From 198a3a556c67bcb76019877fd845d68015df8c5b Mon Sep 17 00:00:00 2001
From: helixhorned <helixhorned@1a8010ca-5511-0410-912e-c29ae57300e0>
Date: Wed, 1 May 2013 17:42:05 +0000
Subject: [PATCH] Classic: optimize background 'rainbow' drawing in use for
 editor/debug.

Also, draw it at shade 18 and don't use fullbright colors.

git-svn-id: https://svn.eduke32.com/eduke32@3721 1a8010ca-5511-0410-912e-c29ae57300e0
---
 polymer/eduke32/build/src/engine.c | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/polymer/eduke32/build/src/engine.c b/polymer/eduke32/build/src/engine.c
index 600a97ff9..566843c3a 100644
--- a/polymer/eduke32/build/src/engine.c
+++ b/polymer/eduke32/build/src/engine.c
@@ -1180,23 +1180,24 @@ void yax_drawrooms(void (*SpriteAnimFunc)(int32_t,int32_t,int32_t,int32_t),
 // must have writable frame buffer, i.e. done begindrawing()
 static void draw_rainbow_background(void)
 {
-    int32_t i, j;
-    const int32_t dimenprod = bytesperline*ydimen;
-    char *const p = (char *)frameplace;
+    int32_t y, i;
+    const int32_t N = 240;  // don't use fullbright colors
+    const int32_t numfull=bytesperline/N, numrest=bytesperline%N;
 
-    j = 0;
-    for (i=0; i<dimenprod; i++)
+    const char *const src = palookup[0] + 256*18;
+    char *dst = (char *)frameplace;
+
+    for (y=0; y<ydim; y++)
     {
-        p[i] = (char)j;
-        j++;
-        if (j >= xdimen)
-        {
-            while (j < bytesperline)
-                i++, j++;
-            j = 0;
-        }
+        for (i=0; i<numfull; i++)
+            Bmemcpy(&dst[N*i], src, N);
+        if (numrest > 0)
+            Bmemcpy(&dst[N*i], src, numrest);
+
+        dst += bytesperline;
     }
 }
+
 //
 // setslope
 //