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Diffstat (limited to 'world.scm')
| -rw-r--r-- | world.scm | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/world.scm b/world.scm new file mode 100644 index 0000000..ee1d60c --- /dev/null +++ b/world.scm @@ -0,0 +1,59 @@ +(module world + * + (import scheme + (chicken base) + (only srfi-1 fold filter) + defstruct + tilemap + entity) + ;; Scene = current level: tilemap (layers, objects) + list of entities. + + ;; Returns tile-id if the cell at (col, row) in this layer is non-zero, #f otherwise. + (define (layer-tile-at layer col row) + (let ((rows (layer-map layer))) + (and (< row (length rows)) + (let ((row-data (list-ref rows row))) + (and (< col (length row-data)) + (let ((tile-id (list-ref row-data col))) + (and (not (zero? tile-id)) tile-id))))))) + + (define (tilemap-tile-at tilemap col row) + "Get the tile ID at grid position (col, row). + Returns 0 if out of bounds or if all layers have 0 at that cell." + (let ((width (tilemap-width tilemap)) + (height (tilemap-height tilemap))) + (if (or (< col 0) (>= col width) (< row 0) (>= row height)) + 0 + (let loop ((layers (tilemap-layers tilemap))) + (if (null? layers) + 0 + (or (layer-tile-at (car layers) col row) + (loop (cdr layers)))))))) + + (defstruct camera x y) + + (defstruct scene + entities + tilemap + camera + tileset-texture) + + (define (scene-add-entity scene entity) + (scene-entities-set! scene (append (scene-entities scene) (list entity))) + scene) + + (define (scene-update-entities scene . procs) + "Apply each proc in sequence to the scene's entities; each proc maps over all entities. + The scene's entity list is replaced once with the final result." + (scene-entities-set! scene + (fold (lambda (proc es) (map proc es)) + (scene-entities scene) + procs)) + scene) + + (define (scene-filter-entities scene pred) + "Remove all entities from scene that do not satisfy pred." + (scene-entities-set! scene + (filter pred (scene-entities scene))) + scene) +) |