Enhance blood stain handling: combine existing and new blood surfaces for better accumulation and add surface management

engine/graphics.py

@@ -47,11 +47,24 @@ class Graphics():
         if not hasattr(self, 'blood_stains'):
             self.blood_stains = {}
         
-        # Generate blood surface
+        # Generate new blood surface
-        blood_surface = self.render_engine.generate_blood_surface()
+        new_blood_surface = self.render_engine.generate_blood_surface()
-        self.blood_stains[position] = blood_surface
         
-        # Regenerate background to include the new blood stain
+        if position in self.blood_stains:
+            # If there's already a blood stain at this position, combine them
+            existing_surface = self.blood_stains[position]
+            combined_surface = self.render_engine.combine_blood_surfaces(existing_surface, new_blood_surface)
+            
+            # Free the old surfaces
+            self.render_engine.free_surface(existing_surface)
+            self.render_engine.free_surface(new_blood_surface)
+            
+            self.blood_stains[position] = combined_surface
+        else:
+            # First blood stain at this position
+            self.blood_stains[position] = new_blood_surface
+        
+        # Regenerate background to include the updated blood stain
         self.regenerate_background()
         
     def scroll_cursor(self, x=0, y=0):

engine/sdl2.py

@@ -304,13 +304,13 @@ class GameWindow:
         pixels = cast(blood_surface.contents.pixels, POINTER(c_uint32))
         pitch = blood_surface.contents.pitch // 4  # pitch in pixel (32-bit)
         
-        # Colori del sangue (variazioni di rosso)
+        # Colori del sangue (variazioni di rosso in formato ABGR)
         blood_colors = [
-            0xFF8B0000,  # Rosso scuro
+            0xFF00008B,  # Rosso scuro (A=FF, B=00, G=00, R=8B)
-            0xFFB22222,  # Rosso mattone
+            0xFF002222,  # Rosso mattone (A=FF, B=00, G=22, R=22)
-            0xFFDC143C,  # Cremisi
+            0xFF003C14,  # Cremisi (A=FF, B=00, G=3C, R=14)
-            0xFFFF0000,  # Rosso puro
+            0xFF0000FF,  # Rosso puro (A=FF, B=00, G=00, R=FF)
-            0xFF800000,  # Marrone
+            0xFF000080,  # Marrone rossastro (A=FF, B=00, G=00, R=80)
         ]
         
         # Genera la macchia con un algoritmo di diffusione
@@ -385,4 +385,85 @@ class GameWindow:
         # Create texture from the temporary surface
         texture = self.factory.from_surface(temp_surface)
         sdl2.SDL_FreeSurface(temp_surface)
-        return texture
+        return texture
+
+    def combine_blood_surfaces(self, existing_surface, new_surface):
+        """Combine two blood surfaces by blending them together"""
+        # Create a new surface for the combined result
+        combined_surface = sdl2.SDL_CreateRGBSurface(
+            0, self.cell_size, self.cell_size, 32,
+            0x000000FF,  # R mask
+            0x0000FF00,  # G mask
+            0x00FF0000,  # B mask
+            0xFF000000   # A mask
+        )
+        
+        if combined_surface is None:
+            return existing_surface
+        
+        # Lock both surfaces for pixel manipulation
+        sdl2.SDL_LockSurface(existing_surface)
+        sdl2.SDL_LockSurface(new_surface)
+        sdl2.SDL_LockSurface(combined_surface)
+        
+        # Get pixel data
+        existing_pixels = cast(existing_surface.contents.pixels, POINTER(c_uint32))
+        new_pixels = cast(new_surface.contents.pixels, POINTER(c_uint32))
+        combined_pixels = cast(combined_surface.contents.pixels, POINTER(c_uint32))
+        
+        pitch = combined_surface.contents.pitch // 4  # pitch in pixels (32-bit)
+        
+        # Combine pixels manually for better blending
+        for y in range(self.cell_size):
+            for x in range(self.cell_size):
+                idx = y * pitch + x
+                
+                existing_pixel = existing_pixels[idx]
+                new_pixel = new_pixels[idx]
+                
+                # Extract RGBA components
+                existing_a = (existing_pixel >> 24) & 0xFF
+                existing_r = (existing_pixel >> 16) & 0xFF
+                existing_g = (existing_pixel >> 8) & 0xFF
+                existing_b = existing_pixel & 0xFF
+                
+                new_a = (new_pixel >> 24) & 0xFF
+                new_r = (new_pixel >> 16) & 0xFF
+                new_g = (new_pixel >> 8) & 0xFF
+                new_b = new_pixel & 0xFF
+                
+                # Blend the colors (additive blending for blood accumulation)
+                if new_a > 0:  # If new pixel has color
+                    if existing_a > 0:  # If existing pixel has color
+                        # Combine both colors, making it darker/more opaque
+                        final_r = min(255, existing_r + (new_r // 2))
+                        final_g = min(255, existing_g + (new_g // 2))
+                        final_b = min(255, existing_b + (new_b // 2))
+                        final_a = min(255, existing_a + (new_a // 2))
+                    else:
+                        # Use new pixel color
+                        final_r = new_r
+                        final_g = new_g
+                        final_b = new_b
+                        final_a = new_a
+                else:
+                    # Use existing pixel color
+                    final_r = existing_r
+                    final_g = existing_g
+                    final_b = existing_b
+                    final_a = existing_a
+                
+                # Pack the final pixel
+                combined_pixels[idx] = (final_a << 24) | (final_r << 16) | (final_g << 8) | final_b
+        
+        # Unlock surfaces
+        sdl2.SDL_UnlockSurface(existing_surface)
+        sdl2.SDL_UnlockSurface(new_surface)
+        sdl2.SDL_UnlockSurface(combined_surface)
+        
+        return combined_surface
+    
+    def free_surface(self, surface):
+        """Safely free an SDL surface"""
+        if surface is not None:
+            sdl2.SDL_FreeSurface(surface)