From c4306b624d00499c148a69a8aa55b7d3c4381d94 Mon Sep 17 00:00:00 2001
From: "chi.miru" <ren_amon@hotmail.com>
Date: Wed, 29 Apr 2015 02:36:18 -0400
Subject: [PATCH] Optimized R_DrawTiltedSpan_8
---
src/r_draw8.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 77 insertions(+), 2 deletions(-)
diff --git a/src/r_draw8.c b/src/r_draw8.c
index 86b06089e..25ca8f3bd 100644
--- a/src/r_draw8.c
+++ b/src/r_draw8.c
@@ -551,8 +551,8 @@ void R_DrawTiltedSpan_8(void)
source = ds_source;
colormap = ds_colormap;
- // The "perfect" reference version of this routine. Pretty slow.
- // Use it only to see how things are supposed to look.
+#if 0 // The "perfect" reference version of this routine. Pretty slow.
+ // Use it only to see how things are supposed to look.
i = 0;
do
{
@@ -566,6 +566,81 @@ void R_DrawTiltedSpan_8(void)
vz += ds_sv.x;
} while (--width >= 0);
}
+#else
+#define SPANSIZE 16
+#define INVSPAN 0.0625f
+
+ double startz = 1.f/iz;
+ double startu = uz*startz;
+ double startv = vz*startz;
+ double izstep, uzstep, vzstep;
+
+ izstep = ds_sz.x * SPANSIZE;
+ uzstep = ds_su.x * SPANSIZE;
+ vzstep = ds_sv.x * SPANSIZE;
+ //x1 = 0;
+ width++;
+
+ while (width >= SPANSIZE)
+ {
+ iz += izstep;
+ uz += uzstep;
+ vz += vzstep;
+
+ double endz = 1.f/iz;
+ double endu = uz*endz;
+ double endv = vz*endz;
+ UINT32 stepu = (INT64)((endu - startu) * INVSPAN);
+ UINT32 stepv = (INT64)((endv - startv) * INVSPAN);
+ u = (INT64)(startu) + viewx;
+ v = (INT64)(startv) + viewy;
+
+ for (i = SPANSIZE-1; i >= 0; i--)
+ {
+ *dest = colormap[source[((v >> nflatyshift) & nflatmask) | (u >> nflatxshift)]];
+ dest++;
+ u += stepu;
+ v += stepv;
+ }
+ startu = endu;
+ startv = endv;
+ width -= SPANSIZE;
+ }
+ if (width > 0)
+ {
+ if (width == 1)
+ {
+ u = (INT64)(startu);
+ v = (INT64)(startv);
+ *dest = colormap[source[((v >> nflatyshift) & nflatmask) | (u >> nflatxshift)]];
+ }
+ else
+ {
+ double left = width;
+ iz += ds_sz.x * left;
+ uz += ds_su.x * left;
+ vz += ds_sv.x * left;
+
+ double endz = 1.f/iz;
+ double endu = uz*endz;
+ double endv = vz*endz;
+ left = 1.f/left;
+ UINT32 stepu = (INT64)((endu - startu) * left);
+ UINT32 stepv = (INT64)((endv - startv) * left);
+ u = (INT64)(startu) + viewx;
+ v = (INT64)(startv) + viewy;
+
+ for (; width != 0; width--)
+ {
+ *dest = colormap[source[((v >> nflatyshift) & nflatmask) | (u >> nflatxshift)]];
+ dest++;
+ u += stepu;
+ v += stepv;
+ }
+ }
+ }
+#endif
+}
#endif // ESLOPE
/** \brief The R_DrawSplat_8 function