gamepad: Make the deadzone circular and customizable, remember the previous direction

extensions/gamepad.js

@@ -8,71 +8,164 @@
 (function (Scratch) {
   "use strict";
 
-  const AXIS_DEADZONE = 0.1;
+  // For joysticks
+  const DEFAULT_AXIS_DEADZONE = 0.1;
+  let axisDeadzone = DEFAULT_AXIS_DEADZONE;
+
+  // For triggers. Drift isn't so big of an issue with these.
   const BUTTON_DEADZONE = 0.05;
 
   /**
-   * @param {number|'any'} index 1-indexed index
-   * @returns {Gamepad[]}
+   * @typedef InternalGamepadState
+   * @property {string} id
+   * @property {Gamepad} realGamepad
+   * @property {number} timestamp
+   * @property {number[]} axisDirections
+   * @property {number[]} axisMagnitudes
+   * @property {number[]} axisValues
+   * @property {number[]} buttonValues
+   * @property {boolean[]} buttonPressed
+   */
+
+  /** @type {Array<InternalGamepadState|null>} */
+  let gamepadState = [];
+
+  const updateState = () => {
+    // In Firefox, the objects returned by getGamepads() change in the background, but in Chrome
+    // we have to call getGamepads() each frame. Easiest for us to just always call it.
+    // But because Firefox changes the objects in the background, we need to track old values
+    // ourselves.
+    const gamepads = navigator.getGamepads();
+
+    const oldState = gamepadState;
+
+    gamepadState = gamepads.map((gamepad) => {
+      if (!gamepad) {
+        return null;
+      }
+
+      /** @type {InternalGamepadState} */
+      const result = {
+        id: gamepad.id,
+        realGamepad: gamepad,
+        timestamp: gamepad.timestamp,
+        axisDirections: [],
+        axisMagnitudes: [],
+        axisValues: [],
+        buttonValues: [],
+        buttonPressed: [],
+      };
+
+      const oldResult = oldState.find((i) => i !== null && i.id === gamepad.id);
+
+      // Each pair of axes is given a circular deadzone.
+      for (let i = 0; i < gamepad.axes.length; i += 2) {
+        const x = gamepad.axes[i];
+        const y = i + 1 >= gamepad.axes.length ? 0 : gamepad.axes[i + 1];
+        const magnitude = Math.sqrt(x ** 2 + y ** 2);
+
+        if (magnitude > axisDeadzone) {
+          let direction = (Math.atan2(y, x) * 180) / Math.PI + 90;
+          if (direction < 0) {
+            direction += 360;
+          }
+
+          result.axisDirections.push(direction, direction);
+          result.axisMagnitudes.push(magnitude, magnitude);
+          result.axisValues.push(x, y);
+        } else {
+          // Set both axes to 0. Use the old direction state, if it exists, so that using the direction
+          // inside of something like "point in direction" won't reset when no inputs.
+          // If we have no information at all, default to 90 degrees, like new sprites.
+          const oldDirection = oldResult ? oldResult.axisDirections[i] : 90;
+          result.axisDirections.push(oldDirection, oldDirection);
+          result.axisMagnitudes.push(0, 0);
+          result.axisValues.push(0, 0);
+        }
+      }
+
+      for (let i = 0; i < gamepad.buttons.length; i++) {
+        let value = gamepad.buttons[i].value;
+        if (value < BUTTON_DEADZONE) {
+          value = 0;
+        }
+        result.buttonValues.push(value);
+        result.buttonPressed.push(gamepad.buttons[i].pressed);
+      }
+
+      return result;
+    });
+  };
+
+  Scratch.vm.runtime.on("BEFORE_EXECUTE", () => {
+    updateState();
+  });
+
+  /**
+   * @param {unknown} index 1-indexed index or 'any'
+   * @returns {InternalGamepadState[]}
    */
   const getGamepads = (index) => {
     if (index === "any") {
-      return navigator.getGamepads().filter((i) => i);
+      return gamepadState.filter((i) => i);
     }
-    const gamepad = navigator.getGamepads()[index - 1];
+    const gamepad = gamepadState[Scratch.Cast.toNumber(index) - 1];
     if (gamepad) {
       return [gamepad];
     }
     return [];
   };
 
   /**
-   * @param {Gamepad} gamepad
-   * @param {number|'any'} buttonIndex 1-indexed index
+   * @param {InternalGamepadState} gamepad
+   * @param {unknown} buttonIndex 1-indexed index or 'any'
    * @returns {boolean} false if button does not exist
    */
   const isButtonPressed = (gamepad, buttonIndex) => {
     if (buttonIndex === "any") {
-      return gamepad.buttons.some((i) => i.pressed);
-    }
-    const button = gamepad.buttons[buttonIndex - 1];
-    if (!button) {
-      return false;
+      return gamepad.buttonPressed.some((i) => i);
     }
-    return button.pressed;
+    return !!gamepad.buttonPressed[Scratch.Cast.toNumber(buttonIndex) - 1];
   };
 
