box2d: disable physics and simulation rate blocks (#1190)

Resolves #1171, #925
TurboWarp · Dec 21, 2023 · 11ca543 · 11ca543
1 parent aefaa88
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diff --git a/docs/box2d.md b/docs/box2d.md
@@ -30,6 +30,15 @@ step simulation :: #0FBD8C
 
 Move forward in time by one step. Run this in a loop to keep the physics going.
 
+
+```scratch
+set simulation rate to (30)/s :: #0FBD8C
+```
+
+Set how much simulation steps is considered one second. Usually this should be project's framerate, but can also be used to slow down or speed up time.
+
+You can get the current simulation rate with the (simulation rate) reporter.
+
 ## Sprites
 
 Manipulate individual sprites.
@@ -48,6 +57,14 @@ Precision mode will make the sprite work extra hard to make sure it doesn't over
 
 ---
 
+```scratch
+disable physics for this sprite :: #0FBD8C
+```
+
+Makes physics no longer apply to this sprite.
+
+---
+
 ```scratch
 go to x: [0] y: [0] [in world v] :: #0FBD8C
 ```

diff --git a/extensions/box2d.js b/extensions/box2d.js
@@ -12244,6 +12244,14 @@
     return body;
   };
 
+  const _removeBody = function (id) {
+    if (!bodies[id]) return;
+
+    world.DestroyBody(bodies[id]);
+    delete bodies[id];
+    delete prevPos[id];
+  };
+
   const _applyForce = function (id, ftype, x, y, dir, pow) {
     const body = bodies[id];
     if (!body) {
@@ -12444,6 +12452,8 @@
     }
   };
 
+  let tickRate = 30;
+
   const blockIconURI =
     "data:image/svg+xml;base64,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";
   const menuIconURI =
@@ -12487,6 +12497,7 @@
         delete bodies[body];
         delete prevPos[body];
       }
+      tickRate = 30;
       // todo: delete joins?
     }
 
@@ -12593,6 +12604,17 @@
             },
             filter: [Scratch.TargetType.SPRITE],
           },
+          {
+            opcode: "disablePhysics",
+            blockType: BlockType.COMMAND,
+            text: Scratch.translate({
+              id: "griffpatch.disablePhysics",
+              default: "disable physics for this sprite",
+              description: "Disable Physics for this Sprite",
+            }),
+            arguments: {},
+            filter: [Scratch.TargetType.SPRITE],
+          },
           // {
           //     opcode: 'setPhysics',
           //     blockType: BlockType.COMMAND,
@@ -12630,6 +12652,32 @@
               description: "Run a single tick of the physics simulation",
             }),
           },
+          {
+            opcode: "setTickRate",
+            blockType: BlockType.COMMAND,
+            text: Scratch.translate({
+              id: "griffpatch.setTickRate",
+              default: "set simulation rate to [rate]/s",
+              description:
+                "Set the number of physics simulation steps to run per second",
+            }),
+            arguments: {
+              rate: {
+                type: ArgumentType.NUMBER,
+                defaultValue: 30,
+              },
+            },
+          },
+          {
+            opcode: "getTickRate",
+            blockType: BlockType.REPORTER,
+            text: Scratch.translate({
+              id: "griffpatch.getTickRate",
+              default: "simulation rate",
+              description:
+                "Get the number of physics simulation steps to run per second",
+            }),
+          },
 
           "---",
 
@@ -13219,7 +13267,7 @@
       this._checkMoved();
 
       // world.Step(1 / 30, 10, 10);
-      world.Step(1 / 30, 10, 10);
+      world.Step(1 / tickRate, 10, 10);
       world.ClearForces();
 
       for (const targetID in bodies) {
@@ -13248,6 +13296,18 @@
       }
     }
 
+    setTickRate(args) {
+      let rate = Scratch.Cast.toNumber(args.rate);
+      if (Number.isNaN(rate) || rate === Infinity) rate = 30;
+      rate = Math.max(rate, 0.01);
+
+      tickRate = rate;
+    }
+
+    getTickRate() {
+      return tickRate;
+    }
+
     _checkMoved() {
       for (const targetID in bodies) {
         const body = bodies[targetID];
@@ -13408,6 +13468,10 @@
       return body;
     }
 
+    disablePhysics(args, util) {
+      _removeBody(util.target.id);
+    }
+
     /**
      *
      * @param svg the svg element