dynamically load SDL_Image at runtime for PNG screenshots

Fixes #31

Source/Makefile.am

@@ -26,6 +26,7 @@ winmbf_SOURCES = \
 	hu_stuff.c hu_stuff.h \
 	i_main.c \
 	i_net.c    i_net.h \
+	i_savepng.c i_savepng.h \
 	i_sound.c  i_sound.h \
 	i_system.c i_system.h \
 	i_video.c  i_video.h \
@@ -80,5 +81,5 @@ winmbf_SOURCES = \
 	w_wad.c    w_wad.h \
 	wi_stuff.c wi_stuff.h \
 	z_zone.c   z_zone.h
-winmbf_CFLAGS = @SDL_CFLAGS@ @SDL_image_CFLAGS@ @SDL_mixer_CFLAGS@ @SDL_net_CFLAGS@
+winmbf_CFLAGS = @SDL_CFLAGS@ @SDL_mixer_CFLAGS@ @SDL_net_CFLAGS@
-winmbf_LDADD = @SDL_LIBS@ @SDL_image_LIBS@ @SDL_mixer_LIBS@ @SDL_net_LIBS@
+winmbf_LDADD = @SDL_LIBS@ @SDL_mixer_LIBS@ @SDL_net_LIBS@

Source/d_main.c

@@ -31,13 +31,12 @@
 
 #include "d_io.h" // haleyjd
 #include "SDL_filesystem.h" // [FG] SDL_GetPrefPath()
+#include "SDL_stdinc.h" // [FG] SDL_qsort()
 
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 
-#include "SDL_stdinc.h" // [FG] SDL_qsort()
-
 #include "doomdef.h"
 #include "doomstat.h"
 #include "dstrings.h"
@@ -52,6 +51,7 @@
 #include "m_misc.h"
 #include "m_misc2.h" // [FG] M_StringDuplicate()
 #include "m_menu.h"
+#include "i_savepng.h" // [FG] SavePNG
 #include "i_system.h"
 #include "i_sound.h"
 #include "i_video.h"
@@ -1372,6 +1372,9 @@ void D_DoomMain(void)
   int p, slot;
   char file[PATH_MAX+1];      // killough 3/22/98
 
+  // [FG] save screenshots in PNG format
+  I_InitSavePNG();
+
   setbuf(stdout,NULL);
 
 #if defined(_WIN32)

Source/i_savepng.c

@@ -0,0 +1,84 @@
+//
+//  Copyright(C) 2020 Fabian Greffrath
+//
+//  This program is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU General Public License
+//  as published by the Free Software Foundation; either version 2
+//  of the License, or (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+//
+//  You should have received a copy of the GNU General Public License
+//  along with this program; if not, write to the Free Software
+//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 
+//  02111-1307, USA.
+//
+// DESCRIPTION:
+//      Dynamically load SDL2_Image for PNG screenshots.
+//
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifdef HAVE_DLOPEN
+#include <dlfcn.h>
+#elif _WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#endif
+
+#include "doomtype.h"
+#include "i_savepng.h"
+
+savepng_t SavePNG = NULL;
+
+static const char *sdl2_image_libs[] = {
+#ifdef HAVE_DLOPEN
+	"libSDL2_image-2.0.so.0",
+	"libSDL2_image-2.0.so",
+	"libSDL2_image.so",
+#elif _WIN32
+	"SDL2_image.dll",
+#endif
+};
+
+void I_InitSavePNG (void)
+{
+	int i;
+
+#ifdef HAVE_DLOPEN
+	void *sdl2_image_lib = NULL;
+	void *savepng_func = NULL;
+#elif _WIN32
+	HMODULE sdl2_image_lib = NULL;
+	FARPROC savepng_func = NULL;
+#endif
+
+	for (i = 0; i < arrlen(sdl2_image_libs); i++)
+	{
+#ifdef HAVE_DLOPEN
+		sdl2_image_lib = dlopen(sdl2_image_libs[i], RTLD_LAZY);
+#elif _WIN32
+		sdl2_image_lib = LoadLibrary(TEXT(sdl2_image_libs[i]));
+#endif
+		if (sdl2_image_lib != NULL)
+		{
+			break;
+		}
+	}
+
+	if (sdl2_image_lib != NULL)
+	{
+#ifdef HAVE_DLOPEN
+		savepng_func = dlsym(sdl2_image_lib, "IMG_SavePNG");
+#elif _WIN32
+		savepng_func = GetProcAddress(sdl2_image_lib, "IMG_SavePNG");
+#endif
+	}
+
+	SavePNG = (savepng_t) savepng_func;
+}

