]> git.jsancho.org Git - lugaru.git/blobdiff - Source/OpenGL_Windows.cpp
Try to use ALSA first, then OSS, plus command lines to change behaviour.
[lugaru.git] / Source / OpenGL_Windows.cpp
index 6535b95d1cd4065abccb9504883eaa5747d110cd..18bb2b90382220146263b122d895ae84139f202b 100644 (file)
@@ -4,9 +4,30 @@
 #endif
 
 #include "Game.h"
-#include "IL/il.h"
-#include "IL/ilu.h"
-#include "IL/ilut.h"
+
+#ifndef USE_DEVIL
+#  ifdef WIN32
+#    define USE_DEVIL
+#  endif
+#endif
+
+#if USE_DEVIL
+    #include "IL/il.h"
+    #include "IL/ilu.h"
+    #include "IL/ilut.h"
+#else
+    // just use libpng and libjpg directly; it's lighter-weight and easier
+    //  to manage the dependencies on Linux...
+    extern "C" {
+        #include "png.h"
+        #include "jpeglib.h"
+    }
+    static bool load_image(const char * fname, TGAImageRec & tex);
+    static bool load_png(const char * fname, TGAImageRec & tex);
+    static bool load_jpg(const char * fname, TGAImageRec & tex);
+    static bool save_image(const char * fname);
+    static bool save_png(const char * fname);
+#endif
 
 // ADDED GWC
 #ifdef _MSC_VER
@@ -113,6 +134,43 @@ typedef struct tagPOINT {
 #endif
 
 #if USE_SDL
+#define GL_FUNC(ret,fn,params,call,rt) \
+    extern "C" { \
+        static ret GLAPIENTRY (*p##fn) params = NULL; \
+        ret GLAPIENTRY fn params { rt p##fn call; } \
+    }
+#include "glstubs.h"
+#undef GL_FUNC
+
+static bool lookup_glsym(const char *funcname, void **func, const char *libname)
+{
+    *func = SDL_GL_GetProcAddress(funcname);
+    if (*func == NULL)
+    {
+        fprintf(stderr, "Failed to find OpenGL symbol \"%s\" in \"%s\"\n",
+                 funcname, libname);
+        return false;
+    }
+    return true;
+}
+
+static bool lookup_all_glsyms(const char *libname)
+{
+    bool retval = true;
+    #define GL_FUNC(ret,fn,params,call,rt) \
+        if (!lookup_glsym(#fn, (void **) &p##fn, libname)) retval = false;
+    #include "glstubs.h"
+    #undef GL_FUNC
+    return retval;
+}
+
+static void GLAPIENTRY glDeleteTextures_doNothing(GLsizei n, const GLuint *textures)
+{
+    // no-op.
+}
+
+
+
 void sdlGetCursorPos(POINT *pt)
 {
     int x, y;
@@ -165,7 +223,24 @@ Boolean gDone = false, gfFrontProcess = true;
 
 Game * pgame = 0;
 
-static bool gMouseGrabbed = true;
+
+static int _argc = 0;
+static char **_argv = NULL;
+
+bool cmdline(const char *cmd)
+{
+    for (int i = 1; i < _argc; i++)
+    {
+        char *arg = _argv[i];
+        while (*arg == '-')
+            arg++;
+        if (stricmp(arg, cmd) == 0)
+            return true;
+    }
+
+    return false;
+}
+
 
 // --------------------------------------------------------------------------
 
@@ -369,16 +444,28 @@ static void initSDLKeyTable(void)
 
 static inline int clamp_sdl_mouse_button(Uint8 button)
 {
+    if (button == 2)   // right mouse button is button 3 in SDL.
+        button = 3;
+    else if (button == 3)
+        button = 2;
+
     if ((button >= 1) && (button <= 3))
         return button - 1;
     return -1;
 }
 
