diff --git a/src/hardware/hw_bsp.c b/src/hardware/hw_bsp.c
index 17eb8761c..2a67f7d56 100644
--- a/src/hardware/hw_bsp.c
+++ b/src/hardware/hw_bsp.c
@@ -916,7 +916,7 @@ static void AdjustSegs(void)
 			}
 			if (nearv1 <= NEARDIST*NEARDIST)
 				// share vertice with segs
-				lseg->v1 = (vertex_t *)&(p->pts[v1found]);
+				lseg->pv1 = &(p->pts[v1found]);
 			else
 			{
 				// BP: here we can do better, using PointInSeg and compute
@@ -927,24 +927,24 @@ static void AdjustSegs(void)
 				polyvertex_t *pv = HWR_AllocVertex();
 				pv->x = FIXED_TO_FLOAT(lseg->v1->x);
 				pv->y = FIXED_TO_FLOAT(lseg->v1->y);
-				lseg->v1 = (vertex_t *)pv;
+				lseg->pv1 = pv;
 			}
 			if (nearv2 <= NEARDIST*NEARDIST)
-				lseg->v2 = (vertex_t *)&(p->pts[v2found]);
+				lseg->pv2 = &(p->pts[v2found]);
 			else
 			{
 				polyvertex_t *pv = HWR_AllocVertex();
 				pv->x = FIXED_TO_FLOAT(lseg->v2->x);
 				pv->y = FIXED_TO_FLOAT(lseg->v2->y);
-				lseg->v2 = (vertex_t *)pv;
+				lseg->pv2 = pv;
 			}
 
 			// recompute length
 			{
 				float x,y;
-				x = ((polyvertex_t *)lseg->v2)->x - ((polyvertex_t *)lseg->v1)->x
+				x = ((polyvertex_t *)lseg->pv2)->x - ((polyvertex_t *)lseg->pv1)->x
 					+ FIXED_TO_FLOAT(FRACUNIT/2);
-				y = ((polyvertex_t *)lseg->v2)->y - ((polyvertex_t *)lseg->v1)->y
+				y = ((polyvertex_t *)lseg->pv2)->y - ((polyvertex_t *)lseg->pv1)->y
 					+ FIXED_TO_FLOAT(FRACUNIT/2);
 				lseg->flength = (float)hypot(x, y);
 				// BP: debug see this kind of segs
diff --git a/src/hardware/hw_main.c b/src/hardware/hw_main.c
index 270229ad0..3d9b82b32 100644
--- a/src/hardware/hw_main.c
+++ b/src/hardware/hw_main.c
@@ -858,11 +858,11 @@ static void HWR_DrawSegsSplats(FSurfaceInfo * pSurf)
 
 	M_ClearBox(segbbox);
 	M_AddToBox(segbbox,
-		FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->v1)->x),
-		FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->v1)->y));
+		FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->pv1)->x),
+		FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->pv1)->y));
 	M_AddToBox(segbbox,
-		FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->v2)->x),
-		FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->v2)->y));
+		FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->pv2)->x),
+		FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->pv2)->y));
 
 	splat = (wallsplat_t *)gr_curline->linedef->splats;
 	for (; splat; splat = splat->next)
@@ -1468,10 +1468,10 @@ static void HWR_StoreWallRange(double startfrac, double endfrac)
 	gr_sidedef = gr_curline->sidedef;
 	gr_linedef = gr_curline->linedef;
 
-	vs.x = ((polyvertex_t *)gr_curline->v1)->x;
-	vs.y = ((polyvertex_t *)gr_curline->v1)->y;
-	ve.x = ((polyvertex_t *)gr_curline->v2)->x;
-	ve.y = ((polyvertex_t *)gr_curline->v2)->y;
+	vs.x = ((polyvertex_t *)gr_curline->pv1)->x;
+	vs.y = ((polyvertex_t *)gr_curline->pv1)->y;
+	ve.x = ((polyvertex_t *)gr_curline->pv2)->x;
+	ve.y = ((polyvertex_t *)gr_curline->pv2)->y;
 
