CVideo: add method for drawing a texture flipped/mirrored.

src/video.cpp

@@ -267,6 +267,19 @@ void CVideo::blit_texture(const texture& tex, const SDL_Rect* dst_rect, const SD
 	SDL_RenderCopy(*window.get(), tex, src_rect, dst_rect);
 }
 
+void CVideo::blit_texture_flipped(
+	const texture& tex,
+	bool flip_horizontal,
+	bool flip_vertical,
+	const SDL_Rect* dst_rect,
+	const SDL_Rect* src_rect)
+{
+	SDL_RendererFlip flip =
+		flip_horizontal ? SDL_FLIP_HORIZONTAL : SDL_FLIP_NONE
+		| flip_vertical ? SDL_FLIP_VERTICAL : SDL_FLIP_NONE;
+	SDL_RenderCopyEx(*window, tex, src_rect, dst_rect, 0.0, nullptr, flip);
+}
+
 void CVideo::make_fake()
 {
 	fake_screen_ = true;

src/video.hpp

@@ -356,6 +356,29 @@ public:
 	 */
 	void blit_texture(const texture& tex, const SDL_Rect* dstrect = nullptr, const SDL_Rect* srcrect = nullptr);
 
+	/**
+	 * Draws a texture, or part of a texture, at the given location,
+	 * also mirroring/flipping the texture horizontally and/or vertically.
+	 *
+	 * Calling this function with no explicit parameters will flip the
+	 * texture horizontally.
+	 *
+	 * @param tex               The texture to be copied / drawn.
+	 * @param flip_horizontal   Whether to flip/mirror the texture horizontally.
+	 * @param flip_vertical     Whether to flip/mirror the texture vertically.
+	 * @param dstrect           The target location to copy the texture to,
+	 *                          in low-resolution game-native drawing coordinates.
+	 *                          If null, this fills the entire render target.
+	 * @param srcrect           The portion of the texture to copy.
+	 *                          If null, this copies the entire texture.
+	 */
+	void blit_texture_flipped(
+		const texture& tex,
+		bool flip_horizontal = true,
+		bool flip_vertical = false,
+		const SDL_Rect* dst_rect = nullptr,
+		const SDL_Rect* src_rect = nullptr);
+
 	/**
 	 * Render a portion of the low-resolution drawing surface.
 	 *