vkdoom_m/src/rendering/hwrenderer/scene/hw_drawinfo.cpp

// 
//---------------------------------------------------------------------------
//
// Copyright(C) 2000-2018 Christoph Oelckers
// All rights reserved.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with this program.  If not, see http://www.gnu.org/licenses/
//
//--------------------------------------------------------------------------
//
/*
** gl_drawinfo.cpp
** Basic scene draw info management class
**
*/

#include "a_sharedglobal.h"
#include "r_utility.h"
#include "r_sky.h"
#include "d_player.h"
#include "g_levellocals.h"
#include "hw_fakeflat.h"
#include "hw_portal.h"
#include "hw_renderstate.h"
#include "hw_drawinfo.h"
#include "hw_drawcontext.h"
#include "hw_walldispatcher.h"
#include "po_man.h"
#include "models.h"
#include "hw_clock.h"
#include "hw_cvars.h"
#include "flatvertices.h"
#include "hw_vrmodes.h"
#include "hw_clipper.h"
#include "v_draw.h"
#include "texturemanager.h"
#include "actorinlines.h"
#include "g_levellocals.h"

EXTERN_CVAR(Float, r_visibility)
EXTERN_CVAR(Int, lm_background_updates);
EXTERN_CVAR(Float, r_actorspriteshadowdist)

CVAR(Bool, lm_always_update, false, 0)

CVAR(Bool, gl_bandedswlight, false, CVAR_ARCHIVE)
CVAR(Bool, gl_sort_textures, false, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
CVAR(Bool, gl_no_skyclear, false, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
CVAR(Int, gl_enhanced_nv_stealth, 3, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)

CVAR(Bool, gl_texture, true, 0)
CVAR(Float, gl_mask_threshold, 0.5f, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
CVAR(Float, gl_mask_sprite_threshold, 0.5f, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)

CVAR(Bool, gl_coronas, true, CVAR_ARCHIVE);

CVAR(Bool, gl_levelmesh, false, 0/*CVAR_ARCHIVE | CVAR_GLOBALCONFIG*/)

sector_t * hw_FakeFlat(sector_t * sec, sector_t * dest, area_t in_area, bool back);


//==========================================================================
//
// Sets up a new drawinfo struct
//
//==========================================================================

HWDrawInfo *HWDrawInfo::StartDrawInfo(HWDrawContext* drawctx, FLevelLocals *lev, HWDrawInfo *parent, FRenderViewpoint &parentvp, HWViewpointUniforms *uniforms)
{
	HWDrawInfo *di = drawctx->di_list.GetNew();
	di->Level = lev;
	di->StartScene(parentvp, uniforms);
	return di;
}

void HWDrawInfo::StartScene(FRenderViewpoint &parentvp, HWViewpointUniforms *uniforms)
{
	drawctx->staticClipper.Clear();
	mClipper = &drawctx->staticClipper;

	Viewpoint = parentvp;
	lightmode = getRealLightmode(Level, true);

	if (uniforms)
	{
		VPUniforms = *uniforms;
		// The clip planes will never be inherited from the parent drawinfo.
		VPUniforms.mClipLine.X = -1000001.f;
		VPUniforms.mClipHeight = 0;
	}
	else
	{
		VPUniforms.mProjectionMatrix.loadIdentity();
		VPUniforms.mViewMatrix.loadIdentity();
		VPUniforms.mNormalViewMatrix.loadIdentity();
		VPUniforms.mViewHeight = viewheight;
		if (lightmode == ELightMode::Build)
		{
			VPUniforms.mGlobVis = 1 / 64.f;
			VPUniforms.mPalLightLevels = 32 | (static_cast<int>(gl_fogmode) << 8) | ((int)lightmode << 16);
		}
		else
		{
			VPUniforms.mGlobVis = (float)R_GetGlobVis(r_viewwindow, r_visibility) / 32.f;
			VPUniforms.mPalLightLevels = static_cast<int>(gl_bandedswlight) | (static_cast<int>(gl_fogmode) << 8) | ((int)lightmode << 16);
		}
		VPUniforms.mClipLine.X = -10000000.0f;
		VPUniforms.mShadowFilter = static_cast<int>(gl_light_shadow_filter);
		VPUniforms.mLightBlendMode = (level.info ? (int)level.info->lightblendmode : 0);
	}
	mClipper->SetViewpoint(Viewpoint);

