blob: b46142dba355019ad6af929360d2762f114c184c (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
;;;; Copyright (C) 2018 Jakob L. Kreuze, All Rights Reserved.
;;;;
;;;; This file is part of slime-the-world.
;;;;
;;;; slime-the-world is free software: you can redistribute it and/or modify it
;;;; under the terms of the GNU General Public License as published by the Free
;;;; Software Foundation, either version 3 of the License, or (at your option)
;;;; any later version.
;;;;
;;;; slime-the-world is distributed in the hope that it will be useful, but
;;;; WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
;;;; or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
;;;; more details.
;;;;
;;;; You should have received a copy of the GNU General Public License along
;;;; with slime-the-world. If not, see <http://www.gnu.org/licenses/>.
(local lume (require :lib.lume))
(local tile-sheet (. (require :world) :tile-sheet))
;; TODO: Document this
(fn focus-on-object [camera object dt]
(let [last-x (. camera :x-pos)
last-y (. camera :y-pos)
max-x (. camera :max-x)
max-y (. camera :max-y)
object-x (. object :x-pos)
object-y (. object :y-pos)
width (. object :width)
height (. object :height)
screen-width (. camera :screen-width)
screen-height (. camera :screen-height)
x-offset (math.floor (- (/ screen-width 2) (/ width 2)))
y-offset (math.floor (- (/ screen-height 2) (/ height 2)))
x (lume.lerp last-x (- object-x x-offset) (* 4 dt))
x (lume.clamp x 0 max-x)
y (lume.lerp last-y (- object-y y-offset) (* 4 dt))
y (lume.clamp y 0 max-y)]
(values x y)))
;; Returns a new camera object, aware of the bounds of `world' and the camera
;; lock parameters entailed by the given screen dimensions.
(fn new-camera [world screen-width screen-height]
(let [tile-width (. tile-sheet :width)
tile-height (. tile-sheet :height)
max-x (- (* tile-width (. world :width)) screen-width)
max-y (- (* tile-height (. world :height)) screen-height)]
{:x-pos 0
:y-pos 0
:screen-width screen-width
:screen-height screen-height
:max-x max-x
:max-y max-y
:focus-on-object focus-on-object}))
{:new new-camera}
|
