WebGL binding to ClojureScript.
Create a library that allows a more convinient functional style for creating WebGL applications in ClojureScript, by means of hiding mutability where possible and wrapping every Javascript value in ClojureScript constructs.
The program below can be run by first building:
$ lein cljsbuild once
And then opening the examples/index.html page in a webGL capable browser.
(ns basic-opengl-program.core
(:require [cljs-webgl.context :as context]
[cljs-webgl.shaders :as shaders]
[cljs-webgl.constants :as constants]
[cljs-webgl.buffers :as buffers]
[cljs-webgl.typed-arrays :as ta]))
(def vertex-shader-source
"attribute vec3 vertex_position;
void main() {
gl_Position = vec4(vertex_position, 1);
}")
(def fragment-shader-source
"uniform int frame;
void main() {
gl_FragColor.r = sin(float(frame) * 0.05) / 2.0 + 0.5;
gl_FragColor.g = sin(float(frame) * 0.1) / 2.0 + 0.5;
gl_FragColor.b = sin(float(frame) * 0.02) / 2.0 + 0.5;
gl_FragColor.a = 1.0;
}")
(let
[gl (context/get-context (.getElementById js/document "canvas"))
shader (shaders/create-program gl [(shaders/create-shader gl constants/vertex-shader vertex-shader-source)
(shaders/create-shader gl constants/fragment-shader fragment-shader-source)])
vertex-buffer (buffers/create-buffer gl (ta/float32 [1.0 1.0 0.0
-1.0 1.0 0.0
1.0 -1.0 0.0])
constants/array-buffer
constants/static-draw)
element-buffer (buffers/create-buffer gl (ta/unsigned-int16 [0 1 2])
constants/element-array-buffer
constants/static-draw)
draw (fn [frame continue]
(-> gl
(buffers/clear-color-buffer 0 0 0 1)
(buffers/draw! shader ; shader
constants/triangles ; draw-mode
0 ; first
3 ; count
; attributes
[{:buffer vertex-buffer
:location (shaders/get-attrib-location gl shader "vertex_position")
:components-per-vertex 3
:type constants/float
:normalized? false
:stride 0
:offset 0}]
; uniforms
[{:name "frame" :type :int :values [frame]}]
;element array
{:buffer element-buffer
:count 3
:type constants/unsigned-short
:offset 0}))
(.requestAnimationFrame js/window (fn [time-elapsed] (continue (inc frame) continue))))]
(.requestAnimationFrame js/window (fn [time-elapsed] (draw 0 draw))))
Leiningen dependency information:
[cljs-webgl "0.1.4-SNAPSHOT"]
For generating the documentation, run lein marg src/cljs.