- fixed dynamic lights in legacy mode.

Since they mess around with the texture coordinates, these need to be backed up and restored afterward.
There was also an issue with the ValidNormal check that was suffering from imprecisions that cause walls to be skipped, so the check was removed because it was mostly pointless.

src/gl/compatibility/gl_20.cpp

@@ -755,11 +755,6 @@ static bool PrepareLight(GLWall *wall, ADynamicLight * light, int pass)
 	auto normal = glseg.Normal();
 	p.Set(normal, -normal.X * glseg.x1 - normal.Z * glseg.y1);
 
-	if (!p.ValidNormal())
-	{
-		return false;
-	}
-
 	if (!gl_SetupLight(wall->seg->frontsector->PortalGroup, p, light, nearPt, up, right, scale, true, pass != GLPASS_LIGHTTEX))
 	{
 		return false;
@@ -817,6 +812,9 @@ void FDrawInfo::RenderLightsCompat(GLWall *wall, int pass)
 		return;
 	}
 
+	auto vertcountsave = wall->vertcount;
+	auto vertindexsave = wall->vertindex;
+
 	texcoord save[4];
 	memcpy(save, wall->tcs, sizeof(wall->tcs));
 	while (node)
@@ -833,12 +831,14 @@ void FDrawInfo::RenderLightsCompat(GLWall *wall, int pass)
 		if (PrepareLight(wall, light, pass))
 		{
 			wall->vertcount = 0;
+			wall->MakeVertices(this, false);
 			RenderWall(wall, GLWall::RWF_TEXTURED);
 		}
 		node = node->nextLight;
 	}
 	memcpy(wall->tcs, save, sizeof(wall->tcs));
-	wall->vertcount = 0;
+	wall->vertcount = vertcountsave;
+	wall->vertindex = vertindexsave;
 }
 
 //==========================================================================

src/gl/scene/gl_walls_draw.cpp

@@ -310,6 +310,8 @@ void FDrawInfo::AddWall(GLWall *wall)
 	bool translucent = !!(wall->flags & GLWall::GLWF_TRANSLUCENT);
 	int list;
 
+	wall->MakeVertices(this, translucent);
+
 	if (translucent) // translucent walls
 	{
 		if (!gl.legacyMode && mDrawer->FixedColormap == CM_DEFAULT && wall->gltexture != nullptr)
@@ -318,7 +320,6 @@ void FDrawInfo::AddWall(GLWall *wall)
 				wall->dynlightindex = GLRenderer->mLights->UploadLights(lightdata);
 		}
 		wall->ViewDistance = (r_viewpoint.Pos - (wall->seg->linedef->v1->fPos() + wall->seg->linedef->Delta() / 2)).XY().LengthSquared();
-		wall->MakeVertices(this, true);
 		auto newwall = drawlists[GLDL_TRANSLUCENT].NewWall();
 		*newwall = *wall;
 	}
@@ -347,12 +348,12 @@ void FDrawInfo::AddWall(GLWall *wall)
 		{
 			list = masked ? GLDL_MASKEDWALLS : GLDL_PLAINWALLS;
 		}
-		wall->MakeVertices(this, false);
 		auto newwall = drawlists[list].NewWall();
 		*newwall = *wall;
 		if (!masked) newwall->ProcessDecals(this);
 	}
 	wall->dynlightindex = -1;
+	wall->vertcount = 0;
 }
 
 //==========================================================================

src/vectors.h

@@ -1704,7 +1704,6 @@ public:
 	}
 
 	bool PointOnSide(FVector3 &v) { return PointOnSide(v.X, v.Y, v.Z); }
-	bool ValidNormal() { return m_normal.LengthSquared() == 1.f; }
 
 	float A() { return m_normal.X; }
 	float B() { return m_normal.Y; }