 #ifdef ESLOPE
 	v1x = FLOAT_TO_FIXED(vs.x);
@@ -2555,7 +2555,7 @@ static void HWR_ClipSolidWallSegment(INT32 first, INT32 last)
 		}
 		else
 		{
-			highfrac = HWR_ClipViewSegment(start->first+1, (polyvertex_t *)gr_curline->v1, (polyvertex_t *)gr_curline->v2);
+			highfrac = HWR_ClipViewSegment(start->first+1, (polyvertex_t *)gr_curline->pv1, (polyvertex_t *)gr_curline->pv2);
 			HWR_StoreWallRange(0, highfrac);
 		}
 		// Now adjust the clip size.
@@ -2579,8 +2579,8 @@ static void HWR_ClipSolidWallSegment(INT32 first, INT32 last)
 		}
 		else
 		{
-			lowfrac  = HWR_ClipViewSegment(next->last-1, (polyvertex_t *)gr_curline->v1, (polyvertex_t *)gr_curline->v2);
-			highfrac = HWR_ClipViewSegment((next+1)->first+1, (polyvertex_t *)gr_curline->v1, (polyvertex_t *)gr_curline->v2);
+			lowfrac  = HWR_ClipViewSegment(next->last-1, (polyvertex_t *)gr_curline->pv1, (polyvertex_t *)gr_curline->pv2);
+			highfrac = HWR_ClipViewSegment((next+1)->first+1, (polyvertex_t *)gr_curline->pv1, (polyvertex_t *)gr_curline->pv2);
 			HWR_StoreWallRange(lowfrac, highfrac);
 		}
 		next++;
@@ -2614,7 +2614,7 @@ static void HWR_ClipSolidWallSegment(INT32 first, INT32 last)
 		}
 		else
 		{
-			lowfrac  = HWR_ClipViewSegment(next->last-1, (polyvertex_t *)gr_curline->v1, (polyvertex_t *)gr_curline->v2);
+			lowfrac  = HWR_ClipViewSegment(next->last-1, (polyvertex_t *)gr_curline->pv1, (polyvertex_t *)gr_curline->pv2);
 			HWR_StoreWallRange(lowfrac, 1);
 		}
 	}
@@ -2677,8 +2677,8 @@ static void HWR_ClipPassWallSegment(INT32 first, INT32 last)
 		else
 		{
 			highfrac = HWR_ClipViewSegment(min(start->first + 1,
-				start->last), (polyvertex_t *)gr_curline->v1,
-				(polyvertex_t *)gr_curline->v2);
+				start->last), (polyvertex_t *)gr_curline->pv1,
+				(polyvertex_t *)gr_curline->pv2);
 			HWR_StoreWallRange(0, highfrac);
 		}
 	}
@@ -2697,8 +2697,8 @@ static void HWR_ClipPassWallSegment(INT32 first, INT32 last)
 		}
 		else
 		{
-			lowfrac  = HWR_ClipViewSegment(max(start->last-1,start->first), (polyvertex_t *)gr_curline->v1, (polyvertex_t *)gr_curline->v2);
-			highfrac = HWR_ClipViewSegment(min((start+1)->first+1,(start+1)->last), (polyvertex_t *)gr_curline->v1, (polyvertex_t *)gr_curline->v2);
+			lowfrac  = HWR_ClipViewSegment(max(start->last-1,start->first), (polyvertex_t *)gr_curline->pv1, (polyvertex_t *)gr_curline->pv2);
+			highfrac = HWR_ClipViewSegment(min((start+1)->first+1,(start+1)->last), (polyvertex_t *)gr_curline->pv1, (polyvertex_t *)gr_curline->pv2);
 			HWR_StoreWallRange(lowfrac, highfrac);
 		}
 		start++;
@@ -2728,8 +2728,8 @@ static void HWR_ClipPassWallSegment(INT32 first, INT32 last)
 		else
 		{
 			lowfrac = HWR_ClipViewSegment(max(start->last - 1,
-				start->first), (polyvertex_t *)gr_curline->v1,
-				(polyvertex_t *)gr_curline->v2);
+				start->first), (polyvertex_t *)gr_curline->pv1,
+				(polyvertex_t *)gr_curline->pv2);
 			HWR_StoreWallRange(lowfrac, 1);
 		}
 	}
@@ -2790,10 +2790,10 @@ static void HWR_AddLine(seg_t * line)
 	gr_curline = line;
 