-static void sdlEventProc(const SDL_Event &e)
+static void sdlEventProc(const SDL_Event &e, Game &game)
 {
     int val;
+    SDLMod mod;
+
     switch(e.type)
        {
+        case SDL_MOUSEMOTION:
+            game.deltah += e.motion.xrel;
+            game.deltav += e.motion.yrel;
+            return;
+
                case SDL_MOUSEBUTTONDOWN:
                        {
                 val = clamp_sdl_mouse_button(e.button.button);
@@ -421,7 +508,15 @@ static void sdlEventProc(const SDL_Event &e)
             if (e.key.keysym.sym == SDLK_g)
             {
                 if (e.key.keysym.mod & KMOD_CTRL)
-                    gMouseGrabbed = !gMouseGrabbed;
+                {
+                    SDL_GrabMode mode = SDL_GRAB_ON;
+                    if ((SDL_GetVideoSurface()->flags & SDL_FULLSCREEN) == 0)
+                    {
+                        mode = SDL_WM_GrabInput(SDL_GRAB_QUERY);
+                        mode = (mode==SDL_GRAB_ON) ? SDL_GRAB_OFF:SDL_GRAB_ON;
+                    }
+                    SDL_WM_GrabInput(mode);
+                }
             }
 
             else if (e.key.keysym.sym == SDLK_RETURN)
@@ -430,19 +525,20 @@ static void sdlEventProc(const SDL_Event &e)
                     SDL_WM_ToggleFullScreen(SDL_GetVideoSurface());
             }
 
-            if (e.key.keysym.sym < SDLK_LAST)
+            else if (e.key.keysym.sym < SDLK_LAST)
             {
                 if (KeyTable[e.key.keysym.sym] != 0xffff)
                     SetKey(KeyTable[e.key.keysym.sym]);
             }
 
-            if (e.key.keysym.mod & KMOD_CTRL)
+            mod = SDL_GetModState();
+            if (mod & KMOD_CTRL)
                 SetKey(MAC_CONTROL_KEY);
-            if (e.key.keysym.mod & KMOD_ALT)
+            if (mod & KMOD_ALT)
                 SetKey(MAC_OPTION_KEY);
-            if (e.key.keysym.mod & KMOD_SHIFT)
+            if (mod & KMOD_SHIFT)
                 SetKey(MAC_SHIFT_KEY);
-            if (e.key.keysym.mod & KMOD_CAPS)
+            if (mod & KMOD_CAPS)
                 SetKey(MAC_CAPS_LOCK_KEY);
 
             return;
@@ -454,13 +550,14 @@ static void sdlEventProc(const SDL_Event &e)
                     ClearKey(KeyTable[e.key.keysym.sym]);
             }
 
-            if (e.key.keysym.mod & KMOD_CTRL)
+            mod = SDL_GetModState();
+            if ((mod & KMOD_CTRL) == 0)
                 ClearKey(MAC_CONTROL_KEY);
-            if (e.key.keysym.mod & KMOD_ALT)
+            if ((mod & KMOD_ALT) == 0)
                 ClearKey(MAC_OPTION_KEY);
-            if (e.key.keysym.mod & KMOD_SHIFT)
+            if ((mod & KMOD_SHIFT) == 0)
                 ClearKey(MAC_SHIFT_KEY);
-            if (e.key.keysym.mod & KMOD_CAPS)
+            if ((mod & KMOD_CAPS) == 0)
                 ClearKey(MAC_CAPS_LOCK_KEY);
             return;
     }
@@ -480,8 +577,7 @@ Boolean SetUp (Game & game)
        randSeed = UpTime().lo;
 
        osx = 0;
-//     ifstream ipstream(":Data:config.txt", std::ios::in /*| std::ios::nocreate*/);
-       ifstream ipstream("./Data/config.txt", std::ios::in /*| std::ios::nocreate*/);
+       ifstream ipstream(ConvertFileName(":Data:config.txt"), std::ios::in /*| std::ios::nocreate*/);
        detail=1;
        ismotionblur=0;
        usermousesensitivity=1;
@@ -531,8 +627,7 @@ Boolean SetUp (Game & game)
        selectDetail(kContextWidth, kContextHeight, kBitsPerPixel, detail);
 
        if(!ipstream) {
-               //ofstream opstream(":Data:config.txt"); 
-               ofstream opstream("./Data/config.txt"); 
+               ofstream opstream(ConvertFileName(":Data:config.txt", "w"));
                opstream << "Screenwidth:\n";
                opstream << kContextWidth;
                opstream << "\nScreenheight:\n";
@@ -777,17 +872,37 @@ Boolean SetUp (Game & game)
             fprintf(stderr, "SDL_Init() failed: %s\n", SDL_GetError());
             return false;
         }
+
+        const char *libname = "libGL.so.1";  // !!! FIXME: Linux specific!
+        if (SDL_GL_LoadLibrary(libname) == -1)
+        {
+            fprintf(stderr, "SDL_GL_LoadLibrary(\"%s\") failed: %s\n",
+                    libname, SDL_GetError());
+            return false;
+        }
+
+        if (!lookup_all_glsyms(libname))
+            return false;
     }
 
