From aa7e7fc98deddaed3b8dbb1942ec954f6b4c016f Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Wed, 21 Apr 2021 14:02:30 +0200
Subject: Experiment with enabling multiple animation states

---
 src/gba-buttons.c | 24 ++++++++++++++++++++++++
 src/main.c        | 46 +++++++++++++++++++++++++---------------------
 2 files changed, 49 insertions(+), 21 deletions(-)

diff --git a/src/gba-buttons.c b/src/gba-buttons.c
index 0f6218a..ee6458d 100644
--- a/src/gba-buttons.c
+++ b/src/gba-buttons.c
@@ -227,3 +227,27 @@ u32 gba_btn_b_data[112][8] = {
     {0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000},
     {0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000},
 };
+
+typedef enum {GBA_BTN_STATE_IDLE, GBA_BTN_STATE_PRESSED} GbaBtnState;
+typedef struct SpriteAnimation {
+    size_t *tile_offsets;
+    size_t n_frames;
+} SpriteAnimation;
+
+static size_t gba_btn_state_idle[] = {0};
+static size_t gba_btn_state_pressed[] = {0, 16, 16, 32, 32, 48, 48, 64, 64, 80, 96};
+
+SpriteAnimation anim_idle = {
+    .tile_offsets = &gba_btn_state_idle,
+    .n_frames = sizeof(gba_btn_state_idle) / sizeof(size_t),
+};
+
+SpriteAnimation anim_pressed = {
+    .tile_offsets = &gba_btn_state_pressed,
+    .n_frames = sizeof(gba_btn_state_pressed) / sizeof(size_t),
+};
+
+SpriteAnimation *animation_states[] = {
+    &anim_idle,
+    &anim_pressed,
+};
diff --git a/src/main.c b/src/main.c
index 831359b..8c1e82d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -460,7 +460,7 @@ typedef struct ButtonSprite {
     int x;
     int y;
     int frame;
-    int n_frames;
+    GbaBtnState state;
 } ButtonSprite;
 
 #define NUM_SPRITES 128
@@ -516,7 +516,7 @@ int main(void) {
         .x = buttons_x,
         .y = buttons_y,
         .frame = 0,
-        .n_frames = 6,
+        .state = GBA_BTN_STATE_IDLE,
     };
     OBJ_ATTR_0(btn_b.id) = btn_b.y;
     OBJ_ATTR_1(btn_b.id) = btn_b.x | (1 << 0xF);
@@ -527,7 +527,7 @@ int main(void) {
         .x = buttons_x + 20,
         .y = buttons_y - 16,
         .frame = 0,
-        .n_frames = 6,
+        .state = GBA_BTN_STATE_IDLE,
     };
     OBJ_ATTR_0(btn_a.id) = btn_a.y;
     OBJ_ATTR_1(btn_a.id) = btn_a.x | (1 << 0xF);
@@ -550,35 +550,39 @@ int main(void) {
         if (key_pressed(KEY_RIGHT) || key_hold(KEY_RIGHT)) {
         }
         if (key_pressed(KEY_B)) {
-            btn_b.frame = 1;
-        } else if (key_pressed(KEY_B) || key_hold(KEY_B)) {
-            // DEBUG: Slowing animation rate. What would be a better solution?
-            if (frame_counter++ % 3 == 0) {
-                if (btn_b.frame < btn_b.n_frames) {
-                    btn_b.frame++;
-                }
+            btn_b.frame = 0;
+            btn_b.state = GBA_BTN_STATE_PRESSED;
+        } else if (key_hold(KEY_B)) {
+            size_t n_frames = animation_states[btn_b.state]->n_frames;
+            if (btn_b.frame < n_frames - 1) {
+                btn_b.frame++;
             }
         } else {
-            if (btn_b.frame > 0 && btn_b.frame < btn_b.n_frames) {
+            size_t n_frames = animation_states[btn_b.state]->n_frames;
+            // Finish the animation and reset idle state.
+            if (btn_b.frame > 0 && btn_b.frame < n_frames - 1) {
                 btn_b.frame++;
             } else {
                 btn_b.frame = 0;
+                btn_b.state = GBA_BTN_STATE_IDLE;
             }
         }
         if (key_pressed(KEY_A)) {
-            btn_a.frame = 1;
-        } else if (key_pressed(KEY_A) || key_hold(KEY_A)) {
-            // DEBUG: Slowing animation rate. What would be a better solution?
-            if (frame_counter % 3 == 0) {
-                if (btn_a.frame < btn_a.n_frames) {
-                    btn_a.frame++;
-                }
+            btn_a.frame = 0;
+            btn_a.state = GBA_BTN_STATE_PRESSED;
+        } else if (key_hold(KEY_A)) {
+            size_t n_frames = animation_states[btn_a.state]->n_frames;
+            if (btn_a.frame < n_frames - 1) {
+                btn_a.frame++;
             }
         } else {
-            if (btn_a.frame > 0 && btn_a.frame < btn_a.n_frames) {
+            size_t n_frames = animation_states[btn_a.state]->n_frames;
+            // Finish the animation and reset idle state.
+            if (btn_a.frame > 0 && btn_a.frame < n_frames - 1) {
                 btn_a.frame++;
             } else {
                 btn_a.frame = 0;
+                btn_a.state = GBA_BTN_STATE_IDLE;
             }
         }
         if (key_pressed(KEY_L)) {
@@ -586,8 +590,8 @@ int main(void) {
         if (key_pressed(KEY_R)) {
         }
 
-        OBJ_ATTR_2(btn_b.id) = sprites[btn_b.id].tile_start + sprites[btn_b.id].n_tiles * btn_b.frame;
-        OBJ_ATTR_2(btn_a.id) = sprites[btn_a.id].tile_start + sprites[btn_a.id].n_tiles * btn_a.frame;
+        OBJ_ATTR_2(btn_b.id) = sprites[btn_b.id].tile_start + animation_states[btn_b.state]->tile_offsets[btn_b.frame];
+        OBJ_ATTR_2(btn_a.id) = sprites[btn_a.id].tile_start + animation_states[btn_a.state]->tile_offsets[btn_a.frame];
         frame_counter++;
     };
 
-- 
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