	ClearBuffers();

	for (int i = 0; i < GLDL_TYPES; i++) drawlists[i].Reset();
	hudsprites.Clear();
	Coronas.Clear();
	Fogballs.Clear();
	VisibleSurfaces.Clear();
	vpIndex = 0;

	// Fullbright information needs to be propagated from the main view.
	if (outer != nullptr) FullbrightFlags = outer->FullbrightFlags;
	else FullbrightFlags = 0;

	outer = drawctx->gl_drawinfo;
	drawctx->gl_drawinfo = this;

}

//==========================================================================
//
//
//
//==========================================================================

HWDrawInfo *HWDrawInfo::EndDrawInfo()
{
	assert(this == drawctx->gl_drawinfo);
	for (int i = 0; i < GLDL_TYPES; i++) drawlists[i].Reset();
	drawctx->gl_drawinfo = outer;
	drawctx->di_list.Release(this);
	if (drawctx->gl_drawinfo == nullptr)
		drawctx->ResetRenderDataAllocator();
	return drawctx->gl_drawinfo;
}


//==========================================================================
//
//
//
//==========================================================================

void HWDrawInfo::ClearBuffers()
{
    otherFloorPlanes.Clear();
    otherCeilingPlanes.Clear();
    floodFloorSegs.Clear();
    floodCeilingSegs.Clear();

	// clear all the lists that might not have been cleared already
	MissingUpperTextures.Clear();
	MissingLowerTextures.Clear();
	MissingUpperSegs.Clear();
	MissingLowerSegs.Clear();
	SubsectorHacks.Clear();
	//CeilingStacks.Clear();
	//FloorStacks.Clear();
	HandledSubsectors.Clear();
	spriteindex = 0;

	if (Level)
	{
		CurrentMapSections.Resize(Level->NumMapSections);
		CurrentMapSections.Zero();

		section_renderflags.Resize(Level->sections.allSections.Size());
		ss_renderflags.Resize(Level->subsectors.Size());
		no_renderflags.Resize(Level->subsectors.Size());

		memset(&section_renderflags[0], 0, Level->sections.allSections.Size() * sizeof(section_renderflags[0]));
		memset(&ss_renderflags[0], 0, Level->subsectors.Size() * sizeof(ss_renderflags[0]));
		memset(&no_renderflags[0], 0, Level->nodes.Size() * sizeof(no_renderflags[0]));
	}

	Decals[0].Clear();
	Decals[1].Clear();

	mClipPortal = nullptr;
	mCurrentPortal = nullptr;
}

//==========================================================================
//
//
//
//==========================================================================

void HWDrawInfo::UpdateCurrentMapSection()
{
	const int mapsection = Level->PointInRenderSubsector(Viewpoint.Pos)->mapsection;
	CurrentMapSections.Set(mapsection);
}


//-----------------------------------------------------------------------------
//
// Sets the area the camera is in
//
//-----------------------------------------------------------------------------

void HWDrawInfo::SetViewArea()
{
    auto &vp = Viewpoint;
	// The render_sector is better suited to represent the current position in GL
	vp.sector = Level->PointInRenderSubsector(vp.Pos)->render_sector;

	// Get the heightsec state from the render sector, not the current one!
	if (vp.sector->GetHeightSec())
	{
		in_area = vp.Pos.Z <= vp.sector->heightsec->floorplane.ZatPoint(vp.Pos) ? area_below :
			(vp.Pos.Z > vp.sector->heightsec->ceilingplane.ZatPoint(vp.Pos) &&
				!(vp.sector->heightsec->MoreFlags&SECMF_FAKEFLOORONLY)) ? area_above : area_normal;
	}
	else
	{
		in_area = Level->HasHeightSecs ? area_default : area_normal;	// depends on exposed lower sectors, if map contains heightsecs.
	}
}

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

int HWDrawInfo::SetFullbrightFlags(player_t *player)
{
	FullbrightFlags = 0;

