Abstract away aspect ratio handling.

gfx/context/drm_egl_ctx.c

@@ -630,6 +630,7 @@ const gfx_ctx_driver_t gfx_ctx_drm_egl = {
    gfx_ctx_swap_interval,
    gfx_ctx_set_video_mode,
    gfx_ctx_get_video_size,
+   NULL,
    gfx_ctx_update_window_title,
    gfx_ctx_check_window,
    gfx_ctx_set_resize,

gfx/context/ps3_ctx.c

@@ -422,6 +422,7 @@ const gfx_ctx_driver_t gfx_ctx_ps3 = {
    gfx_ctx_set_swap_interval,
    gfx_ctx_set_video_mode,
    gfx_ctx_get_video_size,
+   NULL,
    gfx_ctx_update_window_title,
    gfx_ctx_check_window,
    gfx_ctx_set_resize,

gfx/context/sdl_ctx.c

@@ -304,6 +304,7 @@ const gfx_ctx_driver_t gfx_ctx_sdl_gl = {
    gfx_ctx_swap_interval,
    gfx_ctx_set_video_mode,
    gfx_ctx_get_video_size,
+   NULL,
    gfx_ctx_update_window_title,
    gfx_ctx_check_window,
    gfx_ctx_set_resize,

gfx/context/vc_egl_ctx.c

@@ -270,6 +270,15 @@ static bool gfx_ctx_bind_api(enum gfx_ctx_api api)
    }
 }
 
+static float gfx_ctx_translate_aspect(unsigned width, unsigned height)
+{
+   // check for SD televisions: they should always be 4:3.
+   if ((width == 640 || width == 720) && (height == 480 || height == 576))
+      return 4.0f / 3.0f;
+   else
+      return (float)width / height;
+}
+
 const gfx_ctx_driver_t gfx_ctx_videocore = {
    gfx_ctx_init,
    gfx_ctx_destroy,
@@ -277,6 +286,7 @@ const gfx_ctx_driver_t gfx_ctx_videocore = {
    gfx_ctx_swap_interval,
    gfx_ctx_set_video_mode,
    gfx_ctx_get_video_size,
+   gfx_ctx_translate_aspect,
    gfx_ctx_update_window_title,
    gfx_ctx_check_window,
    gfx_ctx_set_resize,

gfx/context/xegl_ctx.c

@@ -469,6 +469,7 @@ const gfx_ctx_driver_t gfx_ctx_x_egl = {
    gfx_ctx_swap_interval,
    gfx_ctx_set_video_mode,
    gfx_ctx_get_video_size,
+   NULL,
    gfx_ctx_update_window_title,
    gfx_ctx_check_window,
    gfx_ctx_set_resize,

gfx/gfx_context.h

@@ -55,6 +55,12 @@ typedef struct gfx_ctx_driver
    // If not initialized yet, it returns current screen size.
    void (*get_video_size)(unsigned*, unsigned*);
 
+   // Translates a window size to an aspect ratio.
+   // In most cases this will be just width / height, but
+   // some contexts will better know which actual aspect ratio is used.
+   // This can be NULL to assume the default behavior.
+   float (*translate_aspect)(unsigned, unsigned);
+
    // Asks driver to update window title (FPS, etc).
    void (*update_window_title)(bool);
 

gfx/gl.c

@@ -609,11 +609,12 @@ void gl_set_viewport(gl_t *gl, unsigned width, unsigned height, bool force_full,
    if (gl->keep_aspect && !force_full)
    {
       float desired_aspect = g_settings.video.aspect_ratio;
-      float device_aspect = (float)width / height;
 
-      // check for SD televisions: they should always be 4:3
+      float device_aspect;
-      if ((width == 640 || width == 720) && (height == 480 || height == 576))
+      if (gl->driver->translate_aspect)
-         device_aspect = 4.0f / 3.0f;
+         device_aspect = gl->driver->translate_aspect(width, height);
+      else
+         device_aspect = (float)width / height;
 
       float delta;