fill out box2d methods

examples/box2d_demo/config.js

@@ -0,0 +1,8 @@
+var config = {
+  title: "Box2D Physics Demo",
+  width: 1280,
+  height: 720,
+  fullscreen: false
+}
+
+return config

examples/box2d_demo/main.js

@@ -0,0 +1,343 @@
+var box2d = use('box2d')
+var moth = use('moth', $_.delay)
+moth.initialize()
+var draw2d = use('draw2d')
+
+// Physics world setup
+var world = new box2d.World({
+  gravity: {x: 0, y: -10}
+})
+
+// Ground body (static)
+var ground = world.createBody({
+  type: 'static',
+  position: {x: 0, y: -10}
+})
+
+var groundShape = ground.createBoxShape({
+  width: 50,
+  height: 0.5,
+  density: 0,
+  friction: 0.7
+})
+
+// Walls
+var leftWall = world.createBody({
+  type: 'static',
+  position: {x: -25, y: 0}
+})
+leftWall.createBoxShape({
+  width: 0.5,
+  height: 30,
+  density: 0
+})
+
+var rightWall = world.createBody({
+  type: 'static',
+  position: {x: 25, y: 0}
+})
+rightWall.createBoxShape({
+  width: 0.5,
+  height: 30,
+  density: 0
+})
+
+// Dynamic bodies array
+var boxes = []
+var circles = []
+
+// Create some dynamic boxes
+for (var i = 0; i < 5; i++) {
+  var box = world.createBody({
+    type: 'dynamic',
+    position: {x: -10 + i * 4, y: 5 + i * 3},
+    angle: Math.random() * Math.PI
+  })
+  
+  box.createBoxShape({
+    width: 2,
+    height: 2,
+    density: 1.0,
+    friction: 0.3,
+    restitution: 0.5
+  })
+  
+  boxes.push(box)
+}
+
+// Create some circles
+for (var i = 0; i < 3; i++) {
+  var circle = world.createBody({
+    type: 'dynamic',
+    position: {x: 5 + i * 3, y: 10 + i * 2}
+  })
+  
+  circle.createCircleShape({
+    radius: 1,
+    density: 0.5,
+    friction: 0.2,
+    restitution: 0.8
+  })
+  
+  circles.push(circle)
+}
+
+// Connected bodies with distance joint
+var bodyA = world.createBody({
+  type: 'dynamic',
+  position: {x: -5, y: 15}
+})
+bodyA.createCircleShape({
+  radius: 0.5,
+  density: 1.0
+})
+
+var bodyB = world.createBody({
+  type: 'dynamic',
+  position: {x: 0, y: 15}
+})
+bodyB.createCircleShape({
+  radius: 0.5,
+  density: 1.0
+})
+
+var joint = world.createDistanceJoint({
+  bodyA: bodyA,
+  bodyB: bodyB,
+  localAnchorA: {x: 0, y: 0},
+  localAnchorB: {x: 0, y: 0},
+  length: 5
+})
+
+// Mouse interaction
+var mouseBody = null
+var mousePressed = false
+
+// Game state
+var camera = {x: 0, y: 0, zoom: 10}
+
+// Input state
+var keys = {}
+var mouse = {
+  pos: {x: 0, y: 0},
+  buttons: [false, false, false]
+}
+
+// Main update function
+prosperon.on('update', function(dt) {
+  // Step physics simulation
+  world.step(dt, 4)
+  
+  // Camera controls
+  if (keys[4]) camera.x -= 20 * dt  // A
+  if (keys[7]) camera.x += 20 * dt  // D
+  if (keys[26]) camera.y += 20 * dt // W
+  if (keys[22]) camera.y -= 20 * dt // S
+  if (keys[20]) camera.zoom *= 1 + dt // Q
+  if (keys[8]) camera.zoom *= 1 - dt  // E
+  
+  // Mouse interaction
+  var mouseWorld = screenToWorld(mouse.pos)
+    // Raycast to find body under mouse
+    var result = world.rayCast(mouseWorld, {x: 0, y: -1}, 0.1)
+    