   /**
-   * @param {Gamepad} gamepad
-   * @param {number} buttonIndex 1-indexed index
+   * @param {InternalGamepadState} gamepad
+   * @param {unknown} buttonIndex 1-indexed index
    * @returns {number} 0 if button does not exist
    */
   const getButtonValue = (gamepad, buttonIndex) => {
-    const button = gamepad.buttons[buttonIndex - 1];
-    if (!button) {
-      return 0;
-    }
-    const value = button.value;
-    if (value < BUTTON_DEADZONE) {
-      return 0;
-    }
-    return value;
+    const value = gamepad.buttonValues[Scratch.Cast.toNumber(buttonIndex) - 1];
+    return value || 0;
   };
 
   /**
-   * @param {Gamepad} gamepad
-   * @param {number} axisIndex 1-indexed index
+   * @param {InternalGamepadState} gamepad
+   * @param {unknown} axisIndex 1-indexed index
    * @returns {number} 0 if axis does not exist
    */
   const getAxisValue = (gamepad, axisIndex) => {
-    const axisValue = gamepad.axes[axisIndex - 1];
-    if (typeof axisValue !== "number") {
-      return 0;
-    }
-    if (Math.abs(axisValue) < AXIS_DEADZONE) {
-      return 0;
-    }
-    return axisValue;
+    const axisValue = gamepad.axisValues[Scratch.Cast.toNumber(axisIndex) - 1];
+    return axisValue || 0;
+  };
+
+  /**
+   * @param {InternalGamepadState} gamepad
+   * @param {unknown} startIndex
+   */
+  const getAxisPairMagnitude = (gamepad, startIndex) => {
+    const magnitude =
+      gamepad.axisMagnitudes[Scratch.Cast.toNumber(startIndex) - 1];
+    return magnitude || 0;
+  };
+
+  /**
+   * @param {InternalGamepadState} gamepad
+   * @param {unknown} startIndex
+   */
+  const getAxisPairDirection = (gamepad, startIndex) => {
+    const direction =
+      gamepad.axisDirections[Scratch.Cast.toNumber(startIndex) - 1];
+    return direction || 0;
   };
 
   class GamepadExtension {
@@ -251,6 +344,20 @@
               },
             },
           },
+
+          "---",
+
+          {
+            opcode: "setAxisDeadzone",
+            blockType: Scratch.BlockType.COMMAND,
+            text: Scratch.translate("set axis deadzone to [DEADZONE]"),
+            arguments: {
+              DEADZONE: {
+                type: Scratch.ArgumentType.NUMBER,
+                defaultValue: DEFAULT_AXIS_DEADZONE.toString(),
+              },
+            },
+          },
         ],
         menus: {
           padMenu: {
@@ -441,20 +548,24 @@
 
     axisDirection({ axis, pad }) {
       let greatestMagnitude = 0;
+      // by default sprites have direction 90 degrees, so that's a reasonable default
       let direction = 90;
-      for (const gamepad of getGamepads(pad)) {
-        const horizontalAxis = getAxisValue(gamepad, axis);
-        const verticalAxis = getAxisValue(gamepad, +axis + 1);
-        const magnitude = Math.sqrt(horizontalAxis ** 2 + verticalAxis ** 2);
+
+      const gamepads = getGamepads(pad);
+      for (const gamepad of gamepads) {
+        const magnitude = getAxisPairMagnitude(gamepad, axis);
         if (magnitude > greatestMagnitude) {
-          greatestMagnitude = magnitude;
-          direction =
-            (Math.atan2(verticalAxis, horizontalAxis) * 180) / Math.PI + 90;
-          if (direction < 0) {
-            direction += 360;
-          }
+          direction = getAxisPairDirection(gamepad, axis);
         }
       }
+
+      // if no sticks are far enough out, instead we'll return the last direction
+      // of the most recently modified gamepad
+      if (greatestMagnitude === 0 && gamepads.length > 0) {
+        gamepads.sort((a, b) => b.timestamp - a.timestamp);
+        direction = getAxisPairDirection(gamepads[0], axis);
+      }
+
       return direction;
     }
 
@@ -473,11 +584,11 @@
 
     rumble({ s, w, t, i }) {
       const gamepads = getGamepads(i);
-      for (const gamepad of gamepads) {
+      for (const { realGamepad } of gamepads) {
         // @ts-ignore
-        if (gamepad.vibrationActuator) {
+        if (realGamepad.vibrationActuator) {
           // @ts-ignore
-          gamepad.vibrationActuator.playEffect("dual-rumble", {
+          realGamepad.vibrationActuator.playEffect("dual-rumble", {
             startDelay: 0,
             duration: t * 1000,
             weakMagnitude: w,
@@ -486,6 +597,11 @@
         }
       }
     }
+
+    setAxisDeadzone({ DEADZONE }) {
+      axisDeadzone = Scratch.Cast.toNumber(DEADZONE);
+      updateState();
+    }
   }
 
   Scratch.extensions.register(new GamepadExtension());