	// check for special colormaps
	player_t * cplayer = player? player->camera->player : nullptr;
	if (cplayer)
	{
		int cm = CM_DEFAULT;
		if (cplayer->extralight == INT_MIN)
		{
			cm = CM_FIRSTSPECIALCOLORMAP + REALINVERSECOLORMAP;
			Viewpoint.extralight = 0;
			FullbrightFlags = Fullbright;
			// This does never set stealth vision.
		}
		else if (cplayer->fixedcolormap != NOFIXEDCOLORMAP)
		{
			cm = CM_FIRSTSPECIALCOLORMAP + cplayer->fixedcolormap;
			FullbrightFlags = Fullbright;
			if (gl_enhanced_nv_stealth > 2) FullbrightFlags |= StealthVision;
		}
		else if (cplayer->fixedlightlevel != -1)
		{
			auto torchtype = PClass::FindActor(NAME_PowerTorch);
			auto litetype = PClass::FindActor(NAME_PowerLightAmp);
			for (AActor *in = cplayer->mo->Inventory; in; in = in->Inventory)
			{
				// Need special handling for light amplifiers 
				if (in->IsKindOf(torchtype))
				{
					FullbrightFlags = Fullbright;
					if (gl_enhanced_nv_stealth > 1) FullbrightFlags |= StealthVision;
				}
				else if (in->IsKindOf(litetype))
				{
					FullbrightFlags = Fullbright;
					if (gl_enhanced_nightvision) FullbrightFlags |= Nightvision;
					if (gl_enhanced_nv_stealth > 0) FullbrightFlags |= StealthVision;
				}
			}
		}
		return cm;
	}
	else
	{
		return CM_DEFAULT;
	}
}

//-----------------------------------------------------------------------------
//
// R_FrustumAngle
//
//-----------------------------------------------------------------------------

angle_t HWDrawInfo::FrustumAngle()
{
	float tilt = fabs(Viewpoint.HWAngles.Pitch.Degrees());

	// If the pitch is larger than this you can look all around at a FOV of 90°
	if (tilt > 46.0f) return 0xffffffff;

	// ok, this is a gross hack that barely works...
	// but at least it doesn't overestimate too much...
	double floatangle = 2.0 + (45.0 + ((tilt / 1.9)))*Viewpoint.FieldOfView.Degrees() * 48.0 / AspectMultiplier(r_viewwindow.WidescreenRatio) / 90.0;
	angle_t a1 = DAngle::fromDeg(floatangle).BAMs();
	if (a1 >= ANGLE_180) return 0xffffffff;
	return a1;
}

//-----------------------------------------------------------------------------
//
// Setup the modelview matrix
//
//-----------------------------------------------------------------------------

void HWDrawInfo::SetViewMatrix(const FRotator &angles, float vx, float vy, float vz, bool mirror, bool planemirror)
{
	float mult = mirror ? -1.f : 1.f;
	float planemult = planemirror ? -Level->info->pixelstretch : Level->info->pixelstretch;

	VPUniforms.mViewMatrix.loadIdentity();
	VPUniforms.mViewMatrix.rotate(angles.Roll.Degrees(), 0.0f, 0.0f, 1.0f);
	VPUniforms.mViewMatrix.rotate(angles.Pitch.Degrees(), 1.0f, 0.0f, 0.0f);
	VPUniforms.mViewMatrix.rotate(angles.Yaw.Degrees(), 0.0f, mult, 0.0f);
	VPUniforms.mViewMatrix.translate(vx * mult, -vz * planemult, -vy);
	VPUniforms.mViewMatrix.scale(-mult, planemult, 1);
}


//-----------------------------------------------------------------------------
//
// SetupView
// Setup the view rotation matrix for the given viewpoint
//
//-----------------------------------------------------------------------------
void HWDrawInfo::SetupView(FRenderState &state, float vx, float vy, float vz, bool mirror, bool planemirror)
{
	auto &vp = Viewpoint;
	vp.SetViewAngle(r_viewwindow);
	SetViewMatrix(vp.HWAngles, vx, vy, vz, mirror, planemirror);
	SetCameraPos(vp.Pos);
	VPUniforms.CalcDependencies();
	vpIndex = state.SetViewpoint(VPUniforms);
}

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

HWPortal * HWDrawInfo::FindPortal(const void * src)
{
	int i = Portals.Size() - 1;

	while (i >= 0 && Portals[i] && Portals[i]->GetSource() != src) i--;
	return i >= 0 ? Portals[i] : nullptr;
}

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

HWDecal *HWDrawInfo::AddDecal(bool onmirror)
{
	auto decal = (HWDecal*)drawctx->RenderDataAllocator.Alloc(sizeof(HWDecal));
	Decals[onmirror ? 1 : 0].Push(decal);
	return decal;
}

