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| -rw-r--r-- | README.org | 76 |
1 files changed, 64 insertions, 12 deletions
@@ -21,28 +21,80 @@ Here is the simplest Guile-2d application (so far). #+BEGIN_SRC scheme - (use-modules (2d sprite) - (2d game) + (use-modules (2d game) + (2d scene) + (2d sprite) (2d vector2)) - (define (demo-sprite) - (load-sprite "images/sprite.png" + (define (make-demo-sprite) + (load-sprite "images/ghost.png" #:position (vector2 320 240))) - (define-scene demo - #:title "Demo" - #:draw (lambda (sprite) (draw-sprite sprite)) - #:state (demo-sprite)) + (define simple-scene + (make-scene + "Simple" + #:init make-demo-sprite + #:draw draw-sprite)) - (define-game simple - #:title "Simple Demo" - #:first-scene demo) + (define simple-demo + (make-game + #:title "Simple Demo" + #:first-scene simple-scene)) - (run-game simple) + (run-game simple-demo) #+END_SRC ** Features +*** Scenes + Game objects are used to define the basic aspects of a Guile-2D + game such as the window title, resolution, whether or not it + is fullscreen, and what the first scene is. + + #+BEGIN_SRC scheme + (define my-game + (make-game + #:title "Simple Demo" + #:resolution (vector2 640 480) + #:fullscreen? #f + #:first-scene main-menu)) + #+END_SRC + + Games can be divided into several smaller pieces, called scenes. A + scene describes how a particular part of a game is initialized, + drawn, updated, etc. + + #+BEGIN_SRC scheme + (define main-menu + (make-scene + "Main Menu" + #:init create-menu + #:enter menu-enter + #:exit menu-exit + #:draw draw-menu + #:update update-menu + #:events `((key-down . ,menu-key-down)))) + #+END_SRC + + In addition to the essential callbacks (draw, update, enter, + exit), scenes can specify an alist of additional arbitrary event + handlers. Some events such as =key-down= are emitted by the game + loop when input events are received. + + Scenes live in a place called the stage. There can be many stages, + but only one is active at any given time. When a stage enters + focus, the scene's enter procedure is applied. When a stage loses + focus, the exit procedure is applied. Stages are stored in a + stack, and they can pushed and popped as needed. To change the + current scene, and thus the current stage, use =push-scene=, + =pop-scene=, or =replace-scene=. + + #+BEGIN_SRC scheme + (push-scene tetris-clone) + (pop-scene) + (replace-scene high-scores) + #+END_SRC + *** Sprites Sprites encapsulate the presentation of an image or a region of an image. |