Player controller

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