SDL-1.2: Implement X mirroring for quads

Surprisingly, as of today (July 2022) CMake ships with FindSDL*.cmake
files for several SDL libraries such as SDL_mixer or SDL_image, but not
for SDL_gfx, so one was created, based on FindSDL_mixer.cmake.

Reference:
8a3004d5c2/Modules/FindSDL_mixer.cmake

CMakeLists.txt

@@ -8,6 +8,7 @@ ExternalProject_Add(tools
         -D CMAKE_INSTALL_PREFIX=${TOOLS_PREFIX})
 
 project(rts)
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_SOURCE_DIR}/cmake)
 
 if(CMAKE_TOOLCHAIN_FILE MATCHES "ps1")
     set(PS1_BUILD 1)

cmake/FindSDL_gfx.cmake

@@ -0,0 +1,106 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+#[=======================================================================[.rst:
+FindSDL_gfx
+-------------
+
+Locate SDL_gfx library
+
+This module defines:
+
+::
+
+  SDL_GFX_LIBRARIES, the name of the library to link against
+  SDL_GFX_INCLUDE_DIRS, where to find the headers
+  SDL_GFX_FOUND, if false, do not try to link against
+  SDL_GFX_VERSION_STRING - human-readable string containing the
+                             version of SDL_gfx
+
+
+
+For backward compatibility the following variables are also set:
+
+::
+
+  SDLGFX_LIBRARY (same value as SDL_GFX_LIBRARIES)
+  SDLGFX_INCLUDE_DIR (same value as SDL_GFX_INCLUDE_DIRS)
+  SDLGFX_FOUND (same value as SDL_GFX_FOUND)
+
+
+
+$SDLDIR is an environment variable that would correspond to the
+./configure --prefix=$SDLDIR used in building SDL.
+
+Created by Xavier Del Campo, heavily based on the original work by
+Eric Wing, FindSDL_mixer.cmake.
+#]=======================================================================]
+
+if(NOT SDL_GFX_INCLUDE_DIR AND SDLGFX_INCLUDE_DIR)
+  set(SDL_GFX_INCLUDE_DIR ${SDLGFX_INCLUDE_DIR} CACHE PATH "directory cache
+entry initialized from old variable name")
+endif()
+find_path(SDL_GFX_INCLUDE_DIR
+    SDL_framerate.h
+    SDL_gfxBlitFunc.h
+    SDL_gfxPrimitives.h
+    SDL_gfxPrimitives_font.h
+    SDL_imageFilter.h
+    SDL_rotozoom.h
+  HINTS
+    ENV SDLGFXDIR
+    ENV SDLDIR
+  PATH_SUFFIXES SDL
+                # path suffixes to search inside ENV{SDLDIR}
+                include/SDL include/SDL12 include/SDL11 include
+)
+
+if(CMAKE_SIZEOF_VOID_P EQUAL 8)
+  set(VC_LIB_PATH_SUFFIX lib/x64)
+else()
+  set(VC_LIB_PATH_SUFFIX lib/x86)
+endif()
+
+if(NOT SDL_GFX_LIBRARY AND SDLGFX_LIBRARY)
+  set(SDL_GFX_LIBRARY ${SDLGFX_LIBRARY} CACHE FILEPATH "file cache entry
+initialized from old variable name")
+endif()
+find_library(SDL_GFX_LIBRARY
+  NAMES SDL_gfx
+  HINTS
+    ENV SDLGFXDIR
+    ENV SDLDIR
+  PATH_SUFFIXES lib ${VC_LIB_PATH_SUFFIX}
+)
+
+if(SDL_GFX_INCLUDE_DIR AND EXISTS "${SDL_GFX_INCLUDE_DIR}/SDL_gfxPrimitives.h")
+  file(STRINGS "${SDL_GFX_INCLUDE_DIR}/SDL_gfxPrimitives.h" SDL_GFX_VERSION_MAJOR_LINE REGEX "^#define[ \t]+SDL_GFXPRIMITIVES_MAJOR[ \t]+[0-9]+$")
+  file(STRINGS "${SDL_GFX_INCLUDE_DIR}/SDL_gfxPrimitives.h" SDL_GFX_VERSION_MINOR_LINE REGEX "^#define[ \t]+SDL_GFXPRIMITIVES_MINOR[ \t]+[0-9]+$")
+  file(STRINGS "${SDL_GFX_INCLUDE_DIR}/SDL_gfxPrimitives.h" SDL_GFX_VERSION_PATCH_LINE REGEX "^#define[ \t]+SDL_GFXPRIMITIVES_MICRO[ \t]+[0-9]+$")
+  string(REGEX REPLACE "^#define[ \t]+SDL_GFXPRIMITIVES_MAJOR[ \t]+([0-9]+)$" "\\1" SDL_GFX_VERSION_MAJOR "${SDL_GFX_VERSION_MAJOR_LINE}")
+  string(REGEX REPLACE "^#define[ \t]+SDL_GFXPRIMITIVES_MINOR[ \t]+([0-9]+)$" "\\1" SDL_GFX_VERSION_MINOR "${SDL_GFX_VERSION_MINOR_LINE}")
+  string(REGEX REPLACE "^#define[ \t]+SDL_GFXPRIMITIVES_MICRO[ \t]+([0-9]+)$" "\\1" SDL_GFX_VERSION_PATCH "${SDL_GFX_VERSION_PATCH_LINE}")
+  set(SDL_GFX_VERSION_STRING ${SDL_GFX_VERSION_MAJOR}.${SDL_GFX_VERSION_MINOR}.${SDL_GFX_VERSION_PATCH})
+  unset(SDL_GFX_VERSION_MAJOR_LINE)
+  unset(SDL_GFX_VERSION_MINOR_LINE)
+  unset(SDL_GFX_VERSION_PATCH_LINE)
+  unset(SDL_GFX_VERSION_MAJOR)
+  unset(SDL_GFX_VERSION_MINOR)
+  unset(SDL_GFX_VERSION_PATCH)
+endif()
+
+set(SDL_GFX_LIBRARIES ${SDL_GFX_LIBRARY})
+set(SDL_GFX_INCLUDE_DIRS ${SDL_GFX_INCLUDE_DIR})
+
+include(FindPackageHandleStandardArgs)
+
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(SDL_gfx
+                                  REQUIRED_VARS SDL_GFX_LIBRARIES SDL_GFX_INCLUDE_DIRS
+                                  VERSION_VAR SDL_GFX_VERSION_STRING)
+
+# for backward compatibility
+set(SDLGFX_LIBRARY ${SDL_GFX_LIBRARIES})
+set(SDLGFX_INCLUDE_DIR ${SDL_GFX_INCLUDE_DIRS})
+set(SDLGFX_FOUND ${SDL_GFX_FOUND})
+
+mark_as_advanced(SDL_GFX_LIBRARY SDL_GFX_INCLUDE_DIR)

