diff options
Diffstat (limited to '2d/sprite.scm')
| -rw-r--r-- | 2d/sprite.scm | 166 |
1 files changed, 159 insertions, 7 deletions
diff --git a/2d/sprite.scm b/2d/sprite.scm index 5a0cf00..f47a38e 100644 --- a/2d/sprite.scm +++ b/2d/sprite.scm @@ -17,17 +17,37 @@ ;;; Commentary: ;; -;; 2D sprite procedures. +;; 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-9) + #:use-module (srfi srfi-42) #:use-module (figl gl) #:use-module (figl contrib packed-struct) - #:use-module (2d texture) + #:use-module ((sdl sdl) #:prefix SDL:) #:use-module (2d vector) - #:export (make-sprite + #:export (make-texture + texture? + texture-id + texture-width + texture-height + surface->texture + load-texture + texture-quad + make-texture-region + texture-region? + texture-region-texture + texture-region-width + texture-region-height + texture-region-u + texture-region-v + texture-region-u2 + texture-region-v2 + split-texture + make-sprite sprite? sprite-texture sprite-position @@ -55,6 +75,138 @@ sprite-batch-draw with-sprite-batch)) +;;; +;;; Textures +;;; + +;; The <texture> object is a simple wrapper around an OpenGL texture +;; id. +(define-record-type <texture> + (make-texture id width height) + texture? + (id texture-id) + (width texture-width) + (height texture-height)) + +;; Use a guardian and an after GC hook that ensures that OpenGL +;; textures are deleted when texture objects are GC'd. +(define texture-guardian (make-guardian)) + +(define (reap-textures) + (let loop ((texture (texture-guardian))) + (when texture + ;; When attempting to reap structures upon guile exit, the + ;; dynamic pointer to gl-delete-textures becomes invalid. So, we + ;; ignore the error and move on. + (catch 'misc-error + (lambda () (gl-delete-textures (list (texture-id texture)))) + (lambda (key . args) #f)) + (loop (texture-guardian))))) + +(add-hook! after-gc-hook reap-textures) + +(define (surface-pixel-format surface) + "Returns the OpenGL pixel format for a surface. RGB and RGBA formats +are supported." + (case (SDL:surface:depth surface) + ((24) (pixel-format rgb)) + ((32) (pixel-format rgba)) + (else (throw 'unsupported-pixel-format)))) + +(define (surface->texture surface) + "Translates an SDL surface into an OpenGL texture. +Currently only works with RGBA format surfaces." + (let ((texture-id (gl-generate-texture)) + (pixel-format (surface-pixel-format surface))) + (with-gl-bind-texture (texture-target texture-2d) texture-id + (gl-texture-parameter (texture-target texture-2d) + (texture-parameter-name texture-min-filter) + (texture-min-filter linear)) + (gl-texture-parameter (texture-target texture-2d) + (texture-parameter-name texture-mag-filter) + (texture-mag-filter linear)) + (gl-texture-image-2d (texture-target texture-2d) + 0 + pixel-format + (SDL:surface:w surface) + (SDL:surface:h surface) + 0 + pixel-format + (color-pointer-type unsigned-byte) + (SDL:surface-pixels surface))) + (let ((texture (make-texture texture-id + (SDL:surface:w surface) + (SDL:surface:h surface)))) + (texture-guardian texture) + texture))) + +(define (load-texture filename) + "Loads a texture from a file." + (surface->texture (SDL:load-image filename))) + +(define* (texture-quad texture x y w h #:optional (color '(1 1 1)) + (u 0) (v 0) (u2 1) (v2 1)) + "Renders a textured quad." + (let ((x2 (+ x w)) + (y2 (+ y h))) + (with-gl-bind-texture (texture-target texture-2d) (texture-id texture) + (gl-begin (begin-mode quads) + (apply gl-color color) + (gl-texture-coordinates u v) + (gl-vertex x y) + (gl-texture-coordinates u2 v) + (gl-vertex x2 y) + (gl-texture-coordinates u2 v2) + (gl-vertex x2 y2) + (gl-texture-coordinates u v2) + (gl-vertex x y2))))) + +;;; +;;; Texture Regions +;;; + +;; Texture regions represent a segment of a texture. + +(define-record-type <texture-region> + (%make-texture-region texture width height u v u2 v2) + texture-region? + (texture texture-region-texture) + (width texture-region-width) + (height texture-region-height) + (u texture-region-u) + (v texture-region-v) + (u2 texture-region-u2) + (v2 texture-region-v2)) + +(define (make-texture-region texture x y width height) + "Creates a new texture region given a texture and a pixel region." + (let* ((w (texture-width texture)) + (h (texture-height texture)) + (u (/ x w)) + (v (/ y h)) + (u2 (/ (+ x width) w)) + (v2 (/ (+ y height) h))) + (%make-texture-region texture width height u v u2 v2))) + +(define* (split-texture texture width height + #:optional #:key (margin 0) (spacing 0)) + "Splits a texture into a vector of texture regions of width x height +size." + (define (build-tile tx ty) + (let* ((x (+ (* tx (+ width spacing)) margin)) + (y (+ (* ty (+ height spacing)) margin))) + (make-texture-region texture x y width height))) + + (let* ((tw (texture-width texture)) + (th (texture-height texture)) + (rows (/ (- tw margin) (+ width spacing))) + (columns (/ (- tw margin) (+ height spacing)))) + (vector-ec (: y rows) (: x columns) (build-tile x y)))) + +;;; +;;; Sprites +;;; + ;; Used to build OpenGL vertex array for a sprite. (define-packed-struct sprite-vertex (x float) @@ -165,13 +317,13 @@ (gl-disable-client-state (enable-cap vertex-array))))) ;;; -;;; Sprite Batch +;;; Sprite batches ;;; ;; 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. - +;; with the same texture are drawn in the same draw call using a +;; vertex array, rather than re-binding the texture for each +;; individual draw call. (define-record-type <sprite-batch> (%make-sprite-batch max-size size texture vertices) sprite-batch? |