Make use of FixedReciprocal and FixedApproxDiv

Author: jserv

src/m_fixed.h

@@ -96,7 +96,10 @@ inline static fixed_t CONSTFUNC FixedMod(fixed_t a, fixed_t b)
     return (a & (b-1));
 }
 
-//Approx Reciprocal of v
+/*
+ * Approximate Reciprocal of v
+ */
+
 inline static CONSTFUNC fixed_t FixedReciprocal(fixed_t v)
 {
     unsigned int val = v < 0 ? -v : v;
@@ -115,7 +118,10 @@ inline static CONSTFUNC fixed_t FixedReciprocal(fixed_t v)
 }
 
 
-//Approx fixed point divide of a/b using reciprocal. -> a * (1/b).
+/*
+ * Approximate fixed point divide of a/b using reciprocal. -> a * (1/b).
+ */
+
 inline static CONSTFUNC fixed_t FixedApproxDiv(fixed_t a, fixed_t b)
 {
     return FixedMul(a, FixedReciprocal(b));

src/r_main.c

@@ -410,7 +410,7 @@ R_PointToDist
     angle = (tantoangle[ FixedDiv(dy,dx)>>DBITS ]+ANG90) >> ANGLETOFINESHIFT;
 
     // use as cosine
-    dist = FixedDiv (dx, finesine[angle] );
+    dist = FixedApproxDiv (dx, finesine[angle] );
 
     return dist;
 }

src/r_segs.c

@@ -172,7 +172,7 @@ R_RenderMaskedSegRange
             }
 
             sprtopscreen = centeryfrac - FixedMul(dc_texturemid, spryscale);
-            dc_iscale = 0xffffffffu / (unsigned)spryscale;
+            dc_iscale = FixedReciprocal((unsigned)spryscale);
 
             // draw the texture
             col = (column_t *)(
@@ -270,7 +270,7 @@ void R_RenderSegLoop (void)
 
             dc_colormap = walllights[index];
             dc_x = rw_x;
-            dc_iscale = 0xffffffffu / (unsigned)rw_scale;
+            dc_iscale = FixedReciprocal((unsigned)rw_scale);
         }
 
         // draw the wall tiers

src/r_things.c

@@ -461,8 +461,6 @@ void R_ProjectSprite (mobj_t* thing)
     fixed_t             tx;
     fixed_t             tz;
 
-    fixed_t             xscale;
-
     int                 x1;
     int                 x2;
 
@@ -478,7 +476,6 @@ void R_ProjectSprite (mobj_t* thing)
     vissprite_t*        vis;
 
     angle_t             ang;
-    fixed_t             iscale;
 
     // transform the origin point
     tr_x = thing->x - viewx;
@@ -493,7 +490,7 @@ void R_ProjectSprite (mobj_t* thing)
     if (tz < MINZ)
         return;
 
-    xscale = FixedDiv(projection, tz);
+    const fixed_t xscale = FixedDiv(projection, tz);
 
     gxt = -FixedMul(tr_x,viewsin);
     gyt = FixedMul(tr_y,viewcos);
@@ -558,7 +555,7 @@ void R_ProjectSprite (mobj_t* thing)
     vis->texturemid = vis->gzt - viewz;
     vis->x1 = x1 < 0 ? 0 : x1;
     vis->x2 = x2 >= viewwidth ? viewwidth-1 : x2;
-    iscale = FixedDiv (FRACUNIT, xscale);
+    const fixed_t iscale = FixedReciprocal(xscale);
 
     if (flip)
     {