From c884f1a354f53fd989a9fd3363fb770c116b5e62 Mon Sep 17 00:00:00 2001
From: Gleb Mazovetskiy <glex.spb@gmail.com>
Date: Wed, 23 Mar 2022 11:03:08 +0000
Subject: [PATCH] An option to RLE-compress masked art

Saves about 200 KiB RAM in dungeon at a large performance cost.
Almost never a good idea, except for severely RAM-constrained devices (e.g. RG99).
---
 CMake/Definitions.cmake   |  1 +
 CMakeLists.txt            |  2 ++
 Source/DiabloUI/art.cpp   | 17 +++++++++++++++--
 Source/utils/sdl_compat.h |  9 ---------
 4 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/CMake/Definitions.cmake b/CMake/Definitions.cmake
index 207815f27..5c48a83a7 100644
--- a/CMake/Definitions.cmake
+++ b/CMake/Definitions.cmake
@@ -15,6 +15,7 @@ foreach(
   GPERF_HEAP_FIRST_GAME_ITERATION
   STREAM_ALL_AUDIO
   PACKET_ENCRYPTION
+  DEVILUTIONX_MASKED_ART_RLE
 )
   if(${def_name})
     list(APPEND DEVILUTIONX_DEFINITIONS ${def_name})
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8ba33c6d2..f49050e2a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -59,6 +59,8 @@ mark_as_advanced(DISABLE_STREAMING_SOUNDS)
 option(STREAM_ALL_AUDIO "Stream all the audio. For extremely RAM-constrained platforms.")
 mark_as_advanced(STREAM_ALL_AUDIO)
 
+option(DEVILUTIONX_MASKED_ART_RLE "RLE-compress masked art in memory (e.g. fonts). Slightly lower RAM usage at a significant performance cost." OFF)
+
 if(TSAN)
   set(ASAN OFF)
 endif()
diff --git a/Source/DiabloUI/art.cpp b/Source/DiabloUI/art.cpp
index 64b048e57..788f654b7 100644
--- a/Source/DiabloUI/art.cpp
+++ b/Source/DiabloUI/art.cpp
@@ -148,8 +148,21 @@ void LoadArt(const char *pszFile, Art *art, int frames, SDL_Color *pPalette, con
 void LoadMaskedArt(const char *pszFile, Art *art, int frames, int mask, const std::array<uint8_t, 256> *colorMapping)
 {
 	LoadArt(pszFile, art, frames, nullptr, colorMapping);
-	if (art->surface != nullptr)
-		SDLC_SetColorKey(art->surface.get(), mask);
+	if (art->surface == nullptr)
+		return;
+	SDL_Surface *surface = art->surface.get();
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+#ifdef DEVILUTIONX_MASKED_ART_RLE
+	SDL_SetSurfaceRLE(surface, 1);
+#endif
+	SDL_SetColorKey(surface, SDL_TRUE, mask);
+#else
+	int flags = SDL_SRCCOLORKEY;
+#ifdef DEVILUTIONX_MASKED_ART_RLE
+	flags |= SDL_RLEACCEL;
+#endif
+	SDL_SetColorKey(surface, flags, mask);
+#endif
 }
 
 void LoadArt(Art *art, const std::uint8_t *artData, int w, int h, int frames)
diff --git a/Source/utils/sdl_compat.h b/Source/utils/sdl_compat.h
index bf1d79d4f..4704f164d 100644
--- a/Source/utils/sdl_compat.h
+++ b/Source/utils/sdl_compat.h
@@ -35,15 +35,6 @@ inline const Uint8 *SDLC_GetKeyState()
 #endif
 }
 
-inline int SDLC_SetColorKey(SDL_Surface *surface, Uint32 key)
-{
-#ifdef USE_SDL1
-	return SDL_SetColorKey(surface, SDL_SRCCOLORKEY, key);
-#else
-	return SDL_SetColorKey(surface, SDL_TRUE, key);
-#endif
-}
-
 // Copies the colors into the surface's palette.
 inline int SDLC_SetSurfaceColors(SDL_Surface *surface, SDL_Color *colors, int firstcolor, int ncolors)
 {