Source/i_savepng.h

@@ -0,0 +1,32 @@
+//
+//  Copyright(C) 2020 Fabian Greffrath
+//
+//  This program is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU General Public License
+//  as published by the Free Software Foundation; either version 2
+//  of the License, or (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+//
+//  You should have received a copy of the GNU General Public License
+//  along with this program; if not, write to the Free Software
+//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 
+//  02111-1307, USA.
+//
+// DESCRIPTION:
+//      Dynamically load SDL2_Image for PNG screenshots.
+//
+
+#ifndef __I_SAVEPNG__
+#define __I_SAVEPNG__
+
+typedef int (*savepng_t)(void *, const char *);
+
+extern savepng_t SavePNG;
+
+extern void I_InitSavePNG (void);
+
+#endif

Source/i_video.c

@@ -28,11 +28,6 @@
 
 #include "SDL.h" // haleyjd
 
-#include "config.h"
-#ifdef HAVE_SDL_IMAGE
-#include "SDL_image.h"
-#endif
-
 #include "z_zone.h"  /* memory allocation wrappers -- killough */
 #include "doomstat.h"
 #include "v_video.h"
@@ -46,6 +41,7 @@
 #include "m_menu.h"
 #include "wi_stuff.h"
 #include "i_video.h"
+#include "i_savepng.h" // [FG] SavePNG()
 
 SDL_Surface *sdlscreen;
 
@@ -840,13 +836,13 @@ void I_ShutdownGraphics(void)
    }
 }
 
+// [FG] save screenshots in PNG format
 boolean I_WritePNGfile(char *filename)
 {
-#ifdef HAVE_SDL_IMAGE
+  if (SavePNG)
-   return IMG_SavePNG(sdlscreen, filename) == 0;
+    return SavePNG(sdlscreen, filename) == 0;
-#else
+  else
-  return false;
+    return false;
-#endif
 }
 
 extern boolean setsizeneeded;

Source/m_menu.c

@@ -49,6 +49,8 @@
 #include "m_menu.h"
 #include "d_deh.h"
 #include "m_misc.h"
+#include "m_misc2.h" // [FG] M_StringDuplicate()
+#include "i_savepng.h" // [FG] SavePNG()
 
 extern patch_t* hu_font[HU_FONTSIZE];
 extern boolean  message_dontfuckwithme;
@@ -2995,11 +2997,7 @@ setup_menu_t gen_settings1[] = { // General Settings screen1
   {"Translucency filter percentage", S_NUM, m_null, G_X,
    G_Y + general_transpct*8, {"tran_filter_pct"}, 0, 0, M_Trans},
 
-#ifdef HAVE_SDL_IMAGE
-  {"PCX instead of PNG for screenshots", S_YESNO, m_null, G_X,
-#else
   {"PCX instead of BMP for screenshots", S_YESNO, m_null, G_X,
-#endif
    G_Y + general_pcx*8, {"screenshot_pcx"}},
 
   {"Flash Icon During Disk IO", S_YESNO, m_null, G_X,
@@ -5621,6 +5619,16 @@ void M_Init(void)
   {
     strcpy(OptionsMenu[scrnsize].name, "M_DISP");
   }
+
+  // [FG] save screenshots in PNG format
+  if (SavePNG)
+  {
+    const char *bmp_text, *png_text;
+
+    bmp_text = gen_settings1[general_pcx+1].m_text;
+    png_text = M_StringReplace(bmp_text, "BMP", "PNG");
+    gen_settings1[general_pcx+1].m_text = png_text;
+  }
 }
 
 // killough 10/98: allow runtime changing of menu order

Source/m_misc.c

@@ -46,6 +46,7 @@
 #include "s_sound.h"
 #include "sounds.h"
 #include "d_main.h"
+#include "i_savepng.h" // [FG] SavePNG()
 
 #include "d_io.h"
 #include <errno.h>
@@ -1054,11 +1055,7 @@ default_t defaults[] = {
     "screenshot_pcx",
     &screenshot_pcx, NULL,
     {1}, {0,1}, number, ss_gen, wad_no,
-#ifdef HAVE_SDL_IMAGE
+    "1 to take a screenshot in PCX format, 0 for BMP (or PNG)"
-    "1 to take a screenshot in PCX format, 0 for PNG"
-#else
-    "1 to take a screenshot in PCX format, 0 for BMP"
-#endif
   },
 
   {
@@ -2429,6 +2426,7 @@ boolean WriteBMPfile(char *filename, byte *data, int width,
   return I_EndRead(), true;       // killough 10/98
 }
 
