]> git.jsancho.org Git - lugaru.git/blobdiff - Source/OpenGL_Windows.cpp
Dynamically load the GL.
[lugaru.git] / Source / OpenGL_Windows.cpp
index 6ac0dd89093d8a19a135ffa82ef1ff05c529b13d..15073ce19546940855d9e54b1a598907c24bcdaf 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;
@@ -165,6 +223,8 @@ Boolean gDone = false, gfFrontProcess = true;
 
 Game * pgame = 0;
 
+static bool gMouseGrabbed = true;
+
 // --------------------------------------------------------------------------
 
 void ReportError (char * strError)
@@ -242,7 +302,129 @@ void DrawGL (Game & game)
 }
 
 
-#if USE_SDL
+static KeyMap g_theKeys;
+
+void SetKey( int key)
+{
+    g_theKeys[ key >> 3] |= (1 << (key & 7));
+}
+
+void ClearKey( int key)
+{
+    g_theKeys[ key >> 3] &= (0xff ^ (1 << (key & 7)));
+}
+
+void GetKeys(  unsigned char theKeys[16])
+{
+    memcpy( theKeys, &g_theKeys, 16);
+}
+
+Boolean Button()
+{
+    return g_button;
+}
+
+#if !USE_SDL
+static void initSDLKeyTable(void) {}
+#else
+#define MAX_SDLKEYS SDLK_LAST
+static unsigned short KeyTable[MAX_SDLKEYS];
+
+static void initSDLKeyTable(void)
+{
+    memset(KeyTable, 0xFF, sizeof (KeyTable));
+    KeyTable[SDLK_BACKSPACE] = MAC_DELETE_KEY;
+    KeyTable[SDLK_TAB] = MAC_TAB_KEY;
+    KeyTable[SDLK_RETURN] = MAC_RETURN_KEY;
+    KeyTable[SDLK_ESCAPE] = MAC_ESCAPE_KEY;
+    KeyTable[SDLK_SPACE] = MAC_SPACE_KEY;
+    KeyTable[SDLK_PAGEUP] = MAC_PAGE_UP_KEY;
+    KeyTable[SDLK_PAGEDOWN] = MAC_PAGE_DOWN_KEY;
+    KeyTable[SDLK_END] = MAC_END_KEY;
+    KeyTable[SDLK_HOME] = MAC_HOME_KEY;
+    KeyTable[SDLK_LEFT] = MAC_ARROW_LEFT_KEY;
+    KeyTable[SDLK_UP] = MAC_ARROW_UP_KEY;
+    KeyTable[SDLK_RIGHT] = MAC_ARROW_RIGHT_KEY;
+    KeyTable[SDLK_DOWN] = MAC_ARROW_DOWN_KEY;
+    KeyTable[SDLK_INSERT] = MAC_INSERT_KEY;
+    KeyTable[SDLK_DELETE] = MAC_DEL_KEY;
+    KeyTable[SDLK_0] = MAC_0_KEY;
+    KeyTable[SDLK_1] = MAC_1_KEY;
+    KeyTable[SDLK_2] = MAC_2_KEY;
+    KeyTable[SDLK_3] = MAC_3_KEY;
+    KeyTable[SDLK_4] = MAC_4_KEY;
+    KeyTable[SDLK_5] = MAC_5_KEY;
+    KeyTable[SDLK_6] = MAC_6_KEY;
+    KeyTable[SDLK_7] = MAC_7_KEY;
+    KeyTable[SDLK_8] = MAC_8_KEY;
+    KeyTable[SDLK_9] = MAC_9_KEY;
+    KeyTable[SDLK_a] = MAC_A_KEY;
+    KeyTable[SDLK_b] = MAC_B_KEY;
+    KeyTable[SDLK_c] = MAC_C_KEY;
+    KeyTable[SDLK_d] = MAC_D_KEY;
+    KeyTable[SDLK_e] = MAC_E_KEY;
+    KeyTable[SDLK_f] = MAC_F_KEY;
+    KeyTable[SDLK_g] = MAC_G_KEY;
+    KeyTable[SDLK_h] = MAC_H_KEY;
+    KeyTable[SDLK_i] = MAC_I_KEY;
+    KeyTable[SDLK_j] = MAC_J_KEY;
+    KeyTable[SDLK_k] = MAC_K_KEY;
+    KeyTable[SDLK_l] = MAC_L_KEY;
+    KeyTable[SDLK_m] = MAC_M_KEY;
+    KeyTable[SDLK_n] = MAC_N_KEY;
+    KeyTable[SDLK_o] = MAC_O_KEY;
+    KeyTable[SDLK_p] = MAC_P_KEY;
+    KeyTable[SDLK_q] = MAC_Q_KEY;
+    KeyTable[SDLK_r] = MAC_R_KEY;
+    KeyTable[SDLK_s] = MAC_S_KEY;
+    KeyTable[SDLK_t] = MAC_T_KEY;
+    KeyTable[SDLK_u] = MAC_U_KEY;
+    KeyTable[SDLK_v] = MAC_V_KEY;
+    KeyTable[SDLK_w] = MAC_W_KEY;
+    KeyTable[SDLK_x] = MAC_X_KEY;
+    KeyTable[SDLK_y] = MAC_Y_KEY;
+    KeyTable[SDLK_z] = MAC_Z_KEY;
+    KeyTable[SDLK_KP0] = MAC_NUMPAD_0_KEY;
+    KeyTable[SDLK_KP1] = MAC_NUMPAD_1_KEY;
+    KeyTable[SDLK_KP2] = MAC_NUMPAD_2_KEY;
+    KeyTable[SDLK_KP3] = MAC_NUMPAD_3_KEY;
+    KeyTable[SDLK_KP4] = MAC_NUMPAD_4_KEY;
+    KeyTable[SDLK_KP5] = MAC_NUMPAD_5_KEY;
+    KeyTable[SDLK_KP6] = MAC_NUMPAD_6_KEY;
+    KeyTable[SDLK_KP7] = MAC_NUMPAD_7_KEY;
+    KeyTable[SDLK_KP8] = MAC_NUMPAD_8_KEY;
+    KeyTable[SDLK_KP9] = MAC_NUMPAD_9_KEY;
+    KeyTable[SDLK_KP_MULTIPLY] = MAC_NUMPAD_ASTERISK_KEY;
+    KeyTable[SDLK_KP_PLUS] = MAC_NUMPAD_PLUS_KEY;
+    KeyTable[SDLK_KP_ENTER] = MAC_NUMPAD_ENTER_KEY;
+    KeyTable[SDLK_KP_MINUS] = MAC_NUMPAD_MINUS_KEY;
+    KeyTable[SDLK_KP_PERIOD] = MAC_NUMPAD_PERIOD_KEY;
+    KeyTable[SDLK_KP_DIVIDE] = MAC_NUMPAD_SLASH_KEY;
+    KeyTable[SDLK_F1] = MAC_F1_KEY;