+    if (!result.hit) {
+      // Create new body at mouse position
+      if (keys[225]) { // LSHIFT
+        // Create circle
+        var newCircle = world.createBody({
+          type: 'dynamic',
+          position: mouseWorld
+        })
+        newCircle.createCircleShape({
+          radius: 0.5 + Math.random(),
+          density: 1.0,
+          restitution: 0.3 + Math.random() * 0.5
+        })
+        circles.push(newCircle)
+      } else {
+        // Create box
+        var newBox = world.createBody({
+          type: 'dynamic',
+          position: mouseWorld,
+          angle: Math.random() * Math.PI * 2
+        })
+        newBox.createBoxShape({
+          width: 1 + Math.random() * 2,
+          height: 1 + Math.random() * 2,
+          density: 1.0,
+          restitution: 0.2 + Math.random() * 0.3
+        })
+        boxes.push(newBox)
+      }
+    }
+  
+    boxes.forEach(function(box) {
+      var dir = {
+        x: box.position.x - mouseWorld.x,
+        y: box.position.y - mouseWorld.y
+      }
+      var dist = Math.sqrt(dir.x * dir.x + dir.y * dir.y)
+      if (dist < 10 && dist > 0.1) {
+        dir.x /= dist
+        dir.y /= dist
+        box.applyLinearImpulse({x: dir.x * 50, y: dir.y * 50})
+      }
+    })
+
+  
+  // Reset with R
+  if (keys[21] && !keys[21 + '_prev']) { // R key pressed
+    // Reset all dynamic bodies
+    boxes.forEach(function(box) {
+      box.position = {x: Math.random() * 20 - 10, y: 10 + Math.random() * 10}
+      box.angle = Math.random() * Math.PI * 2
+      box.linearVelocity = {x: 0, y: 0}
+      box.angularVelocity = 0
+    })
+    
+    circles.forEach(function(circle) {
+      circle.position = {x: Math.random() * 20 - 10, y: 10 + Math.random() * 10}
+      circle.linearVelocity = {x: 0, y: 0}
+    })
+  }
+  
+  // Update previous key states
+  for (var k in keys) {
+    if (k.indexOf('_prev') === -1) {
+      keys[k + '_prev'] = keys[k]
+    }
+  }
+})
+
+// Event handlers
+prosperon.on('key_down', function(e) {
+  keys[e.scancode] = true
+})
+
+prosperon.on('key_up', function(e) {
+  keys[e.scancode] = false
+})
+
+prosperon.on('mouse_button_down', function(e) {
+  mouse.buttons[e.which] = true
+  
+  if (e.which === 0 && !mousePressed) {
+    mousePressed = true
+    var mouseWorld = screenToWorld(mouse.pos)
+    
+    // Raycast to find body under mouse
+    var result = world.rayCast(mouseWorld, {x: 0, y: -1}, 0.1)
+    
+    if (!result.hit) {
+      // Create new body at mouse position
+      if (keys[225]) { // LSHIFT
+        // Create circle
+        var newCircle = world.createBody({
+          type: 'dynamic',
+          position: mouseWorld
+        })
+        newCircle.createCircleShape({
+          radius: 0.5 + Math.random(),
+          density: 1.0,
+          restitution: 0.3 + Math.random() * 0.5
+        })
+        circles.push(newCircle)
+      } else {
+        // Create box
+        var newBox = world.createBody({
+          type: 'dynamic',
+          position: mouseWorld,
