From 312e50b50b467b905c5753b39571c0aa63709721 Mon Sep 17 00:00:00 2001
From: Calvin Spealman <ironfroggy@gmail.com>
Date: Mon, 25 May 2020 23:16:15 -0400
Subject: [PATCH] Implement sprite flipping.

---
 ppb/flags.py            | 25 +++++++++++++++++++++++++
 ppb/systems/renderer.py | 13 +++++++++++--
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/ppb/flags.py b/ppb/flags.py
index af48506a..312030d6 100644
--- a/ppb/flags.py
+++ b/ppb/flags.py
@@ -81,3 +81,28 @@ class BlendModeNone(BlendMode):
     """
     Indicate a sprite, if translucent, should be rendered in NONE mode.
     """
+
+class Flip(Flag, abstract=True):
+    """
+    Indicate sprite flipping at render time.
+    """
+
+class FlipNone(Flip):
+    """
+    Do not flip the sprite.
+    """
+
+class FlipVertical(Flip):
+    """
+    Flip the sprite vertically.
+    """
+
+class FlipHorizontal(Flip):
+    """
+    Flip the sprite horizontally.
+    """
+
+class FlipBoth(Flip):
+    """
+    Flip the sprite both horizontally and vertically.
+    """
diff --git a/ppb/systems/renderer.py b/ppb/systems/renderer.py
index 79e88b70..9821e925 100644
--- a/ppb/systems/renderer.py
+++ b/ppb/systems/renderer.py
@@ -11,7 +11,8 @@
     rw_from_object,  # https://pysdl2.readthedocs.io/en/latest/modules/sdl2.html#sdl2.sdl2.rw_from_object
     SDL_Window, SDL_Renderer,
     SDL_Rect,  # https://wiki.libsdl.org/SDL_Rect
-    SDL_INIT_VIDEO, SDL_BLENDMODE_BLEND, SDL_FLIP_NONE,
+    SDL_INIT_VIDEO, SDL_BLENDMODE_BLEND,
+    SDL_FLIP_NONE, SDL_FLIP_HORIZONTAL, SDL_FLIP_VERTICAL,
     SDL_CreateWindowAndRenderer,  # https://wiki.libsdl.org/SDL_CreateWindowAndRenderer
     SDL_DestroyRenderer,  # https://wiki.libsdl.org/SDL_DestroyRenderer
     SDL_DestroyWindow,  # https://wiki.libsdl.org/SDL_DestroyWindow
@@ -67,6 +68,13 @@
     flags.BlendModeNone: SDL_BLENDMODE_NONE,
 }
 
+FLIP = {
+    flags.FlipNone: SDL_FLIP_NONE,
+    flags.FlipVertical: SDL_FLIP_VERTICAL,
+    flags.FlipHorizontal: SDL_FLIP_HORIZONTAL,
+    flags.FlipBoth: SDL_FLIP_HORIZONTAL | SDL_FLIP_VERTICAL,
+}
+
 
 # TODO: Move Image out of the renderer so sprites can type hint appropriately.
 class Image(assets.Asset):
@@ -201,10 +209,11 @@ def on_render(self, render_event, signal):
             src_rect, dest_rect, angle = self.compute_rectangles(
                 texture.inner, game_object, camera
             )
+            flip = FLIP[getattr(game_object, 'flip', flags.FlipNone)]
             sdl_call(
                 SDL_RenderCopyEx, self.renderer, texture.inner,
                 ctypes.byref(src_rect), ctypes.byref(dest_rect),
-                angle, None, SDL_FLIP_NONE,
+                angle, None, flip,
                 _check_error=lambda rv: rv < 0
             )
         sdl_call(SDL_RenderPresent, self.renderer)