//-----------------------------------------------------------------------------
//
// CreateScene
//
// creates the draw lists for the current scene
//
//-----------------------------------------------------------------------------

void HWDrawInfo::CreateScene(bool drawpsprites, FRenderState& state)
{
	const auto &vp = Viewpoint;
	angle_t a1 = FrustumAngle();
	mClipper->SafeAddClipRangeRealAngles(vp.Angles.Yaw.BAMs() + a1, vp.Angles.Yaw.BAMs() - a1);

	// reset the portal manager
	drawctx->portalState.StartFrame();

	ProcessAll.Clock();

	// clip the scene and fill the drawlists

	if (gl_levelmesh)
	{
		// Give the DrawInfo the viewpoint in fixed point because that's what the nodes are.
		viewx = FLOAT2FIXED(Viewpoint.Pos.X);
		viewy = FLOAT2FIXED(Viewpoint.Pos.Y);

		validcount++;	// used for processing sidedefs only once by the renderer.

		auto& wallPortals = static_cast<DoomLevelSubmesh*>(level.levelMesh->StaticMesh.get())->WallPortals;

		// draw level into depth buffer
		state.SetColorMask(false);
		state.SetCulling(Cull_CW);
		state.DrawLevelMeshDepthPass();

		// use occlusion queries on all portals in level to decide which are visible
		int queryStart = state.GetNextQueryIndex();
		state.SetDepthMask(false);
		state.EnableTexture(false);
		state.SetEffect(EFF_FOGBOUNDARY);
		state.AlphaFunc(Alpha_GEqual, 0.f);
		for (HWWall& wall : wallPortals)
		{
			state.BeginQuery();

			wall.MakeVertices(state, false);
			wall.RenderWall(state, HWWall::RWF_BLANK);
			wall.vertcount = 0;

			state.EndQuery();
		}
		state.SetEffect(EFF_NONE);
		state.EnableTexture(true);
		state.SetColorMask(true);
		state.SetDepthMask(true);
		int queryEnd = state.GetNextQueryIndex();

		// draw opaque level so the GPU has something to do while we examine the query results
		state.DrawLevelMeshOpaquePass();
		state.SetCulling(Cull_None);

		// retrieve the query results and use them to fill the portal manager with portals
		state.GetQueryResults(queryStart, queryEnd - queryStart, QueryResultsBuffer);
		for (unsigned int i = 0, count = QueryResultsBuffer.Size(); i < count; i++)
		{
			bool portalVisible = QueryResultsBuffer[i];
			if (portalVisible)
			{
				PutWallPortal(wallPortals[i], state);
			}
		}

		// Draw sprites
		auto it = level.GetThinkerIterator<AActor>();
		AActor* thing;
		while ((thing = it.Next()) != nullptr)
		{
			HWSprite sprite;

			if (R_ShouldDrawSpriteShadow(thing))
			{
				double dist = (thing->Pos() - vp.Pos).LengthSquared();
				double check = r_actorspriteshadowdist;
				if (dist <= check * check)
				{
					sprite.Process(this, state, thing, thing->Sector, in_area, false, true);
				}
			}

			sprite.Process(this, state, thing, thing->Sector, in_area, false);
		}

		// Process all the sprites on the current portal's back side which touch the portal.
		if (mCurrentPortal != nullptr) mCurrentPortal->RenderAttached(this, state);

		if (drawpsprites)
			PreparePlayerSprites(Viewpoint.sector, in_area, state);
	}
	else
	{
		RenderBSP(Level->HeadNode(), drawpsprites, state);
	}

	// And now the crappy hacks that have to be done to avoid rendering anomalies.
	// These cannot be multithreaded when the time comes because all these depend
	// on the global 'validcount' variable.

