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;;; guile-2d
;;; Copyright (C) 2013, 2014 David Thompson <dthompson2@worcester.edu>
;;;
;;; This program 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.
;;;
;;; This program 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 this program. If not, see
;;; <http://www.gnu.org/licenses/>.
;;; Commentary:
;;
;; Sprites are typically the most important part of a 2D game. This
;; module provides sprites as an abstraction around OpenGL textures.
;;
;;; Code:
(define-module (2d sprite)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (gl)
#:use-module (gl contrib packed-struct)
#:use-module ((sdl sdl) #:prefix SDL:)
#:use-module (2d agenda)
#:use-module (2d animation)
#:use-module (2d color)
#:use-module (2d config)
#:use-module (2d game)
#:use-module (2d helpers)
#:use-module (2d math)
#:use-module (2d shader)
#:use-module (2d signal)
#:use-module (2d texture)
#:use-module (2d vector2)
#:use-module (2d window)
#:use-module (2d wrappers gl)
#:export (enable-sprites
make-sprite
sprite?
animated-sprite?
sprite-drawable
sprite-position
set-sprite-drawable!
set-sprite-position!
set-sprite-scale!
set-sprite-rotation!
set-sprite-color!
set-sprite-anchor!
sprite-scale
sprite-rotation
sprite-color
sprite-anchor
load-sprite
draw-sprite))
;;;
;;; Sprites
;;;
(define sprite-shader #f)
(define (enable-sprites)
(set! sprite-shader
(make-shader-program
(load-vertex-shader
(string-append %pkgdatadir
"/shaders/sprite-vertex.glsl"))
(load-fragment-shader
(string-append %pkgdatadir
"/shaders/sprite-fragment.glsl")))))
;; The <sprite> type represents a drawable object (texture,
;; texture-region, animation, etc.) with a given position, scale,
;; rotation, and color.
(define-record-type <sprite>
(%make-sprite drawable position scale rotation color anchor vertices animator)
sprite?
(drawable sprite-drawable set-sprite-drawable!)
(position sprite-position set-sprite-position!)
(scale sprite-scale set-sprite-scale!)
(rotation sprite-rotation set-sprite-rotation!)
(color sprite-color set-sprite-color!)
(anchor sprite-anchor %set-sprite-anchor!)
(vertices sprite-vertices)
(animator sprite-animator))
(define (update-sprite-vertices! sprite)
(let ((texture (sprite-texture sprite)))
(pack-texture-vertices (sprite-vertices sprite)
0
(texture-width texture)
(texture-height texture)
(texture-s1 texture)
(texture-t1 texture)
(texture-s2 texture)
(texture-t2 texture))))
(define* (make-sprite drawable #:optional #:key
(position (vector2 0 0)) (scale (vector2 1 1))
(rotation 0) (color white) (anchor 'center))
"Create a new sprite object. DRAWABLE is either a texture or
animation object. All keyword arguments are optional. POSITION is a
vector2 object with a default of (0, 0). SCALE is a vector2 object
that describes how much DRAWABLE should be strected on the x and y
axes, with a default of 1x scale. ROTATION is an angle in degrees
with a default of 0. COLOR is a color object with a default of white.
ANCHOR is either a vector2 that represents the center point of the
sprite, or 'center which will place the anchor at the center of
DRAWABLE. Sprites are centered by default."
(let* ((vertices (make-packed-array texture-vertex 4))
(animator (if (animation? drawable)
(make-animator drawable)
#f))
(anchor (anchor-texture (drawable-texture drawable animator) anchor))
(sprite (%make-sprite drawable position scale rotation color
anchor vertices animator)))
(update-sprite-vertices! sprite)
sprite))
(define* (load-sprite filename #:optional #:key
(position (vector2 0 0)) (scale (vector2 1 1))
(rotation 0) (color white) (anchor 'center))
"Load a sprite from the file at FILENAME. See make-sprite for
optional keyword arguments."
(make-sprite (load-texture filename)
#:position position
#:scale scale
#:rotation rotation
#:color color
#:anchor anchor))
(define (animated-sprite? sprite)
"Return #t if SPRITE has an animation as its drawable object."
(animation? (sprite-drawable sprite)))
(define (drawable-texture drawable animator)
(cond ((texture? drawable)
drawable)
((animation? drawable)
(animator-texture animator))))
(define (sprite-texture sprite)
"Return the texture for the SPRITE's drawable object."
(let ((drawable (sprite-drawable sprite)))
(drawable-texture (sprite-drawable sprite)
(sprite-animator sprite))))
(define (set-sprite-anchor! sprite anchor)
(%set-sprite-anchor! sprite (anchor-texture (sprite-texture sprite) anchor)))
(define (update-sprite-animator! sprite)
(animator-update! (sprite-animator sprite))
(update-sprite-vertices! sprite))
(define (draw-sprite sprite)
"Render SPRITE to the screen. A sprite batch will be used if one is
currently bound."
(register-animated-sprite-maybe sprite)
(with-shader-program sprite-shader
(uniforms ((position (sprite-position sprite))
(anchor (sprite-anchor sprite))
(scale (sprite-scale sprite))
(rotation (sprite-rotation sprite))
(color (sprite-color sprite))
(projection (signal-ref window-projection)))
(draw-texture-vertices (sprite-texture sprite)
(sprite-vertices sprite)
1))))
;; A hash table for all of the animated sprites that have been drawn
;; since the last game update. It is cleared after every game-agenda
;; tick.
(define animated-sprites (make-hash-table))
(define (register-animated-sprite-maybe sprite)
(when (animated-sprite? sprite)
(hash-set! animated-sprites sprite sprite)))
(define (update-animated-sprites!)
"Update all animators for sprites that have been drawn this frame."
(hash-for-each (lambda (key val)
(update-sprite-animator! val))
animated-sprites)
(hash-clear! animated-sprites))
;; Update animated sprites upon every update.
(schedule-each game-agenda update-animated-sprites!)
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