cmake/host.cmake

@@ -1,6 +1,7 @@
 file(MAKE_DIRECTORY ${cdroot})
 find_package(SDL 1.2 REQUIRED)
 find_package(SDL_mixer 1.2 REQUIRED)
+find_package(SDL_gfx 2.0 REQUIRED)
 set(SDL1_2_BUILD 1)
 
 if(CMAKE_BUILD_TYPE STREQUAL "Debug")

cmake/win9x.cmake

@@ -3,6 +3,8 @@ if("$ENV{SDL_PATH}" STREQUAL "")
     message(FATAL_ERROR "please define env variable SDL_PATH")
 elseif("$ENV{SDL_MIXER_PATH}" STREQUAL "")
     message(FATAL_ERROR "please define env variable SDL_MIXER_PATH")
+elseif("$ENV{SDL_GFX_PATH}" STREQUAL "")
+    message(FATAL_ERROR "please define env variable SDL_GFX_PATH")
 endif()
 
 add_custom_command(OUTPUT ${cdroot}/${PROJECT_NAME}
@@ -24,6 +26,12 @@ set_property(TARGET SDL_mixer PROPERTY IMPORTED_LOCATION
 target_include_directories(SDL_mixer INTERFACE $ENV{SDL_MIXER_PATH}/include)
 target_link_libraries(SDL_mixer INTERFACE SDL)
 
+add_library(SDL_gfx STATIC IMPORTED)
+set_property(TARGET SDL_gfx PROPERTY IMPORTED_LOCATION
+    $ENV{SDL_GFX_PATH}/lib/libSDL_gfx.a)
+target_include_directories(SDL_gfx INTERFACE $ENV{SDL_GFX_PATH}/include)
+target_link_libraries(SDL_gfx INTERFACE SDL)
+
 add_compile_options(-march=i386)
 set(SDL1_2_BUILD 1)
 

