shadow caster pass from this one

        return deriveShadowCasterPass(pass);

    }

    if (mSceneManager->_getCurrentRenderStage() == IRS_RENDER_RECEIVER_PASS)

    {

        return deriveShadowReceiverPass(pass);

    }

    return pass;

}

//---------------------------------------------------------------------

const VisibleObjectsBoundsInfo&

SceneManager::TextureShadowRenderer::getShadowCasterBoundsInfo( const Light* light, size_t iteration ) const

{

    static VisibleObjectsBoundsInfo nullBox;

    // find light

    unsigned int foundCount = 0;

    for (auto& m : mShadowCamLightMapping)

    {

        if (m.second == light )

        {

            if (foundCount == iteration)

            {

                // search the camera-aab list for the texture cam

                auto camIt = mSceneManager->mCamVisibleObjectsMap.find(m.first);

                if (camIt == mSceneManager->mCamVisibleObjectsMap.end())

                {

                    return nullBox;

                }

                else

                {

                    return camIt->second;