WebGL1.0でtextureを生成して使うサンプル。意味はともかく一応動く。

short05.4.html

<h1>WebGLTexture</h1>
<hr/><canvas id="CNVS" width="256px" height="256px"></canvas><hr/>
<script>
var cx=CNVS.getContext("webgl");
var data=new Uint8Array(256*256*4);for(var i=0; i<256*256*4; i++)data[i]=Math.random()*0xff;
with(cx){
	var tx=createTexture();
	var fb=createFramebuffer();
	bindTexture(TEXTURE_2D, tx);
	texParameteri(TEXTURE_2D, TEXTURE_MIN_FILTER, NEAREST);
	texParameteri(TEXTURE_2D, TEXTURE_MAG_FILTER, NEAREST);
	texImage2D(TEXTURE_2D,0, RGBA, 256,256,0,RGBA, UNSIGNED_BYTE,data);
	bindFramebuffer(FRAMEBUFFER, fb);
	framebufferTexture2D(FRAMEBUFFER, COLOR_ATTACHMENT0, TEXTURE_2D, tx, 0);
	console.log(`fb:${checkFramebufferStatus(FRAMEBUFFER)}`);
	bindFramebuffer(FRAMEBUFFER, null);
}
cx.clearColor(.1,.3,0,1);cx.clear(0x4000);
with(cx){
	var vsrc=`void main(){gl_PointSize=256.;gl_Position=vec4(0,0,0,1);}`;
	var fsrc=`uniform sampler2D tx;
	void main(){gl_FragColor=texture2D(tx, gl_PointCoord.xy);}`;
	var vs=createShader(VERTEX_SHADER);		shaderSource(vs, vsrc);	compileShader(vs);
	var fs=createShader(FRAGMENT_SHADER);	shaderSource(fs, fsrc);	compileShader(fs);
	var pg=createProgram();	attachShader(pg, vs);	attachShader(pg, fs);
	linkProgram(pg);
	console.log(`vs:${getShaderInfoLog(vs)}`);
	console.log(`fs:${getShaderInfoLog(fs)}`);
	console.log(`pg:${getProgramInfoLog(pg)}`);
	useProgram(pg);	deleteShader(vs);	deleteShader(fs);
}
cx.drawArrays(0, 0,1);
</script>