From 4643f72634a8cfc4e683b243633a08c11ef08572 Mon Sep 17 00:00:00 2001
From: rexim <reximkut@gmail.com>
Date: Thu, 28 Nov 2019 21:08:51 +0700
Subject: [PATCH 1/3] Make dragging feel super good Kreygasm

---
 src/boomer.nim | 5 ++++-
 src/config.nim | 6 ++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/boomer.nim b/src/boomer.nim
index 4c89573..ec01333 100644
--- a/src/boomer.nim
+++ b/src/boomer.nim
@@ -301,7 +301,10 @@ proc main() =
         if mouse.drag:
           let delta = world(camera, mouse.prev) - world(camera, mouse.curr)
           camera.position += delta
-          camera.velocity = delta * config.dragVelocityFactor
+          # delta is the distance the mouse traveled in a single
+          # frame. To turn the velocity into units/second we need to
+          # multiple it by FPS.
+          camera.velocity = delta * config.fps.float
 
         mouse.prev = mouse.curr
 
diff --git a/src/config.nim b/src/config.nim
index 1221923..4a5d1ed 100644
--- a/src/config.nim
+++ b/src/config.nim
@@ -2,15 +2,13 @@ import macros, strutils
 
 type Config* = object
   scrollSpeed*: float
-  dragVelocityFactor*: float
   dragFriction*: float
   scaleFriction*: float
   fps*: int
 
 const defaultConfig* = Config(
-  scrollSpeed: 1.0,
-  dragVelocityFactor: 10.0,
-  dragFriction: 2.0,
+  scrollSpeed: 1.5,
+  dragFriction: 6.0,
   scaleFriction: 4.0,
   fps: 60
 )

From c3ab91f65888d2c5d81ae923f8699d121c97913b Mon Sep 17 00:00:00 2001
From: rexim <reximkut@gmail.com>
Date: Thu, 28 Nov 2019 21:13:33 +0700
Subject: [PATCH 2/3] Fix scale pivot until scaling animation is finished

---
 src/boomer.nim     | 2 ++
 src/navigation.nim | 7 ++++---
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/boomer.nim b/src/boomer.nim
index ec01333..beff16a 100644
--- a/src/boomer.nim
+++ b/src/boomer.nim
@@ -358,12 +358,14 @@ proc main() =
             flashlight.deltaRadius += INITIAL_FL_DELTA_RADIUS
           else:
             camera.deltaScale += config.scrollSpeed
+            camera.scalePivot = mouse.curr
 
         of Button5:             # Scoll down
           if (xev.xkey.state and ControlMask) > 0.uint32 and flashlight.isEnabled:
             flashlight.deltaRadius -= INITIAL_FL_DELTA_RADIUS
           else:
             camera.deltaScale -= config.scrollSpeed
+            camera.scalePivot = mouse.curr
 
         else:
           discard
diff --git a/src/navigation.nim b/src/navigation.nim
index 0aafc5e..ef0d363 100644
--- a/src/navigation.nim
+++ b/src/navigation.nim
@@ -3,7 +3,7 @@ import config
 import la
 import image
 
-const VELOCITY_THRESHOLD = 10.0
+const VELOCITY_THRESHOLD = 15.0
 
 type Mouse* = object
   curr*: Vec2f
@@ -15,6 +15,7 @@ type Camera* = object
   velocity*: Vec2f
   scale*: float32
   deltaScale*: float
+  scalePivot*: Vec2f
 
 proc world*(camera: Camera, v: Vec2f): Vec2f =
   v / camera.scale
@@ -22,9 +23,9 @@ proc world*(camera: Camera, v: Vec2f): Vec2f =
 proc update*(camera: var Camera, config: Config, dt: float, mouse: Mouse, image: Image,
              windowSize: Vec2f) =
   if abs(camera.deltaScale) > 0.5:
-    let p0 = (mouse.curr - (windowSize * 0.5)) / camera.scale
+    let p0 = (camera.scalePivot - (windowSize * 0.5)) / camera.scale
     camera.scale = max(camera.scale + camera.delta_scale * dt, 0.01)
-    let p1 = (mouse.curr - (windowSize * 0.5)) / camera.scale
+    let p1 = (camera.scalePivot - (windowSize * 0.5)) / camera.scale
     camera.position += p0 - p1
 
     camera.delta_scale -= camera.delta_scale * dt * config.scale_friction

From 88530c9eb8924f03431742aa9b7d494d30b5e499 Mon Sep 17 00:00:00 2001
From: rexim <reximkut@gmail.com>
Date: Thu, 28 Nov 2019 21:17:25 +0700
Subject: [PATCH 3/3] Make radius animation sort of okay for now

---
 src/boomer.nim | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/boomer.nim b/src/boomer.nim
index beff16a..be74ffd 100644
--- a/src/boomer.nim
+++ b/src/boomer.nim
@@ -83,13 +83,13 @@ type Flashlight = object
   deltaRadius: float32
 
 const
-  INITIAL_FL_DELTA_RADIUS = 100.0
-  FL_DELTA_RADIUS_DECELERATION = 5.0
+  INITIAL_FL_DELTA_RADIUS = 250.0
+  FL_DELTA_RADIUS_DECELERATION = 10.0
 
 proc update(flashlight: var Flashlight, dt: float32) =
   flashlight.radius = max(0.0, flashlight.radius + flashlight.deltaRadius * dt)
 
-  if abs(flashlight.deltaRadius) > 0.5:
+  if abs(flashlight.deltaRadius) > 1.0:
     flashlight.deltaRadius -= flashlight.deltaRadius * FL_DELTA_RADIUS_DECELERATION * dt
 
   if flashlight.isEnabled: