Initial implementation of mode4 rendering and parameter editing on CH3

5 files changed, 253 insertions, 198 deletions

diff --git a/src/bitmap.h b/src/bitmap.h
index bae9b40..c839900 100644
--- a/src/bitmap.h
+++ b/src/bitmap.h
@@ -1,30 +1,8 @@
 #ifndef GBAEXP_BITMAP_H
 #define GBAEXP_BITMAP_H
 
-// #include "bd-font.c"
 #include "common.h"
 
-// Using bd-font, an 8x8 bitmap font.
-// static void
-// put_char(int x, int y, Color clr, u8 chr) {
-//     for (size_t i = 0; i < 8; ++i) {
-//         for (size_t j = 0; j < 8; ++j) {
-//             if ((font[chr][i] >> (7 - j)) & 0x1) {
-//                 FRAMEBUFFER[y + i][x + j] = clr;
-//             }
-//         }
-//     }
-// }
-
-// static void
-// put_text(int x, int y, Color clr, char *msg) {
-//     int count = 0;
-//     while (*msg) {
-//         put_char(x + count, y, clr, *msg++);
-//         count += 8;
-//     }
-// }
-
 // Draws a line with the given color between (x0,y0) and (x1,y1) using the
 // Bresenham's line drawing algorithm using exclusively integer arithmetic.
 static void
@@ -146,17 +124,31 @@ draw_fill_rect(int x0, int y0, int x1, int y1, Color clr) {
 // GBA needs to meet memory alignment requirements, we can't write a u8 into
 // memory, instead we need to read a u16 word, mask and or the corresponding
 // bits and wave the updated u16.
-static void
-put_pixel_m4(int x, int y, u8 col_index, vu16 *buffer) {
+static inline void
+put_pixel_m4(int x, int y, u8 clr_idx, vu16 *buffer) {
     int buffer_index = (y * SCREEN_WIDTH + x) / 2;
     vu16 *destination = &buffer[buffer_index];
     // Odd pixels will go to the top 8 bits of the destination. Even pixels to
     // the lower 8 bits.
     int odd = x & 0x1;
     if(odd) {
-        *destination= (*destination & 0xFF) | (col_index << 8);
+        *destination= (*destination & 0xFF) | (clr_idx << 8);
     } else {
-        *destination= (*destination & ~0xFF) |  col_index;
+        *destination= (*destination & ~0xFF) |  clr_idx;
+    }
+}
+
+static inline void
+put_pixel_m3(int x, int y, u16 color, Scanline *buffer) {
+    buffer[y][x] = color;
+}
+
+static inline void
+clear_screen_m4() {
+    size_t size = SCREEN_WIDTH * SCREEN_HEIGHT / 8;
+    u32 *buf = backbuffer;
+    for (size_t i = 0; i < size; ++i) {
+        buf[i] = 0;
     }
 }
 
@@ -205,24 +197,4 @@ draw_logo(void) {
     draw_line(x + height, y + 1, x + height + line, y + 1, COLOR_WHITE);
 }
 
-// void
-// copy_font_to_tile_memory(Tile *tile) {
-//     // Hex to bits translation table.
-//     const u32 conversion_u32[16] = {
-//         0x00000000, 0x00001000, 0x00000100, 0x00001100,
-//         0x00000010, 0x00001010, 0x00000110, 0x00001110,
-//         0x00000001, 0x00001001, 0x00000101, 0x00001101,
-//         0x00000011, 0x00001011, 0x00000111, 0x00001111,
-//     };
-//     for (size_t i = 0; i < 250; ++i) {
-//         for (size_t j = 0; j < 8; ++j) {
-//             u8 row = font[i][j];
-//             u32 tile_idx = 0x00000000;
-//             tile_idx = conversion_u32[row & 0xF] << 16;
-//             tile_idx |= conversion_u32[(row >> 4) & 0xF];
-//             (tile + i)->data[j] = tile_idx;
-//         }
-//     }
-// }
-
 #endif // GBAEXP_BITMAP_H
diff --git a/src/common.h b/src/common.h
index aa7261e..cf263db 100644
--- a/src/common.h
+++ b/src/common.h
@@ -147,6 +147,7 @@ typedef Color Scanline[SCREEN_WIDTH];
 #define PAL_BUFFER_SPRITES ((u16*)(MEM_PAL + 0x200))
 #define PAL_BANK_BG        ((Palette*) MEM_PAL)
 #define PAL_BANK_SPRITES   ((Palette*)(MEM_PAL + 0x200))
+static u16 *backbuffer = ((vu16*)(MEM_VRAM + 0x0A000));
 
 //
 // Sprites.
@@ -198,6 +199,7 @@ typedef Color Scanline[SCREEN_WIDTH];
 
 static inline void
 flip_page(void) {
+    backbuffer = (u16*)((u32)backbuffer ^ 0x0A000);
     DISP_CTRL ^= DISP_PAGE;
 }
 
diff --git a/src/main.c b/src/main.c
index 3065842..d4d49cc 100644
--- a/src/main.c
+++ b/src/main.c
@@ -15,7 +15,12 @@
 int main(void) {
     // Configure the display in mode 0 to show OBJs, where tile memory is
     // sequential.
-    DISP_CTRL = DISP_ENABLE_SPRITES | DISP_MODE_3 | DISP_BG_2;
+    DISP_CTRL = DISP_ENABLE_SPRITES | DISP_MODE_4 | DISP_BG_2;
+    // DISP_CTRL = DISP_ENABLE_SPRITES | DISP_MODE_3 | DISP_BG_2;
+
+    PAL_BUFFER_BG[1] = COLOR_WHITE;
+    PAL_BUFFER_BG[2] = COLOR_RED;
+    PAL_BUFFER_BG[3] = COLOR_CYAN;
 
     // Initialize text engine.
     txt_init_bitmap(
diff --git a/src/sequencer.c b/src/sequencer.c
index a19cef7..c09fb01 100644
--- a/src/sequencer.c
+++ b/src/sequencer.c
@@ -15,6 +15,10 @@
 #define SEQ_DUTYCYCLE_POS_Y 10 - 8
 #define SEQ_SWEEP_POS_X SEQ_DUTYCYCLE_POS_X + SEQ_ENV_DIST
 #define SEQ_SWEEP_POS_Y SEQ_ENV_POS_Y
+#define SEQ_CH3_PARAM_X SEQ_TRIG_POS_X
+#define SEQ_CH3_PARAM_Y SEQ_ENV_POS_Y
+#define SEQ_CH3_PARAM_SEL_X SEQ_CH3_PARAM_X - 5
+#define SEQ_CH3_PARAM_SEL_Y SEQ_CH3_PARAM_Y + 22
 #define SEQ_N_CHANNELS 3
 
 u32 sprite_note_names[] = {
@@ -522,6 +526,7 @@ set_time(int bpm) {
 // - 054-054 channel 4.
 // - 055-055 RESERVED: FM synth?.
 // - 056-056 channel selector.
+// - 057-057 ch3 selector.
 //
 
 
@@ -548,18 +553,20 @@ int param_selection_loc = 0;
 int channel_selection_loc = 2;
 SeqSelect current_selection = SEQ_SELECT_TRIGGER;
 
-SeqSprite seq_sprites[57] = {0};
+SeqSprite seq_sprites[58] = {0};
 
 void
-draw_wave_pattern(u8 *pattern, int x, int y, Color clr) {
+draw_wave_pattern(u8 *pattern, int x, int y, u16 clr_idx) {
     for (size_t i = 0; i < 16; ++i) {
         u8 byte = pattern[i];
         u8 first = (byte >> 4) & 0xF;
         u8 second = byte & 0xF;
-        FRAMEBUFFER[y + 16 - first][x + i * 4] = clr;
-        FRAMEBUFFER[y + 16 - first][x + i * 4 + 1] = clr;
-        FRAMEBUFFER[y + 16 - second][x + i * 4 + 2] = clr;
-        FRAMEBUFFER[y + 16 - second][x + i * 4 + 3] = clr;
+        u8 a = x + i * 4;
+        u8 b = y + 16;
+        put_pixel_m4(a, b - first, clr_idx, backbuffer);
+        put_pixel_m4(a + 1, b - first, clr_idx, backbuffer);
+        put_pixel_m4(a + 2, b - second, clr_idx, backbuffer);
+        put_pixel_m4(a + 3, b - second, clr_idx, backbuffer);
     }
 }
 
