From 9226c3c783717e4f6af92843f5fff8589d065243 Mon Sep 17 00:00:00 2001
From: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Date: Sat, 25 Jan 2014 08:58:58 +0100
Subject: [PATCH] video_lima: adjust aspect ratio depending on frame dimensions

With this the emulator framebuffer is no longer stretched to the entire
screen. However it's still not entirely correct. For example the aspect
ratio value provided by the frontend is not used yet.
Also I noticed this behaviour: When using the game "Secret of Mana 2"
(unofficial english translation) on the snes9x-next core, the game
normally uses a framebuffer of dimension 256x224. But when rendering
text windows, it increases resolution to 512x224. With the current
behaviour this alters aspect ratio and let's the image "explode"
when text boxes are displayed, only to "implode" again when they close.
This should not happen! (Needs further investigation...)
---
 gfx/lima_gfx.c | 32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/gfx/lima_gfx.c b/gfx/lima_gfx.c
index 41060f81be..f1540f46f7 100644
--- a/gfx/lima_gfx.c
+++ b/gfx/lima_gfx.c
@@ -75,6 +75,7 @@ typedef struct limare_data {
   int program_rgui_rgba32;
 
   float screen_aspect;
+  float frame_aspect;
 
   unsigned upload_format;
   unsigned upload_bpp; /* bytes per pixel */
@@ -156,13 +157,28 @@ float get_screen_aspect(limare_state_t *state) {
 
 void apply_aspect(limare_data_t *pdata, float ratio) {
   vec3f_t *vertices = pdata->vertices;
-  float value;
+  float x, y;
 
-  if (ratio == 0.0f) return;
-  value = 1.0f / ratio;
+  if (fabsf(pdata->screen_aspect - pdata->frame_aspect) < 0.0001f) {
+    x = 1.0f;
+    y = 1.0f;
+  } else {
+    if (pdata->screen_aspect > pdata->frame_aspect) {
+      x = pdata->frame_aspect / pdata->screen_aspect;
+      y = 1.0f;
+    } else {
+      x = 1.0f;
+      y = pdata->screen_aspect / pdata->frame_aspect;
+    }
+  }
 
-  vertices[0].x = vertices[2].x = -value;
-  vertices[1].x = vertices[3].x =  value;
+  /* TODO: use ratio parameter */
+
+  vertices[0].x = vertices[2].x = -x;
+  vertices[1].x = vertices[3].x =  x;
+
+  vertices[0].y = vertices[1].y = -y;
+  vertices[2].y = vertices[3].y =  y;
 }
 
 int destroy_textures(limare_data_t *pdata) {
@@ -560,8 +576,12 @@ static bool lima_gfx_frame(void *data, const void *frame,
       }
 
       lima->cur_texture = tex;
+
       vid->width = width;
       vid->height = height;
+
+      lima->frame_aspect = (float)width / (float)height;
+      vid->aspect_changed = true;
     }
 
     if (upload_frame) {
@@ -666,8 +686,6 @@ static void lima_gfx_viewport_info(void *data, struct rarch_viewport *vp){
 static void lima_set_aspect_ratio(void *data, unsigned aspect_ratio_idx) {
   lima_video_t *vid = data;
 
-  printf("debug: lima_set_aspect_ratio = %u\n", aspect_ratio_idx);
-
   switch (aspect_ratio_idx) {
     case ASPECT_RATIO_SQUARE:
       gfx_set_square_pixel_viewport(g_extern.system.av_info.geometry.base_width, g_extern.system.av_info.geometry.base_height);