+          angle: Math.random() * Math.PI * 2
+        })
+        newBox.createBoxShape({
+          width: 1 + Math.random() * 2,
+          height: 1 + Math.random() * 2,
+          density: 1.0,
+          restitution: 0.2 + Math.random() * 0.3
+        })
+        boxes.push(newBox)
+      }
+    }
+  }
+  
+  if (e.which === 1) {
+    // Apply impulse with right click
+    var mouseWorld = screenToWorld(mouse.pos)
+    boxes.forEach(function(box) {
+      var dir = {
+        x: box.position.x - mouseWorld.x,
+        y: box.position.y - mouseWorld.y
+      }
+      var dist = Math.sqrt(dir.x * dir.x + dir.y * dir.y)
+      if (dist < 10 && dist > 0.1) {
+        dir.x /= dist
+        dir.y /= dist
+        box.applyLinearImpulse({x: dir.x * 50, y: dir.y * 50})
+      }
+    })
+  }
+})
+
+prosperon.on('mouse_button_up', function(e) {
+  mouse.buttons[e.which] = false
+  if (e.which === 0) {
+    mousePressed = false
+  }
+})
+
+prosperon.on('mouse_motion', function(e) {
+  mouse.pos = e.pos
+})
+
+// Rendering
+prosperon.on('draw', function() {
+  // Clear background
+  
+  // Draw ground
+  drawBox(ground.position, 50, 0.5, ground.angle, {r: 0.5, g: 0.5, b: 0.5, a: 1})
+  
+  // Draw walls
+  drawBox(leftWall.position, 0.5, 30, 0, {r: 0.5, g: 0.5, b: 0.5, a: 1})
+  drawBox(rightWall.position, 0.5, 30, 0, {r: 0.5, g: 0.5, b: 0.5, a: 1})
+  
+  // Draw boxes
+  boxes.forEach(function(box) {
+    drawBox(box.position, 2, 2, box.angle, {r: 0.8, g: 0.3, b: 0.3, a: 1})
+  })
+  
+  // Draw circles
+  circles.forEach(function(circle) {
+    draw2d.circle(circle.position, 1, {r: 0.3, g: 0.8, b: 0.3, a: 1})
+  })
+  
+  // Draw connected bodies
+  draw2d.circle(bodyA.position, 0.5, {r: 0.8, g: 0.8, b: 0.3, a: 1})
+  draw2d.circle(bodyB.position, 0.5, {r: 0.8, g: 0.8, b: 0.3, a: 1})
+  draw2d.line([bodyA.position, bodyB.position], {r: 1, g: 1, b: 0, a: 0.5})
+  
+  // Draw UI
+  draw2d.text("Box2D Demo", {x: 10, y: 10}, 20, {r: 1, g: 1, b: 1, a: 1})
+  draw2d.text("Controls:", {x: 10, y: 40}, 16, {r: 1, g: 1, b: 1, a: 1})
+  draw2d.text("- WASD: Move camera", {x: 10, y: 60}, 14, {r: 1, g: 1, b: 1, a: 1})
+  draw2d.text("- Q/E: Zoom in/out", {x: 10, y: 80}, 14, {r: 1, g: 1, b: 1, a: 1})
+  draw2d.text("- Left click: Create box", {x: 10, y: 100}, 14, {r: 1, g: 1, b: 1, a: 1})
+  draw2d.text("- Shift + Left click: Create circle", {x: 10, y: 120}, 14, {r: 1, g: 1, b: 1, a: 1})
+  draw2d.text("- Right click: Apply impulse", {x: 10, y: 140}, 14, {r: 1, g: 1, b: 1, a: 1})
+  draw2d.text("- R: Reset bodies", {x: 10, y: 160}, 14, {r: 1, g: 1, b: 1, a: 1})
+  
+  // Show physics stats
+  draw2d.text("Bodies: " + (boxes.length + circles.length + 4), {x: 10, y: 200}, 14, {r: 1, g: 1, b: 1, a: 1})
+})
+
+// Helper functions
+function drawBox(pos, width, height, angle, color) {
+  draw2d.rectangle({x:pos.x,y:pos.y,width, height})
+}
+
+function screenToWorld(screenPos) {
+  return {
+    x: (screenPos.x - prosperon.x * 0.5) / camera.zoom + camera.x,
+    y: (screenPos.y - prosperon.y * 0.5) / camera.zoom + camera.y
+  }
+}

