Shader compile errors

Question

I am trying to compile a "garbage" shader, feeding in some garbage code to WebGL (see here for a fiddle):

gl = $('canvas')[0].getContext('experimental-webgl');

source = 'garbage12398sv;aa[]|\[12';

shader = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(shader, source);
gl.compileShader(shader);

console.log(gl.getError() === gl.NO_ERROR);

Surprisingly, gl.getError() === gl.NO_ERROR is true despite asking WebGL to compile some garbage.

Why doesn't getError flag an error? How can I get error information regarding the compilation status of my shaders?

Cutch · Accepted Answer · 2012-10-05 23:33:42Z

15

gl.getError only returns errors for the OpenGL pipeline. A shader failing to compile does not cause an error in the pipeline. You can read about gl.getError here. You can query the status of shader like so:

var compiled = gl.getShaderParameter(shader, gl.COMPILE_STATUS);
console.log('Shader compiled successfully: ' + compiled);
var compilationLog = gl.getShaderInfoLog(shader);
console.log('Shader compiler log: ' + compilationLog);

Similarly, shader program linking errors do not invalidate the OpenGL pipeline and can't be detected with gl.getError() you must call the object (shader, program, render buffer, etc) specific error query functions.

answered Oct 5, 2012 at 23:33

Cutch

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2 Comments

DavidsKanal Over a year ago

Just a quick reminder that this answer got a dead link! Please fix.

Nikola Lukic Over a year ago

In my case i get true but still not passing ` if (gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) `

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