@@ -616,10 +623,20 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[32].id = obj_counter++;
         seq_sprites[32].base_tile = base_tile;
-        seq_sprites[32].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y);
+        seq_sprites[32].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[32].obj_attr_1 = OBJ_SIZE_SMALL | OBJ_X_COORD(x);
         seq_sprites[32].obj_attr_2 = base_tile | OBJ_PAL_BANK(1);
     }
+    {
+        int x = SEQ_CH3_PARAM_SEL_X;
+        int y = SEQ_CH3_PARAM_SEL_Y;
+        int base_tile = sprites[sprite_id].tile_start;
+        seq_sprites[57].id = obj_counter++;
+        seq_sprites[57].base_tile = base_tile;
+        seq_sprites[57].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y);
+        seq_sprites[57].obj_attr_1 = OBJ_SIZE_SMALL | OBJ_X_COORD(x);
+        seq_sprites[57].obj_attr_2 = base_tile | OBJ_PAL_BANK(2);
+    }
 
     sprite_id = load_packed_sprite_data(&sprite_trigger_selection, 16, 1);
     {
@@ -632,7 +649,7 @@ init_sequencer_sprites(void) {
         }
         seq_sprites[33].id = obj_counter++;
         seq_sprites[33].base_tile = base_tile;
-        seq_sprites[33].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y);
+        seq_sprites[33].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[33].obj_attr_1 = OBJ_SIZE_BIG | OBJ_X_COORD(x);
         seq_sprites[33].obj_attr_2 = base_tile | OBJ_PAL_BANK(2);
     }
@@ -644,7 +661,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[34].id = obj_counter++;
         seq_sprites[34].base_tile = base_tile;
-        seq_sprites[34].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[34].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[34].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[34].obj_attr_2 = base_tile;
     }
@@ -656,7 +673,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[35].id = obj_counter++;
         seq_sprites[35].base_tile = base_tile;
-        seq_sprites[35].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[35].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[35].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[35].obj_attr_2 = base_tile;
     }
@@ -668,7 +685,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[36].id = obj_counter++;
         seq_sprites[36].base_tile = base_tile;
-        seq_sprites[36].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[36].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[36].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[36].obj_attr_2 = base_tile;
     }
@@ -678,7 +695,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[45].id = obj_counter++;
         seq_sprites[45].base_tile = base_tile;
-        seq_sprites[45].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[45].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[45].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[45].obj_attr_2 = base_tile;
     }
@@ -690,7 +707,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[37].id = obj_counter++;
         seq_sprites[37].base_tile = base_tile;
-        seq_sprites[37].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[37].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[37].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[37].obj_attr_2 = base_tile;
     }
@@ -702,7 +719,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[38].id = obj_counter++;
         seq_sprites[38].base_tile = base_tile;
-        seq_sprites[38].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[38].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[38].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[38].obj_attr_2 = base_tile;
     }
@@ -712,7 +729,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[47].id = obj_counter++;
         seq_sprites[47].base_tile = base_tile;
-        seq_sprites[47].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[47].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[47].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[47].obj_attr_2 = base_tile;
     }
@@ -724,7 +741,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[39].id = obj_counter++;
         seq_sprites[39].base_tile = base_tile;
-        seq_sprites[39].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[39].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[39].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[39].obj_attr_2 = base_tile;
     }