+    KeyTable[SDLK_F2] = MAC_F2_KEY;
+    KeyTable[SDLK_F3] = MAC_F3_KEY;
+    KeyTable[SDLK_F4] = MAC_F4_KEY;
+    KeyTable[SDLK_F5] = MAC_F5_KEY;
+    KeyTable[SDLK_F6] = MAC_F6_KEY;
+    KeyTable[SDLK_F7] = MAC_F7_KEY;
+    KeyTable[SDLK_F8] = MAC_F8_KEY;
+    KeyTable[SDLK_F9] = MAC_F9_KEY;
+    KeyTable[SDLK_F10] = MAC_F10_KEY;
+    KeyTable[SDLK_F11] = MAC_F11_KEY;
+    KeyTable[SDLK_F12] = MAC_F12_KEY;
+    KeyTable[SDLK_SEMICOLON] = MAC_SEMICOLON_KEY;
+    KeyTable[SDLK_PLUS] = MAC_PLUS_KEY;
+    KeyTable[SDLK_COMMA] = MAC_COMMA_KEY;
+    KeyTable[SDLK_MINUS] = MAC_MINUS_KEY;
+    KeyTable[SDLK_PERIOD] = MAC_PERIOD_KEY;
+    KeyTable[SDLK_SLASH] = MAC_SLASH_KEY;
+    KeyTable[SDLK_BACKQUOTE] = MAC_TILDE_KEY;
+    KeyTable[SDLK_LEFTBRACKET] = MAC_LEFTBRACKET_KEY;
+    KeyTable[SDLK_BACKSLASH] = MAC_BACKSLASH_KEY;
+    KeyTable[SDLK_RIGHTBRACKET] = MAC_RIGHTBRACKET_KEY;
+    KeyTable[SDLK_QUOTE] = MAC_APOSTROPHE_KEY;
+}
+
 static inline int clamp_sdl_mouse_button(Uint8 button)
 {
     if ((button >= 1) && (button <= 3))
@@ -261,7 +443,14 @@ static void sdlEventProc(const SDL_Event &e)
                 if (val >= 0)
                 {
                     if (val == 0)
+                    {
                                    g_button = true;
+                        SetKey(MAC_MOUSEBUTTON1);
+                    }
+
+                    else if (val == 1)
+                        SetKey(MAC_MOUSEBUTTON2);
+
                                buttons[val] = true;
                 }
                        }
@@ -273,11 +462,65 @@ static void sdlEventProc(const SDL_Event &e)
                 if (val >= 0)
                 {
                     if (val == 0)
+                    {
                                    g_button = false;
+                        ClearKey(MAC_MOUSEBUTTON1);
+                    }
+
+                    else if (val == 1)
+                        ClearKey(MAC_MOUSEBUTTON2);
+
                                buttons[val] = false;
                 }
                        }
             return;
+
+        case SDL_KEYDOWN:
+            if (e.key.keysym.sym == SDLK_g)
+            {
+                if (e.key.keysym.mod & KMOD_CTRL)
+                    gMouseGrabbed = !gMouseGrabbed;
+            }
+
+            else if (e.key.keysym.sym == SDLK_RETURN)
+            {
+                if (e.key.keysym.mod & KMOD_ALT)
+                    SDL_WM_ToggleFullScreen(SDL_GetVideoSurface());
+            }
+
+            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)
+                SetKey(MAC_CONTROL_KEY);
+            if (e.key.keysym.mod & KMOD_ALT)
+                SetKey(MAC_OPTION_KEY);
+            if (e.key.keysym.mod & KMOD_SHIFT)
+                SetKey(MAC_SHIFT_KEY);
+            if (e.key.keysym.mod & KMOD_CAPS)
+                SetKey(MAC_CAPS_LOCK_KEY);
+
+            return;
+
+        case SDL_KEYUP:
+            if (e.key.keysym.sym < SDLK_LAST)
+            {
+                if (KeyTable[e.key.keysym.sym] != 0xffff)
+                    ClearKey(KeyTable[e.key.keysym.sym]);
+            }
+
+            if (e.key.keysym.mod & KMOD_CTRL)
+                ClearKey(MAC_CONTROL_KEY);
+            if (e.key.keysym.mod & KMOD_ALT)
+                ClearKey(MAC_OPTION_KEY);
+            if (e.key.keysym.mod & KMOD_SHIFT)
+                ClearKey(MAC_SHIFT_KEY);
+            if (e.key.keysym.mod & KMOD_CAPS)
+                ClearKey(MAC_CAPS_LOCK_KEY);
+            return;
     }
 }
 #endif
@@ -592,9 +835,20 @@ 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;
+    Uint32 sdlflags = SDL_OPENGL;  // !!! FIXME: SDL_FULLSCREEN?
     SDL_WM_SetCaption("Lugaru", "lugaru");
     SDL_ShowCursor(0);
     if (SDL_SetVideoMode(kContextWidth, kContextHeight, 0, sdlflags) == NULL)
@@ -603,6 +857,8 @@ Boolean SetUp (Game & game)
         return false;
     }
 
