Make navigation actually usable

src/boomer.nim

@@ -71,7 +71,8 @@ proc draw(screenshot: Image, camera: var Camera, shader, vao, texture: GLuint) =
 
   glUseProgram(shader)
 
-  glUniformMatrix4fv(glGetUniformLocation(shader, "transform".cstring), 1, false, camera.matrix.caddr)
+  glUniform2f(glGetUniformLocation(shader, "cameraPos".cstring), camera.position[0], camera.position[1])
+  glUniform1f(glGetUniformLocation(shader, "cameraScale".cstring), camera.scale)
 
   glBindVertexArray(vao)
   glDrawElements(GL_TRIANGLES, count = 6, GL_UNSIGNED_INT, indices = nil)
@@ -248,7 +249,7 @@ proc main() =
 
   var
     quitting = false
-    camera = Camera(scale: 1.0, matrix: mat4f(1))
+    camera = Camera(scale: 1.0)
     mouse: Mouse
 
   while not quitting:
@@ -263,13 +264,13 @@ proc main() =
         discard
 
       of MotionNotify:
-        mouse.curr = vec2(xev.xmotion.x.float32 / screenshot.width.float32 * 2.0'f32 - 1.0'f32,
-                          xev.xmotion.y.float32 / screenshot.height.float32 * 2.0'f32 - 1.0'f32)
+        mouse.curr = vec2(xev.xmotion.x.float32,
+                          xev.xmotion.y.float32)
 
         if mouse.drag:
-          let mouseDelta = mouse.prev - mouse.curr
-          camera.position += mouseDelta
-          camera.velocity = mouseDelta * config.dragVelocityFactor
+          let delta = world(mouse.prev, screenshot, camera) - world(mouse.curr, screenshot, camera)
+          camera.position += delta
+          camera.velocity = delta * config.dragVelocityFactor
           mouse.prev = mouse.curr
 
       of ClientMessage:
@@ -316,7 +317,7 @@ proc main() =
       else:
         discard
 
-    camera.update(config, 1.0 / config.fps.float, mouse)
+    camera.update(config, 1.0 / config.fps.float, mouse, screenshot)
 
     screenshot.draw(camera, shaderProgram, vao, texture)
 

src/config.nim

@@ -5,7 +5,6 @@ type Config* = object
   dragVelocityFactor*: float
   dragFriction*: float
   scaleFriction*: float
-  scalePanning*: float
   fps*: int
 
 const defaultConfig* = Config(
@@ -13,7 +12,6 @@ const defaultConfig* = Config(
   dragVelocityFactor: 10.0,
   dragFriction: 1.0,
   scaleFriction: 10.0,
-  scalePanning: 0.05,
   fps: 60
 )
 

src/la.nim

@@ -1,18 +1,23 @@
 import math
 
 type Vec2f* = tuple[x: float32, y: float32]
-type Mat4f* = array[0 .. 15, float32]
 
 proc vec2*(x: float32, y: float32): Vec2f = (x, y)
 
-proc caddr*(a: var Mat4f): ptr float32 =
-  addr a[0]
-
 proc `*`*(a: Vec2f, s: float32): Vec2f =
-  (a.x * s, a.y * s)
+  vec2(a.x * s, a.y * s)
+
+proc `*`*(a: Vec2f, b: Vec2f): Vec2f =
+  vec2(a.x * b.x, a.y * b.y)
+
+proc `/`*(a: Vec2f, b: Vec2f): Vec2f =
+  vec2(a.x / b.x, a.y / b.y)
 
 proc `-`*(a: Vec2f, b: Vec2f): Vec2f =
-  (a.x - b.x, a.y - b.y)
+  vec2(a.x - b.x, a.y - b.y)
+
+proc `+`*(a: Vec2f, b: Vec2f): Vec2f =
+  vec2(a.x + b.x, a.y + b.y)
 