	HandleMissingTextures(in_area, state);	// Missing upper/lower textures
	HandleHackedSubsectors(state);	// open sector hacks for deep water
	PrepareUnhandledMissingTextures(state);
	DispatchRenderHacks(state);

	// Sort fogballs by view order
	FVector3 campos(vp.Pos);
	std::sort(Fogballs.begin(), Fogballs.end(), [&](const Fogball& a, const Fogball& b) -> bool {
		FVector3 rayA = a.Position - campos;
		FVector3 rayB = b.Position - campos;
		float distSqrA = rayA | rayA;
		float distSqrB = rayB | rayB;
		return distSqrA > distSqrB;
		});

	ProcessAll.Unclock();

}

void HWDrawInfo::PutWallPortal(HWWall wall, FRenderState& state)
{
	HWWallDispatcher ddi(this);

	int portaltype = wall.portaltype;
	int portalplane = wall.portalplane;

	HWSkyInfo skyinfo;
	if (portaltype == PORTALTYPE_SKY)
	{
		skyinfo.init(this, wall.frontsector->sky, wall.Colormap.FadeColor);
		wall.sky = &skyinfo;
	}
	else if (portaltype == PORTALTYPE_SECTORSTACK)
	{
		if (screen->instack[1 - portalplane])
			return;
	}
	else if (portaltype == PORTALTYPE_PLANEMIRROR)
	{
		auto vpz = Viewpoint.Pos.Z;
		if ((portalplane == sector_t::ceiling && vpz > wall.frontsector->ceilingplane.fD()) || (portalplane == sector_t::floor && vpz < -wall.frontsector->floorplane.fD()))
			return;
		wall.planemirror = (portalplane == sector_t::ceiling) ? &wall.frontsector->ceilingplane : &wall.frontsector->floorplane;
	}
	wall.PutPortal(&ddi, state, portaltype, portalplane);
}

void HWDrawInfo::UpdateLightmaps()
{
	if (!outer && VisibleSurfaces.Size() < unsigned(lm_background_updates))
	{
		for (auto& e : static_cast<DoomLevelSubmesh*>(level.levelMesh->StaticMesh.get())->Surfaces)
		{
			if (e.NeedsUpdate && !e.IsSky && !e.PortalIndex)
			{
				VisibleSurfaces.Push(&e);

				if (VisibleSurfaces.Size() >= unsigned(lm_background_updates))
					break;
			}
		}
	}
	screen->UpdateLightmaps(VisibleSurfaces);
}

//-----------------------------------------------------------------------------
//
// RenderScene
//
// Draws the current draw lists for the non GLSL renderer
//
//-----------------------------------------------------------------------------

void HWDrawInfo::RenderScene(FRenderState &state)
{
	const auto &vp = Viewpoint;
	RenderAll.Clock();

	UpdateLightmaps();

	state.SetLightMode((int)lightmode);

	state.SetDepthMask(true);

	state.EnableFog(true);
	state.SetRenderStyle(STYLE_Source);

	if (gl_sort_textures)
	{
		drawlists[GLDL_PLAINWALLS].SortWalls();
		drawlists[GLDL_PLAINFLATS].SortFlats();
		drawlists[GLDL_MASKEDWALLS].SortWalls();
		drawlists[GLDL_MASKEDFLATS].SortFlats();
		drawlists[GLDL_MASKEDWALLSOFS].SortWalls();
	}

	// Part 1: solid geometry. This is set up so that there are no transparent parts
	state.SetDepthFunc(DF_Less);
	state.AlphaFunc(Alpha_GEqual, 0.f);
	state.ClearDepthBias();

	state.EnableTexture(gl_texture);
	state.EnableBrightmap(true);
	drawlists[GLDL_PLAINWALLS].DrawWalls(this, state, false);
	drawlists[GLDL_PLAINFLATS].DrawFlats(this, state, false);

	// Part 2: masked geometry. This is set up so that only pixels with alpha>gl_mask_threshold will show
	state.AlphaFunc(Alpha_GEqual, gl_mask_threshold);
	drawlists[GLDL_MASKEDWALLS].DrawWalls(this, state, false);
	drawlists[GLDL_MASKEDFLATS].DrawFlats(this, state, false);

	// Part 3: masked geometry with polygon offset. This list is empty most of the time so only waste time on it when in use.
	if (drawlists[GLDL_MASKEDWALLSOFS].Size() > 0)
	{
		state.SetDepthBias(-1, -128);
		drawlists[GLDL_MASKEDWALLSOFS].DrawWalls(this, state, false);
		state.ClearDepthBias();
	}

	drawlists[GLDL_MODELS].Draw(this, state, false);

	state.SetRenderStyle(STYLE_Translucent);

	// Part 4: Draw decals (not a real pass)
	state.SetDepthFunc(DF_LEqual);
	DrawDecals(state, Decals[0]);

