Add R_SpriteRotationAngle function

Gets the rotation angle for the mobj's sprite. Meant for pitch & roll later, but that part is if'd out currently and just returns mobj->rollangle

src/hardware/hw_main.c

@@ -4902,6 +4902,7 @@ static void HWR_ProjectSprite(mobj_t *thing)
 #ifdef ROTSPRITE
 	patch_t *rotsprite = NULL;
 	INT32 rollangle = 0;
+	angle_t spriterotangle = 0;
 #endif
 
 	if (!thing)
@@ -5025,9 +5026,11 @@ static void HWR_ProjectSprite(mobj_t *thing)
 	spr_topoffset = spritecachedinfo[lumpoff].topoffset;
 
 #ifdef ROTSPRITE
-	if (thing->rollangle)
+	spriterotangle = R_SpriteRotationAngle(thing);
+
+	if (spriterotangle != 0)
 	{
-		rollangle = R_GetRollAngle(thing->rollangle);
+		rollangle = R_GetRollAngle(spriterotangle);
 		if (!(sprframe->rotsprite.cached & (1<<rot)))
 			R_CacheRotSprite(thing->sprite, (thing->frame & FF_FRAMEMASK), sprinfo, sprframe, rot, flip);
 		rotsprite = sprframe->rotsprite.patch[rot][rollangle];

src/r_picformats.c

@@ -23,6 +23,7 @@
 #include "v_video.h"
 #include "z_zone.h"
 #include "w_wad.h"
+#include "r_main.h" // R_PointToAngle
 
 #ifdef HWRENDER
 #include "hardware/hw_glob.h"
@@ -1605,6 +1606,27 @@ void R_LoadSpriteInfoLumps(UINT16 wadnum, UINT16 numlumps)
 }
 
 #ifdef ROTSPRITE
+//
+// R_SpriteRotationAngle
+//
+// Gets the rollangle for the input object.
+//
+angle_t R_SpriteRotationAngle(mobj_t *mobj)
+{
+#if 0
+	angle_t viewingAngle = R_PointToAngle(mobj->x, mobj->y);
+
+	fixed_t pitchMul = -FINESINE(viewingAngle >> ANGLETOFINESHIFT);
+	fixed_t rollMul = FINECOSINE(viewingAngle >> ANGLETOFINESHIFT);
+
+	angle_t rollOrPitch = FixedMul(mobj->pitch, pitchMul) + FixedMul(mobj->roll, rollMul);
+
+	return (rollOrPitch + mobj->rollangle);
+#else
+	return mobj->rollangle;
+#endif
+}
+
 //
 // R_GetRollAngle
 //

src/r_picformats.h

@@ -122,6 +122,7 @@ void R_ParseSPRTINFOLump(UINT16 wadNum, UINT16 lumpNum);
 
 // Sprite rotation
 #ifdef ROTSPRITE
+angle_t R_SpriteRotationAngle(mobj_t *mobj);
 INT32 R_GetRollAngle(angle_t rollangle);
 void R_CacheRotSprite(spritenum_t sprnum, UINT8 frame, spriteinfo_t *sprinfo, spriteframe_t *sprframe, INT32 rot, UINT8 flip);
 void R_FreeSingleRotSprite(spritedef_t *spritedef);

src/r_things.c

@@ -1446,6 +1446,7 @@ static void R_ProjectSprite(mobj_t *thing)
 #ifdef ROTSPRITE
 	patch_t *rotsprite = NULL;
 	INT32 rollangle = 0;
+	angle_t spriterotangle = 0;
 #endif
 
 	// transform the origin point
@@ -1571,9 +1572,11 @@ static void R_ProjectSprite(mobj_t *thing)
 	spr_topoffset = spritecachedinfo[lump].topoffset;
 
 #ifdef ROTSPRITE
-	if (thing->rollangle)
+	spriterotangle = R_SpriteRotationAngle(thing);
+
+	if (spriterotangle != 0)
 	{
-		rollangle = R_GetRollAngle(thing->rollangle);
+		rollangle = R_GetRollAngle(spriterotangle);
 		if (!(sprframe->rotsprite.cached & (1<<rot)))
 			R_CacheRotSprite(thing->sprite, frame, sprinfo, sprframe, rot, flip);
 		rotsprite = sprframe->rotsprite.patch[rot][rollangle];