Add lightlevel field to mobj_t

Adds r_spritefx.cpp

lightlevel should be -255 to 255, relative offset to
normal sector lightlevel.

If RF_ABSOLUTELIGHTLEVEL, mobj_t.lightlevel becomes an
absolute lightlevel in the range 0 to 255.

src/CMakeLists.txt

@@ -75,6 +75,7 @@ add_executable(SRB2SDL2 MACOSX_BUNDLE WIN32
 	r_skins.c
 	r_sky.c
 	r_splats.c
+	r_spritefx.cpp
 	r_things.c
 	r_bbox.c
 	r_textures.c

src/deh_tables.c

@@ -6323,6 +6323,7 @@ struct int_const_s const INT_CONST[] = {
 	{"RF_SHADOWDRAW",RF_SHADOWDRAW},
 	{"RF_SHADOWEFFECTS",RF_SHADOWEFFECTS},
 	{"RF_DROPSHADOW",RF_DROPSHADOW},
+	{"RF_ABSOLUTELIGHTLEVEL",RF_ABSOLUTELIGHTLEVEL},
 	{"RF_DONTDRAW",RF_DONTDRAW},
 	{"RF_DONTDRAWP1",RF_DONTDRAWP1},
 	{"RF_DONTDRAWP2",RF_DONTDRAWP2},

src/lua_mobjlib.c

@@ -42,6 +42,7 @@ enum mobj_e {
 	mobj_spritexoffset,
 	mobj_spriteyoffset,
 	mobj_floorspriteslope,
+	mobj_lightlevel,
 	mobj_touching_sectorlist,
 	mobj_subsector,
 	mobj_floorz,
@@ -124,6 +125,7 @@ static const char *const mobj_opt[] = {
 	"spritexoffset",
 	"spriteyoffset",
 	"floorspriteslope",
+	"lightlevel",
 	"touching_sectorlist",
 	"subsector",
 	"floorz",
@@ -266,6 +268,9 @@ static int mobj_get(lua_State *L)
 	case mobj_floorspriteslope:
 		LUA_PushUserdata(L, mo->floorspriteslope, META_SLOPE);
 		break;
+	case mobj_lightlevel:
+		lua_pushinteger(L, mo->lightlevel);
+		break;
 	case mobj_touching_sectorlist:
 		return UNIMPLEMENTED;
 	case mobj_subsector:
@@ -569,6 +574,9 @@ static int mobj_set(lua_State *L)
 		break;
 	case mobj_floorspriteslope:
 		return NOSET;
+	case mobj_lightlevel:
+		mo->lightlevel = (INT16)luaL_checkinteger(L, 3);
+		break;
 	case mobj_touching_sectorlist:
 		return UNIMPLEMENTED;
 	case mobj_subsector:

src/p_mobj.h

@@ -312,6 +312,7 @@ struct mobj_t
 	fixed_t old_spritexscale, old_spriteyscale;
 	fixed_t old_spritexoffset, old_spriteyoffset;
 	pslope_t *floorspriteslope; // The slope that the floorsprite is rotated by
+	INT16 lightlevel; // Add to sector lightlevel, -255 - 255
 
 	msecnode_t *touching_sectorlist; // a linked list of sectors where this object appears
 
@@ -469,6 +470,7 @@ struct precipmobj_t
 	fixed_t old_spritexscale, old_spriteyscale;
 	fixed_t old_spritexoffset, old_spriteyoffset;
 	pslope_t *floorspriteslope; // The slope that the floorsprite is rotated by
+	INT16 lightlevel; // Add to sector lightlevel, -255 - 255
 
 	mprecipsecnode_t *touching_sectorlist; // a linked list of sectors where this object appears
 

src/p_saveg.c

@@ -2228,6 +2228,7 @@ typedef enum
 	MD2_LASTMOMZ     = 1<<28,
 	MD2_TERRAIN      = 1<<29,
 	MD2_WATERSKIP    = 1<<30,
+	MD2_LIGHTLEVEL   = (INT32)(1U<<31),
 } mobj_diff2_t;
 
 typedef enum
@@ -2466,6 +2467,8 @@ static void SaveMobjThinker(savebuffer_t *save, const thinker_t *th, const UINT8
 		|| (slope->normal.z != FRACUNIT))
 			diff2 |= MD2_FLOORSPRITESLOPE;
 	}
+	if (mobj->lightlevel)
+		diff2 |= MD2_LIGHTLEVEL;
 	if (mobj->hitlag)
 		diff2 |= MD2_HITLAG;
 	if (mobj->waterskip)
@@ -2675,6 +2678,10 @@ static void SaveMobjThinker(savebuffer_t *save, const thinker_t *th, const UINT8
 		WRITEFIXED(save->p, slope->normal.y);
 		WRITEFIXED(save->p, slope->normal.z);
 	}
+	if (diff2 & MD2_LIGHTLEVEL)
+	{
+		WRITEINT16(save->p, mobj->lightlevel);
+	}
 	if (diff2 & MD2_HITLAG)
 	{
 		WRITEINT32(save->p, mobj->hitlag);
@@ -3834,6 +3841,10 @@ static thinker_t* LoadMobjThinker(savebuffer_t *save, actionf_p1 thinker)
 
 		P_UpdateSlopeLightOffset(slope);
 	}
+	if (diff2 & MD2_LIGHTLEVEL)
+	{
+		mobj->lightlevel = READINT16(save->p);
+	}
 	if (diff2 & MD2_HITLAG)
 	{
 		mobj->hitlag = READINT32(save->p);

src/r_defs.h

@@ -961,6 +961,8 @@ typedef enum
 	RF_SHADOWEFFECTS    = 0x00008000,  // Scales and becomes transparent like a shadow.
 	RF_DROPSHADOW       = (RF_SHADOWDRAW | RF_SHADOWEFFECTS | RF_FULLDARK),
 
