Player controller

game/game.c

@@ -8,16 +8,6 @@
 
 uint32_t game_frame;
 
-game_bbox game_player_bbox = {
-    .x=0x9000,
-    // .y=0x5800,
-    .y=0x0000,
-    .w=0x1000,
-    .h=0x1000,
-};
-sys_i32 game_player_dx = 0;
-sys_i32 game_player_dy = 0;
-
 const char* game_title() {
     return "Croc Party!";
 }
@@ -26,6 +16,7 @@ void game_init() {
     sys_init();
 
     game_palette_init();
+    game_player_init();
 }
 
 void game_destroy() {
@@ -33,32 +24,16 @@ void game_destroy() {
 }
 
 void game_update() {
+    sys_update();
+
     game_frame += 1;
+    game_player_update();
 
-    game_player_dy += 1;
-
-    if (device_buttons[0]) { game_player_dx -= 16; }
-    if (device_buttons[1]) { game_player_dx += 16; }
-
-    game_collision collision = game_collision_move_to_contact(
-        &game_player_bbox, 
-        game_player_dx, 
-        game_player_dy
-    );
-    if (collision.collided_x) { game_player_dx = 0; }
-    if (collision.collided_y) { game_player_dy = 0; }
 }
 
 void game_draw() {
     sys_cls(9);
 
     sys_map_draw(map_game_map, spr_game_tiles, 0, 0, 0, 0, 32, 18);
-    sys_sprite_draw_ext(
-        spr_game_player,
-        (game_frame / 8) % 4 * 2, 
-        game_player_bbox.x / 0x100, 
-        game_player_bbox.y / 0x100, 
-        2, 2, 
-        false, false
-    );
+    game_player_draw();
 }

game/game.h

@@ -3,6 +3,7 @@
 
 #include "game_collision.h"
 #include "game_palette.h"
+#include "game_player.h"
 
 const char* game_title();
 void game_init();

game/game_player.c

@@ -0,0 +1,159 @@
+#include "art/game_player.h"
+#include "art/game_tiles.h"
+#include "device/device.h"
+#include "map/game_map.h"
+#include "game.h"
+#include "sys/sys.h"
+
+game_bbox game_player_bbox = {
+    .x=0x9000,
+    // .y=0x5800,
+    .y=0x0000,
+    .w=0x1000,
+    .h=0x1000,
+};
+bool game_player_grounded = false;
+sys_i32 game_player_jump_frames = 0;
+sys_i32 game_player_coyote_frames = 0;
+sys_i32 game_player_dx = 0;
+sys_i32 game_player_dy = 0;
+bool game_player_faceleft = false;
+
+typedef enum {
+    GAME_PLAYER_ANIM_STANDING,
+    GAME_PLAYER_ANIM_WALKING,
+    GAME_PLAYER_ANIM_FLOATING,
+} game_player_anim;
+
+game_player_anim game_player_anim_state = GAME_PLAYER_ANIM_STANDING;
+uint8_t game_player_anim_progress = 0;
+
+void game_player_anim_transition(game_player_anim anim);
+void game_player_anim_add_progress(uint8_t amt);
+
+void game_player_init() {
+}
+
+void game_player_update() {
+    game_collision collision = game_collision_move_to_contact(
+        &game_player_bbox, 
+        game_player_dx, 
+        game_player_dy
+    );
+
+    if (collision.collided_x) { game_player_dx = 0; }
+    if (collision.collided_y) { game_player_dy = 0; }
+
+    game_player_grounded = !game_collision_can_move(game_player_bbox, 0, 1);
+
+    {
+        sys_i32 fric_numerator = game_player_grounded ? 0x70 : 0x7f;
+        game_player_dx = (
+            game_player_dx * fric_numerator + 
+            // round up
+            0x7f * sys_sgn_i32(game_player_dx)
+        ) / 0x80;
+        if (sys_abs_i32(game_player_dx) > 0x200) { 
+            game_player_dx = sys_sgn_i32(game_player_dx) * 0x200;
+        }
+
+        int wanted_dx = game_player_dx;
+        if (sys_btn(DEVICE_BUTTON_L)) { wanted_dx -= 0x50; }
+        if (sys_btn(DEVICE_BUTTON_R)) { wanted_dx += 0x50; }
+    
+        // allow this if grounded or if it's not a change of direction
+        if (
+            game_player_grounded || 
+            (sys_sgn_i32(wanted_dx) == sys_sgn_i32(game_player_dx))
+        ) {
+            game_player_dx = wanted_dx;
+        } else {
+            // the smallest possible amount of movement without changing sign
+            game_player_dx = sys_sgn_i32(game_player_dx);
+        }
+    }
+
+    if (game_player_grounded || game_player_coyote_frames > 0) {
+        if (sys_btn(DEVICE_BUTTON_U)) { 
+            game_player_dy = -0x300; 
+            game_player_jump_frames = 15;
+            game_player_grounded = false;
+        } 
+    }
+
+    bool wants_to_go_higher = false;
+    if (game_player_grounded) {
+        game_player_coyote_frames = 5;  
+        if (game_player_dy > 0) { game_player_dy = 0; }
+        if (game_player_dx < 0) { game_player_faceleft = true; }
+        if (game_player_dx > 0) { game_player_faceleft = false; }
+        if (sys_abs_i32(game_player_dx) < 0x20) { game_player_dx = 0; }
+    }
+    else {
+        game_player_coyote_frames = 
+            sys_max_i32(0, game_player_coyote_frames - 1);
+        wants_to_go_higher = sys_btn(DEVICE_BUTTON_U);
+        bool is_going_higher = wants_to_go_higher && game_player_jump_frames > 0;
+        if (game_player_dy >= 0 || !is_going_higher) {
+            game_player_dy += 48;
+        } else {
+            game_player_jump_frames -= 1;
+        }
+    }
+
+    // deduce animation state
+    if (game_player_grounded) {
+        if (game_player_dx == 0) {
+            game_player_anim_transition(GAME_PLAYER_ANIM_STANDING);
+        } else {
+            game_player_anim_transition(GAME_PLAYER_ANIM_WALKING);
+            game_player_anim_add_progress(
+                sys_min_i32(sys_abs_i32(game_player_dx) / 0x10, 0x8)
+            );
+        }
+    } else {
+        if (wants_to_go_higher) {
+            game_player_anim_transition(GAME_PLAYER_ANIM_FLOATING);
+        } else {
+            game_player_anim_transition(GAME_PLAYER_ANIM_STANDING);
+        }
+    }
+}
+
+void game_player_draw() {
+    int game_player_image;
+    switch (game_player_anim_state) {
+    case GAME_PLAYER_ANIM_WALKING:
+        game_player_image = 2 + (game_player_anim_progress / 0x80) * 2;
+        break;
+    case GAME_PLAYER_ANIM_FLOATING:
+        game_player_image = 6;
+        break;
+    default:
+    case GAME_PLAYER_ANIM_STANDING:
+        game_player_image = 0;
+        break;
+    }
+
+    sys_sprite_draw_ext(
+        spr_game_player,
+        game_player_image,
+        game_player_bbox.x / 0x100, 
+        game_player_bbox.y / 0x100, 
+        2, 2, 
+        game_player_faceleft, false
+    );
+}
+
+void game_player_anim_transition(game_player_anim anim) {
+    if (game_player_anim_state == anim) { return ;}
+    game_player_anim_state = anim;
+    game_player_anim_progress = 0;
+}
+
+void game_player_anim_add_progress(uint8_t amt) {
+    game_player_anim_progress = (
+        (uint32_t) game_player_anim_progress +
+        (uint32_t) amt
+    ) & 0xff;
+}

