From eaa147519f92c1460bb0fb317d700fec63cf00ef Mon Sep 17 00:00:00 2001
From: notaz <notasas@gmail.com>
Date: Tue, 17 Oct 2017 01:01:26 +0300
Subject: [PATCH] sms: more md-consistent drawing

---
 pico/mode4.c | 76 +++++++++++++++++++++++-----------------------------
 1 file changed, 34 insertions(+), 42 deletions(-)

diff --git a/pico/mode4.c b/pico/mode4.c
index a13c38b0..37f752bb 100644
--- a/pico/mode4.c
+++ b/pico/mode4.c
@@ -26,48 +26,34 @@ static int screen_offset;
     pd[x] = pal|t; \
   }
 
-static int TileNormM4(int sx, int addr, int pal)
+static void TileNormM4(int sx, unsigned int pack, int pal)
 {
   unsigned char *pd = Pico.est.HighCol + sx;
-  unsigned int pack, t;
-
-  pack = *(unsigned int *)(PicoMem.vram + addr); /* Get 4 bitplanes / 8 pixels */
-  if (pack)
-  {
-    PLANAR_PIXEL(0, 0)
-    PLANAR_PIXEL(1, 1)
-    PLANAR_PIXEL(2, 2)
-    PLANAR_PIXEL(3, 3)
-    PLANAR_PIXEL(4, 4)
-    PLANAR_PIXEL(5, 5)
-    PLANAR_PIXEL(6, 6)
-    PLANAR_PIXEL(7, 7)
-    return 0;
-  }
+  unsigned int t;
 
-  return 1; /* Tile blank */
+  PLANAR_PIXEL(0, 0)
+  PLANAR_PIXEL(1, 1)
+  PLANAR_PIXEL(2, 2)
+  PLANAR_PIXEL(3, 3)
+  PLANAR_PIXEL(4, 4)
+  PLANAR_PIXEL(5, 5)
+  PLANAR_PIXEL(6, 6)
+  PLANAR_PIXEL(7, 7)
 }
 
-static int TileFlipM4(int sx,int addr,int pal)
+static void TileFlipM4(int sx, unsigned int pack, int pal)
 {
   unsigned char *pd = Pico.est.HighCol + sx;
-  unsigned int pack, t;
-
-  pack = *(unsigned int *)(PicoMem.vram + addr); /* Get 4 bitplanes / 8 pixels */
-  if (pack)
-  {
-    PLANAR_PIXEL(0, 7)
-    PLANAR_PIXEL(1, 6)
-    PLANAR_PIXEL(2, 5)
-    PLANAR_PIXEL(3, 4)
-    PLANAR_PIXEL(4, 3)
-    PLANAR_PIXEL(5, 2)
-    PLANAR_PIXEL(6, 1)
-    PLANAR_PIXEL(7, 0)
-    return 0;
-  }
+  unsigned int t;
 
-  return 1; /* Tile blank */
+  PLANAR_PIXEL(0, 7)
+  PLANAR_PIXEL(1, 6)
+  PLANAR_PIXEL(2, 5)
+  PLANAR_PIXEL(3, 4)
+  PLANAR_PIXEL(4, 3)
+  PLANAR_PIXEL(5, 2)
+  PLANAR_PIXEL(6, 1)
+  PLANAR_PIXEL(7, 0)
 }
 
 static void draw_sprites(int scanline)
@@ -75,6 +61,7 @@ static void draw_sprites(int scanline)
   struct PicoVideo *pv = &Pico.video;
   unsigned int sprites_addr[8];
   unsigned int sprites_x[8];
+  unsigned int pack;
   unsigned char *sat;
   int xoff = 8; // relative to HighCol, which is (screen - 8)
   int sprite_base, addr_mask;
@@ -115,8 +102,10 @@ static void draw_sprites(int scanline)
     pv->status |= SR_C;
 
   // now draw all sprites backwards
-  for (--s; s >= 0; s--)
-    TileNormM4(sprites_x[s], sprites_addr[s], 0x10);
+  for (--s; s >= 0; s--) {
+    pack = *(unsigned int *)(PicoMem.vram + sprites_addr[s]);
+    TileNormM4(sprites_x[s], pack, 0x10);
+  }
 }
 
 // tilex_ty_prio merged to reduce register pressure
@@ -128,7 +117,8 @@ static void draw_strip(const unsigned short *nametab, int dx, int cells, int til
   // Draw tiles across screen:
   for (; cells > 0; dx += 8, tilex_ty_prio++, cells--)
   {
-    int code, zero;
+    unsigned int pack;
+    int code;
 
     code = nametab[tilex_ty_prio & 0x1f];
     if (code == blank)
@@ -147,11 +137,13 @@ static void draw_strip(const unsigned short *nametab, int dx, int cells, int til
       pal = (code>>7) & 0x10;
     }
 
-    if (code&0x0200) zero = TileFlipM4(dx, addr, pal);
-    else             zero = TileNormM4(dx, addr, pal);
-
-    if (zero)
-      blank = code; // We know this tile is blank now
+    pack = *(unsigned int *)(PicoMem.vram + addr); /* Get 4 bitplanes / 8 pixels */
+    if (pack == 0) {
+      blank = code;
+      continue;
+    }
+    if (code & 0x0200) TileFlipM4(dx, pack, pal);
+    else               TileNormM4(dx, pack, pal);
   }
 }
 
-- 
2.39.5