212 box2d dynamic scale

physics/box2d_dynamic_scale/all.texture_profiles

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+path_settings {
+  path: "**"
+  profile: "Default"
+}
+profiles {
+  name: "Default"
+  platforms {
+    os: OS_ID_GENERIC
+    formats {
+      format: TEXTURE_FORMAT_RGBA
+      compression_level: BEST
+      compression_type: COMPRESSION_TYPE_DEFAULT
+    }
+    mipmaps: false
+    max_texture_size: 0
+    premultiply_alpha: true
+  }
+}

physics/box2d_dynamic_scale/box2d_v2.appmanifest

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+platforms:
+  arm64-ios:
+    context:
+      excludeLibs: []
+      excludeSymbols: []
+      symbols: []
+      libs: []
+      frameworks: []
+      linkFlags: []
+  x86_64-ios:
+    context:
+      excludeLibs: []
+      excludeSymbols: []
+      symbols: []
+      libs: []
+      frameworks: []
+      linkFlags: []
+  armv7-android:
+    context:
+      excludeLibs: []
+      excludeJars: []
+      excludeSymbols: []
+      symbols: []
+      libs: []
+      linkFlags: []
+      jetifier: true
+  arm64-android:
+    context:
+      excludeLibs: []
+      excludeJars: []
+      excludeSymbols: []
+      symbols: []
+      libs: []
+      linkFlags: []
+      jetifier: true
+  arm64-osx:
+    context:
+      excludeLibs: []
+      excludeSymbols: []
+      symbols: []
+      libs: []
+      frameworks: []
+      linkFlags: []
+  x86_64-osx:
+    context:
+      excludeLibs: []
+      excludeSymbols: []
+      symbols: []
+      libs: []
+      frameworks: []
+      linkFlags: []
+  x86_64-linux:
+    context:
+      excludeLibs: []
+      excludeSymbols: []
+      symbols: []
+      libs: []
+      linkFlags: []
+  arm64-linux:
+    context:
+      excludeLibs: []
+      excludeSymbols: []
+      symbols: []
+      libs: []
+      linkFlags: []
+  x86-win32:
+    context:
+      excludeLibs: []
+      excludeSymbols: []
+      symbols: []
+      libs: []
+      linkFlags: []
+  x86_64-win32:
+    context:
+      excludeLibs: []
+      excludeSymbols: []
+      symbols: []
+      libs: []
+      linkFlags: []
+  wasm-web:
+    context:
+      excludeLibs: []
+      excludeJsLibs: []
+      excludeSymbols: []
+      symbols: []
+      libs: []
+      linkFlags: []
+  wasm_pthread-web:
+    context:
+      excludeLibs: []
+      excludeJsLibs: []
+      excludeSymbols: []
+      symbols: []
+      libs: []
+      linkFlags: []

physics/box2d_dynamic_scale/box2d_v3.appmanifest

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+platforms:
+  armv7-ios:
+    context:
+      excludeLibs: [physics, box2d_defold, script_box2d_defold]
+      excludeSymbols: []
+      libs: [physics_2d, box2d, script_box2d, physics_3d]
+  arm64-ios:
+    context:
+      excludeLibs: [physics, box2d_defold, script_box2d_defold]
+      excludeSymbols: []
+      symbols: []
+      libs: [physics_2d, box2d, script_box2d, physics_3d]
+      frameworks: []
+      linkFlags: []
+  x86_64-ios:
+    context:
+      excludeLibs: [physics, box2d_defold, script_box2d_defold]
+      excludeSymbols: []
+      symbols: []
+      libs: [physics_2d, box2d, script_box2d, physics_3d]
+      frameworks: []
+      linkFlags: []
+  armv7-android:
+    context:
+      excludeLibs: [physics, box2d_defold, script_box2d_defold]
+      excludeJars: []
+      excludeSymbols: []
+      symbols: []
+      libs: [physics_2d, box2d, script_box2d, physics_3d]
+      linkFlags: []
+      jetifier: true
+  arm64-android:
+    context:
+      excludeLibs: [physics, box2d_defold, script_box2d_defold]
+      excludeJars: []
+      excludeSymbols: []
+      symbols: []
+      libs: [physics_2d, box2d, script_box2d, physics_3d]
+      linkFlags: []
+      jetifier: true
+  arm64-osx:
+    context:
+      excludeLibs: [physics, box2d_defold, script_box2d_defold]
+      excludeSymbols: []
+      symbols: []
+      libs: [physics_2d, box2d, script_box2d, physics_3d]
+      frameworks: []
+      linkFlags: []
+  x86_64-osx:
+    context:
+      excludeLibs: [physics, box2d_defold, script_box2d_defold]
+      excludeSymbols: []
+      symbols: []
+      libs: [physics_2d, box2d, script_box2d, physics_3d]
+      frameworks: []
+      linkFlags: []
+  x86_64-linux:
+    context:
+      excludeLibs: [physics, box2d_defold, script_box2d_defold]
+      excludeSymbols: []
+      symbols: []
+      libs: [physics_2d, box2d, script_box2d, physics_3d]
+      linkFlags: []
+  arm64-linux:
+    context:
+      excludeLibs: [physics, box2d_defold, script_box2d_defold]
+      excludeSymbols: []
+      symbols: []
+      libs: [physics_2d, box2d, script_box2d, physics_3d]
+      linkFlags: []
+  x86-win32:
+    context:
+      excludeLibs: [libphysics, libbox2d_defold, script_box2d_defold]
+      excludeSymbols: []
+      symbols: []
+      libs: [libphysics_2d.lib, libbox2d.lib, libscript_box2d.lib, libphysics_3d.lib]
+      linkFlags: []
+  x86_64-win32:
+    context:
+      excludeLibs: [libphysics, libbox2d_defold, script_box2d_defold]
+      excludeSymbols: []
+      symbols: []
+      libs: [libphysics_2d.lib, libbox2d.lib, libscript_box2d.lib, libphysics_3d.lib]
+      linkFlags: []
+  wasm-web:
+    context:
+      excludeLibs: [physics, box2d_defold, script_box2d_defold]
+      excludeJsLibs: []
+      excludeSymbols: []
+      symbols: []
+      libs: [physics_2d, box2d, script_box2d, physics_3d]
+      linkFlags: []
+  wasm_pthread-web:
+    context:
+      excludeLibs: [physics, box2d_defold, script_box2d_defold]
+      excludeJsLibs: []
+      excludeSymbols: []
+      symbols: []
+      libs: [physics_2d, box2d, script_box2d, physics_3d]
+      linkFlags: []

