Doc shrink_window, rename system to Letterbox (#1341)

* docs

* missed some hex

* document Gfx_SetupFrame

* review

1 files changed, 51 insertions, 40 deletions

diff --git a/src/code/shrink_window.c b/src/code/shrink_window.c
index cc68129e2..8232ee838 100644
--- a/src/code/shrink_window.c
+++ b/src/code/shrink_window.c
@@ -1,79 +1,89 @@
 #include "global.h"
 
-s32 D_8012CED0 = 0;
+typedef enum {
+    /* 0 */ LETTERBOX_STATE_IDLE,
+    /* 1 */ LETTERBOX_STATE_GROWING,
+    /* 2 */ LETTERBOX_STATE_SHRINKING
+} LetterboxState;
 
-s32 sShrinkWindowVal = 0;
-s32 sShrinkWindowCurrentVal = 0;
+s32 sLetterboxState = LETTERBOX_STATE_IDLE;
 
-void ShrinkWindow_SetVal(s32 value) {
+s32 sLetterboxSizeTarget = 0;
+s32 sLetterboxSize = 0;
+
+void Letterbox_SetSizeTarget(s32 target) {
     if (HREG(80) == 0x13 && HREG(81) == 1) {
-        osSyncPrintf("shrink_window_setval(%d)\n", value);
+        osSyncPrintf("shrink_window_setval(%d)\n", target);
     }
-    sShrinkWindowVal = value;
+
+    sLetterboxSizeTarget = target;
 }
 
-u32 ShrinkWindow_GetVal(void) {
-    return sShrinkWindowVal;
+u32 Letterbox_GetSizeTarget(void) {
+    return sLetterboxSizeTarget;
 }
 
-void ShrinkWindow_SetCurrentVal(s32 currentVal) {
+void Letterbox_SetSize(s32 size) {
     if (HREG(80) == 0x13 && HREG(81) == 1) {
-        osSyncPrintf("shrink_window_setnowval(%d)\n", currentVal);
+        osSyncPrintf("shrink_window_setnowval(%d)\n", size);
     }
-    sShrinkWindowCurrentVal = currentVal;
+
+    sLetterboxSize = size;
 }
 
-u32 ShrinkWindow_GetCurrentVal(void) {
-    return sShrinkWindowCurrentVal;
+u32 Letterbox_GetSize(void) {
+    return sLetterboxSize;
 }
 
-void ShrinkWindow_Init(void) {
+void Letterbox_Init(void) {
     if (HREG(80) == 0x13 && HREG(81) == 1) {
         osSyncPrintf("shrink_window_init()\n");
     }
-    D_8012CED0 = 0;
-    sShrinkWindowVal = 0;
-    sShrinkWindowCurrentVal = 0;
+
+    sLetterboxState = LETTERBOX_STATE_IDLE;
+    sLetterboxSizeTarget = 0;
+    sLetterboxSize = 0;
 }
 
-void ShrinkWindow_Destroy(void) {
+void Letterbox_Destroy(void) {
     if (HREG(80) == 0x13 && HREG(81) == 1) {
         osSyncPrintf("shrink_window_cleanup()\n");
     }
-    sShrinkWindowCurrentVal = 0;
+
+    sLetterboxSize = 0;
 }
 
-void ShrinkWindow_Update(s32 updateRate) {
-    s32 off;
+void Letterbox_Update(s32 updateRate) {
+    s32 step;
 
     if (updateRate == 3) {
-        off = 10;
+        step = 10;
     } else {
-        off = 30 / updateRate;
+        step = 30 / updateRate;
     }
 
-    if (sShrinkWindowCurrentVal < sShrinkWindowVal) {
-        if (D_8012CED0 != 1) {
-            D_8012CED0 = 1;
+    if (sLetterboxSize < sLetterboxSizeTarget) {
+        if (sLetterboxState != LETTERBOX_STATE_GROWING) {
+            sLetterboxState = LETTERBOX_STATE_GROWING;
         }
 
-        if (sShrinkWindowCurrentVal + off < sShrinkWindowVal) {
-            sShrinkWindowCurrentVal += off;
+        if (sLetterboxSize + step < sLetterboxSizeTarget) {
+            sLetterboxSize += step;
         } else {
-            sShrinkWindowCurrentVal = sShrinkWindowVal;
+            sLetterboxSize = sLetterboxSizeTarget;
         }
-    } else if (sShrinkWindowVal < sShrinkWindowCurrentVal) {
-        if (D_8012CED0 != 2) {
-            D_8012CED0 = 2;
+    } else if (sLetterboxSizeTarget < sLetterboxSize) {
+        if (sLetterboxState != LETTERBOX_STATE_SHRINKING) {
+            sLetterboxState = LETTERBOX_STATE_SHRINKING;
         }
 
-        if (sShrinkWindowVal < sShrinkWindowCurrentVal - off) {
-            sShrinkWindowCurrentVal -= off;
+        if (sLetterboxSizeTarget < sLetterboxSize - step) {
+            sLetterboxSize -= step;
         } else {
-            sShrinkWindowCurrentVal = sShrinkWindowVal;
+            sLetterboxSize = sLetterboxSizeTarget;
         }
     } else {
-        D_8012CED0 = 0;
+        sLetterboxState = LETTERBOX_STATE_IDLE;
     }
 
     if (HREG(80) == 0x13) {
@@ -89,9 +99,10 @@ void ShrinkWindow_Update(s32 updateRate) {
             HREG(88) = 0;
             HREG(89) = 0;
         }
-        HREG(83) = D_8012CED0;
-        HREG(84) = sShrinkWindowCurrentVal;
-        HREG(85) = sShrinkWindowVal;
-        HREG(86) = off;
+
+        HREG(83) = sLetterboxState;
+        HREG(84) = sLetterboxSize;
+        HREG(85) = sLetterboxSizeTarget;
+        HREG(86) = step;
     }
 }