Get WebGL texture/buffer/shader count

Question

Is there a way to get the count of the currently existing textures, buffers or shaders of a WebGL context? Like the numbers you can get in Firefox if you look at about:memory .

I'd like to check if all these are deleted successfully when my application closes.

Answer 1

There is no way to get that info directly from the WebGLRenderingContext but you could easily augment the context yourself something like

var numTextures = 0;
var originalCreateTextureFn = gl.createTexture;
var originalDeleteTextureFn = gl.deleteTexture;
gl.createTexture = function() {
   ++numTextures;
   return originalCreateTextureFn.call(gl);
};
gl.deleteTexture = function(texture) {
   --numTextures;
   originalDeleteTextureFn.call(gl, texture);
};

You can write similar functions for other resources.

Of course if you want to be perfect you'd probably need to add a flag to each object just incase you try to delete something twice and also check the object passed in is actually the right kind. Something like

var numTextures = 0;
var originalCreateTextureFn = gl.createTexture;
var originalDeleteTextureFn = gl.deleteTexture;
gl.createTexture = function() {
   ++numTextures;
   var texture = originalCreateTextureFn.call(gl);
   texture.__deleted__ = false;
};
gl.deleteTexture = function(texture) {
   if (texture && texture instanceof WebGLTexture && !texture.__deleted__) {
     texture.__deleted__ = true;
     --numTextures;
   }
   originalDeleteTextureFn.call(gl, texture);
};