From aec44b093e3aaeb73c1d11df8f1a982c78fdb73f Mon Sep 17 00:00:00 2001
From: Themaister <maister@archlinux.us>
Date: Thu, 26 May 2011 16:23:11 +0200
Subject: [PATCH] Add new transition_previous.

---
 gfx/shader_glsl.c |  2 ++
 gfx/snes_state.c  | 34 ++++++++++++++++++++++------------
 gfx/snes_state.h  |  3 ++-
 3 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/gfx/shader_glsl.c b/gfx/shader_glsl.c
index bdfb6c4f35..22591ef69c 100644
--- a/gfx/shader_glsl.c
+++ b/gfx/shader_glsl.c
@@ -448,6 +448,8 @@ static bool get_import_value(xmlNodePtr ptr)
       tracker_type = SSNES_STATE_CAPTURE_PREV;
    else if (strcmp((const char*)semantic, "transition") == 0)
       tracker_type = SSNES_STATE_TRANSITION;
+   else if (strcmp((const char*)semantic, "transition_previous") == 0)
+      tracker_type = SSNES_STATE_TRANSITION_PREV;
    else
    {
       SSNES_ERR("Invalid semantic for import value.\n");
diff --git a/gfx/snes_state.c b/gfx/snes_state.c
index 591d58e418..ceedd2af26 100644
--- a/gfx/snes_state.c
+++ b/gfx/snes_state.c
@@ -104,18 +104,6 @@ static void update_element(
          uniform->value = info->ptr[info->addr];
          break;
 
-      case SSNES_STATE_TRANSITION:
-         if (info->old_value != info->ptr[info->addr])
-         {
-            info->old_value = info->ptr[info->addr];
-            info->frame_count = frame_count;
-            uniform->value = info->frame_count;
-         }
-         else
-            uniform->value = info->frame_count;
-
-         break;
-
       case SSNES_STATE_CAPTURE_PREV:
          if (info->prev[0] != info->ptr[info->addr])
          {
@@ -125,6 +113,28 @@ static void update_element(
          uniform->value = info->prev[1];
          break;
 
+      case SSNES_STATE_TRANSITION:
+         if (info->old_value != info->ptr[info->addr])
+         {
+            info->old_value = info->ptr[info->addr];
+            info->frame_count = frame_count;
+         }
+         uniform->value = info->frame_count;
+
+         break;
+
+      case SSNES_STATE_TRANSITION_PREV:
+         if (info->prev[0] != info->ptr[info->addr])
+         {
+            info->old_value = info->ptr[info->addr];
+            info->prev[1] = info->prev[0];
+            info->prev[0] = frame_count;
+            info->frame_count = frame_count;
+         }
+         uniform->value = info->prev[1];
+
+         break;
+      
       default:
          break;
    }
diff --git a/gfx/snes_state.h b/gfx/snes_state.h
index a8f370ffc2..93179af188 100644
--- a/gfx/snes_state.h
+++ b/gfx/snes_state.h
@@ -24,7 +24,8 @@ enum snes_tracker_type
 {
    SSNES_STATE_CAPTURE,
    SSNES_STATE_TRANSITION,
-   SSNES_STATE_CAPTURE_PREV
+   SSNES_STATE_CAPTURE_PREV,
+   SSNES_STATE_TRANSITION_PREV
 };
 
 enum snes_ram_type