@@ -734,7 +751,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[48].id = obj_counter++;
         seq_sprites[48].base_tile = base_tile;
-        seq_sprites[48].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[48].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[48].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[48].obj_attr_2 = base_tile;
     }
@@ -746,7 +763,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[40].id = obj_counter++;
         seq_sprites[40].base_tile = base_tile;
-        seq_sprites[40].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[40].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[40].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[40].obj_attr_2 = base_tile;
     }
@@ -758,7 +775,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[41].id = obj_counter++;
         seq_sprites[41].base_tile = base_tile;
-        seq_sprites[41].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[41].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[41].obj_attr_1 = OBJ_SIZE_BIG | OBJ_X_COORD(x);
         seq_sprites[41].obj_attr_2 = base_tile;
     }
@@ -770,7 +787,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[42].id = obj_counter++;
         seq_sprites[42].base_tile = base_tile;
-        seq_sprites[42].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[42].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[42].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[42].obj_attr_2 = base_tile;
     }
@@ -782,7 +799,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[43].id = obj_counter++;
         seq_sprites[43].base_tile = base_tile;
-        seq_sprites[43].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[43].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[43].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[43].obj_attr_2 = base_tile;
     }
@@ -794,7 +811,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[44].id = obj_counter++;
         seq_sprites[44].base_tile = base_tile;
-        seq_sprites[44].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y);
+        seq_sprites[44].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[44].obj_attr_1 = OBJ_SIZE_SMALL | OBJ_X_COORD(x);
         seq_sprites[44].obj_attr_2 = base_tile;
     }
@@ -804,7 +821,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[46].id = obj_counter++;
         seq_sprites[46].base_tile = base_tile;
-        seq_sprites[46].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y);
+        seq_sprites[46].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[46].obj_attr_1 = OBJ_SIZE_SMALL | OBJ_X_COORD(x);
         seq_sprites[46].obj_attr_2 = base_tile;
     }
@@ -816,7 +833,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[49].id = obj_counter++;
         seq_sprites[49].base_tile = base_tile;
-        seq_sprites[49].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
+        seq_sprites[49].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[49].obj_attr_1 = OBJ_SIZE_MID | OBJ_X_COORD(x);
         seq_sprites[49].obj_attr_2 = base_tile;
     }
@@ -828,7 +845,7 @@ init_sequencer_sprites(void) {
         int base_tile = sprites[sprite_id].tile_start;
         seq_sprites[50].id = obj_counter++;
         seq_sprites[50].base_tile = base_tile;
-        seq_sprites[50].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y);
+        seq_sprites[50].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y) | OBJ_HIDDEN;
         seq_sprites[50].obj_attr_1 = OBJ_SIZE_BIG | OBJ_X_COORD(x);
         seq_sprites[50].obj_attr_2 = base_tile | OBJ_PAL_BANK(2);
     }
@@ -1017,19 +1034,7 @@ update_sequencer_sprites(void) {
         seq_sprites[48].obj_attr_2 = tile;
     }
 
-    // 51: Parameter selector.
-    {
-        int x = SEQ_ENV_POS_X + 1 + (param_selection_loc % 7) * SEQ_ENV_DIST;
-        int y = SEQ_ENV_POS_Y - 3;
-        int hidden = 0;
-        if (current_selection != SEQ_SELECT_PARAMETER) {
-            hidden = OBJ_HIDDEN;
-        }
-        seq_sprites[50].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y) | hidden;
-        seq_sprites[50].obj_attr_1 = OBJ_SIZE_BIG | OBJ_X_COORD(x);
-    }
-
-    // 57: Parameter selector.
+    // 57: Channel selector.
     {
         int x = SEQ_CHANNEL_POS_X;
         int y = SEQ_CHANNEL_POS_Y - 2;
@@ -1044,31 +1049,17 @@ update_sequencer_sprites(void) {
         }
     }
 
