Particle physics experiment

Sources/arm/Context.hx

@@ -140,6 +140,7 @@ class Context {
 	public static var particleHitX = 0.0;
 	public static var particleHitY = 0.0;
 	public static var particleHitZ = 0.0;
+	public static var paintBody: arm.plugin.PhysicsBody = null;
 	#end
 
 	public static var layerFilter = 0;

Sources/arm/node/MakeParticle.hx

@@ -97,7 +97,9 @@ class MakeParticle {
 			vert.add_uniform('mat4 W', '_worldMatrix');
 			vert.write_attrib('wpos = mul(vec4(pos.xyz, 1.0), W);');
 			frag.add_uniform('vec3 particleHit', '_particleHit');
-			frag.write('float str = clamp(1.0 - distance(particleHit, wpos.xyz) * 2.0, 0.0, 1.0);');
+			frag.write('dist = distance(particleHit, wpos.xyz) * 20.0;');
+			frag.write('if (dist > 1.0) discard;');
+			frag.write('float str = 1.0;');
 			frag.write('if (particleHit.x == 0.0 && particleHit.y == 0.0 && particleHit.z == 0.0) str = 0.0;');
 			return;
 		}

Sources/arm/plugin/PhysicsWorld.hx

@@ -47,8 +47,8 @@ class PhysicsWorld extends iron.Trait {
 		init();
 
 		// Ensure physics are updated first in the lateUpdate list
-		_lateUpdate = [lateUpdate];
-		@:privateAccess iron.App.traitLateUpdates.insert(0, lateUpdate);
+		// _lateUpdate = [lateUpdate];
+		// @:privateAccess iron.App.traitLateUpdates.insert(0, lateUpdate);
 	}
 
 	public function reset() {
@@ -106,7 +106,7 @@ class PhysicsWorld extends iron.Trait {
 		return res;
 	}
 
-	function lateUpdate() {
+	public function lateUpdate() {
 		var t = Time.delta * timeScale;
 		if (t == 0.0) return; // Simulation paused
 

Sources/arm/render/RenderPathPaint.hx

@@ -122,7 +122,12 @@ class RenderPathPaint {
 		var tid = Context.layer.id;
 
 		if (Context.pdirty > 0) {
-			if (Context.tool == ToolParticle) {
+			#if arm_physics
+			var particlePhysics = Context.particlePhysics;
+			#else
+			var particlePhysics = false;
+			#end
+			if (Context.tool == ToolParticle && !particlePhysics) {
 				path.setTarget("texparticle");
 				path.clearTarget(0x00000000);
 				path.bindTarget("_main", "gbufferD");

Sources/arm/ui/UIHeader.hx

@@ -342,6 +342,11 @@ class UIHeader {
 				if (Context.tool == ToolParticle) {
 					ui._x += 10 * ui.SCALE();
 					var physHandle = Id.handle({ selected: false });
+					Context.particlePhysics = ui.check(physHandle, tr("Physics"));
+					if (physHandle.changed) {
+						arm.util.ParticleUtil.initParticlePhysics();
+						MakeMaterial.parsePaintMaterial();
+					}
 				}
 				#end
 			}

Sources/arm/ui/UISidebar.hx

@@ -431,6 +431,51 @@ class UISidebar {
 			borderHandle = null;
 			App.isResizing = false;
 		}
+
+		#if arm_physics
+		if (Context.tool == ToolParticle && Context.particlePhysics && inViewport && !Context.paint2d) {
+			var world = arm.plugin.PhysicsWorld.active;
+			world.lateUpdate();
+			Context.ddirty = 2;
+			Context.rdirty = 2;
+			if (mouse.started()) {
+				Scene.active.spawnObject(".Sphere", null, function(o: Object) {
+					iron.data.Data.getMaterial("Scene", ".Gizmo", function(md: MaterialData) {
+						var mo: MeshObject = cast o;
+						mo.name = ".Bullet";
+						mo.materials[0] = md;
+						mo.visible = true;
+
+						var camera = iron.Scene.active.camera;
+						var ct = camera.transform;
+						mo.transform.loc.set(ct.worldx(), ct.worldy(), ct.worldz());
+						mo.transform.scale.set(Context.brushRadius * 0.2, Context.brushRadius * 0.2, Context.brushRadius * 0.2);
+						mo.transform.buildMatrix();
+
+						var body = new arm.plugin.PhysicsBody();
+						body.shape = arm.plugin.PhysicsBody.ShapeType.ShapeSphere;
+						body.mass = 1.0;
+						mo.addTrait(body);
+
+						var ray = iron.math.RayCaster.getRay(mouse.viewX, mouse.viewY, camera);
+						body.applyImpulse(ray.direction.mult(0.1));
+
+						iron.system.Tween.timer(5, mo.remove);
+					});
+				});
+			}
+
+			var pairs = world.getContactPairs(Context.paintBody);
+			if (pairs != null) {
+				for (p in pairs) {
+					Context.particleHitX = p.posA.x;
+					Context.particleHitY = p.posA.y;
+					Context.particleHitZ = p.posA.z;
+					Context.pdirty = 1;
+				}
+			}
+		}
+		#end
 	}
 
 	public function toggleDistractFree() {
@@ -534,6 +579,13 @@ class UISidebar {
 		}
 		#end
 
+
+		#if arm_physics
+		if (Context.particlePhysics) {
+			down = false;
+		}
+		#end
+
 		#if krom_ios
 		// No hover on iPad, decals are painted by pen release
 		if (decal) {

Sources/arm/util/ParticleUtil.hx

@@ -109,9 +109,9 @@ class ParticleUtil {
 			po.transform.scale.y = po.parent.transform.scale.y;
 			po.transform.scale.z = po.parent.transform.scale.z;
 
-			var paintBody = new arm.plugin.PhysicsBody();
-			paintBody.shape = arm.plugin.PhysicsBody.ShapeType.ShapeMesh;
-			po.addTrait(paintBody);
+			Context.paintBody = new arm.plugin.PhysicsBody();
+			Context.paintBody.shape = arm.plugin.PhysicsBody.ShapeType.ShapeMesh;
+			po.addTrait(Context.paintBody);
 		});
 	}