doc/BUILD-win9x.md

@@ -125,3 +125,10 @@ WAVE files, support for other audio formats is not required.
     --disable-music-flac CC=i386-mingw32-gcc --with-sdl-prefix=$HOME/sdl-1.2.15 \
     CFLAGS='-ffunction-sections -fdata-sections'
 ```
+
+```sh
+../SDL_gfx-2.0.26-src/configure --host=i386-mingw32 --enable-shared=no \
+    --prefix=$HOME/SDL_gfx-2.0.26 --with-sdl-prefix=$HOME/sdl-1.2.15 \
+    CFLAGS='-ffunction-sections -fdata-sections' \
+    CC=i386-mingw32-gcc
+```

src/gfx/CMakeLists.txt

@@ -25,7 +25,7 @@ elseif(SDL1_2_BUILD)
         "sdl-1.2/src/sprite.c"
         "sdl-1.2/src/quad.c")
     set(deps ${deps} SDL)
-    set(privdeps ${privdeps} header)
+    set(privdeps ${privdeps} header SDL_gfx)
 endif()
 
 add_library(gfx ${src})

src/gfx/sdl-1.2/inc/gfx/port.h

@@ -11,7 +11,7 @@ extern "C"
 
 struct sprite
 {
-    SDL_Surface *s;
+    SDL_Surface *s, *s_x;
     short x, y, w, h;
     unsigned char u, v;
     bool transparent;
@@ -24,8 +24,9 @@ struct quad
     short y0, y1, y2, y3;
     unsigned char u0, u1, u2, u3;
     unsigned char v0, v1, v2, v3;
+    short w, h;
     bool transparent;
-    SDL_Surface *s;
+    SDL_Surface *s, *s_x;
 };
 
 struct rect

src/gfx/sdl-1.2/src/quad.c

@@ -7,29 +7,38 @@
 int quad_from_sprite(const struct sprite *const s, struct quad *const q)
 {
     q->s = s->s;
+    q->s_x = s->s_x;
     q->u0 = q->u2 = s->u;
     q->v0 = q->v1 = s->v;
     q->u1 = q->u3 = s->u + s->w - 1;
     q->v2 = q->v3 = s->v + s->h - 1;
+    q->w = s->w;
+    q->h = s->h;
     return 0;
 }
 
 void quad_sort(struct quad *const q)
 {
+    const bool xflip = q->x0 > q->x1;
+
     SDL_Rect r =
     {
-        .x = q->x0,
+        .x = xflip ? q->x1 : q->x0,
         .y = q->y0
     };
 
+    const short w = q->u1 - q->u0 + 1, h = q->v2 - q->v0 + 1;
+
     SDL_Rect clip =
     {
-        .x = q->u0,
+        .x = xflip ? q->w - q->u0 - w: q->u0,
         .y = q->v0,
-        .w = q->u1 - q->u0 + 1,
-        .h= q->v2 - q->v0 + 1
+        .w = w,
+        .h = h
     };
 
-    if (SDL_BlitSurface(q->s, &clip, gfx_screen(), &r))
+    SDL_Surface *const s = xflip ? q->s_x : q->s;
+
+    if (SDL_BlitSurface(s, &clip, gfx_screen(), &r))
         fprintf(stderr, "SDL_BlitSurface: %s\n", SDL_GetError());
 }

src/gfx/sdl-1.2/src/rect.c

@@ -2,10 +2,6 @@
 #include <gfx/port.h>
 #include <sdl-1.2/gfx_private.h>
 #include <SDL/SDL.h>
-#include <stdbool.h>
-#include <stddef.h>
-#include <stdlib.h>
-#include <string.h>
 
 void rect_sort(struct rect *const r)
 {
@@ -29,7 +25,7 @@ void rect_sort(struct rect *const r)
 
 void rect_init(struct rect *const r)
 {
-    memset(r, 0, sizeof *r);
+    *r = (const struct rect){0};
 }
 
 void semitrans_rect_init(struct rect *const r)

src/gfx/sdl-1.2/src/sprite.c

@@ -3,10 +3,10 @@
 #include <header.h>
 #include <sdl-1.2/gfx_private.h>
 #include <SDL/SDL.h>
+#include <SDL/SDL_rotozoom.h>
 #include <errno.h>
 #include <stddef.h>
 #include <stdlib.h>
-#include <string.h>
 
 void sprite_free(struct sprite *const s)
 {
@@ -20,20 +20,32 @@ int sprite_clone(const struct sprite *const src, struct sprite *const dst)
     return 0;
 }
 
+static int set_transparent(SDL_Surface *const s)
+{
+    /* Magenta as transparent. */
+    const Uint32 map = SDL_MapRGB(s->format, 255, 0, 255);
+    const int ret = SDL_SetColorKey(s, SDL_SRCCOLORKEY | SDL_RLEACCEL, map);
+
+    if (ret)
