Begin particle physics

Sources/arm/Context.hx

@@ -134,6 +134,10 @@ class Context {
 	public static var textToolImage: Image = null;
 	public static var textToolText: String;
 	public static var particleMaterial: MaterialData = null;
+	public static var particlePhysics = false;
+	public static var particleHitX = 0.0;
+	public static var particleHitY = 0.0;
+	public static var particleHitZ = 0.0;
 
 	public static var layerFilter = 0;
 	public static var runBrush: Int->Void = null;

Sources/arm/node/MakePaint.hx

@@ -318,12 +318,20 @@ class MakePaint {
 		frag.write('if (opacity == 0.0) discard;');
 
 		if (Context.tool == ToolParticle) { // Particle mask
-			frag.add_uniform('sampler2D texparticle', '_texparticle');
-			#if (kha_direct3d11 || kha_direct3d12 || kha_metal || kha_vulkan)
-			frag.write('float str = textureLod(texparticle, sp.xy, 0.0).r;');
-			#else
-			frag.write('float str = textureLod(texparticle, vec2(sp.x, (1.0 - sp.y)), 0.0).r;');
-			#end
+			if (Context.particlePhysics) {
+				vert.add_out('vec4 wpos');
+				vert.add_uniform('mat4 W', '_worldMatrix');
+				vert.write_attrib('wpos = mul(vec4(pos.xyz, 1.0), W);');
+				frag.add_uniform('vec3 particleHit', '_particleHit');
+			}
+			else {
+				frag.add_uniform('sampler2D texparticle', '_texparticle');
+				#if (kha_direct3d11 || kha_direct3d12 || kha_metal || kha_vulkan)
+				frag.write('float str = textureLod(texparticle, sp.xy, 0.0).r;');
+				#else
+				frag.write('float str = textureLod(texparticle, vec2(sp.x, (1.0 - sp.y)), 0.0).r;');
+				#end
+			}
 		}
 		else { // Brush cursor mask
 			frag.write('float str = clamp((brushRadius - dist) * brushHardness * 400.0, 0.0, 1.0) * opacity;');

Sources/arm/render/Uniforms.hx

@@ -214,6 +214,11 @@ class Uniforms {
 				v.set(Context.swatch.normal.R, Context.swatch.normal.G, Context.swatch.normal.B);
 				return v;
 			}
+			case "_particleHit": {
+				v = iron.object.Uniforms.helpVec;
+				v.set(Context.particleHitX, Context.particleHitY, Context.particleHitZ);
+				return v;
+			}
 		}
 
 		return v;

Sources/arm/ui/UIHeader.hx

@@ -325,6 +325,11 @@ class UIHeader {
 						MakeMaterial.parsePaintMaterial();
 					}
 				}
+
+				if (Context.tool == ToolParticle) {
+					ui._x += 10 * ui.SCALE();
+					var physHandle = Id.handle({selected: false});
+				}
 			}
 		}
 	}

Sources/arm/util/ParticleUtil.hx

@@ -86,6 +86,7 @@ class ParticleUtil {
 			Scene.active.spawnObject(".Sphere", null, function(o: Object) {
 				var mo: MeshObject = cast o;
 				mo.name = ".ParticleEmitter";
+				mo.raw = Json.parse(Json.stringify(mo.raw));
 				mo.raw.particle_refs = particle_refs;
 				#if arm_particles
 				mo.setupParticleSystem("Scene", particle_refs[0]);
@@ -93,4 +94,26 @@ class ParticleUtil {
 			});
 		});
 	}
+
+	#if arm_physics
+
+	public static function initParticlePhysics() {
+		if (arm.plugin.PhysicsWorld.active != null) return;
+
+		arm.plugin.PhysicsWorld.load(function() {
+			Scene.active.sceneParent.addTrait(new arm.plugin.PhysicsWorld());
+
+			var po = Context.mergedObject != null ? Context.mergedObject : Context.paintObject;
+
+			po.transform.scale.x = po.parent.transform.scale.x;
+			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);
+		});
+	}
+
+	#end
 }