source/jsffi.c

@@ -32,6 +32,7 @@
 #include "qjs_dmon.h"
 #include "qjs_nota.h"
 #include "qjs_wota.h"
+#include "qjs_box2d.h"
 #include "qjs_enet.h"
 #include "qjs_soloud.h"
 #include "qjs_qr.h"
@@ -2896,6 +2897,7 @@ void ffi_load(JSContext *js)
   arrput(rt->module_registry, MISTLINE(enet));
   arrput(rt->module_registry, MISTLINE(qr));
   arrput(rt->module_registry, MISTLINE(wota));
+  arrput(rt->module_registry, MISTLINE(box2d));
   arrput(rt->module_registry, MISTLINE(crypto));
   arrput(rt->module_registry, MISTLINE(blob));
   arrput(rt->module_registry, MISTLINE(http));

tests/box2d.js

@@ -1,13 +1,90 @@
 var box2d = use('box2d')
 
-var world = box2d.world()
-console.log(world.gravity)
-world.gravity = {x:0,y:-9.8}
-console.log(world.gravity)
-var body = world.body()
+// Create world with constructor
+var world = new box2d.World({gravity: {x: 0, y: -9.8}})
+console.log("Initial gravity:", world.gravity)
 
-world.step(10, 4);
-world.step(10, 4);
-world.step(10, 4);
+// Create a dynamic body
+var body = world.createBody({
+  type: 'dynamic',
+  position: {x: 0, y: 10}
+})
 
-console.log(body.getPosition())
+// Add a box shape to the body
+var shape = body.createBoxShape({
+  width: 1,
+  height: 1,
+  density: 1.0,
+  friction: 0.3,
+  restitution: 0.5
+})
+
+console.log("Initial position:", body.position)
+console.log("Initial velocity:", body.linearVelocity)
+
+// Simulate
+world.step(1/60, 4);
+console.log("After 1 step:", body.position)
+
+world.step(1/60, 4);
+console.log("After 2 steps:", body.position)
+
+world.step(1/60, 4);
+console.log("After 3 steps:", body.position)
+
+// Test applying forces
+body.applyForce({x: 100, y: 0})
+world.step(1/60, 4);
+console.log("After force:", body.position, "velocity:", body.linearVelocity)
+
+// Test properties
+console.log("Body type:", body.type)
+console.log("Body mass:", body.getMass())
+console.log("Body angle:", body.angle)
+
+// Test string body types
+var staticBody = world.createBody({
+  type: 'static',
+  position: {x: 0, y: 0}
+})
+console.log("Static body type:", staticBody.type)
+
+// Test ray casting
+var rayResult = world.rayCast({x: -5, y: 10}, {x: 10, y: 0}, 1.0)
+console.log("Ray cast result:", rayResult)
+
+// Test distance joint
+var bodyA = world.createBody({
+  type: 'dynamic',
+  position: {x: -2, y: 5}
+})
+bodyA.createCircleShape({
+  radius: 0.5,
+  density: 1.0
+})
+
+var bodyB = world.createBody({
+  type: 'dynamic',
+  position: {x: 2, y: 5}
+})
+bodyB.createCircleShape({
+  radius: 0.5,
+  density: 1.0
+})
+
+var joint = world.createDistanceJoint({
+  bodyA: bodyA,
+  bodyB: bodyB,
+  localAnchorA: {x: 0, y: 0},
+  localAnchorB: {x: 0, y: 0},
+  length: 4.0
+})
+
+console.log("Created distance joint")
+
+// Test multiple steps with joint
+for (var i = 0; i < 10; i++) {
+  world.step(1/60, 4)
+}
+console.log("Body A position after joint simulation:", bodyA.position)
+console.log("Body B position after joint simulation:", bodyB.position)