introduce BGCNT constants

3 files changed, 62 insertions, 24 deletions

diff --git a/include/gba/io_reg.h b/include/gba/io_reg.h
index 5234e5b6c..c0874bcbb 100644
--- a/include/gba/io_reg.h
+++ b/include/gba/io_reg.h
@@ -495,12 +495,12 @@
 // I/O register fields
 
 // DISPCNT
-#define DISPCNT_MODE_0       0x0000
-#define DISPCNT_MODE_1       0x0001
-#define DISPCNT_MODE_2       0x0002
-#define DISPCNT_MODE_3       0x0003
-#define DISPCNT_MODE_4       0x0004
-#define DISPCNT_MODE_5       0x0005
+#define DISPCNT_MODE_0       0x0000 // BG0: text, BG1: text, BG2: text,   BG3: text
+#define DISPCNT_MODE_1       0x0001 // BG0: text, BG1: text, BG2: affine, BG3: off
+#define DISPCNT_MODE_2       0x0002 // BG0: off,  BG1: off,  BG2: affine, BG3: affine
+#define DISPCNT_MODE_3       0x0003 // Bitmap mode, 240x160, BGR555 color
+#define DISPCNT_MODE_4       0x0004 // Bitmap mode, 240x160, 256 color palette
+#define DISPCNT_MODE_5       0x0005 // Bitmap mode, 160x128, BGR555 color
 #define DISPCNT_OBJ_1D_MAP   0x0040
 #define DISPCNT_FORCED_BLANK 0x0080
 #define DISPCNT_BG0_ON       0x0100
@@ -521,6 +521,26 @@
 #define DISPSTAT_HBLANK_INTR 0x0010 // H-Blank interrupt enabled
 #define DISPSTAT_VCOUNT_INTR 0x0020 // V-Count interrupt enabled
 