+// [FG] save screenshots in PNG format
 boolean WritePNGfile(char *filename, byte *data, int width,
                      int height, byte *palette)
 {
@@ -2457,11 +2455,7 @@ void M_ScreenShot (void)
 
       do
         sprintf(lbmname,                         //jff 3/30/98 pcx or bmp?
-#ifdef HAVE_SDL_IMAGE
+                screenshot_pcx ? "doom%02d.pcx" : (SavePNG ? "doom%02d.png" : "doom%02d.bmp"), shot++);
-                screenshot_pcx ? "doom%02d.pcx" : "doom%02d.png", shot++);
-#else
-                screenshot_pcx ? "doom%02d.pcx" : "doom%02d.bmp", shot++);
-#endif
       while (!access(lbmname,0) && --tries);
 
       if (tries)
@@ -2479,11 +2473,7 @@ void M_ScreenShot (void)
 
           // killough 10/98: detect failure and remove file if error
 	  // killough 11/98: add hires support
-#ifdef HAVE_SDL_IMAGE
+          if (!(success = (screenshot_pcx ? WritePCXfile : (SavePNG ? WritePNGfile : WriteBMPfile))
-          if (!(success = (screenshot_pcx ? WritePCXfile : WritePNGfile)
-#else
-          if (!(success = (screenshot_pcx ? WritePCXfile : WriteBMPfile)
-#endif
                 (lbmname,linear, SCREENWIDTH<<hires, SCREENHEIGHT<<hires,pal)))
 	    {
 	      int t = errno;

Source/m_misc2.c

@@ -121,6 +121,67 @@ char *M_StringDuplicate(const char *orig)
     return result;
 }
 
+// String replace function.
+
+char *M_StringReplace(const char *haystack, const char *needle,
+                      const char *replacement)
+{
+    char *result, *dst;
+    const char *p;
+    size_t needle_len = strlen(needle);
+    size_t result_len, dst_len;
+
+    // Iterate through occurrences of 'needle' and calculate the size of
+    // the new string.
+    result_len = strlen(haystack) + 1;
+    p = haystack;
+
+    for (;;)
+    {
+        p = strstr(p, needle);
+        if (p == NULL)
+        {
+            break;
+        }
+
+        p += needle_len;
+        result_len += strlen(replacement) - needle_len;
+    }
+
+    // Construct new string.
+
+    result = malloc(result_len);
+    if (result == NULL)
+    {
+        I_Error("M_StringReplace: Failed to allocate new string");
+        return NULL;
+    }
+
+    dst = result; dst_len = result_len;
+    p = haystack;
+
+    while (*p != '\0')
+    {
+        if (!strncmp(p, needle, needle_len))
+        {
+            M_StringCopy(dst, replacement, dst_len);
+            p += needle_len;
+            dst += strlen(replacement);
+            dst_len -= strlen(replacement);
+        }
+        else
+        {
+            *dst = *p;
+            ++dst; --dst_len;
+            ++p;
+        }
+    }
+
+    *dst = '\0';
+
+    return result;
+}
+
 // Safe string copy function that works like OpenBSD's strlcpy().
 // Returns true if the string was not truncated.
 

Source/m_misc2.h

@@ -28,6 +28,8 @@ void M_ForceLowercase(char *text);
 char *M_StringDuplicate(const char *orig);
 boolean M_StringCopy(char *dest, const char *src, size_t dest_size);
 boolean M_StringConcat(char *dest, const char *src, size_t dest_size);
+char *M_StringReplace(const char *haystack, const char *needle,
+                      const char *replacement);
 char *M_StringJoin(const char *s, ...);
 boolean M_StringEndsWith(const char *s, const char *suffix);
 

configure.ac

@@ -18,18 +18,12 @@ fi
 
 # Checks for libraries.
 AC_SEARCH_LIBS([pow], [m])
+AC_SEARCH_LIBS([dlopen], [dl dld])
 PKG_CHECK_MODULES([SDL],       [sdl2])
 PKG_CHECK_MODULES([SDL_mixer], [SDL2_mixer])
 PKG_CHECK_MODULES([SDL_net],   [SDL2_net])
 AC_DEFINE([MY_SDL_VER], [1], [This is WinMBF])
 
-AC_ARG_WITH([sdlimage], AS_HELP_STRING([--with-sdlimage], [Build with SDL2_Image for PNG screenshots]))
-AS_IF([test "x$with_sdlimage" = "xyes"],
-	[PKG_CHECK_MODULES([SDL_image], [SDL2_image],
-		[AC_DEFINE([HAVE_SDL_IMAGE], [1], [PNG screenshots])]
-	)]
-)
-
 # Checks for header files.
 AC_CHECK_HEADERS([fcntl.h limits.h malloc.h stddef.h stdint.h stdlib.h string.h unistd.h])