     Uint32 sdlflags = SDL_OPENGL;
+    if (!cmdline("windowed"))
+        sdlflags |= SDL_FULLSCREEN;
+
     SDL_WM_SetCaption("Lugaru", "lugaru");
+
+    if (!cmdline("nomousegrab"))
+        SDL_WM_GrabInput(SDL_GRAB_ON);
+
     SDL_ShowCursor(0);
+
     if (SDL_SetVideoMode(kContextWidth, kContextHeight, 0, sdlflags) == NULL)
     {
         fprintf(stderr, "SDL_SetVideoMode() failed: %s\n", SDL_GetError());
         return false;
     }
 
+
 #elif (defined WIN32)
        //------------------------------------------------------------------
        // create window
@@ -940,6 +1055,7 @@ Boolean SetUp (Game & game)
        glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glAlphaFunc( GL_GREATER, 0.5f);
 
+#if USE_DEVIL
        if (ilGetInteger(IL_VERSION_NUM) < IL_VERSION ||
                iluGetInteger(ILU_VERSION_NUM) < ILU_VERSION ||
                ilutGetInteger(ILUT_VERSION_NUM) < ILUT_VERSION)
@@ -956,6 +1072,7 @@ Boolean SetUp (Game & game)
 
        ilEnable(IL_ORIGIN_SET);
        ilOriginFunc(IL_ORIGIN_LOWER_LEFT);
+#endif
 
        GLint width = kContextWidth;
        GLint height = kContextHeight;
@@ -976,6 +1093,23 @@ Boolean SetUp (Game & game)
 
 static void DoMouse(Game & game)
 {
+#if USE_SDL
+       if(mainmenu||(abs(game.deltah)<10*realmultiplier*1000&&abs(game.deltav)<10*realmultiplier*1000))
+       {
+               game.deltah *= usermousesensitivity;
+               game.deltav *= usermousesensitivity;
+               game.mousecoordh += game.deltah;
+               game.mousecoordv += game.deltav;
+        if (game.mousecoordh < 0)
+            game.mousecoordh = 0;
+        else if (game.mousecoordh >= kContextWidth)
+            game.mousecoordh = kContextWidth - 1;
+        if (game.mousecoordv < 0)
+            game.mousecoordv = 0;
+        else if (game.mousecoordv >= kContextHeight)
+            game.mousecoordv = kContextHeight - 1;
+       }
+#else
        static Point lastMouse = {-1,-1};
        Point globalMouse;
 
@@ -1007,7 +1141,7 @@ static void DoMouse(Game & game)
                        game.mousecoordv=globalMouse.v;
                }
 
-               if((!mainmenu)&&(gMouseGrabbed))
+               if(!mainmenu)
                {
                        if(lastMouse.h>gMidPoint.h+100||lastMouse.h<gMidPoint.h-100||lastMouse.v>gMidPoint.v+100||lastMouse.v<gMidPoint.v-100){
                                pos.x = gMidPoint.h;
@@ -1019,6 +1153,7 @@ static void DoMouse(Game & game)
                        }
                }
        }
+#endif
 }
 
 
@@ -1154,10 +1289,18 @@ void CleanUp (void)
 
 //     game.Dispose();
 
+#if USE_DEVIL
        ilShutDown();
+#endif
 
 #if USE_SDL
     SDL_Quit();
+    #define GL_FUNC(ret,fn,params,call,rt) p##fn = NULL;
+    #include "glstubs.h"
+    #undef GL_FUNC
+    // cheat here...static destructors are calling glDeleteTexture() after
+    //  the context is destroyed and libGL unloaded by SDL_Quit().
+    pglDeleteTextures = glDeleteTextures_doNothing;
 
 #elif (defined WIN32)
        if (hRC)
@@ -1206,8 +1349,187 @@ static bool IsFocused()
        return true;
 }
 