+// BGCNT
+#define BGCNT_PRIORITY(n)          (n) // Values 0 - 3. Lower priority BGs will be drawn on top of higher priority BGs.
+#define BGCNT_CHARBASE(n)   ((n) << 2) // Values 0 - 3. Base block for tile pixel data.
+#define BGCNT_MOSAIC            0x0040
+#define BGCNT_16COLOR           0x0000 // 4 bits per pixel
+#define BGCNT_256COLOR          0x0080 // 8 bits per pixel
+#define BGCNT_SCREENBASE(n) ((n) << 8) // Values 0 - 31. Base block for tile map.
+#define BGCNT_WRAP              0x2000 // Only affects affine BGs. Text BGs wrap by default.
+#define BGCNT_TXT256x256        0x0000 // Internal screen size size of text mode BG in pixels.
+#define BGCNT_TXT512x256        0x4000
+#define BGCNT_TXT256x512        0x8000
+#define BGCNT_TXT512x512        0xC000
+#define BGCNT_AFF128x128        0x0000 // Internal screen size size of affine mode BG in pixels.
+#define BGCNT_AFF256x256        0x4000
+#define BGCNT_AFF512x512        0x8000
+#define BGCNT_AFF1024x1024      0xC000
+
+// BLDCNT
+
+
 // SOUNDCNT_H
 #define SOUND_CGB_MIX_QUARTER 0x0000
 #define SOUND_CGB_MIX_HALF    0x0001
diff --git a/src/intro.c b/src/intro.c
index ce13fee6a..72478b773 100644
--- a/src/intro.c
+++ b/src/intro.c
@@ -879,7 +879,11 @@ static u8 SetUpCopyrightScreen(void)
         ResetSpriteData();
         FreeAllSpritePalettes();
         BeginNormalPaletteFade(0xFFFFFFFF, 0, 0x10, 0, 0xFFFF);
-        REG_BG0CNT = 1792;
+        REG_BG0CNT = BGCNT_PRIORITY(0)
+                   | BGCNT_CHARBASE(0)
+                   | BGCNT_SCREENBASE(7)
+                   | BGCNT_16COLOR
+                   | BGCNT_TXT256x256;
         ime = REG_IME;
         REG_IME = 0;
         REG_IE |= INTR_FLAG_VBLANK;
@@ -959,10 +963,10 @@ static void Task_IntroLoadPart1Graphics(u8 taskId)
     LZ77UnCompVram(gIntro1BG3_Tilemap, (void *)(VRAM + 0xB000));
     DmaClear16(3, VRAM + 0xB800, 0x800);
     LoadPalette(gIntro1BGPals, 0, sizeof(gIntro1BGPals));
-    REG_BG3CNT = 0x9603;
-    REG_BG2CNT = 0x9402;
-    REG_BG1CNT = 0x9201;
-    REG_BG0CNT = 0x9000;
+    REG_BG3CNT = BGCNT_PRIORITY(3) | BGCNT_CHARBASE(0) | BGCNT_SCREENBASE(22) | BGCNT_16COLOR | BGCNT_TXT256x512;
+    REG_BG2CNT = BGCNT_PRIORITY(2) | BGCNT_CHARBASE(0) | BGCNT_SCREENBASE(20) | BGCNT_16COLOR | BGCNT_TXT256x512;
+    REG_BG1CNT = BGCNT_PRIORITY(1) | BGCNT_CHARBASE(0) | BGCNT_SCREENBASE(18) | BGCNT_16COLOR | BGCNT_TXT256x512;
+    REG_BG0CNT = BGCNT_PRIORITY(0) | BGCNT_CHARBASE(0) | BGCNT_SCREENBASE(16) | BGCNT_16COLOR | BGCNT_TXT256x512;
     LoadCompressedObjectPic(&gUnknown_0840B008[0]);
     LoadCompressedObjectPic(&gUnknown_0840B018[0]);
     LoadSpritePalettes(gUnknown_0840B028);
@@ -1179,7 +1183,7 @@ static void Task_IntroLoadPart3Graphics(u8 taskId)
     ResetSpriteData();
     FreeAllSpritePalettes();
     BeginNormalPaletteFade(0xFFFFFFFF, 0, 0x10, 0, 0xFFFF);
-    REG_BG2CNT = 0x4883;
+    REG_BG2CNT = BGCNT_PRIORITY(3) | BGCNT_CHARBASE(0) | BGCNT_SCREENBASE(8) | BGCNT_256COLOR | BGCNT_AFF256x256;
     REG_DISPCNT = DISPCNT_MODE_1 | DISPCNT_OBJ_1D_MAP | DISPCNT_BG2_ON | DISPCNT_OBJ_ON;
     gTasks[taskId].func = Task_IntroSpinAndZoomPokeball;
     gIntroFrameCounter = 0;
@@ -1257,8 +1261,16 @@ static void task_intro_14(u8 taskId)
     REG_WIN0V = 0xA0;
     REG_WININ = 0x1C;
     REG_WINOUT = 0x1D;
-    REG_BG3CNT = 0x603;
-    REG_BG0CNT = 0x700;
+    REG_BG3CNT = BGCNT_PRIORITY(3)
+               | BGCNT_CHARBASE(0)
+               | BGCNT_SCREENBASE(6)
+               | BGCNT_16COLOR
+               | BGCNT_TXT256x256;
+    REG_BG0CNT = BGCNT_PRIORITY(0)
+               | BGCNT_CHARBASE(0)
+               | BGCNT_SCREENBASE(7)
+               | BGCNT_16COLOR
+               | BGCNT_TXT256x256;
     REG_DISPCNT = DISPCNT_MODE_0 | DISPCNT_OBJ_1D_MAP | DISPCNT_BG0_ON | DISPCNT_BG3_ON | DISPCNT_OBJ_ON | DISPCNT_WIN0_ON;
     gTasks[taskId].data[15] = CreateTask(task_intro_20, 0);
     gTasks[gTasks[taskId].data[15]].data[0] = 0;
@@ -1412,18 +1424,21 @@ static void task_intro_19(u8 taskId)
 
