Fix blending errors (original fix by @ekaitz-zarraga)

Fixes #320 Fixes #315
LibreSprite · Dec 23, 2023 · ec92a86 · ec92a86
1 parent bf65b1a
commit ec92a86
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Showing 2 changed files with 18 additions and 2 deletions.
diff --git a/src/she/sdl2/sdl2_display.cpp b/src/she/sdl2/sdl2_display.cpp
@@ -41,6 +41,7 @@ namespace she {
 
   namespace sdl {
     she::SDL2Surface* screen;
+    she::SDL2Surface* tempSurface;
     extern bool isMaximized;
     extern bool isMinimized;
     std::unordered_map<int, SDL2Display*> windowIdToDisplay;
@@ -85,6 +86,8 @@ namespace she {
   SDL2Display::~SDL2Display()
   {
     unique_display = NULL;
+    if (sdl::tempSurface)
+        sdl::tempSurface->dispose();
     if (m_window) {
       sdl::windowIdToDisplay.erase(SDL_GetWindowID(m_window));
       m_surface->dispose();

diff --git a/src/she/sdl2/sdl2_surface.cpp b/src/she/sdl2/sdl2_surface.cpp
@@ -31,6 +31,7 @@ namespace she {
 
   namespace sdl {
     extern SDL2Surface* screen;
+    extern SDL2Surface* tempSurface;
   }
 
   inline gfx::Color from_sdl(SDL_PixelFormat *format, int color)
@@ -421,8 +422,20 @@ namespace she {
 
   void SDL2Surface::fillRect(gfx::Color color, const gfx::Rect& rc)
   {
-    SDL_Rect rect{rc.x, rc.y, rc.w, rc.h};
-    SDL_FillRect(m_bmp, &rect, to_sdl(m_bmp->format, color));
+    auto alpha = gfx::geta(color);
+    if (!alpha)
+      return;
+    if (alpha != 255) {
+      if (!sdl::tempSurface)
+        sdl::tempSurface = new SDL2Surface(1, 1, SDL2Surface::DeleteAndDestroy);
+      SDL_FillRect(sdl::tempSurface->m_bmp, nullptr, to_sdl(sdl::tempSurface->m_bmp->format, color));
+      SDL_Rect rect{rc.x, rc.y, rc.w, rc.h};
+      SDL_Rect srcRect{0, 0, 1, 1};
+      SDL_BlitScaled(sdl::tempSurface->m_bmp, &srcRect, m_bmp, &rect);
+    } else {
+      SDL_Rect rect{rc.x, rc.y, rc.w, rc.h};
+      SDL_FillRect(m_bmp, &rect, to_sdl(m_bmp->format, color));
+    }
   }
 
   void SDL2Surface::blitTo(Surface* dest, int srcx, int srcy, int dstx, int dsty, int width, int height) const