Added gfx_dimensions.h

include/gfx_dimensions.h

@@ -0,0 +1,24 @@
+#pragma once
+/*
+
+This file is for ports that want to enable widescreen.
+The idea is that SCREEN_WIDTH and SCREEN_HEIGHT are still hardcoded to 320 and 240, and that
+x=0 lies at where a 4:3 left edge would be. On 16:9 widescreen, the left edge is hence at -53.33.
+
+To get better accuracy, consider using floats instead of shorts for coordinates in Vertex and Matrix structures.
+
+The conversion to integers above is for RECT commands which naturally only accept integer values.
+Note that RECT commands must be enhanced to support negative coordinates with this modification.
+
+*/
+#include "port/Engine.h"
+#include <math.h>
+
+#define GFX_DIMENSIONS_ASPECT_RATIO GameEngine_GetAspectRatio()
+#define GFX_DIMENSIONS_FROM_LEFT_EDGE(v) (SCREEN_WIDTH / 2 - SCREEN_HEIGHT / 2 * GFX_DIMENSIONS_ASPECT_RATIO + (v))
+#define GFX_DIMENSIONS_FROM_RIGHT_EDGE(v) (SCREEN_WIDTH / 2 + SCREEN_HEIGHT / 2 * GFX_DIMENSIONS_ASPECT_RATIO - (v))
+#define GFX_DIMENSIONS_RECT_FROM_LEFT_EDGE(v) ((int)floorf(GFX_DIMENSIONS_FROM_LEFT_EDGE(v)))
+#define GFX_DIMENSIONS_RECT_FROM_RIGHT_EDGE(v) ((int)ceilf(GFX_DIMENSIONS_FROM_RIGHT_EDGE(v)))
+// If screen is taller than it is wide, radius should be equal to SCREEN_HEIGHT since we scale horizontally
+#define GFX_DIMENSIONS_FULL_RADIUS (SCREEN_HEIGHT * (GFX_DIMENSIONS_ASPECT_RATIO > 1 ? GFX_DIMENSIONS_ASPECT_RATIO : 1))
+#define GFX_FULL_WIDTH GFX_DIMENSIONS_FROM_RIGHT_EDGE(0)

include/global.h

@@ -20,6 +20,7 @@
 #include "i5.h"
 #include "i6.h"
 #include "assets/ast_common.h"
+#include "gfx_dimensions.h"
 #include <libultraship.h>
 
 #endif // GLOBAL_H