-    // TODO: Hide all parameter control sprites for now, we unhide it later.
-    // Very inefficient but we may change the parameter rendering of all modes
-    // to use bitmaps instead of sprites later.
-    for (size_t i = 34; i <= 50; ++i) {
-        seq_sprites[i].obj_attr_0 |= OBJ_HIDDEN;
-    }
-
-    if (update_params_screen) {
-        // Clear screen.
-        // draw_fill_rect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT / 2, COLOR_BLACK);
-        int zero = 0;
-        dma_fill(FRAMEBUFFER, zero, SCREEN_WIDTH * SCREEN_HEIGHT * 2, 3);
-
-    }
     if (channel_selection_loc == 2) {
         if (update_params_screen) {
             u8 *wave_a = sequences[channel_selection_loc][trig_selection_loc].wave_a;
             u8 *wave_b = sequences[channel_selection_loc][trig_selection_loc].wave_b;
 
             // Draw wave patterns for this trig.
-            int x = SEQ_ENV_POS_X;
-            int y = SEQ_ENV_POS_Y;
+            int x = SEQ_CH3_PARAM_X;
+            int y = SEQ_CH3_PARAM_Y;
 
             // Wave A.
-            draw_wave_pattern(wave_a, x, y, COLOR_RED);
+            draw_wave_pattern(wave_a, x, y, 2);
             txt_position(x - 1, y + 20);
             txt_printf("%02x%02x%02x%02x %02x%02x%02x%02x",
                     wave_a[0], wave_a[1], wave_a[2], wave_a[3],
@@ -1079,8 +1070,8 @@ update_sequencer_sprites(void) {
                     wave_a[12], wave_a[13], wave_a[14], wave_a[15]);
 
             // Wave B.
-            x += 64 + 32 + 12;
-            draw_wave_pattern(wave_b, x, y, COLOR_CYAN);
+            x += 64 + 12;
+            draw_wave_pattern(wave_b, x, y, 3);
             txt_position(x - 1, y + 20);
             txt_printf("%02x%02x%02x%02x %02x%02x%02x%02x",
                     wave_b[0], wave_b[1], wave_b[2], wave_b[3],
@@ -1089,27 +1080,66 @@ update_sequencer_sprites(void) {
             txt_printf("%02x%02x%02x%02x %02x%02x%02x%02x",
                     wave_b[8], wave_b[9], wave_b[10], wave_b[11],
                     wave_b[12], wave_b[13], wave_b[14], wave_b[15]);
+
+            // Clear the backbuffer.
+            flip_page();
+            clear_screen_m4();
         }
-    } else if ((current_selection == SEQ_SELECT_TRIGGER
-                || current_selection == SEQ_SELECT_PARAMETER)
-                    && channel_selection_loc == 0) {
-        for (size_t i = 34; i <= 50; ++i) {
-            seq_sprites[i].obj_attr_0 &= ~OBJ_HIDDEN;
+
+        // Update parameter selection.
+        {
+            int x = SEQ_CH3_PARAM_SEL_X + param_selection_loc * 4;
+            int y = SEQ_CH3_PARAM_SEL_Y;
+            int base_tile = seq_sprites[57].base_tile;
+            int hidden = 0;
+            if (current_selection != SEQ_SELECT_PARAMETER) {
+                hidden = OBJ_HIDDEN;
+            }
+            seq_sprites[57].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y) | hidden;
+            seq_sprites[57].obj_attr_1 = OBJ_SIZE_SMALL | OBJ_X_COORD(x);
+            seq_sprites[57].obj_attr_2 = base_tile | OBJ_PAL_BANK(2);
         }
-    } else if ((current_selection == SEQ_SELECT_TRIGGER
-                || current_selection == SEQ_SELECT_PARAMETER)
-                    && channel_selection_loc == 1) {
-        for (size_t i = 34; i < 43; ++i) {
-            seq_sprites[i].obj_attr_0 &= ~OBJ_HIDDEN;
+    }
+
+    if (channel_selection_loc == 0) {
+        if (current_selection == SEQ_SELECT_TRIGGER
+                || current_selection == SEQ_SELECT_PARAMETER) {
+            for (size_t i = 34; i < 50; ++i) {
+                seq_sprites[i].obj_attr_0 &= ~OBJ_HIDDEN;
+            }
         }
-        seq_sprites[50].obj_attr_0 &= ~OBJ_HIDDEN;
-    } else {
-        int x = SEQ_ENV_POS_X + 8;
-        int y = SEQ_ENV_POS_Y;
+    }
 