-int main (void)
+
+#if PLATFORM_LINUX
+#include <stdlib.h>
+#include <ctype.h>
+#include <unistd.h>
+static bool try_launch_browser(const char *browser, const char *url)
+{
+    // make sure string isn't empty...
+    while ( (*browser) && (isspace(*browser)) ) browser++;
+    if (*browser == '\0') return false;
+
+    bool seenurl = false;
+    char buf[4096];  // !!! FIXME: we aren't checking for overflow here!
+    char *dst = buf;
+    while (*browser)
+    {
+        char ch = *(browser++);
+        if (ch == '%')
+        {
+            ch = *(browser++);
+            if (ch == '%')
+                *(dst++) = '%';
+            else if (ch == 's')  // "%s" == insert URL here.
+            {
+                *(dst++) = '\'';
+                strcpy(dst, url);
+                dst += strlen(url);
+                *(dst++) = '\'';
+                seenurl = true;
+            }
+            // (not %% or %s? Drop the char.)
+        }
+        else
+        {
+            *(dst++) = ch;
+        }
+    }
+
+    *dst = '\0';
+    if (!seenurl)
+    {
+        strcat(dst, " ");
+        strcat(dst, url);
+    }
+    return(system(buf) == 0);
+}
+#endif
+
+
+static void launch_web_browser(const char *url)
 {
+#ifdef WIN32
+    ShellExecute(NULL, "open", url, NULL, NULL, SW_SHOWNORMAL);
+
+// lousy linux doesn't have a clean way to do this, but you can point people
+//  to docs on the BROWSER variable:
+//     http://www.catb.org/~esr/BROWSER/
+#elif PLATFORM_LINUX
+    if (strchr(url, '\'') != NULL)  // Prevent simple shell injection.
+        return;
+
+    const char *envr = getenv("BROWSER");
+    if (envr == NULL)  // not specified? We'll try a pseudo-sane list...
+        envr = "opera:mozilla:konqueror:firefox:netscape:xterm -e links:xterm -e lynx:";
+
+    char *ptr = (char *) alloca(strlen(envr) + 1);
+    if (ptr == NULL)
+        return;
+    strcpy(ptr, envr);
+    envr = ptr;
+
+    while ((ptr = strchr(envr, ':')) != NULL)
+    {
+        *ptr = '\0';
+        if (try_launch_browser(envr, url))
+            return;
+        envr = ptr + 1;
+    }
+
+    try_launch_browser(envr, url);
+#endif
+}
+
+
+#ifndef WIN32
+// (code lifted from physfs: http://icculus.org/physfs/ ... zlib license.)
+static char *findBinaryInPath(const char *bin, char *envr)
+{
+    size_t alloc_size = 0;
+    char *exe = NULL;
+    char *start = envr;
+    char *ptr;
+
+    do
+    {
+        size_t size;
+        ptr = strchr(start, ':');  /* find next $PATH separator. */
+        if (ptr)
+            *ptr = '\0';
+
+        size = strlen(start) + strlen(bin) + 2;
+        if (size > alloc_size)
+        {
+            char *x = (char *) realloc(exe, size);
+            if (x == NULL)
+            {
+                if (exe != NULL)
+                    free(exe);
+                return(NULL);
+            } /* if */
+
+            alloc_size = size;
+            exe = x;
+        } /* if */
+
+        /* build full binary path... */
+        strcpy(exe, start);
+        if ((exe[0] == '\0') || (exe[strlen(exe) - 1] != '/'))
+            strcat(exe, "/");
+        strcat(exe, bin);
+
+        if (access(exe, X_OK) == 0)  /* Exists as executable? We're done. */
+        {
+            strcpy(exe, start);  /* i'm lazy. piss off. */
+            return(exe);
+        } /* if */
+
+        start = ptr + 1;  /* start points to beginning of next element. */
+    } while (ptr != NULL);
+
+    if (exe != NULL)
+        free(exe);
+
+    return(NULL);  /* doesn't exist in path. */
+} /* findBinaryInPath */
+
+
+char *calcBaseDir(const char *argv0)
+{
+    /* If there isn't a path on argv0, then look through the $PATH for it. */
+    char *retval;
+    char *envr;
+
+    char *ptr = strrchr(argv0, '/');
+    if (strchr(argv0, '/'))
+    {
+        retval = strdup(argv0);
+        if (retval)
+            *(strrchr(retval, '/')) = '\0';
+        return(retval);
+    }
+
+    envr = getenv("PATH");
+    if (!envr) return NULL;
+    envr = strdup(envr);
+    if (!envr) return NULL;
+    retval = findBinaryInPath(argv0, envr);
+    free(envr);
+    return(retval);
+}
+
+static inline void chdirToAppPath(const char *argv0)
+{
+    char *dir = calcBaseDir(argv0);
+    if (dir)
+    {
+        chdir(dir);
+        free(dir);
+    }
+}
+#endif
+
+
+int main(int argc, char **argv)
+{
+    _argc = argc;
+    _argv = argv;
+#ifndef WIN32
+    chdirToAppPath(argv[0]);
+#endif
+
        LOGFUNC;
 
