(define-library (substratic engine assets)

(import (gambit)

(substratic sdl2)

(substratic engine transform))

(export load-asset

assets-path

assets-base-path-set!

image-loader-set!

image-width

image-height

image-texture

rect

*default-font*

*default-font-small*

load-default-fonts)

(begin

(define *assets-base-path* "./dist/assets")

(define (assets-base-path-set! assets-base-path)

(set! *assets-base-path* assets-base-path))

(define (assets-path subpath)

(path-normalize subpath #f *assets-base-path*))

(define *image-loader* #f)

(define (image-loader-set! image-loader)

(set! *image-loader* image-loader))

(define (load-asset asset-path #!optional (asset-cache #f))

(let ((ext (path-extension asset-path)))

(cond

((equal? ext ".png")

(if *image-loader*

(*image-loader* (assets-path asset-path))

(raise (string-append "load-asset: No *image-loader* is registered for file: " asset-path))))

((equal? ext ".scm")

(read (open-file (assets-path asset-path))))

(else (raise (string-append "load-asset: Unexpected file extension: " asset-path))))))

(define (set-rect! rect x y width height)

(SDL_Rect-x-set! rect (exact (truncate x)))

(SDL_Rect-y-set! rect (exact (truncate y)))

(SDL_Rect-w-set! rect (exact (truncate width)))

(SDL_Rect-h-set! rect (exact (truncate height)))

rect)

(define (make-rect x y width height)

(let ((rect (alloc-SDL_Rect)))

(set-rect! rect x y width height)))

(define *reusable-rect* #f)

(define rect

(case-lambda

((transform)

(rect (transform-x transform)

(transform-y transform)

(transform-width transform)

(transform-height transform)))

((x y width height)

(unless *reusable-rect*

(set! *reusable-rect* (make-rect 0 0 0 0)))

(set-rect! *reusable-rect* x y width height))))

(define (load-image renderer image-path)

(let* ((img (IMG_Load image-path))

(texture (SDL_CreateTextureFromSurface renderer img)))

(list (SDL_Surface-w img) (SDL_Surface-h img) texture)))

(define (image-width image)

(car image))

(define (image-height image)

(cadr image))

(define (image-texture image)

(caddr image))

(define (load-font font-path font-size)

(let* ((font (TTF_OpenFont font-path font-size))

(height (TTF_FontHeight font)))

(cons font height)))

(define (font-height font)

(cdr font))

;; TODO: Implement font atlases!

(define (generate-font-atlas font output-path)

#f)

(define *default-font* #f)

(define *default-font-small* #f)

(define (load-default-fonts)

(set! *default-font* (load-font (assets-path "fonts/Thintel.ttf") 32))

(set! *default-font-small* (load-font (assets-path "fonts/Thintel.ttf") 16)))))