-        // Clear parameters for channel 3.
-        draw_fill_rect(x, y, x + 64, y + 16, COLOR_BLACK);
-        draw_fill_rect(x + 64 + 16, y, x + 64 * 2 + 16, y + 16, COLOR_BLACK);
+    if (channel_selection_loc == 1) {
+        if (current_selection == SEQ_SELECT_TRIGGER
+                || current_selection == SEQ_SELECT_PARAMETER) {
+            for (size_t i = 34; i <= 42; ++i) {
+                seq_sprites[i].obj_attr_0 &= ~OBJ_HIDDEN;
+            }
+        }
+    }
+
+    if (channel_selection_loc == 0 || channel_selection_loc == 1) {
+        // 51: Parameter selector.
+        int x = SEQ_ENV_POS_X + 1 + (param_selection_loc % 7) * SEQ_ENV_DIST;
+        int y = SEQ_ENV_POS_Y - 3;
+        int hidden = 0;
+        if (current_selection != SEQ_SELECT_PARAMETER) {
+            hidden = OBJ_HIDDEN;
+        }
+        seq_sprites[50].obj_attr_0 = OBJ_SHAPE_SQUARE | OBJ_Y_COORD(y) | hidden;
+        seq_sprites[50].obj_attr_1 = OBJ_SIZE_BIG | OBJ_X_COORD(x);
+    }
+
+    if (current_selection == SEQ_SELECT_CHANNEL && update_params_screen) {
+        // TODO: Hide all parameter control sprites for now, we unhide it later.
+        // Very inefficient but we may change the parameter rendering of all
+        // modes to use bitmaps instead of sprites later.
+        for (size_t i = 34; i <= 50; ++i) {
+            seq_sprites[i].obj_attr_0 |= OBJ_HIDDEN;
+        }
+        flip_page();
+        clear_screen_m4();
     }
     update_params_screen = false;
 }
@@ -1133,91 +1163,129 @@ handle_sequencer_input(void) {
         } else if (key_pressed(KEY_B)) {
             trig->trigger ^= 1;
         } else if (key_pressed(KEY_L)) {
-            trig->note = MAX(trig->note - 1, NOTE_C_2);
+            if (trig->trigger) {
+                trig->note = MAX(trig->note - 1, NOTE_C_2);
+            }
         } else if (key_pressed(KEY_R)) {
-            trig->note = MIN( trig->note + 1, NOTE_C_8);
+            if (trig->trigger) {
+                trig->note = MIN( trig->note + 1, NOTE_C_8);
+            }
         } else if (key_pressed(KEY_A)) {
             // Switch to parameter selection.
             current_selection = SEQ_SELECT_PARAMETER;
         }
     } else if (current_selection == SEQ_SELECT_PARAMETER) {
-        // Move through the selected synth parameters.
-        if (key_pressed(KEY_LEFT)) {
-            int max_param = 6;
-            if (channel_selection_loc == 1) {
-                max_param = 3;
+        if (channel_selection_loc < 2) {
+            // Move through the selected synth parameters.
+            if (key_pressed(KEY_LEFT)) {
+                int max_param = 6;
+                if (channel_selection_loc == 1) {
+                    max_param = 3;
+                }
+                if (param_selection_loc == 0) {
+                    param_selection_loc = max_param;
+                } else {
+                    param_selection_loc = MAX(param_selection_loc - 1, 0);
+                }
             }
-            if (param_selection_loc == 0) {
-                param_selection_loc = max_param;
-            } else {
-                param_selection_loc = MAX(param_selection_loc - 1, 0);
+            if (key_pressed(KEY_RIGHT)) {
+                int max_param = 6;
+                if (channel_selection_loc == 1) {
+                    max_param = 3;
+                }
+                if (param_selection_loc == max_param) {
+                    param_selection_loc = 0;
+                } else {
+                    param_selection_loc = MIN(param_selection_loc + 1, max_param);
+                }
             }
-        }
-        if (key_pressed(KEY_RIGHT)) {
-            int max_param = 6;
-            if (channel_selection_loc == 1) {
-                max_param = 3;
+
+            // Adjust the parameters up or down.
+            if (key_pressed(KEY_L)) {
+                switch (param_selection_loc) {
+                    case 0: {
+                                trig->env_volume = MAX(trig->env_volume - 1, 0);
+                            } break;
+                    case 1: {
+                                trig->env_time = MAX(trig->env_time - 1, 0);
+                            } break;
+                    case 2: {
+                                trig->env_direction ^= 1;
+                            } break;
+                    case 3: {
+                                trig->duty_cycle = MAX(trig->duty_cycle - 1, 0);
+                            } break;
+                    case 4: {
+                                trig->sweep_number = MAX(trig->sweep_number - 1, 0);
+                            } break;
+                    case 5: {
+                                trig->sweep_time = MAX(trig->sweep_time - 1, 0);
+                            } break;
+                    case 6: {
+                                if (trig->sweep_direction == 0) {
+                                    trig->sweep_direction = 1;
