Merge pull request #34 from tsoding/33

(#33) Add config

src/boomer.nim

@@ -1,12 +1,13 @@
+import os
+import math
+
 import x11/xlib, x11/x, x11/xutil
 import opengl, opengl/glx
-import math
 
 import vec2
 import navigation
 import image
-
-const FPS: int = 60
+import config
 
 template checkError(context: string) =
   let error = glGetError()
@@ -49,6 +50,15 @@ const
   WHEEL_DOWN = 5
 
 proc main() =
+  var config = defaultConfig
+  var configFile = ""
+
+  if paramCount() > 0:
+    configFile = paramStr(1)
+    config = loadConfig(configFile)
+
+  echo "Using config: ", config
+
   var display = XOpenDisplay(nil)
   if display == nil:
     quit "Failed to open display"
@@ -149,6 +159,7 @@ proc main() =
   var camera = Camera(scale: 1.0)
   var mouse: Mouse
 
+
   while not quitting:
     var xev: TXEvent
     while XPending(display) > 0:
@@ -163,7 +174,7 @@ proc main() =
 
         if mouse.drag:
           camera.position += camera.world(mouse.curr) - camera.world(mouse.prev)
-          camera.velocity = (mouse.curr - mouse.prev) * DRAG_VELOCITY_FACTOR
+          camera.velocity = (mouse.curr - mouse.prev) * config.drag_velocity_factor
           mouse.prev = mouse.curr
 
       of ClientMessage:
@@ -177,6 +188,11 @@ proc main() =
           camera.delta_scale = 0.0
           camera.position = (0.0, 0.0)
           camera.velocity = (0.0, 0.0)
+        of 24:
+          quitting = true
+        of 27:
+          if configFile.len > 0:
+            config = loadConfig(configFile)
         else:
           discard
 
@@ -187,10 +203,10 @@ proc main() =
           mouse.drag = true
 
         of WHEEL_UP:
-          camera.delta_scale += SCROLL_SPEED
+          camera.delta_scale += config.scroll_speed
 
         of WHEEL_DOWN:
-          camera.delta_scale -= SCROLL_SPEED
+          camera.delta_scale -= config.scroll_speed
 
         else:
           discard
@@ -204,7 +220,7 @@ proc main() =
       else:
         discard
 
-    camera.update(1.0 / FPS.float, mouse)
+    camera.update(config, 1.0 / config.fps.float, mouse)
     screenshot.display(camera)
 
     glXSwapBuffers(display, win)

src/config.nim

@@ -0,0 +1,37 @@
+import macros
+import strutils
+
+type Config* = object
+  scrollSpeed*: float
+  dragVelocityFactor*: float
+  dragFriction*: float
+  scaleFriction*: float
+  fps*: int
+
+const defaultConfig* = Config(
+  scroll_speed: 1.0,
+  drag_velocity_factor: 20.0,
+  drag_friction: 2000.0,
+  scale_friction: 5.0,
+  fps: 60
+)
+
+proc loadConfig*(filePath: string): Config =
+  result = defaultConfig
+  for line in filePath.lines:
+    let pair = line.split('=')
+    let key = pair[0].strip
+    let value = pair[1].strip
+    case key
+    of "scroll_speed":
+      result.scroll_speed = value.parseFloat
+    of "drag_velocity_factor":
+      result.drag_velocity_factor = value.parseFloat
+    of "drag_friction":
+      result.drag_friction = value.parseFloat
+    of "scale_friction":
+      result.scale_friction = value.parseFloat
+    of "fps":
+      result.fps = value.parseInt
+    else:
+      raise newException(Exception, "Unknown config key " & key)

src/navigation.nim

@@ -1,10 +1,6 @@
 import vec2
 import math
-
-const SCROLL_SPEED* = 1.0
-const DRAG_VELOCITY_FACTOR*: float = 20.0
-const FRICTION*: float = 2000.0
-const SCALE_FRICTION*: float = 5.0
+import config
 
 type Mouse* = object
   curr*: Vec2
@@ -23,15 +19,15 @@ proc world*(camera: Camera, v: Vec2): Vec2 =
 proc screen*(camera: Camera, v: Vec2): Vec2 =
   v * camera.scale + camera.position
 
-proc update*(camera: var Camera, dt: float, mouse: Mouse) =
+proc update*(camera: var Camera, config: Config, dt: float, mouse: Mouse) =
   if abs(camera.delta_scale) > 0.5:
     let wp0 = camera.world(mouse.curr)
     camera.scale = max(camera.scale + camera.delta_scale * dt, 1.0)
     let wp1 = camera.world(mouse.curr)
     let dwp = wp1 - wp0
     camera.position += dwp
-    camera.delta_scale -= sgn(camera.delta_scale).float * SCALE_FRICTION * dt
+    camera.delta_scale -= sgn(camera.delta_scale).float * config.scale_friction * dt
 
   if not mouse.drag and (camera.velocity.len > 20.0):
     camera.position += camera.velocity * dt
-    camera.velocity = camera.velocity - camera.velocity.norm * FRICTION * dt
+    camera.velocity = camera.velocity - camera.velocity.norm * config.drag_friction * dt