	RenderAll.Unclock();
}

//-----------------------------------------------------------------------------
//
// RenderTranslucent
//
//-----------------------------------------------------------------------------

void HWDrawInfo::RenderTranslucent(FRenderState &state)
{
	RenderAll.Clock();

	// final pass: translucent stuff
	state.AlphaFunc(Alpha_GEqual, gl_mask_sprite_threshold);
	state.SetRenderStyle(STYLE_Translucent);

	state.EnableBrightmap(true);
	drawlists[GLDL_TRANSLUCENTBORDER].Draw(this, state, true);
	state.SetDepthMask(false);

	drawlists[GLDL_TRANSLUCENT].DrawSorted(this, state);
	state.EnableBrightmap(false);


	state.AlphaFunc(Alpha_GEqual, 0.5f);
	state.SetDepthMask(true);

	RenderAll.Unclock();
}


//-----------------------------------------------------------------------------
//
// RenderTranslucent
//
//-----------------------------------------------------------------------------

void HWDrawInfo::RenderPortal(HWPortal *p, FRenderState &state, bool usestencil)
{
	auto gp = static_cast<HWPortal *>(p);
	gp->SetupStencil(this, state, usestencil);
	auto new_di = StartDrawInfo(drawctx, this->Level, this, Viewpoint, &VPUniforms);
	new_di->mCurrentPortal = gp;
	state.SetLightIndex(-1);
	gp->DrawContents(new_di, state);
	new_di->EndDrawInfo();
	state.SetFlatVertexBuffer();
	state.SetViewpoint(vpIndex);
	gp->RemoveStencil(this, state, usestencil);

}

void HWDrawInfo::DrawCorona(FRenderState& state, AActor* corona, float coronaFade, double dist)
{
	spriteframe_t* sprframe = &SpriteFrames[sprites[corona->sprite].spriteframes + (size_t)corona->SpawnState->GetFrame()];
	FTextureID patch = sprframe->Texture[0];
	if (!patch.isValid()) return;
	auto tex = TexMan.GetGameTexture(patch, false);
	if (!tex || !tex->isValid()) return;

	// Project the corona sprite center
	FVector4 worldPos((float)corona->X(), (float)corona->Z(), (float)corona->Y(), 1.0f);
	FVector4 viewPos, clipPos;
	VPUniforms.mViewMatrix.multMatrixPoint(&worldPos[0], &viewPos[0]);
	VPUniforms.mProjectionMatrix.multMatrixPoint(&viewPos[0], &clipPos[0]);
	if (clipPos.W < -1.0f) return; // clip z nearest
	float halfViewportWidth = screen->GetWidth() * 0.5f;
	float halfViewportHeight = screen->GetHeight() * 0.5f;
	float invW = 1.0f / clipPos.W;
	float screenX = halfViewportWidth + clipPos.X * invW * halfViewportWidth;
	float screenY = halfViewportHeight - clipPos.Y * invW * halfViewportHeight;

	float alpha = coronaFade * float(corona->Alpha);

	// distance-based fade - looks better IMO
	float distNearFadeStart = float(corona->RenderRadius()) * 0.1f;
	float distFarFadeStart = float(corona->RenderRadius()) * 0.5f;
	float distFade = 1.0f;

	if (float(dist) < distNearFadeStart)
		distFade -= abs(((float(dist) - distNearFadeStart) / distNearFadeStart));
	else if (float(dist) >= distFarFadeStart)
		distFade -= (float(dist) - distFarFadeStart) / distFarFadeStart;

	alpha *= distFade;

	state.SetColorAlpha(0xffffff, alpha, 0);
	if (isSoftwareLighting(lightmode)) state.SetSoftLightLevel(255);
	else state.SetNoSoftLightLevel();

	state.SetLightIndex(-1);
	state.SetRenderStyle(corona->RenderStyle);
	state.SetTextureMode(corona->RenderStyle);

	state.SetMaterial(tex, UF_Sprite, CTF_Expand, CLAMP_XY_NOMIP, 0, 0);

	float scale = screen->GetHeight() / 1000.0f;
	float tileWidth = corona->Scale.X * tex->GetDisplayWidth() * scale;
	float tileHeight = corona->Scale.Y * tex->GetDisplayHeight() * scale;
	float x0 = screenX - tileWidth, y0 = screenY - tileHeight;
	float x1 = screenX + tileWidth, y1 = screenY + tileHeight;