 #ifndef WIN32  // this is in WinMain, too.
@@ -1229,7 +1551,8 @@ int main (void)
                        //ofstream os("log.txt");
                        //os.close();
 
-                       SetUp (game);
+                       if (!SetUp (game))
+                return 42;
 
                        while (!gDone&&!game.quit&&(!game.tryquit||!game.registered))
                        {
@@ -1238,7 +1561,9 @@ int main (void)
                                        gameFocused = true;
 
                                        // check windows messages
-                    #if USE_SDL
+                                       #if USE_SDL
+                                       game.deltah = 0;
+                                       game.deltav = 0;
                                        SDL_Event e;
                                        // message pump
                                        while( SDL_PollEvent( &e ) )
@@ -1248,9 +1573,10 @@ int main (void)
                                                        gDone=true;
                                                        break;
                                                }
-                        sdlEventProc(e);
+                                               sdlEventProc(e, game);
                                        }
-                    #elif (defined WIN32)
+
+                                       #elif (defined WIN32)
                                        MSG msg;
                                        // message pump
                                        while( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE | PM_NOYIELD ) )
@@ -1266,7 +1592,7 @@ int main (void)
                                                        DispatchMessage( &msg );
                                                }
                                        }
-                    #endif
+                                       #endif
 
                                        // game
                                        DoUpdate(game);
@@ -1317,14 +1643,7 @@ int main (void)
 //             if(game.registernow){
                if(regnow)
                {
-            #ifndef WIN32
-            STUBBED("launch a web browser");
-            #else
-                       char url[100];
-                       sprintf(url,"http://www.wolfire.com/registerpc.html");
-                       //                      LaunchURL(url);
-                       ShellExecute(NULL, "open", url, NULL, NULL, SW_SHOWNORMAL);
-            #endif
+            launch_web_browser("http://www.wolfire.com/registerpc.html");
                }
                return 0;
        }
@@ -1878,6 +2197,7 @@ int main (void)
                if(width==840 && height==524)whichres=5;
                if(width==1024 && height==640)whichres=6;
                if(width==1344 && height==840)whichres=7;
+               if(width==1920 && height==1200)whichres=8;
 
                return whichres;
        }
@@ -1894,6 +2214,7 @@ int main (void)
                if(width==840 && height==524)whichres=5;
                if(width==1024 && height==640)whichres=6;
                if(width==1344 && height==840)whichres=7;
+               if(width>=1920 && height>=1200)whichres=8;
 
                return whichres;
        }
@@ -1905,7 +2226,7 @@ int main (void)
 
                while (true)
                {
-                       if(whichres<=0 || whichres>7){
+                       if(whichres<=0 || whichres>8){
                                whichres = 0;
                                width=640;
                                height=480;
@@ -1938,6 +2259,16 @@ int main (void)
                                width=1344;
                                height=840;
                        }
+                       if(whichres==8){
+                               width=1920;
+                               height=1200;
+                       }
+
+            // currently with SDL, we just use whatever the native bitdepth
+            //  of the display is and don't care.
+            #if USE_SDL
+            break;
+            #endif
 
                        if ((detail != 0) && (resolutionDepths[whichres][1] != 0))
                        {
@@ -1953,7 +2284,9 @@ int main (void)
                                detail = 0;
                                break;
                        }
-                       else if (0 == whichres)
+                       else
+
+            if (0 == whichres)
                        {
                                break;
                        }
@@ -2022,7 +2355,7 @@ int main (void)
 
                g_appInstance=hInstance;
 
-               main();
+               main(0, NULL);
 
                UnregisterClass( g_wndClassName, hInstance);
 