game/game_player.h

@@ -0,0 +1,8 @@
+#ifndef GAME_PLAYER_H
+#define GAME_PLAYER_H
+
+void game_player_init();
+void game_player_update();
+void game_player_draw();
+
+#endif // GAME_PLAYER_H

sdl_host/main.c

@@ -65,16 +65,16 @@ int main(int argc, char** argv) {
 
     sdl_host_loop();
 
-    // renderer_cleanup:
-    SDL_DestroyRenderer(sdl_host_renderer);
-    sdl_host_renderer = NULL;
-    renderer_done: ;
-
     // target_cleanup:
     SDL_DestroyTexture(sdl_host_target);
     sdl_host_target = NULL;
     target_done: ;
 
+    // renderer_cleanup:
+    SDL_DestroyRenderer(sdl_host_renderer);
+    sdl_host_renderer = NULL;
+    renderer_done: ;
+
     // window_cleanup:
     SDL_DestroyWindow(sdl_host_window);
     sdl_host_window = NULL;

sys/sys.c

@@ -15,6 +15,10 @@ void sys_init() {
     sys_dpal_reset();
 }
 
+void sys_update() {
+    sys_input_update();
+}
+
 bool sys_get_initialized() {
     return sys_initialized;
 }

sys/sys.h

@@ -10,6 +10,11 @@
  */
 void sys_init();
 
+/**
+ * Update sys -- usually for input state.
+ */
+void sys_update();
+
 /**
  * Return whether sys was initialized.
  */

sys/sys_input.c

@@ -0,0 +1,36 @@
+#include "device/device.h"
+#include "sys/sys.h"
+#include "sys_input.h"
+
+sys_i32 sys_input_down_frames[DEVICE_BUTTON_N];
+
+void sys_input_update() {
+    for (DeviceButton db = 0; db < DEVICE_BUTTON_N; db++) {
+        if (device_buttons[db]) {
+            sys_input_down_frames[db] += 1;
+        } else {
+            sys_input_down_frames[db] = 0;
+        }
+    }
+}
+
+void sys_input_reset() {
+    for (DeviceButton db = 0; db < DEVICE_BUTTON_N; db++) {
+        sys_input_down_frames[db] = 0;
+    }
+}
+
+bool sys_btn(DeviceButton button) {
+    if (button >= DEVICE_BUTTON_N) { return false; }
+    return sys_input_down_frames[button] >= 1;
+}
+
+bool sys_btnp(DeviceButton button) {
+    if (button >= DEVICE_BUTTON_N) { return false; }
+    if (sys_input_down_frames[button] == 1) { return true; }
+    // 31 and every 8 frames after that
+    if (sys_input_down_frames[button] >= 31 && (sys_input_down_frames[button] - 31) % 8 == 0) { 
+        return true; 
+    }
+    return false;
+}

sys/sys_input.h

@@ -0,0 +1,33 @@
+#ifndef SYS_INPUT_H
+#define SYS_INPUT_H
+
+/**
+ * Update the state of every button. Each button's btnp state depends
+ * on how long it's been down, and calling this function adds one frame.
+ * 
+ * Usually this is called by sys_update(), at the start of frame.
+ */
+void sys_input_update();
+
+/**
+ * Resets the input state -- all buttons have been held for 0 frames.
+ * 
+ * If the buttons are held next frame, this will lead to a btnp().
+ * 
+ * There's rarely any reason for user code to call this.
+ */
+void sys_input_reset();
+
+/**
+ * Return whether a button is down.
+ */
+bool sys_btn(DeviceButton button);
+
+/**
+ * Return whether a button was just pressed.
+ * 
+ * Repeats after 30 frames, returning true every 8 frames after that.
+ */
+bool sys_btnp(DeviceButton button);
+
+#endif // SYS_INPUT_H