 proc `+=`*(a: var Vec2f, b: Vec2f) =
   a.x += b.x
@@ -28,24 +33,6 @@ proc length*(a: Vec2f): float32 =
 proc normalize*(a: Vec2f): Vec2f =
   let b = a.length
   if b == 0.0'f32:
-    return (0.0'f32, 0.0'f32)
+    return vec2(0.0'f32, 0.0'f32)
   else:
-    return (a.x / b, a.y / b)
-
-proc mat4f*(x: float32): Mat4f =
-  [x,       0.0'f32, 0.0'f32, 0.0'f32,
-   0.0'f32, x,       0.0'f32, 0.0'f32,
-   0.0'f32, 0.0'f32, x,       0.0'f32,
-   0.0'f32, 0.0'f32, 0.0'f32, x]
-
-proc translate*(mat: Mat4f, x: float32, y: float32, z: float32): Mat4f =
-  result = mat
-  result[12] += x
-  result[13] += y
-  result[14] += z
-
-proc scale*(mat: Mat4f, s: float32): Mat4f =
-  result = mat
-  result[0 * 4 + 0] *= s
-  result[1 * 4 + 1] *= s
-  result[2 * 4 + 2] *= s
+    return vec2(a.x / b, a.y / b)

src/navigation.nim

@@ -1,6 +1,7 @@
 import math
 import config
 import la
+import image
 
 type Mouse* = object
   curr*: Vec2f
@@ -10,19 +11,22 @@ type Mouse* = object
 type Camera* = object
   position*: Vec2f
   velocity*: Vec2f
-  scale*: float
+  scale*: float32
   deltaScale*: float
-  matrix*: Mat4f
 
-proc update*(camera: var Camera, config: Config, dt: float, mouse: Mouse) =
+proc world*(point: Vec2f, image: Image, camera: Camera): Vec2f =
+  let f = (camera.position + vec2(1.0f32, 1.0f32)) / vec2(2.0f32, 2.0f32)
+  let ps = vec2(image.width.float32 * camera.scale, image.height.float32 * camera.scale) * f
+  let ms = vec2(point.x.float32, point.y.float32) + ps
+  return vec2(ms.x / (image.width.float32 * camera.scale) * 2.0f32 - 1.0f32,
+              ms.y / (image.height.float32 * camera.scale) * 2.0f32 - 1.0f32)
+
+proc update*(camera: var Camera, config: Config, dt: float, mouse: Mouse, image: Image) =
   if abs(camera.deltaScale) > 0.5:
-    camera.scale = max(camera.scale + camera.deltaScale * dt, 1.0)
-    if camera.scale > 1.0:
-      camera.position += mouse.curr * (camera.deltaScale / camera.scale * config.scalePanning)
-    camera.deltaScale -= sgn(camera.deltaScale).float * config.scaleFriction * dt
+    # TODO: camera position adjustment doesn't work anymore
+    camera.scale = max(camera.scale + camera.delta_scale * dt, 1.0)
+    camera.delta_scale -= sgn(camera.delta_scale).float * config.scale_friction * dt
 
   if not mouse.drag and (camera.velocity.length > 0.01):
     camera.position += camera.velocity * dt
     camera.velocity -= camera.velocity.normalize * (config.dragFriction * dt)
-
-  camera.matrix = mat4f(1).translate(-camera.position.x, camera.position.y, 0).scale(camera.scale)

src/vert.glsl

@@ -2,9 +2,10 @@
 in vec3 aPos;
 in vec2 aTexCoord;
 out vec2 texcoord;
-uniform mat4 transform;
+uniform vec2 cameraPos;
+uniform float cameraScale;
 void main()
 {
-	gl_Position = transform * vec4(aPos, 1.0f);
+	gl_Position = vec4((aPos.x - cameraPos.x) * cameraScale, (aPos.y + cameraPos.y) * cameraScale, 0.0, 1.0);
 	texcoord = aTexCoord;
 }