From d643a42c4f808436ba5b619f51ab6ccfe3bd284f Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Sat, 6 Jun 2020 15:18:07 +0200
Subject: [PATCH] - added per pixel lighting for decals.

---
 src/rendering/hwrenderer/scene/hw_decal.cpp     | 16 +++-------------
 .../hwrenderer/scene/hw_drawlistadd.cpp         |  8 ++++++++
 src/rendering/hwrenderer/scene/hw_drawstructs.h |  1 +
 src/rendering/hwrenderer/scene/hw_walls.cpp     | 17 ++++++++++++++++-
 4 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/src/rendering/hwrenderer/scene/hw_decal.cpp b/src/rendering/hwrenderer/scene/hw_decal.cpp
index 88c78ceda..ec835c01c 100644
--- a/src/rendering/hwrenderer/scene/hw_decal.cpp
+++ b/src/rendering/hwrenderer/scene/hw_decal.cpp
@@ -47,23 +47,13 @@
 
 void HWDecal::DrawDecal(HWDrawInfo *di, FRenderState &state)
 {
-	// calculate dynamic light effect.
-	if (di->Level->HasDynamicLights && !di->isFullbrightScene() && gl_light_sprites)
-	{
-		// Note: This should be replaced with proper shader based lighting.
-		double x, y;
-		float out[3];
-		decal->GetXY(decal->Side, x, y);
-		di->GetDynSpriteLight(nullptr, x, y, zcenter, decal->Side->lighthead, decal->Side->sector->PortalGroup, out);
-		state.SetDynLight(out[0], out[1], out[2]);
-	}
-
 	// alpha color only has an effect when using an alpha texture.
 	if (decal->RenderStyle.Flags & (STYLEF_RedIsAlpha | STYLEF_ColorIsFixed))
 	{
 		state.SetObjectColor(decal->AlphaColor | 0xff000000);
 	}
 
+	state.SetLightIndex(dynlightindex);
 	state.SetTextureMode(decal->RenderStyle);
 	state.SetRenderStyle(decal->RenderStyle);
 	state.SetMaterial(texture, UF_Sprite, 0, CLAMP_XY, decal->Translation, -1);
@@ -133,7 +123,6 @@ void HWDrawInfo::DrawDecals(FRenderState &state, TArray<HWDecal *> &decals)
 	side_t *wall = nullptr;
 	state.SetDepthMask(false);
 	state.SetDepthBias(-1, -128);
-	state.SetLightIndex(-1);
 	for (auto gldecal : decals)
 	{
 		if (gldecal->decal->Side != wall)
@@ -167,7 +156,6 @@ void HWWall::DrawDecalsForMirror(HWDrawInfo *di, FRenderState &state, TArray<HWD
 {
 	state.SetDepthMask(false);
 	state.SetDepthBias(-1, -128);
-	state.SetLightIndex(-1);
 	di->SetFog(state, lightlevel, rellight + getExtraLight(), di->isFullbrightScene(), &Colormap, false);
 	for (auto gldecal : decals)
 	{
@@ -389,11 +377,13 @@ void HWWall::ProcessDecal(HWDrawInfo *di, DBaseDecal *decal, const FVector3 &nor
 	{
 		gldecal->lightlevel = 255;
 		gldecal->rellight = 0;
+		gldecal->dynlightindex = -1;
 	}
 	else
 	{
 		gldecal->lightlevel = lightlevel;
 		gldecal->rellight = rellight + getExtraLight();
+		gldecal->dynlightindex = dynlightindex;
 	}
 
 	gldecal->Colormap = Colormap;
diff --git a/src/rendering/hwrenderer/scene/hw_drawlistadd.cpp b/src/rendering/hwrenderer/scene/hw_drawlistadd.cpp
index a034276a4..9b2e9d57c 100644
--- a/src/rendering/hwrenderer/scene/hw_drawlistadd.cpp
+++ b/src/rendering/hwrenderer/scene/hw_drawlistadd.cpp
@@ -27,6 +27,7 @@
 #include "hwrenderer/scene/hw_drawinfo.h"
 #include "hw_material.h"
 #include "actor.h"
+#include "g_levellocals.h"
 
 EXTERN_CVAR(Bool, gl_seamless)
 
@@ -81,7 +82,14 @@ void HWDrawInfo::AddMirrorSurface(HWWall *w)
 	tcs[HWWall::LOLFT].u = tcs[HWWall::LORGT].u = tcs[HWWall::UPLFT].u = tcs[HWWall::UPRGT].u = v.X;
 	tcs[HWWall::LOLFT].v = tcs[HWWall::LORGT].v = tcs[HWWall::UPLFT].v = tcs[HWWall::UPRGT].v = v.Z;
 	newwall->MakeVertices(this, false);
+
+	bool hasDecals = newwall->seg->sidedef && newwall->seg->sidedef->AttachedDecals;
+	if (hasDecals && Level->HasDynamicLights && !isFullbrightScene())
+	{
+		newwall->SetupLights(this, lightdata);
+	}
 	newwall->ProcessDecals(this);
+	newwall->dynlightindex = -1; // the environment map should not be affected by lights - only the decals.
 }
 
 //==========================================================================
diff --git a/src/rendering/hwrenderer/scene/hw_drawstructs.h b/src/rendering/hwrenderer/scene/hw_drawstructs.h
index 1d20ced4a..113c0aaac 100644
--- a/src/rendering/hwrenderer/scene/hw_drawstructs.h
+++ b/src/rendering/hwrenderer/scene/hw_drawstructs.h
@@ -414,6 +414,7 @@ struct HWDecal
 	int rellight;
 	float alpha;
 	FColormap Colormap;
+	int dynlightindex;
 	sector_t *frontsector;
 	FVector3 Normal;
 
diff --git a/src/rendering/hwrenderer/scene/hw_walls.cpp b/src/rendering/hwrenderer/scene/hw_walls.cpp
index 37ccd66bb..3137679be 100644
--- a/src/rendering/hwrenderer/scene/hw_walls.cpp
+++ b/src/rendering/hwrenderer/scene/hw_walls.cpp
@@ -504,11 +504,26 @@ void HWWall::PutWall(HWDrawInfo *di, bool translucent)
 	}
 
 
+
 	bool solid;
 	if (passflag[type] == 1) solid = true;
 	else if (type == RENDERWALL_FFBLOCK) solid = texture && !texture->isMasked();
 	else solid = false;
-	if (solid) ProcessDecals(di);
+
+	bool hasDecals = solid && seg->sidedef && seg->sidedef->AttachedDecals;
+	if (hasDecals)
+	{
+		// If we want to use the light infos for the decal we cannot delay the creation until the render pass.
+		if (screen->BuffersArePersistent())
+		{
+			if (di->Level->HasDynamicLights && !di->isFullbrightScene() && texture != nullptr)
+			{
+				SetupLights(di, lightdata);
+			}
+		}
+		ProcessDecals(di);
+	}
+
 
 	di->AddWall(this);