From 48cc046fce3837c401c04d2dd4e3d9b48c07a8aa Mon Sep 17 00:00:00 2001
From: Tom Aisthorpe <tomaisthorpe@gmail.com>
Date: Wed, 4 Sep 2024 20:55:30 +0100
Subject: [PATCH] feat(cameras): add max lead to fixed axis

---
 .changeset/thick-rockets-drive.md             |  5 +++++
 .../examples/cameras/fixed-axis-controller.ts |  2 ++
 .../cameras/fixed-axis-camera-controller.ts   | 21 +++++++++++++++++--
 3 files changed, 26 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/thick-rockets-drive.md

diff --git a/.changeset/thick-rockets-drive.md b/.changeset/thick-rockets-drive.md
new file mode 100644
index 0000000..84b2d55
--- /dev/null
+++ b/.changeset/thick-rockets-drive.md
@@ -0,0 +1,5 @@
+---
+'@tedengine/ted': minor
+---
+
+Add max lead option to fixed axis controller
diff --git a/apps/docs/src/examples/cameras/fixed-axis-controller.ts b/apps/docs/src/examples/cameras/fixed-axis-controller.ts
index 9d321c5..5ebb7d8 100644
--- a/apps/docs/src/examples/cameras/fixed-axis-controller.ts
+++ b/apps/docs/src/examples/cameras/fixed-axis-controller.ts
@@ -76,6 +76,7 @@ class ColliderState extends TGameState {
     this.addActor(plane);
 
     const camera = new TPerspectiveCamera(engine);
+    camera.lerp = 0.1;
     this.addActor(camera);
     // this.activeCamera = camera;
     camera.cameraComponent.showDebugCamera(engine);
@@ -90,6 +91,7 @@ class ColliderState extends TGameState {
       distance: 5,
       axis: 'z',
       leadFactor: 0.5,
+      maxLead: 0.9,
     });
     controller.attachTo(box.rootComponent);
     camera.controller = controller;
diff --git a/packages/ted/src/cameras/fixed-axis-camera-controller.ts b/packages/ted/src/cameras/fixed-axis-camera-controller.ts
index ccfa816..133fdbb 100644
--- a/packages/ted/src/cameras/fixed-axis-camera-controller.ts
+++ b/packages/ted/src/cameras/fixed-axis-camera-controller.ts
@@ -28,6 +28,7 @@ export default class TFollowAxisCameraController implements TCameraController {
 
   private lastPosition?: vec3;
   public leadFactor = 0; // Adjustable lead factor
+  public maxLead = 0; // Maximum lead distance
 
   constructor(config?: {
     distance?: number;
@@ -35,6 +36,7 @@ export default class TFollowAxisCameraController implements TCameraController {
     deadzone?: number;
     bounds?: { min: vec3; max: vec3 };
     leadFactor?: number;
+    maxLead?: number;
   }) {
     if (config?.distance !== undefined) {
       this.distance = config.distance;
@@ -65,6 +67,10 @@ export default class TFollowAxisCameraController implements TCameraController {
     if (config?.leadFactor !== undefined) {
       this.leadFactor = config.leadFactor;
     }
+
+    if (config?.maxLead !== undefined) {
+      this.maxLead = config.maxLead;
+    }
   }
 
   attachTo(component: TSceneComponent) {
@@ -88,9 +94,20 @@ export default class TFollowAxisCameraController implements TCameraController {
     }
     this.lastPosition = vec3.clone(currentPosition);
 
-    // Calculate lead position
+    // Calculate lead position with maximum lead
     const leadPosition = vec3.create();
-    vec3.scaleAndAdd(leadPosition, currentPosition, velocity, this.leadFactor);
+    const leadVector = vec3.create();
+    vec3.scale(leadVector, velocity, this.leadFactor);
+
+    // Limit the lead vector to the maximum lead distance
+    if (this.maxLead > 0) {
+      const leadDistance = vec3.length(leadVector);
+      if (leadDistance > this.maxLead) {
+        vec3.scale(leadVector, leadVector, this.maxLead / leadDistance);
+      }
+    }
+
+    vec3.add(leadPosition, currentPosition, leadVector);
 
     const distance = vec3.multiply(
       vec3.create(),