+                                } else {
+                                    trig->sweep_direction = 0;
+                                }
+                            } break;
+                }
             }
-            if (param_selection_loc == max_param) {
-                param_selection_loc = 0;
-            } else {
-                param_selection_loc = MIN(param_selection_loc + 1, max_param);
+            if (key_pressed(KEY_R)) {
+                switch (param_selection_loc) {
+                    case 0: {
+                                trig->env_volume = MIN(trig->env_volume + 1, 15);
+                            } break;
+                    case 1: {
+                                trig->env_time = MIN(trig->env_time + 1, 7);
+                            } break;
+                    case 2: {
+                                trig->env_direction ^= 1;
+                            } break;
+                    case 3: {
+                                trig->duty_cycle = MIN(trig->duty_cycle + 1, 3);
+                            } break;
+                    case 4: {
+                                trig->sweep_number = MIN(trig->sweep_number + 1, 7);
+                            } break;
+                    case 5: {
+                                trig->sweep_time = MIN(trig->sweep_time + 1, 7);
+                            } break;
+                    case 6: {
+                                trig->sweep_direction ^= 1;
+                            } break;
+                }
             }
-        }
-
-        // Adjust the parameters up or down.
-        if (key_pressed(KEY_L)) {
-            switch (param_selection_loc) {
-                case 0: {
-                    trig->env_volume = MAX(trig->env_volume - 1, 0);
-                } break;
-                case 1: {
-                    trig->env_time = MAX(trig->env_time - 1, 0);
-                } break;
-                case 2: {
-                    trig->env_direction ^= 1;
-                } break;
-                case 3: {
-                    trig->duty_cycle = MAX(trig->duty_cycle - 1, 0);
-                } break;
-                case 4: {
-                    trig->sweep_number = MAX(trig->sweep_number - 1, 0);
-                } break;
-                case 5: {
-                    trig->sweep_time = MAX(trig->sweep_time - 1, 0);
-                } break;
-                case 6: {
-                    if (trig->sweep_direction == 0) {
-                        trig->sweep_direction = 1;
-                    } else {
-                        trig->sweep_direction = 0;
-                    }
-                } break;
+        } else if (channel_selection_loc == 2) {
+            // TODO:...
+            if (key_pressed(KEY_LEFT)) {
+                param_selection_loc -= 1;
+                // int max_param = 6;
+                // if (channel_selection_loc == 1) {
+                //     max_param = 3;
+                // }
+                // if (param_selection_loc == 0) {
+                //     param_selection_loc = max_param;
+                // } else {
+                //     param_selection_loc = MAX(param_selection_loc - 1, 0);
+                // }
             }
-        }
-        if (key_pressed(KEY_R)) {
-            switch (param_selection_loc) {
-                case 0: {
-                    trig->env_volume = MIN(trig->env_volume + 1, 15);
-                } break;
-                case 1: {
-                    trig->env_time = MIN(trig->env_time + 1, 7);
-                } break;
-                case 2: {
-                    trig->env_direction ^= 1;
-                } break;
-                case 3: {
-                    trig->duty_cycle = MIN(trig->duty_cycle + 1, 3);
-                } break;
-                case 4: {
-                    trig->sweep_number = MIN(trig->sweep_number + 1, 7);
-                } break;
-                case 5: {
-                    trig->sweep_time = MIN(trig->sweep_time + 1, 7);
-                } break;
-                case 6: {
-                    trig->sweep_direction ^= 1;
-                } break;
+            if (key_pressed(KEY_RIGHT)) {
+                param_selection_loc += 1;
+                // int max_param = 6;
+                // if (channel_selection_loc == 1) {
+                //     max_param = 3;
+                // }
+                // if (param_selection_loc == max_param) {
+                //     param_selection_loc = 0;
+                // } else {
+                //     param_selection_loc = MIN(param_selection_loc + 1, max_param);
+                // }
+            }
+            if (key_pressed(KEY_R)) {
+                sequences[2][trig_selection_loc].wave_a[param_selection_loc] += 1;
+            }
+            if (key_pressed(KEY_L)) {
+                sequences[2][trig_selection_loc].wave_a[param_selection_loc] -= 1;
             }
         }
 
