[Add] save png method to save a surface to a file as png.

src/opengl.c

@@ -157,6 +157,83 @@ void gl_screenshot(const char* filename) {
   gl_checkErr();
 }
 
+/* Save a surface to a file as a png. */
+int SDL_savePNG(SDL_Surface* surface, const char* file) {
+  static unsigned char** ss_rows;
+  static int ss_size;
+  static int ss_w, ss_h;
+  SDL_Surface* ss_surface;
+  SDL_Rect ss_rect;
+  int r, i;
+  int alpha = 0;
+  int pixel_bits = 32;
+
+  unsigned surf_flags;
+  unsigned surf_alpha;
+
+  ss_rows = 0;
+  ss_size = 0;
+  ss_surface = 0;
+
+  ss_w = surface->w;
+  ss_h = surface->h;
+
+  if(surface->format->Amask) {
+    alpha = 1;
+    pixel_bits = 32;
+  } else {
+    pixel_bits = 24;
+  }
+
+  ss_surface = SDL_CreateRGBSurface(SDL_SWSURFACE | SDL_SRCALPHA, ss_w, ss_h,
+      pixel_bits, RGBAMASK);
+
+  if(ss_surface == 0) {
+    return -1;
+  }
+
+  surf_flags = surface->flags & (SDL_SRCALPHA | SDL_SRCCOLORKEY);
+  surf_alpha = surface->format->alpha;
+  if(surf_flags & SDL_SRCALPHA)
+    SDL_SetAlpha(surface, 0, SDL_ALPHA_OPAQUE);
+  if(surf_flags & SDL_SRCCOLORKEY)
+    SDL_SetColorKey(surface, 0, surface->format->colorkey);
+
+  ss_rect.x = 0;
+  ss_rect.y = 0;
+  ss_rect.w = ss_w;
+  ss_rect.h = ss_h;
+  SDL_BlitSurface(surface, &ss_rect, ss_surface, 0);
+
+  if(ss_size == 0) {
+    ss_size = ss_h;
+    ss_rows = (unsigned char**)malloc(sizeof(unsigned char*)*ss_size);
+    if(ss_rows == 0) {
+      return -1;
+    }
+  }
+  if(surf_flags & SDL_SRCALPHA)
+    SDL_SetAlpha(surface, SDL_SRCALPHA, (Uint8)surf_alpha);
+  if(surf_flags & SDL_SRCCOLORKEY)
+    SDL_SetColorKey(surface, SDL_SRCCOLORKEY, surface->format->colorkey);
+
+  for(i = 0; i < ss_h; i++) {
+    ss_rows[i] = ((unsigned char*)ss_surface->pixels) + i * ss_surface->pitch;
+  }
+
+  if(alpha) {
+    r = write_png(file, ss_rows, surface->w, surface->h, PNG_COLOR_TYPE_RGB_ALPHA, 8);
+  } else {
+    r = write_png(file, ss_rows, surface->w, surface->h, PNG_COLOR_TYPE_RGB, 8);
+  }
+  
+  free(ss_rows);
+  SDL_FreeSurface(ss_surface);
+  ss_surface = NULL;
+
+  return r;
+}
+
 /* ================ */
 /* TEXTURE! */
 /* ================ */
@@ -191,7 +268,7 @@ static GLuint gl_loadSurface(SDL_Surface* surface, int* rw, int* rh) {
 
   /* Create the temp POT surface. */
   tmp = SDL_CreateRGBSurface(SDL_SRCCOLORKEY,
-      potw, poth, surface->format->BytesPerPixel*8, RGBMASK);
+      potw, poth, surface->format->BytesPerPixel*8, RGBAMASK);
   if(tmp == NULL) {
     WARN("Unable to create POT surface: %s", SDL_GetError());
     return 0;

src/opengl.h

@@ -17,7 +17,7 @@
 #  define BMASK 0x00ff0000
 #  define AMASK 0xff000000
 #endif
-#define RGBMASK RMASK,GMASK,BMASK,AMASK
+#define RGBAMASK RMASK,GMASK,BMASK,AMASK
 
 /* Info about opengl screen. */
 #define OPENGL_FULLSCREEN   (1<<0)
@@ -105,6 +105,7 @@ void gl_exit(void);
 int gl_isTrans(const glTexture* t, const int x, const int y);
 void gl_getSpriteFromDir(int* x, int* y, const glTexture* t, const double dir);
 void gl_screenshot(const char* filename);
+int SDL_SavePNG(SDL_Surface* surface, const char* file);
 /*#if DEBUG == 1 */
 void gl_checkErr(void);
 /*#else */

src/perlin.c

@@ -287,7 +287,7 @@ glTexture* noise_genCloud(const int w, const int h, double rug) {
 
   map = noise_genNebulae(w, h, 1, rug);
 
-  sur = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32, RGBMASK);
+  sur = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32, RGBAMASK);
   pix = sur->pixels;
 
   /* Convert from mapping to actual colours. */