diff options
| -rw-r--r-- | 2d/sprite.scm | 117 |
1 files changed, 116 insertions, 1 deletions
diff --git a/2d/sprite.scm b/2d/sprite.scm index e7c0259..c55e1d0 100644 --- a/2d/sprite.scm +++ b/2d/sprite.scm @@ -43,7 +43,17 @@ sprite-vertices set-sprite-vertices! load-sprite - draw-sprite)) + draw-sprite + make-sprite-batch + sprite-batch? + sprite-batch-max-size + sprite-batch-size + set-sprite-batch-size! + sprite-batch-texture + set-sprite-batch-texture! + sprite-batch-vertices + sprite-batch-draw + with-sprite-batch)) ;; Used to build OpenGL vertex array for a sprite. (define-packed-struct sprite-vertex @@ -153,3 +163,108 @@ (gl-disable-client-state (enable-cap texture-coord-array)) (gl-disable-client-state (enable-cap color-array)) (gl-disable-client-state (enable-cap vertex-array))))) + +;;; +;;; Sprite Batch +;;; + +;; Sprite batches allow for efficient texture rendering. Sprites drawn +;; with the same texture are drawn with the same draw call, rather +;; than binding the texture for each individual draw call. + +(define-record-type <sprite-batch> + (%make-sprite-batch max-size size texture vertices) + sprite-batch? + (max-size sprite-batch-max-size) + (size sprite-batch-size set-sprite-batch-size!) + (texture sprite-batch-texture set-sprite-batch-texture!) + (vertices sprite-batch-vertices)) + +(define* (make-sprite-batch #:optional (max-size 1000)) + "Creates a new sprite batch. The default max-size is 1000." + (%make-sprite-batch max-size 0 #f (make-packed-array sprite-vertex (* 4 max-size)))) + +;; TODO add transformation logic for scaling and rotating. +;; TODO add support for colors +;; TODO add support for different blending modes. +(define (sprite-batch-draw batch texture x y center-x center-y + width height scale-x scale-y rotation) + ;; Render the batch when it's full or the texture changes. + (cond ((= (sprite-batch-size batch) (sprite-batch-max-size batch)) + (sprite-batch-render batch)) + ((not (equal? texture (sprite-batch-texture batch))) + (sprite-batch-switch-texture batch texture))) + ;; Add 4 new vertices. + (let ((base (* 4 (sprite-batch-size batch))) + (vertices (sprite-batch-vertices batch)) + (x (- x center-x)) + (y (- y center-y)) + (x2 (+ x width)) + (y2 (+ y height))) + (pack vertices base sprite-vertex + x y + 1 1 1 1 + 0 0) + (pack vertices (+ base 1) sprite-vertex + x2 y + 1 1 1 1 + 1 0) + (pack vertices (+ base 2) sprite-vertex + x2 y2 + 1 1 1 1 + 1 1) + (pack vertices (+ base 3) sprite-vertex + x y2 + 1 1 1 1 + 0 1)) + ;; Increment batch size + (set-sprite-batch-size! batch (1+ (sprite-batch-size batch)))) + +(define (sprite-batch-switch-texture batch texture) + "Change the currently bound texture. This requires flushing the +batched texture vertices first." + (sprite-batch-render batch) + (set-sprite-batch-texture! batch texture)) + +(define (sprite-batch-render batch) + "Renders and flushes the currently batched texture vertices." + (unless (= (sprite-batch-size batch) 0) + ;; Draw vertex array. + (gl-enable-client-state (enable-cap vertex-array)) + (gl-enable-client-state (enable-cap color-array)) + (gl-enable-client-state (enable-cap texture-coord-array)) + (let* ((texture (sprite-batch-texture batch)) + (size (sprite-batch-size batch)) + (struct-size (packed-struct-size sprite-vertex)) + (vertices (sprite-batch-vertices batch)) + (vertex-count (* 4 size))) + (with-gl-bind-texture (texture-target texture-2d) (texture-id texture) + (set-gl-vertex-array (vertex-pointer-type float) + vertices + 2 + #:stride struct-size + #:offset (packed-struct-offset sprite-vertex x)) + (set-gl-color-array (color-pointer-type float) + vertices + 4 + #:stride struct-size + #:offset (packed-struct-offset sprite-vertex r)) + (set-gl-texture-coordinates-array (tex-coord-pointer-type float) + vertices + #:stride struct-size + #:offset (packed-struct-offset sprite-vertex s)) + (gl-draw-arrays (begin-mode quads) 0 size))) + (gl-disable-client-state (enable-cap texture-coord-array)) + (gl-disable-client-state (enable-cap color-array)) + (gl-disable-client-state (enable-cap vertex-array)) + ;; Reset batch size to 0. + (set-sprite-batch-size! batch 0))) + +;; emacs: (put 'with-sprite-batch 'scheme-indent-function 1) +(define-syntax-rule (with-sprite-batch batch body ...) + (begin + (set-sprite-batch-size! batch 0) + (set-sprite-batch-texture! batch #f) + body + ... + (sprite-batch-render batch))) |