@@ -2096,6 +2429,7 @@ int main (void)
                        return false;
                }
 
+        #if USE_DEVIL
                ILstring f = strdup(ConvertFileName(fname));
                if (!f)
                {
@@ -2152,12 +2486,17 @@ int main (void)
                }
 */
                free(f);
+        #else
+        res = load_image(fname, tex);
+        //if (!res) printf("failed to load %s\n", fname);
+        #endif
 
                return res;
        }
 
        void ScreenShot(const char * fname)
        {
+        #if USE_DEVIL
                ILstring f = strdup(fname);
                if (!f)
                {
@@ -2174,6 +2513,263 @@ int main (void)
                ilDeleteImages(1, &iid);
 
                free(f);
+        #else
+        save_image(fname);
+        #endif
        }
 
 
+#if !USE_DEVIL
+static bool load_image(const char *file_name, TGAImageRec &tex)
+{
+    char *ptr = strrchr(file_name, '.');
+    if (ptr)
+    {
+        if (stricmp(ptr+1, "png") == 0)
+            return load_png(file_name, tex);
+        else if (stricmp(ptr+1, "jpg") == 0)
+            return load_jpg(file_name, tex);
+    }
+
+    STUBBED("Unsupported image type");
+    return false;
+}
+
+
+struct my_error_mgr {
+  struct jpeg_error_mgr pub;   /* "public" fields */
+  jmp_buf setjmp_buffer;       /* for return to caller */
+};
+typedef struct my_error_mgr * my_error_ptr;
+
+
+static void my_error_exit(j_common_ptr cinfo)
+{
+       struct my_error_mgr *err = (struct my_error_mgr *)cinfo->err;
+       longjmp(err->setjmp_buffer, 1);
+}
+
+/* stolen from public domain example.c code in libjpg distribution. */
+static bool load_jpg(const char *file_name, TGAImageRec &tex)
+{
+    struct jpeg_decompress_struct cinfo;
+    struct my_error_mgr jerr;
+    JSAMPROW buffer[1];                /* Output row buffer */
+    int row_stride;            /* physical row width in output buffer */
+    FILE *infile = fopen(file_name, "rb");
+
+    if (infile == NULL)
+        return false;
+
+    cinfo.err = jpeg_std_error(&jerr.pub);
+    jerr.pub.error_exit = my_error_exit;
+    if (setjmp(jerr.setjmp_buffer)) {
+        jpeg_destroy_decompress(&cinfo);
+        fclose(infile);
+        return false;
+    }
+
+    jpeg_create_decompress(&cinfo);
+    jpeg_stdio_src(&cinfo, infile);
+    (void) jpeg_read_header(&cinfo, TRUE);
+
+    cinfo.out_color_space = JCS_RGB;
+    cinfo.quantize_colors = 0;
+    (void) jpeg_calc_output_dimensions(&cinfo);
+    (void) jpeg_start_decompress(&cinfo);
+
+    row_stride = cinfo.output_width * cinfo.output_components;
+    tex.sizeX = cinfo.output_width;
+    tex.sizeY = cinfo.output_height;
+    tex.bpp = 24;
+
+    while (cinfo.output_scanline < cinfo.output_height) {
+        buffer[0] = (JSAMPROW)(char *)tex.data +
+                        ((cinfo.output_height-1) - cinfo.output_scanline) * row_stride;
+        (void) jpeg_read_scanlines(&cinfo, buffer, 1);
+    }
+
+    (void) jpeg_finish_decompress(&cinfo);
+    jpeg_destroy_decompress(&cinfo);
+    fclose(infile);
+
+    return true;
+}
+
+
+/* stolen from public domain example.c code in libpng distribution. */
+static bool load_png(const char *file_name, TGAImageRec &tex)
+{
+    bool hasalpha = false;
+    png_structp png_ptr = NULL;
+    png_infop info_ptr = NULL;
+    png_uint_32 width, height;
+    int bit_depth, color_type, interlace_type;
+    png_byte **rows = NULL;
+    bool retval = false;
+    png_byte **row_pointers = NULL;
+    FILE *fp = fopen(file_name, "rb");
+
+    if (fp == NULL)
+        return(NULL);
+
+    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if (png_ptr == NULL)
+        goto png_done;
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (info_ptr == NULL)
+        goto png_done;
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+        goto png_done;
+
+    png_init_io(png_ptr, fp);