+        fprintf(stderr, "SDL_SetColorKey: %s\n", SDL_GetError());
+
+    return ret;
+}
+
 int sprite_screen_resize_ev(struct sprite *const s)
 {
     int ret = -1;
-    SDL_Surface *const old = s->s;
+    SDL_Surface *const old = s->s, *const old_x = s->s_x;
 
     /* Magenta as transparent. */
-    if (s->transparent
-        && SDL_SetColorKey(old, SDL_SRCCOLORKEY | SDL_RLEACCEL,
-            SDL_MapRGB(old->format, 255, 0, 255)))
+    if (s->transparent && (set_transparent(old) || set_transparent(old_x)))
+        goto end;
+    else if (!(s->s = SDL_DisplayFormat(old)))
     {
-        fprintf(stderr, "SDL_SetColorKey: %s\n", SDL_GetError());
+        fprintf(stderr, "SDL_DisplayFormat: %s\n", SDL_GetError());
         goto end;
     }
-    else if (!(s->s = SDL_DisplayFormat(old)))
+    else if (!(s->s_x = SDL_DisplayFormat(old_x)))
     {
         fprintf(stderr, "SDL_DisplayFormat: %s\n", SDL_GetError());
         goto end;
@@ -43,6 +55,7 @@ int sprite_screen_resize_ev(struct sprite *const s)
 
 end:
     SDL_FreeSurface(old);
+    SDL_FreeSurface(old_x);
     return ret;
 }
 
@@ -58,31 +71,35 @@ static int load_bitmap(struct sprite *const s, FILE *const f)
 {
     int ret = -1;
     SDL_RWops *ops = NULL;
-    SDL_Surface *ts = NULL;
+    SDL_Surface *ts = NULL, *zs = NULL;
 
     if (!(ops = SDL_RWFromFP(f, 0)))
     {
         fprintf(stderr, "SDL_RWFromFP: %s\n", SDL_GetError());
         goto end;
     }
-    if (!(ts = SDL_LoadBMP_RW(ops, 0)))
+    else if (!(ts = SDL_LoadBMP_RW(ops, 0)))
     {
         fprintf(stderr, "SDL_LoadBMP_RW: %s\n", SDL_GetError());
         goto end;
     }
-    /* Magenta as transparent. */
-    else if (s->transparent
-        && SDL_SetColorKey(ts, SDL_SRCCOLORKEY | SDL_RLEACCEL,
-            SDL_MapRGB(ts->format, 255, 0, 255)))
+    else if (!(zs = zoomSurface(ts, -1, 1, 0)))
     {
-        fprintf(stderr, "SDL_SetColorKey: %s\n", SDL_GetError());
+        fprintf(stderr, "zoomSurface: %s\n", SDL_GetError());
         goto end;
     }
+    else if (s->transparent && (set_transparent(ts) || set_transparent(zs)))
+        goto end;
     else if (!(s->s = SDL_DisplayFormat(ts)))
     {
         fprintf(stderr, "SDL_DisplayFormat: %s\n", SDL_GetError());
         goto end;
     }
+    else if (!(s->s_x = SDL_DisplayFormat(zs)))
+    {
+        fprintf(stderr, "SDL_DisplayFormat: %s\n", SDL_GetError());
+        goto end;
+    }
 
     gfx_register_sprite(s);
     s->w = ts->w;
@@ -92,12 +109,13 @@ static int load_bitmap(struct sprite *const s, FILE *const f)
 end:
     SDL_FreeRW(ops);
     SDL_FreeSurface(ts);
+    SDL_FreeSurface(zs);
     return ret;
 }
 
 int sprite_from_fp(struct sprite *const s, FILE *const f)
 {
-    memset(s, 0, sizeof *s);
+    *s = (const struct sprite){0};
 
     if (load_header(s, f) || load_bitmap(s, f))
         return -1;

src/gui/src/gui.c

@@ -79,10 +79,10 @@ void gui_add_child(struct gui_common *const p,
 int gui_update(struct gui_common *const g, const union peripheral *const p,
     const struct camera *const c)
 {
-    if (g->cb && g->cb->update && g->cb->update(g, p, c))
+    if (g->child && gui_update(g->child, p, c))
         return -1;
 
-    if (g->child && gui_update(g->child, p, c))
+    if (g->cb && g->cb->update && g->cb->update(g, p, c))
         return -1;
 
     for (struct gui_common *s = g->sibling; s; s = s->sibling)