Experimental giflib support

meson.build

@@ -28,6 +28,19 @@ if discord_libpath != ''
     endif
 endif
 
+# GIFLIB
+
+gif = false
+gif_prefix = get_option('giflib_prefix')
+if gif_prefix != ''
+    giflib = compiler.find_library('gif', required: false, dirs: gif_prefix+'/lib')
+    if giflib.found() == true
+        add_project_arguments(['-I@0@/include'.format(gif_prefix), '-DHAVE_GIFLIB'], language: 'cpp')
+        ext_dependencies += giflib
+        gif = true
+    endif
+endif
+
 # ====================
 # Main source
 # ====================

meson_options.txt

@@ -11,3 +11,4 @@ option('no_preload_scripts', type: 'boolean', value: false, description: 'Disabl
 option('workdir_current', type: 'boolean', value: false, description: 'Keep current directory on startup')
 
 option('discord_sdk_path', type: 'string', value: '', description: 'Path to Discord GameSDK')
+option('giflib_prefix', type: 'string', value: '', description: 'Path to the prefix where giflib is installed')

src/bitmap.cpp

@@ -44,6 +44,10 @@
 #include "font.h"
 #include "eventthread.h"
 
+#ifdef HAVE_GIFLIB
+#include <gif_lib.h>
+#endif
+
 #define GUARD_MEGA \
 	{ \
 		if (p->megaSurface) \
@@ -102,10 +106,21 @@ struct BitmapPrivate
 	 * ourselves the expensive blending calculation */
 	pixman_region16_t tainted;
     
+    /* If the image is a gif, its frames are located here. */
+#ifdef HAVE_GIFLIB
+    SDL_Surface* gifSurfaces[256];
+    int nFrames;
+    int currentFrame;
+#endif
+
 	BitmapPrivate(Bitmap *self)
 	    : self(self),
 	      megaSurface(0),
-	      surface(0)
+	      surface(0),
+#ifdef HAVE_GIFLIB
+          nFrames(1),
+          currentFrame(0)
+#endif
 	{
 		format = SDL_AllocFormat(SDL_PIXELFORMAT_ABGR8888);
 
@@ -117,6 +132,10 @@ struct BitmapPrivate
 	{
 		SDL_FreeFormat(format);
 		pixman_region_fini(&tainted);
+#ifdef HAVE_GIFLIB
+        if (nFrames > 1)
+            for (int i = 0; i < nFrames; i++) SDL_FreeSurface(gifSurfaces[i]);
+#endif
 	}
 
 	void allocSurface()
@@ -251,6 +270,53 @@ struct BitmapOpenHandler : FileSystem::OpenHandler
 Bitmap::Bitmap(const char *filename)
 {
 	BitmapOpenHandler handler;
+    
+    // If the file is a gif, try opening it with giflib first
+    // and read every frame
+#ifdef HAVE_GIFLIB
+    char *extension = strrchr((char*)filename, '.');
+    int *rc{};
+    if (extension && !strcmp((extension+1), "gif"))
+    {
+        GifFileType *gif = DGifOpenFileName(filename, rc);
+        if (rc && DGifSlurp(gif) == GIF_OK)
+        {
+            p->nFrames = gif->ImageCount;
+            int colorReso = gif->SColorResolution;
+            for (int i = 0; i < p->nFrames; i++)
+            {
+                SDL_Surface *frame = SDL_CreateRGBSurface(0,
+                                                          gif->SWidth,
+                                                          gif->SHeight,
+                                                          colorReso,
+                                                          p->format->Rmask,
+                                                          p->format->Gmask,
+                                                          p->format->Bmask,
+                                                          p->format->Amask);
+                if (frame)
+                {
+                    memcpy(frame->pixels,
+                           gif->SavedImages[i].RasterBits,
+                           frame->w*frame->h*(colorReso/8));
+                    p->gifSurfaces[i] = frame;
+                }
+                else
+                {
+                    for (int b = i; b >= 0; b--)
+                    {
+                        SDL_FreeSurface(p->gifSurfaces[b]);
+                        p->gifSurfaces[b] = 0;
+                    }
+                    break;
+                }
+            }
+            GifFreeSavedImages(gif);
+            handler.surf = p->gifSurfaces[0];
+        }
+    }
+    
+    if (!handler.surf)
+#endif
 	shState->fileSystem().openRead(handler, filename);
 	SDL_Surface *imgSurf = handler.surf;
 
@@ -814,6 +880,31 @@ void Bitmap::clear()
 	p->onModified();
 }
 
+void Bitmap::update()
+{
+#ifdef HAVE_GIFLIB
+    if (p->nFrames < 2) return;
+    
+    guardDisposed();
+    
+    GUARD_MEGA;
+    
+    if (p->currentFrame >= p->nFrames)
+    {
+        p->currentFrame = 0;
+    }
+    else
+    {
+        p->currentFrame++;
+    }
+    SDL_Surface *surf = p->gifSurfaces[p->currentFrame];
+    
+    replaceRaw(surf->pixels, surf->w, surf->h);
+#else
+    return;
+#endif
+}
+
 static uint32_t &getPixelAt(SDL_Surface *surf, SDL_PixelFormat *form, int x, int y)
 {
 	size_t offset = x*form->BytesPerPixel + y*surf->pitch;
@@ -902,6 +993,7 @@ void Bitmap::replaceRaw(void *pixel_data, int w, int h)
     TEXFBO::fini(buf);
     
     taintArea(IntRect(0,0,w,h));
+    p->onModified();
     
 }
 

src/bitmap.h

@@ -79,6 +79,8 @@ public:
 
 	void clear();
     
+    void update();
+
 	Color getPixel(int x, int y) const;
 	void setPixel(int x, int y, const Color &color);
     

src/graphics.cpp

@@ -975,7 +975,6 @@ void Graphics::screenshot(const char *filename)
     SDL_Surface *img = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32, 0,0,0,0);
     if (!img) throw Exception(Exception::SDLError, "%s", SDL_GetError());
 
-    glReadBuffer(GL_FRONT);
     glReadPixels(0,0,w,h,GL_BGRA,GL_UNSIGNED_BYTE, img->pixels);
 #else
     SDL_Surface *tmp, *img;
@@ -988,7 +987,6 @@ void Graphics::screenshot(const char *filename)
         throw Exception(Exception::SDLError, "%s", SDL_GetError());
     }
     
-    glReadBuffer(GL_FRONT);
     glReadPixels(0,0,w,h,GL_BGRA,GL_UNSIGNED_BYTE, tmp->pixels);
     
     for (int i = 0; i < h; i++)