+    png_read_png(png_ptr, info_ptr,
+                 PNG_TRANSFORM_STRIP_16 | PNG_TRANSFORM_PACKING,
+                 png_voidp_NULL);
+    png_get_IHDR(png_ptr, info_ptr, &width, &height,
+                 &bit_depth, &color_type, &interlace_type, NULL, NULL);
+
+    if (bit_depth != 8)  // transform SHOULD handle this...
+        goto png_done;
+
+    if (color_type & PNG_COLOR_MASK_PALETTE)  // !!! FIXME?
+        goto png_done;
+
+    if ((color_type & PNG_COLOR_MASK_COLOR) == 0)  // !!! FIXME?
+        goto png_done;
+
+    hasalpha = ((color_type & PNG_COLOR_MASK_ALPHA) != 0);
+    row_pointers = png_get_rows(png_ptr, info_ptr);
+    if (!row_pointers)
+        goto png_done;
+
+    retval = malloc(width * height * 4);
+    if (!retval)
+        goto png_done;
+
+    if (!hasalpha)
+    {
+        png_byte *dst = tex.data;
+        for (int i = height-1; i >= 0; i--)
+        {
+            png_byte *src = row_pointers[i];
+            for (int j = 0; j < width; j++)
+            {
+                dst[0] = src[0];
+                dst[1] = src[1];
+                dst[2] = src[2];
+                dst[3] = 0xFF;
+                src += 3;
+                dst += 4;
+            }
+        }
+    }
+
+    else
+    {
+        png_byte *dst = tex.data;
+        int pitch = width * 4;
+        for (int i = height-1; i >= 0; i--, dst += pitch)
+            memcpy(dst, row_pointers[i], pitch);
+    }
+
+    tex.sizeX = width;
+    tex.sizeY = height;
+    tex.bpp = 32;
+    retval = true;
+
+png_done:
+    png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL);
+    if (fp)
+        fclose(fp);
+    return (retval);
+}
+
+
+static bool save_image(const char *file_name)
+{
+    char *ptr = strrchr(file_name, '.');
+    if (ptr)
+    {
+        if (stricmp(ptr+1, "png") == 0)
+            return save_png(file_name);
+    }
+
+    STUBBED("Unsupported image type");
+    return false;
+}
+
+
+static bool save_png(const char *file_name)
+{
+    FILE *fp = NULL;
+    png_structp png_ptr = NULL;
+    png_infop info_ptr = NULL;
+    bool retval = false;
+
+    fp = fopen(file_name, "wb");
+    if (fp == NULL)
+        return false;
+
+    png_bytep *row_pointers = new png_bytep[kContextHeight];
+    png_bytep screenshot = new png_byte[kContextWidth * kContextHeight * 3];
+    if ((!screenshot) || (!row_pointers))
+        goto save_png_done;
+
+    glGetError();
+    glReadPixels(0, 0, kContextWidth, kContextHeight,
+                 GL_RGB, GL_UNSIGNED_BYTE, screenshot);
+    if (glGetError() != GL_NO_ERROR)
+        goto save_png_done;
+
+    for (int i = 0; i < kContextHeight; i++)
+        row_pointers[i] = screenshot + ((kContextWidth * ((kContextHeight-1) - i)) * 3);
+
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if (png_ptr == NULL)
+        goto save_png_done;
+
+    info_ptr = png_create_info_struct(png_ptr);
+    if (info_ptr == NULL)
+        goto save_png_done;
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+        goto save_png_done;
+
+    png_init_io(png_ptr, fp);
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+        goto save_png_done;
+
+    png_set_IHDR(png_ptr, info_ptr, kContextWidth, kContextHeight,
+                 8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
+                 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+    png_write_info(png_ptr, info_ptr);
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+        goto save_png_done;
+
+       png_write_image(png_ptr, row_pointers);
+
+       if (setjmp(png_jmpbuf(png_ptr)))
+        goto save_png_done;
+
+    png_write_end(png_ptr, NULL);
+    retval = true;
+
+save_png_done:
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+    delete[] screenshot;
+    delete[] row_pointers;
+    if (fp)
+        fclose(fp);
+    if (!retval)
+        unlink(ConvertFileName(file_name));
+    return retval;
+}
+
+#endif
+