@@ -1234,6 +1302,7 @@ handle_sequencer_input(void) {
         if (key_pressed(KEY_RIGHT)) {
             current_selection = SEQ_SELECT_TRIGGER;
             trig_selection_loc = 0;
+            param_selection_loc = 0;
         }
         if (key_pressed(KEY_UP)) {
             if (channel_selection_loc == 0) {
@@ -1294,6 +1363,7 @@ render_sequencer_sprites(void) {
 void init_sequencer() {
     init_sequencer_sprites();
     SOUND_STATUS = SOUND_ENABLE;
-    SOUND_DMG_MASTER = sound_volume(SOUND_SQUARE1 | SOUND_SQUARE2 | SOUND_WAVE, 3);
+    SOUND_DMG_MASTER = sound_volume(
+            SOUND_SQUARE1 | SOUND_SQUARE2 | SOUND_WAVE, 3);
     SOUND_DSOUND_MASTER = SOUND_DMG25;
 }
diff --git a/src/text.h b/src/text.h
index 3c0b3a8..9aa3fdd 100644
--- a/src/text.h
+++ b/src/text.h
@@ -5,6 +5,7 @@
 #include <stdio.h>
 
 #include "common.h"
+#include "bitmap.h"
 
 typedef enum {
     TXT_MODE_TILED_BG,
@@ -15,7 +16,7 @@ typedef struct Font {
     // A pointer to an area of memory containing font data.
     // TODO: Should we unpack each char everytime or unpack everything into RAM?
     // Maybe this should be optional?
-    u32 *data;
+    u16 *data;
     // The char_map stores the index to the character position within the font
     // array depending on the ascii number we want to render. This allows
     // the usage reduced font sets, for example just uppercase letters and
@@ -93,7 +94,12 @@ txt_putc_m3(char c) {
         for (size_t i = 0; i < text_engine.font.char_height; ++i) {
             for (size_t j = 0; j < text_engine.font.char_width; ++j) {
                 if ((tile.row[i] >> 4 * j) & 0x1) {
-                    FRAMEBUFFER[y + i][x + j] = text_engine.font.color;
+                    put_pixel_m4(x + j, y + i, 1, backbuffer);
+                    // TODO: Clean this up please.
+                    // put_pixel_m3(x + j,
+                    //         y + i,
+                    //         text_engine.font.color,
+                    //         FRAMEBUFFER);
                 }
             }
         }