+
+
 #elif (defined WIN32)
        //------------------------------------------------------------------
        // create window
@@ -755,6 +1011,7 @@ 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)
@@ -771,6 +1028,7 @@ Boolean SetUp (Game & game)
 
        ilEnable(IL_ORIGIN_SET);
        ilOriginFunc(IL_ORIGIN_LOWER_LEFT);
+#endif
 
        GLint width = kContextWidth;
        GLint height = kContextHeight;
@@ -822,7 +1080,7 @@ static void DoMouse(Game & game)
                        game.mousecoordv=globalMouse.v;
                }
 
-               if(!mainmenu)
+               if((!mainmenu)&&(gMouseGrabbed))
                {
                        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;
@@ -969,10 +1227,18 @@ 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)
@@ -1021,11 +1287,17 @@ static bool IsFocused()
        return true;
 }
 
-
 int main (void)
 {
        LOGFUNC;
 
+#ifndef WIN32  // this is in WinMain, too.
+       logger.start(true);
+       memset( &g_theKeys, 0, sizeof( KeyMap));
+#endif
+
+    initSDLKeyTable();
+
        try
        {
                bool regnow = false;
@@ -1038,7 +1310,8 @@ int main (void)
                        //ofstream os("log.txt");
                        //os.close();
 
-                       SetUp (game);
+                       if (!SetUp (game))
+                return 42;
 
                        while (!gDone&&!game.quit&&(!game.tryquit||!game.registered))
                        {
@@ -1158,7 +1431,7 @@ int main (void)
 
        // --------------------------------------------------------------------------
 
-
+#ifdef WIN32
 #define MAX_WINKEYS 256
        static unsigned short KeyTable[MAX_WINKEYS]=
        {
@@ -1420,31 +1693,6 @@ int main (void)
                        0xffff,  // (255)
        };
 
-
-       static KeyMap g_theKeys;
-
-       void SetKey( int key)
-       {
-               g_theKeys[ key >> 3] |= (1 << (key & 7));
-       }
-
-       void ClearKey( int key)
-       {
-               g_theKeys[ key >> 3] &= (0xff ^ (1 << (key & 7)));
-       }
-
-       void GetKeys(  unsigned char theKeys[16])
-       {
-               memcpy( theKeys, &g_theKeys, 16);
-       }
-
-       Boolean Button()
-       {
-               return g_button;
-       }
-
-
-#ifdef WIN32
        void ClipMouseToWindow(HWND window)
        {
                RECT wRect;
@@ -1930,6 +2178,7 @@ int main (void)
                        return false;
                }
 
+        #if USE_DEVIL
                ILstring f = strdup(ConvertFileName(fname));
                if (!f)
                {
@@ -1986,12 +2235,17 @@ 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)
                {
@@ -2008,6 +2262,263 @@ 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
+