 static void task_intro_20(u8 taskId)
 {
+#define BG2_FLAGS (BGCNT_PRIORITY(3) | BGCNT_CHARBASE(1) | BGCNT_SCREENBASE(14) | BGCNT_16COLOR | BGCNT_TXT256x256)
+#define DISPCNT_FLAGS (DISPCNT_MODE_0 | DISPCNT_OBJ_1D_MAP | DISPCNT_BG0_ON | DISPCNT_BG2_ON | DISPCNT_BG3_ON | DISPCNT_OBJ_ON | DISPCNT_WIN0_ON)
+
     gTasks[taskId].data[15]++;
     switch (gTasks[taskId].data[0])
     {
     case 0:
-        REG_DISPCNT = 0x3940;
+        REG_DISPCNT = DISPCNT_MODE_0 | DISPCNT_OBJ_1D_MAP | DISPCNT_BG0_ON | DISPCNT_BG3_ON | DISPCNT_OBJ_ON | DISPCNT_WIN0_ON;
         REG_BG2CNT = 0;
         gTasks[taskId].data[0] = 0xFF;
         break;
     case 2:
         BeginNormalPaletteFade(1, 0, 0x10, 0, 0xFFFF);
-        REG_BG2CNT = 0x0E07;
-        REG_DISPCNT = 0x3D40;
+        REG_BG2CNT = BG2_FLAGS;
+        REG_DISPCNT = DISPCNT_FLAGS;
         gTasks[taskId].data[1] = 0;
         gTasks[taskId].data[2] = 0;
         gTasks[taskId].data[0] = 20;
@@ -1436,8 +1451,8 @@ static void task_intro_20(u8 taskId)
         break;
     case 3:
         BeginNormalPaletteFade(1, 0, 0x10, 0, 0xFFFF);
-        REG_BG2CNT = 0x0E07;
-        REG_DISPCNT = 0x3D40;
+        REG_BG2CNT = BG2_FLAGS;
+        REG_DISPCNT = DISPCNT_FLAGS;
         gTasks[taskId].data[1] = 0;
         gTasks[taskId].data[2] = 0;
         gTasks[taskId].data[0] = 0x1E;
@@ -1450,8 +1465,8 @@ static void task_intro_20(u8 taskId)
         break;
     case 4:
         BeginNormalPaletteFade(1, 5, 0, 0x10, 0x37F7);
-        REG_BG2CNT = 0x0E07;
-        REG_DISPCNT = 0x3D40;
+        REG_BG2CNT = BG2_FLAGS;
+        REG_DISPCNT = DISPCNT_FLAGS;
         gTasks[taskId].data[1] = 0;
         gTasks[taskId].data[2] = 0;
         gTasks[taskId].data[3] = 8;
@@ -1468,6 +1483,9 @@ static void task_intro_20(u8 taskId)
     case 0xFF:  //needed to prevent jump table optimization
         break;
     }
+
+#undef BG2_FLAGS
+#undef DISPCNT_FLAGS
 }
 
 static void intro_reset_and_hide_bgs(void)
diff --git a/src/title_screen.c b/src/title_screen.c
index 86ca1c365..1565abf62 100644
--- a/src/title_screen.c
+++ b/src/title_screen.c
@@ -540,9 +540,9 @@ void CB2_InitTitleScreen(void)
         REG_BLDCNT = 0x84;
         REG_BLDALPHA = 0;
         REG_BLDY = 0x8;
-        REG_BG0CNT = 0x180B;
-        REG_BG1CNT = 0x190A;
-        REG_BG2CNT = 0x4981;
+        REG_BG0CNT = BGCNT_PRIORITY(3) | BGCNT_CHARBASE(2) | BGCNT_SCREENBASE(24) | BGCNT_16COLOR | BGCNT_TXT256x256;
+        REG_BG1CNT = BGCNT_PRIORITY(2) | BGCNT_CHARBASE(2) | BGCNT_SCREENBASE(25) | BGCNT_16COLOR | BGCNT_TXT256x256;
+        REG_BG2CNT = BGCNT_PRIORITY(1) | BGCNT_CHARBASE(0) | BGCNT_SCREENBASE(9) | BGCNT_256COLOR | BGCNT_AFF256x256;
         savedIme = REG_IME;
         REG_IME = 0;
         REG_IE |= INTR_FLAG_VBLANK;