+	RF_ABSOLUTELIGHTLEVEL = 0x00010000, //  mobj_t.lightlevel is absolute instead of relative
+
 	RF_DONTDRAW         = 0x00F00000,   // --Don't generate a vissprite
 	RF_DONTDRAWP1       = 0x00100000,   // No P1
 	RF_DONTDRAWP2       = 0x00200000,   // No P2

src/r_spritefx.cpp

@@ -0,0 +1,18 @@
+// DR. ROBOTNIK'S RING RACERS
+//-----------------------------------------------------------------------------
+// Copyright (C) 2023 by Kart Krew.
+//
+// This program is free software distributed under the
+// terms of the GNU General Public License, version 2.
+// See the 'LICENSE' file for more details.
+//-----------------------------------------------------------------------------
+/// \brief Special effects for sprite rendering
+
+#include "r_things.h"
+
+INT32 R_ThingLightLevel(mobj_t* thing)
+{
+	INT32 lightlevel = thing->lightlevel;
+
+	return lightlevel;
+}

src/r_things.c

@@ -1690,6 +1690,7 @@ static void R_ProjectSprite(mobj_t *thing)
 	fixed_t gz = 0, gzt = 0;
 	INT32 heightsec, phs;
 	INT32 light = 0;
+	lighttable_t **lights_array = spritelights;
 	fixed_t this_scale;
 	fixed_t spritexscale, spriteyscale;
 
@@ -2239,29 +2240,46 @@ static void R_ProjectSprite(mobj_t *thing)
 			return;
 	}
 
-	if (thing->subsector->sector->numlights)
+	if (thing->renderflags & RF_ABSOLUTELIGHTLEVEL)
+	{
+		const UINT8 n = R_ThingLightLevel(thing);
+
+		// n = uint8 aka 0 - 255, so the shift will always be 0 - LIGHTLEVELS - 1
+		lights_array = scalelight[n >> LIGHTSEGSHIFT];
+	}
+	else
 	{
 		INT32 lightnum;
-		fixed_t top = (splat) ? gz : gzt;
-		light = thing->subsector->sector->numlights - 1;
 
-		// R_GetPlaneLight won't work on sloped lights!
-		for (lightnum = 1; lightnum < thing->subsector->sector->numlights; lightnum++) {
-			fixed_t h = P_GetLightZAt(&thing->subsector->sector->lightlist[lightnum], interp.x, interp.y);
-			if (h <= top) {
-				light = lightnum - 1;
-				break;
+		if (thing->subsector->sector->numlights)
+		{
+			fixed_t top = (splat) ? gz : gzt;
+			light = thing->subsector->sector->numlights - 1;
+
+			// R_GetPlaneLight won't work on sloped lights!
+			for (lightnum = 1; lightnum < thing->subsector->sector->numlights; lightnum++) {
+				fixed_t h = P_GetLightZAt(&thing->subsector->sector->lightlist[lightnum], interp.x, interp.y);
+				if (h <= top) {
+					light = lightnum - 1;
+					break;
+				}
 			}
+			//light = R_GetPlaneLight(thing->subsector->sector, gzt, false);
+			lightnum = *thing->subsector->sector->lightlist[light].lightlevel;
 		}
-		//light = R_GetPlaneLight(thing->subsector->sector, gzt, false);
-		lightnum = (*thing->subsector->sector->lightlist[light].lightlevel >> LIGHTSEGSHIFT);
+		else
+		{
+			lightnum = thing->subsector->sector->lightlevel;
+		}
+
+		lightnum = (lightnum + R_ThingLightLevel(thing)) >> LIGHTSEGSHIFT;
 
 		if (lightnum < 0)
-			spritelights = scalelight[0];
+			lights_array = scalelight[0];
 		else if (lightnum >= LIGHTLEVELS)
-			spritelights = scalelight[LIGHTLEVELS-1];
+			lights_array = scalelight[LIGHTLEVELS-1];
 		else
-			spritelights = scalelight[lightnum];
+			lights_array = scalelight[lightnum];
 	}
 
 	heightsec = thing->subsector->sector->heightsec;
@@ -2414,7 +2432,7 @@ static void R_ProjectSprite(mobj_t *thing)
 		if (vis->cut & SC_SEMIBRIGHT)
 			lindex = (MAXLIGHTSCALE/2) + (lindex >> 1);
 
-		vis->colormap = spritelights[lindex];
+		vis->colormap = lights_array[lindex];
 	}
 
 	if (vflip)
@@ -2425,7 +2443,7 @@ static void R_ProjectSprite(mobj_t *thing)
 	vis->patch = patch;
 	vis->bright = R_CacheSpriteBrightMap(sprinfo, frame);
 
-	if (thing->subsector->sector->numlights && !(shadowdraw || splat))
+	if (thing->subsector->sector->numlights && !(shadowdraw || splat) && !(thing->renderflags & RF_ABSOLUTELIGHTLEVEL))
 		R_SplitSprite(vis);
 
 	if (oldthing->shadowscale && cv_shadow.value)

src/r_things.h

@@ -93,6 +93,8 @@ boolean R_ThingIsFullDark (mobj_t *thing);
 
 boolean R_ThingIsFlashing(mobj_t *thing);
 
+INT32 R_ThingLightLevel(mobj_t *thing);
+
 // --------------
 // MASKED DRAWING
 // --------------