Various blend state fixes (#2208)

* NinePatchTexture should support blending

* blend_func -> prev_blend_func

* SpriteList should restore old blend func

* Surface.draw_sprite should use draw_sprite

Author: einarf

arcade/gui/nine_patch.py

@@ -197,7 +197,8 @@ def draw_rect(
         self,
         *,
         rect: arcade.types.Rect,
-        pixelated: bool = False,
+        pixelated: bool = True,
+        blend: bool = True,
         **kwargs,
     ):
         """
@@ -212,6 +213,11 @@ def draw_rect(
         :param rect: Rectangle to draw the 9-patch texture in
         :param pixelated: Whether to draw with nearest neighbor interpolation
         """
+        if blend:
+            self._ctx.enable_only(self._ctx.BLEND)
+        else:
+            self._ctx.disable(self._ctx.BLEND)
+
         self.program.set_uniform_safe("texture_id", self._atlas.get_texture_id(self._texture))
         if pixelated:
             self._atlas.texture.filter = self._ctx.NEAREST, self._ctx.NEAREST
@@ -228,6 +234,9 @@ def draw_rect(
         self._atlas.texture.use(1)
         self._geometry.render(self._program, vertices=1)
 
+        if blend:
+            self._ctx.disable(self._ctx.BLEND)
+
     def _check_sizes(self):
         """Raise a ValueError if any dimension is invalid."""
         # Sanity check values

arcade/gui/surface.py

@@ -121,12 +121,12 @@ def draw_texture(
         else:
             arcade.draw_texture_rect(tex, LBWH(x, y, width, height), angle=angle, alpha=alpha)
 
-    def draw_sprite(self, x, y, width, height, sprite):
+    def draw_sprite(self, x: float, y: float, width: float, height: float, sprite: arcade.Sprite):
         """Draw a sprite to the surface"""
         sprite.position = x + width // 2, y + height // 2
         sprite.width = width
         sprite.height = height
-        sprite.draw()
+        arcade.draw_sprite(sprite)
 
     @contextmanager
     def activate(self):
@@ -137,15 +137,15 @@ def activate(self):
         # Set viewport and projection
         self.limit(LBWH(0, 0, *self.size))
         # Set blend function
-        blend_func = self.ctx.blend_func
+        prev_blend_func = self.ctx.blend_func
 
         try:
             self.ctx.blend_func = self.blend_func_render_into
             with self.fbo.activate():
                 yield self
         finally:
             # Restore blend function.
-            self.ctx.blend_func = blend_func
+            self.ctx.blend_func = prev_blend_func
 
     def limit(self, rect: Rect):  # TODO track limit usage
         """Reduces the draw area to the given rect"""

arcade/gui/widgets/__init__.py

@@ -671,7 +671,8 @@ def on_update(self, dt):
     def do_render(self, surface: Surface):
         self.prepare_render(surface)
         surface.clear(color=TRANSPARENT_BLACK)
-        surface.draw_sprite(0, 0, self.width, self.height, self._sprite)
+        if self._sprite is not None:
+            surface.draw_sprite(0, 0, self.width, self.height, self._sprite)
 
 
 class UILayout(UIWidget):

arcade/sprite_list/sprite_list.py

@@ -1041,6 +1041,7 @@ def draw(
             raise ValueError("Attempting to render without shader program.")
         self._write_sprite_buffers_to_gpu()
 
+        prev_blend_func = self.ctx.blend_func
         if self._blend:
             self.ctx.enable(self.ctx.BLEND)
             # Set custom blend function or revert to default
@@ -1088,7 +1089,8 @@ def draw(
         # Leave global states to default
         if self._blend:
             self.ctx.disable(self.ctx.BLEND)
-            self.ctx.blend_func = self.ctx.BLEND_DEFAULT
+            if blend_function is not None:
+                self.ctx.blend_func = prev_blend_func
 
     def draw_hit_boxes(self, color: RGBA255 = (0, 0, 0, 255), line_thickness: float = 1.0) -> None:
         """Draw all the hit boxes in this list"""