From e781055ddb3142d2d309a98e67ec66cf261eb179 Mon Sep 17 00:00:00 2001
From: Holger Schemel <info@artsoft.org>
Date: Wed, 6 Mar 2024 10:19:13 +0100
Subject: [PATCH] added support for level-specific preview colors for BD engine

---
 src/game_bd/export_bd.h |  4 ++++
 src/game_bd/main_bd.c   | 15 +++++++++++++++
 src/tools.c             | 37 +++++++++++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+)

diff --git a/src/game_bd/export_bd.h b/src/game_bd/export_bd.h
index 1db82520..ae3e4527 100644
--- a/src/game_bd/export_bd.h
+++ b/src/game_bd/export_bd.h
@@ -100,6 +100,10 @@ void setLevelInfoToDefaults_BD(void);
 boolean LoadNativeLevel_BD(char *, int, boolean);
 boolean SaveNativeLevel_BD(char *);
 
+void PreparePreviewTileBitmap_BD(Bitmap *, int);
+void SetPreviewTileBitmapReference_BD(Bitmap *);
+Bitmap *GetPreviewTileBitmap_BD(Bitmap *);
+
 unsigned int InitEngineRandom_BD(int);
 void InitGameEngine_BD(void);
 void GameActions_BD(byte[MAX_PLAYERS]);
diff --git a/src/game_bd/main_bd.c b/src/game_bd/main_bd.c
index e7844fcb..56e448a7 100644
--- a/src/game_bd/main_bd.c
+++ b/src/game_bd/main_bd.c
@@ -255,6 +255,21 @@ static void PrepareGameTileBitmap_BD(void)
   gd_prepare_tile_bitmap(native_bd_level.cave, g->bitmap, 1);
 }
 
+void PreparePreviewTileBitmap_BD(Bitmap *bitmap, int scale_down_factor)
+{
+  gd_prepare_tile_bitmap(native_bd_level.cave, bitmap, scale_down_factor);
+}
+
+void SetPreviewTileBitmapReference_BD(Bitmap *bitmap)
+{
+  gd_set_tile_bitmap_reference(bitmap);
+}
+
+Bitmap *GetPreviewTileBitmap_BD(Bitmap *bitmap)
+{
+  return gd_get_tile_bitmap(bitmap);
+}
+
 unsigned int InitEngineRandom_BD(int seed)
 {
   if (seed == NEW_RANDOMIZE)
diff --git a/src/tools.c b/src/tools.c
index e1b79cbf..c271314e 100644
--- a/src/tools.c
+++ b/src/tools.c
@@ -3396,6 +3396,14 @@ static void ShowEnvelopeRequest(char *text, unsigned int req_state, int action)
   game.envelope_active = FALSE;
 }
 
+static Bitmap *GetPreviewTileBitmap(Bitmap *bitmap)
+{
+  if (level.game_engine_type == GAME_ENGINE_TYPE_BD)
+    return GetPreviewTileBitmap_BD(bitmap);
+
+  return bitmap;
+}
+
 static void DrawPreviewElement(int dst_x, int dst_y, int element, int tilesize)
 {
   if (IS_MM_WALL(element))
@@ -3409,6 +3417,10 @@ static void DrawPreviewElement(int dst_x, int dst_y, int element, int tilesize)
     int graphic = el2preimg(element);
 
     getSizedGraphicSource(graphic, 0, tilesize, &src_bitmap, &src_x, &src_y);
+
+    // for BD style levels, maybe use bitmap with level-specific colors
+    src_bitmap = GetPreviewTileBitmap(src_bitmap);
+
     BlitBitmap(src_bitmap, drawto, src_x, src_y, tilesize, tilesize,
 	       dst_x, dst_y);
   }
@@ -3815,8 +3827,33 @@ void DrawPreviewPlayers(void)
   }
 }
 
+static void PreparePreviewTileBitmap(void)
+{
+  // check if special preview bitmap with level-specific colors should be created
+  if (level.game_engine_type != GAME_ENGINE_TYPE_BD)
+    return;
+
+  // use original sized bitmap (else reduced color palette is lost by downscaling)
+  int original_tilesize = MAX(MINI_TILESIZE, preview.tile_size);
+  int scale_down_factor = original_tilesize / preview.tile_size;
+  Bitmap *src_bitmap;
+  int src_x, src_y;
+  int element = EL_BD_ROCK;
+  int graphic = el2preimg(element);
+
+  // create special preview bitmap and scale it down to preview tile size
+  getSizedGraphicSource(graphic, 0, original_tilesize, &src_bitmap, &src_x, &src_y);
+  PreparePreviewTileBitmap_BD(src_bitmap, scale_down_factor);
+
+  // force using special preview bitmap to replace original preview bitmap
+  getSizedGraphicSource(graphic, 0, preview.tile_size, &src_bitmap, &src_x, &src_y);
+  SetPreviewTileBitmapReference_BD(src_bitmap);
+}
+
 void DrawPreviewLevelInitial(void)
 {
+  PreparePreviewTileBitmap();	// only needed for native BD style levels
+
   DrawPreviewLevelExt(TRUE);
   DrawPreviewPlayers();
 }
-- 
2.34.1