From f169aa5071bbeb5ca7fba596fc19be937bf4f7bf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Nov=C3=A1k?= <ondra-novak@email.cz>
Date: Wed, 29 Jan 2025 20:46:35 +0100
Subject: [PATCH] improve MGF video quality

---
 game/globals.h         |  1 +
 game/kouzla.c          |  2 +-
 libs/mgifmapmem.c      | 86 ++++++++++++++++++++++++++++++++++++++++--
 platform/sdl/sound.cpp |  2 +-
 4 files changed, 86 insertions(+), 5 deletions(-)

diff --git a/game/globals.h b/game/globals.h
index f469006..76b72b4 100644
--- a/game/globals.h
+++ b/game/globals.h
@@ -85,6 +85,7 @@
 
 #define get_string(t) texty[t]
 static __inline unsigned int rnd(unsigned int max) {
+    if (max == 0) return 0;
     return rand() % max;
 }
 
diff --git a/game/kouzla.c b/game/kouzla.c
index bd46e0a..e7c0359 100644
--- a/game/kouzla.c
+++ b/game/kouzla.c
@@ -745,7 +745,7 @@ void spell_hit(int cil,int min,int max,int owner)
 
      cil--;
      h=&postavy[cil];
-     vysl=min+rnd(max-min);
+     vysl=min+rnd(max-min+1);
      if (vysl<0)
       {
       h->lives-=vysl>h->vlastnosti[VLS_MAXHIT]?h->vlastnosti[VLS_MAXHIT]:vysl;
diff --git a/libs/mgifmapmem.c b/libs/mgifmapmem.c
index 5aeee60..4cab8ba 100644
--- a/libs/mgifmapmem.c
+++ b/libs/mgifmapmem.c
@@ -19,10 +19,79 @@ static word *picture;
 static word *anim_render_buffer;
 static void *sound;
 
-static void StretchImageHQ(word *src, word *trg, uint32_t linelen, char full)
+static inline word avg_pixels(word a, word b) {
+    return ((a & 0xF7DE)+(a & 0xF7DE)) >> 1;
+}
+
+static void StretchImageHQ(word *src, word *trg, int32_t linelen, char full)
   {
   word xs=src[0],ys=src[1];
-  word *s,*t;
+
+  word *src_row = src+3;
+  word *trg_row = trg;
+
+  for(int y = 0; y < ys; ++y) {
+
+      for (int x = 0; x < xs; ++x) {
+          word n = src_row[x];
+          trg_row[2*x] = n;
+      }
+
+      trg_row += linelen;
+
+/*
+      if (y+1 < ys ) {
+          for (int x = 0; x < xs; ++x) {
+              word n1 = src_row[x];
+              word n2 = src_row[x+xs];
+              word n3 = y > 0?src_row[x-xs]:n1;
+              word n4 = y < (ys-2)?src_row[x+2*xs]:n2;
+              word n5 = avg_pixels(n1, n2);
+              word n6 = avg_pixels(n3, n4);
+              word n7 = avg_pixels(n5, n6);
+              trg_row[2*x] = n7;
+              trg_row[2*x+1] = n7;
+          }
+      }
+*/
+      trg_row += linelen;
+
+      src_row += xs;
+  }
+
+  trg_row = trg;
+
+  for (int y = 0; y < ys; ++y) {
+      for (int x = 0; x < xs-1; ++x) {
+          word n1 = trg_row[2*x];
+          word n2 = trg_row[2*x+2];
+          word n3 = x > 0?trg_row[2*x-2]:n1;
+          word n4 = x < (xs-2)?trg_row[2*x+2]:n2;
+          word n5 = avg_pixels(n1, n2);
+          word n6 = avg_pixels(n3, n4);
+          word n7 = avg_pixels(n5, n6);
+          trg_row[2*x+1] = n7;
+      }
+      trg_row += 2*linelen;
+  }
+
+  trg_row = trg;
+
+  for (int y = 0; y < ys-1; ++y) {
+      for (int x = 0; x < 2*xs; ++x) {
+          word n1 = trg_row[x];
+          word n2 = trg_row[x+2*linelen];
+          word n3 = y > 1?trg_row[x-2*linelen]:n1;
+          word n4 = y < (ys-2)?trg_row[x+4*linelen]:n2;
+          word n5 = avg_pixels(n1, n2);
+          word n6 = avg_pixels(n3, n4);
+          word n7 = avg_pixels(n5, n6);
+          trg_row[x+linelen] = n7;
+      }
+      trg_row += 2*linelen;
+  }
+
+#if 0
   int x,y;
   src+=3;
   for (y=0,s=src,t=trg;y<ys;y++,t+=linelen*2,s+=xs)
@@ -49,8 +118,11 @@ static void StretchImageHQ(word *src, word *trg, uint32_t linelen, char full)
 		  }
 		}
 	  }
+#endif
   }
 
+
+
 static void PlayMGFFile(void *file, MGIF_PROC proc,int ypos,char full)
   {
   int32_t scr_linelen2 = GetScreenPitch();
@@ -93,6 +165,14 @@ void show_delta_lfb12e_dx(void *target,void *buff,void *paleta);
 void show_full_lfb12e_dx(void *target,void *buff,void *paleta);
 
 
+word * load_mgf_palette(word *pal) {
+    static word paleta[256];
+    for (int i = 0; i < 256; ++i) {
+        paleta[i] = pal[i]+(pal[i]&0x7fe0);
+    }
+    return paleta;
+}
+
 void BigPlayProc(int act,void *data,int csize)
   {
   switch (act)
@@ -100,7 +180,7 @@ void BigPlayProc(int act,void *data,int csize)
      case MGIF_LZW:
      case MGIF_COPY:show_full_lfb12e(anim_render_buffer,data,paleta);break;
      case MGIF_DELTA:show_delta_lfb12e(anim_render_buffer,data,paleta);break;
-     case MGIF_PAL:paleta=data;break;
+     case MGIF_PAL:paleta=load_mgf_palette(data);break;
 	 case MGIF_SOUND:
 	   while (LoadNextVideoFrame(sound,data,csize,mgif_header->ampl_table,mgif_accnums,&mgif_writepos)==0);
      }
diff --git a/platform/sdl/sound.cpp b/platform/sdl/sound.cpp
index 839d426..367e815 100644
--- a/platform/sdl/sound.cpp
+++ b/platform/sdl/sound.cpp
@@ -68,7 +68,7 @@ void *PrepareVideoSound(int mixfreq, int buffsize) {
     return 0;
 }
 char LoadNextVideoFrame(void *buffer, char *data, int size, short *xlat, short *accnums, int32_t *writepos) {
-    std::this_thread::sleep_for(std::chrono::milliseconds(50));
+    std::this_thread::sleep_for(std::chrono::milliseconds(20));
     return 1;
 
 }