	float u0 = 0.0f, v0 = 0.0f;
	float u1 = 1.0f, v1 = 1.0f;

	auto vert = state.AllocVertices(4);
	auto vp = vert.first;
	unsigned int vertexindex = vert.second;

	vp[0].Set(x0, y0, 1.0f, u0, v0);
	vp[1].Set(x1, y0, 1.0f, u1, v0);
	vp[2].Set(x0, y1, 1.0f, u0, v1);
	vp[3].Set(x1, y1, 1.0f, u1, v1);

	state.Draw(DT_TriangleStrip, vertexindex, 4);
}

static ETraceStatus CheckForViewpointActor(FTraceResults& res, void* userdata)
{
	FRenderViewpoint* data = (FRenderViewpoint*)userdata;
	if (res.HitType == TRACE_HitActor && res.Actor && res.Actor == data->ViewActor)
	{
		return TRACE_Skip;
	}

	return TRACE_Stop;
}


void HWDrawInfo::DrawCoronas(FRenderState& state)
{
	state.EnableDepthTest(false);
	state.SetDepthMask(false);

	HWViewpointUniforms vp = VPUniforms;
	vp.mViewMatrix.loadIdentity();
	vp.mProjectionMatrix = VRMode::GetVRMode(true)->GetHUDSpriteProjection();
	state.SetViewpoint(vp);

	float timeElapsed = (screen->FrameTime - LastFrameTime) / 1000.0f;
	LastFrameTime = screen->FrameTime;

	for (AActor* corona : Coronas)
	{
		auto& coronaFade = corona->specialf1;
		auto cPos = corona->Vec3Offset(0., 0., corona->Height * 0.5);
		DVector3 direction = Viewpoint.Pos - cPos;
		double dist = direction.Length();

		// skip coronas that are too far
		if (dist > corona->RenderRadius())
			continue;

		static const float fadeSpeed = 9.0f;

		direction.MakeUnit();
		FTraceResults results;
		if (!Trace(cPos, corona->Sector, direction, dist, MF_SOLID, ML_BLOCKEVERYTHING, corona, results, 0, CheckForViewpointActor, &Viewpoint))
		{
			coronaFade = std::min(coronaFade + timeElapsed * fadeSpeed, 1.0);
		}
		else
		{
			coronaFade = std::max(coronaFade - timeElapsed * fadeSpeed, 0.0);
		}

		if (coronaFade > 0.0f)
			DrawCorona(state, corona, (float)coronaFade, dist);
	}

	state.SetTextureMode(TM_NORMAL);
	state.SetViewpoint(vpIndex);
	state.EnableDepthTest(true);
	state.SetDepthMask(true);
}


//-----------------------------------------------------------------------------
//
// Draws player sprites and color blend
//
//-----------------------------------------------------------------------------


void HWDrawInfo::EndDrawScene(sector_t * viewsector, FRenderState &state)
{
	state.EnableFog(false);

	if (gl_coronas && Coronas.Size() > 0)
	{
		DrawCoronas(state);
	}

	// [BB] HUD models need to be rendered here. 
	const bool renderHUDModel = IsHUDModelForPlayerAvailable(players[consoleplayer].camera->player);
	if (renderHUDModel)
	{
		// [BB] The HUD model should be drawn over everything else already drawn.
		state.Clear(CT_Depth);
		DrawPlayerSprites(true, state);
	}

	state.EnableStencil(false);
	state.SetViewport(screen->mScreenViewport.left, screen->mScreenViewport.top, screen->mScreenViewport.width, screen->mScreenViewport.height);

	// Restore standard rendering state
	state.SetRenderStyle(STYLE_Translucent);
	state.ResetColor();
	state.EnableTexture(true);
	state.SetScissor(0, 0, -1, -1);
}

void HWDrawInfo::DrawEndScene2D(sector_t * viewsector, FRenderState &state)
{
	const bool renderHUDModel = IsHUDModelForPlayerAvailable(players[consoleplayer].camera->player);
	auto vrmode = VRMode::GetVRMode(true);

	HWViewpointUniforms vp = VPUniforms;
	vp.mViewMatrix.loadIdentity();
	vp.mProjectionMatrix = vrmode->GetHUDSpriteProjection();
	state.SetViewpoint(vp);
	state.EnableDepthTest(false);

	DrawPlayerSprites(false, state);

	state.SetNoSoftLightLevel();