physics/box2d_dynamic_scale/example.md

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+---
+tags: physics, box2d
+title: Box2D dynamic shape scale and mass
+brief: Resize dynamic Box2D collision shapes at runtime and recalculate body mass.
+author: Defold Foundation
+scripts: box2d_dynamic_scale_v3.script, box2d_dynamic_scale_v2.script
+thumbnail: thumbnail.webp
+---
+
+This example shows how to change bodies shapes and mass in runtime.
+
+It includes 4 independent dynamic Box2D bodies.
+
+Click or tap to give every square body a new random size,
+update its collision shape, recalculate its mass, and apply a random  impulse.
+
+## What You'll Learn
+
+- How to get a Box2D body from a Defold collision object
+- How to detect the active Box2D version with `b2d.get_version()`
+- How to resize collision geometry through the V2 fixture API
+- How to resize collision geometry through the V3 shape API
+- How `update_mass = true` makes body mass follow the new collision size
+- How to apply a dynamic impulse to the body
+
+## Setup
+
+The collection contains four instances of `block.go` game object.
+The `block.go` prototype contains:
+
+- `script_v3`, which runs only with the Box2D V3 backend
+- `script_v2`, which runs only with the Box2D V2 backend
+- a square sprite
+- a dynamic box collision object with base half-extents of `40.0`
+
+The collection also contains `walls` game object with:
+
+- one static collision object with four box shapes around the play area
+- a label that explains the click or tap interaction.
+
+![setup](setup.png)
+
+The `game.project` of this example is configured to build with `/box2d_v3.appmanifest` by default.
+To test V2 locally after downloading the example, change `Native Extensions -> App Manifest` in `game.project` to `/box2d_v2.appmanifest`.
+
+## How It Works
+
+Both scripts read `b2d.get_version()` in `init()` and are only active if a matching version is used -
+`box2d_dynamic_scale_v2.script` only continues when the major version is 2,
+while `box2d_dynamic_scale_v3.script` only continues when the major version is 3.
+
+The active script acquires input focus and initialized a random number generator.
+
+When the built-in `touch` action is pressed, each block picks a random uniform scale from `0.5` to `1.5`.
+The script multiplies the base sprite size and base collision half-extent by that scale,
+so the visible square and physics box stay aligned.
+
+The mass changes because `update_mass = true` makes Box2D recalculate the body mass from the resized shape.
+
+In Box2D V2, collision geometry is attached to a body through fixtures.
+The V2 script reads the first fixture with `b2d.body.get_fixtures()`
+and resizes it with `b2d.fixture.set_shape(body, fixture.index, shape, true)`.
+
+In Box2D V3, collision geometry is attached through shapes.
+The V3 script reads the first shape with `b2d.body.get_shapes()`
+and resizes it with `b2d.shape.set_shape(shape.shape_id, shape, true)`.
+
+After resizing, the active script applies a random linear impulse at the body's world center.
+Since each body has just recalculated its mass from its new collision size,
+the resulting movement makes the size and mass changes visible.

physics/box2d_dynamic_scale/example/block.go

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+components {
+  id: "script_v3"
+  component: "/example/box2d_dynamic_scale_v3.script"
+}
+components {
+  id: "script_v2"
+  component: "/example/box2d_dynamic_scale_v2.script"
+}
+embedded_components {
+  id: "sprite"
+  type: "sprite"
+  data: "default_animation: \"body_soft\"\n"
+  "material: \"/builtins/materials/sprite.material\"\n"
+  "size {\n"
+  "  x: 80.0\n"
+  "  y: 80.0\n"
+  "}\n"
+  "size_mode: SIZE_MODE_MANUAL\n"
+  "textures {\n"
+  "  sampler: \"texture_sampler\"\n"
+  "  texture: \"/textures/textures.atlas\"\n"
+  "}\n"
+  ""
+}
+embedded_components {
+  id: "collisionobject"
+  type: "collisionobject"
+  data: "type: COLLISION_OBJECT_TYPE_DYNAMIC\n"
+  "mass: 1.0\n"
+  "friction: 0.2\n"
+  "restitution: 0.2\n"
+  "group: \"block\"\n"
+  "mask: \"block\"\n"
+  "mask: \"wall\"\n"
+  "embedded_collision_shape {\n"
+  "  shapes {\n"
+  "    shape_type: TYPE_BOX\n"
+  "    position {\n"
+  "    }\n"
+  "    rotation {\n"
+  "    }\n"
+  "    index: 0\n"
+  "    count: 3\n"
+  "    id: \"box\"\n"
+  "  }\n"
+  "  data: 40.0\n"
+  "  data: 40.0\n"
+  "  data: 10.0\n"
+  "}\n"
+  "linear_damping: 0.2\n"
+  "angular_damping: 0.1\n"
+  ""
+}