- Added 'canonical transparency' cvar r_canontrans - this simply turns off transparency for Doom objects that were marked as transparent sometime in ZDoom's development cycle

src/actor.h

@@ -402,6 +402,7 @@ enum ActorFlag8
 {
 	MF8_FRIGHTENING		= 0x00000001,	// for those moments when halloween just won't do
 	MF8_INSCROLLSEC		= 0x00000002,	// actor is partially inside a scrolling sector
+	MF8_ZDOOMTRANS		= 0x00000004,	// is not normally transparent in Vanilla Doom
 };
 
 // --- mobj.renderflags ---

src/gl/scene/gl_sprite.cpp

@@ -75,6 +75,7 @@ CUSTOM_CVAR(Int, gl_fuzztype, 0, CVAR_ARCHIVE)
 }
 
 EXTERN_CVAR (Float, transsouls)
+EXTERN_CVAR (Bool, r_canontrans)
 
 extern TArray<spritedef_t> sprites;
 extern TArray<spriteframe_t> SpriteFrames;
@@ -992,6 +993,13 @@ void GLSprite::Process(AActor* thing, sector_t * sector, int thruportal)
 	{
 		trans = 1.f;
 	}
+	if ((thing->flags8 & MF8_ZDOOMTRANS) && r_canontrans)
+	{	// [SP] "canonical transparency" - with the flip of a CVar, disable transparency for Doom objects
+		trans = 1.f;
+		RenderStyle.BlendOp = STYLEOP_Add;
+		RenderStyle.SrcAlpha = STYLEALPHA_One;
+		RenderStyle.DestAlpha = STYLEALPHA_Zero;
+	}
 
 	if (trans >= 1.f - FLT_EPSILON && RenderStyle.BlendOp != STYLEOP_Shadow && (
 		(RenderStyle.SrcAlpha == STYLEALPHA_One && RenderStyle.DestAlpha == STYLEALPHA_Zero) ||

src/polyrenderer/scene/poly_sprite.cpp

@@ -31,6 +31,7 @@
 
 EXTERN_CVAR(Float, transsouls)
 EXTERN_CVAR(Int, r_drawfuzz)
+EXTERN_CVAR (Bool, r_canontrans)
 
 bool RenderPolySprite::GetLine(AActor *thing, DVector2 &left, DVector2 &right)
 {
@@ -145,7 +146,10 @@ void RenderPolySprite::Render(const TriMatrix &worldToClip, const PolyClipPlane
 	args.SetStencilTestValue(stencilValue);
 	args.SetWriteStencil(true, stencilValue);
 	args.SetClipPlane(clipPlane);
-	args.SetStyle(thing->RenderStyle, thing->Alpha, thing->fillcolor, thing->Translation, tex, fullbrightSprite);
+	if ((thing->flags8 & MF8_ZDOOMTRANS) && r_canontrans)
+		args.SetStyle(LegacyRenderStyles[STYLE_Normal], 1.0f, thing->fillcolor, thing->Translation, tex, fullbrightSprite);
+	else
+		args.SetStyle(thing->RenderStyle, thing->Alpha, thing->fillcolor, thing->Translation, tex, fullbrightSprite);
 	args.SetSubsectorDepthTest(true);
 	args.SetWriteSubsectorDepth(false);
 	args.SetWriteStencil(false);

src/r_data/renderstyle.cpp

@@ -38,6 +38,7 @@
 #include "serializer.h"
 
 CVAR (Bool, r_drawtrans, true, 0)
+CVAR (Bool, r_canontrans, false, CVAR_ARCHIVE)
 CVAR (Int, r_drawfuzz, 1, CVAR_ARCHIVE)
 
 // Convert legacy render styles to flexible render styles.

src/scripting/thingdef_data.cpp

@@ -325,6 +325,7 @@ static FFlagDef ActorFlagDefs[]=
 	DEFINE_FLAG(MF7, SPRITEFLIP, AActor, flags7),
 
 	DEFINE_FLAG(MF8, FRIGHTENING, AActor, flags8),
+	DEFINE_FLAG(MF8, ZDOOMTRANS, AActor, flags8),
 
 	// Effect flags
 	DEFINE_FLAG(FX, VISIBILITYPULSE, AActor, effects),

src/swrenderer/things/r_sprite.cpp

@@ -68,6 +68,7 @@
 
 EXTERN_CVAR(Bool, r_fullbrightignoresectorcolor)
 EXTERN_CVAR(Bool, gl_light_sprites)
+EXTERN_CVAR (Bool, r_canontrans)
 
 namespace swrenderer
 {
@@ -212,6 +213,8 @@ namespace swrenderer
 		if (thing->flags5 & MF5_BRIGHT)
 			vis->renderflags |= RF_FULLBRIGHT; // kg3D
 		vis->RenderStyle = thing->RenderStyle;
+		if ((thing->flags8 & MF8_ZDOOMTRANS) && r_canontrans)
+			vis->RenderStyle = LegacyRenderStyles[STYLE_Normal];
 		vis->FillColor = thing->fillcolor;
 		vis->Translation = thing->Translation;		// [RH] thing translation table
 		vis->FakeFlatStat = fakeside;