	// Restore standard rendering state
	state.SetRenderStyle(STYLE_Translucent);
	state.ResetColor();
	state.EnableTexture(true);
	state.SetScissor(0, 0, -1, -1);
}

//-----------------------------------------------------------------------------
//
// sets 3D viewport and initial state
//
//-----------------------------------------------------------------------------

void HWDrawInfo::Set3DViewport(FRenderState &state)
{
	// Always clear all buffers with scissor test disabled.
	// This is faster on newer hardware because it allows the GPU to skip
	// reading from slower memory where the full buffers are stored.
	state.SetScissor(0, 0, -1, -1);
	state.Clear(CT_Color | CT_Depth | CT_Stencil);

	const auto &bounds = screen->mSceneViewport;
	state.SetViewport(bounds.left, bounds.top, bounds.width, bounds.height);
	state.SetScissor(bounds.left, bounds.top, bounds.width, bounds.height);
	state.EnableDepthTest(true);
	state.EnableStencil(true);
	state.SetStencil(0, SOP_Keep, SF_AllOn);
}

//-----------------------------------------------------------------------------
//
// gl_drawscene - this function renders the scene from the current
// viewpoint, including mirrors and skyboxes and other portals
// It is assumed that the HWPortal::EndFrame returns with the 
// stencil, z-buffer and the projection matrix intact!
//
//-----------------------------------------------------------------------------

void HWDrawInfo::DrawScene(int drawmode, FRenderState& state)
{
	static int recursion = 0;
	static int ssao_portals_available = 0;
	const auto& vp = Viewpoint;

	bool applySSAO = false;
	if (drawmode == DM_MAINVIEW)
	{
		ssao_portals_available = gl_ssao_portals;
		applySSAO = true;
	}
	else if (drawmode == DM_OFFSCREEN)
	{
		ssao_portals_available = 0;
	}
	else if (drawmode == DM_PORTAL && ssao_portals_available > 0)
	{
		applySSAO = (mCurrentPortal->AllowSSAO() || Level->flags3&LEVEL3_SKYBOXAO);
		ssao_portals_available--;
	}

	if (vp.camera != nullptr)
	{
		ActorRenderFlags savedflags = vp.camera->renderflags;
		CreateScene(drawmode == DM_MAINVIEW, state);
		vp.camera->renderflags = savedflags;
	}
	else
	{
		CreateScene(false, state);
	}

	if (!outer) // Fogballs have no portal support. Always use the outermost scene's fogballs for now
	{
		int fogballIndex = state.UploadFogballs(Fogballs);
		state.SetFogballIndex(fogballIndex);
	}

	state.SetDepthMask(true);
	if (!gl_no_skyclear && !gl_levelmesh) drawctx->portalState.RenderFirstSkyPortal(recursion, this, state);

	RenderScene(state);

	if (applySSAO && state.GetPassType() == GBUFFER_PASS)
	{
		screen->AmbientOccludeScene(VPUniforms.mProjectionMatrix.get()[5]);
		state.SetViewpoint(vpIndex);
	}

	// Handle all portals after rendering the opaque objects but before
	// doing all translucent stuff
	recursion++;
	drawctx->portalState.EndFrame(this, state);
	recursion--;

	RenderTranslucent(state);

	if (!outer)
	{
		state.SetFogballIndex(-1);
	}
}

//-----------------------------------------------------------------------------
//
// R_RenderView - renders one view - either the screen or a camera texture
//
//-----------------------------------------------------------------------------

void HWDrawInfo::ProcessScene(bool toscreen, FRenderState& state)
{
	drawctx->portalState.BeginScene();

	int mapsection = Level->PointInRenderSubsector(Viewpoint.Pos)->mapsection;
	CurrentMapSections.Set(mapsection);
	DrawScene(toscreen ? DM_MAINVIEW : DM_OFFSCREEN, state);

}

//==========================================================================
//
//
//
//==========================================================================

void HWDrawInfo::AddSubsectorToPortal(FSectorPortalGroup *ptg, subsector_t *sub)
{
	auto portal = FindPortal(ptg);
	if (!portal)
	{
        portal = new HWSectorStackPortal(&drawctx->portalState, ptg);
		Portals.Push(portal);
	}
    auto ptl = static_cast<HWSectorStackPortal*>(portal);
	ptl->AddSubsector(sub);
}