 	// OPTIMIZE: quickly reject orthogonal back sides.
-	angle1 = R_PointToAngle(FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->v1)->x),
-	                        FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->v1)->y));
-	angle2 = R_PointToAngle(FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->v2)->x),
-	                        FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->v2)->y));
+	angle1 = R_PointToAngle(FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->pv1)->x),
+	                        FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->pv1)->y));
+	angle2 = R_PointToAngle(FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->pv2)->x),
+	                        FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->pv2)->y));
 
 	// Clip to view edges.
 	span = angle1 - angle2;
@@ -2835,8 +2835,8 @@ static void HWR_AddLine(seg_t * line)
 		float fx1,fx2,fy1,fy2;
 		//BP: test with a better projection than viewangletox[R_PointToAngle(angle)]
 		// do not enable this at release 4 mul and 2 div
-		fx1 = ((polyvertex_t *)(line->v1))->x-gr_viewx;
-		fy1 = ((polyvertex_t *)(line->v1))->y-gr_viewy;
+		fx1 = ((polyvertex_t *)(line->pv1))->x-gr_viewx;
+		fy1 = ((polyvertex_t *)(line->pv1))->y-gr_viewy;
 		fy2 = (fx1 * gr_viewcos + fy1 * gr_viewsin);
 		if (fy2 < 0)
 			// the point is back
@@ -2844,8 +2844,8 @@ static void HWR_AddLine(seg_t * line)
 		else
 			fx1 = gr_windowcenterx + (fx1 * gr_viewsin - fy1 * gr_viewcos) * gr_centerx / fy2;
 
-		fx2 = ((polyvertex_t *)(line->v2))->x-gr_viewx;
-		fy2 = ((polyvertex_t *)(line->v2))->y-gr_viewy;
+		fx2 = ((polyvertex_t *)(line->pv2))->x-gr_viewx;
+		fy2 = ((polyvertex_t *)(line->pv2))->y-gr_viewy;
 		fy1 = (fx2 * gr_viewcos + fy2 * gr_viewsin);
 		if (fy1 < 0)
 			// the point is back
@@ -2888,10 +2888,10 @@ static void HWR_AddLine(seg_t * line)
 		fixed_t frontf1,frontf2, frontc1, frontc2; // front floor/ceiling ends
 		fixed_t backf1, backf2, backc1, backc2; // back floor ceiling ends
 
-		v1x = FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->v1)->x);
-		v1y = FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->v1)->y);
-		v2x = FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->v2)->x);
-		v2y = FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->v2)->y);
+		v1x = FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->pv1)->x);
+		v1y = FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->pv1)->y);
+		v2x = FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->pv2)->x);
+		v2y = FLOAT_TO_FIXED(((polyvertex_t *)gr_curline->pv2)->y);
 #define SLOPEPARAMS(slope, end1, end2, normalheight) \
 		if (slope) { \
 			end1 = P_GetZAt(slope, v1x, v1y); \
@@ -3086,8 +3086,8 @@ static inline void HWR_AddPolyObjectSegs(void)
 			pv2->x = FIXED_TO_FLOAT(gr_fakeline->v2->x);
 			pv2->y = FIXED_TO_FLOAT(gr_fakeline->v2->y);
 
-			gr_fakeline->v1 = (vertex_t *)pv1;
-			gr_fakeline->v2 = (vertex_t *)pv2;
+			gr_fakeline->pv1 = pv1;
+			gr_fakeline->pv2 = pv2;
 
 			HWR_AddLine(gr_fakeline);
 		}
diff --git a/src/p_setup.c b/src/p_setup.c
index f1d3a68c8..f8653502a 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -451,6 +451,7 @@ static void P_LoadSegs(lumpnum_t lumpnum)
 			//Hurdler: 04/12/2000: for now, only used in hardware mode
 			li->lightmaps = NULL; // list of static lightmap for this seg
 		}
+		li->pv1 = li->pv2 = NULL;
 #endif
 
 		li->angle = (SHORT(ml->angle))<<FRACBITS;
diff --git a/src/r_defs.h b/src/r_defs.h
index 9109ac7c3..018abf4b8 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -581,6 +581,9 @@ typedef struct seg_s
 	sector_t *backsector;
 
 #ifdef HWRENDER
+	// new pointers so that AdjustSegs doesn't mess with v1/v2
+	void *pv1; // polyvertex_t
+	void *pv2; // polyvertex_t
 	float flength; // length of the seg, used by hardware renderer
 
 	lightmap_t *lightmaps; // for static lightmap