diff --git a/src/r_segs.c b/src/r_segs.c
index 502ff3304dab17ec4f54283608ee33fb74145b60..dee0703050343b33d030c84bbf9e15655b308bd0 100644
--- a/src/r_segs.c
+++ b/src/r_segs.c
@@ -198,7 +198,7 @@ static void R_DrawWallSplats(void)
 		// draw the columns
 		for (dc_x = x1; dc_x <= x2; dc_x++, spryscale += rw_scalestep)
 		{
-			pindex = FixedMul(spryscale, FixedDiv(640, vid.width))>>LIGHTSCALESHIFT;
+			pindex = FixedMul(spryscale, FixedDiv(320, vid.width))>>LIGHTSCALESHIFT;
 			if (pindex >= MAXLIGHTSCALE)
 				pindex = MAXLIGHTSCALE - 1;
 			dc_colormap = walllights[pindex];
@@ -580,7 +580,7 @@ void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2)
 						else
 							xwalllights = scalelight[rlight->lightnum];
 
-						pindex = FixedMul(spryscale, FixedDiv(640, vid.width))>>LIGHTSCALESHIFT;
+						pindex = FixedMul(spryscale, FixedDiv(320, vid.width))>>LIGHTSCALESHIFT;
 
 						if (pindex >= MAXLIGHTSCALE)
 							pindex = MAXLIGHTSCALE - 1;
@@ -625,7 +625,7 @@ void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2)
 				}
 
 				// calculate lighting
-				pindex = FixedMul(spryscale, FixedDiv(640, vid.width))>>LIGHTSCALESHIFT;
+				pindex = FixedMul(spryscale, FixedDiv(320, vid.width))>>LIGHTSCALESHIFT;
 
 				if (pindex >= MAXLIGHTSCALE)
 					pindex = MAXLIGHTSCALE - 1;
@@ -1099,7 +1099,7 @@ void R_RenderThickSideRange(drawseg_t *ds, INT32 x1, INT32 x2, ffloor_t *pfloor)
 						else
 							xwalllights = scalelight[lightnum];
 
-						pindex = FixedMul(spryscale, FixedDiv(640, vid.width))>>LIGHTSCALESHIFT;
+						pindex = FixedMul(spryscale, FixedDiv(320, vid.width))>>LIGHTSCALESHIFT;
 
 						if (pindex >=  MAXLIGHTSCALE)
 							pindex = MAXLIGHTSCALE-1;
@@ -1189,7 +1189,7 @@ void R_RenderThickSideRange(drawseg_t *ds, INT32 x1, INT32 x2, ffloor_t *pfloor)
 			}
 
 			// calculate lighting
-			pindex = FixedMul(spryscale, FixedDiv(640, vid.width))>>LIGHTSCALESHIFT;
+			pindex = FixedMul(spryscale, FixedDiv(320, vid.width))>>LIGHTSCALESHIFT;
 
 			if (pindex >= MAXLIGHTSCALE)
 				pindex = MAXLIGHTSCALE - 1;
@@ -1419,7 +1419,7 @@ static void R_RenderSegLoop (void)
 		if (segtextured)
 		{
 			// calculate lighting
-			pindex = FixedMul(rw_scale, FixedDiv(640, vid.width))>>LIGHTSCALESHIFT;
+			pindex = FixedMul(rw_scale, FixedDiv(320, vid.width))>>LIGHTSCALESHIFT;
 
 			if (pindex >=  MAXLIGHTSCALE)
 				pindex = MAXLIGHTSCALE-1;
@@ -1454,7 +1454,7 @@ static void R_RenderSegLoop (void)
 				else
 					xwalllights = scalelight[lightnum];
 
-				pindex = FixedMul(rw_scale, FixedDiv(640, vid.width))>>LIGHTSCALESHIFT;
+				pindex = FixedMul(rw_scale, FixedDiv(320, vid.width))>>LIGHTSCALESHIFT;
 
 				if (pindex >=  MAXLIGHTSCALE)
 					pindex = MAXLIGHTSCALE-1;