function initGLContext() {

		extensions = new WebGLExtensions( _gl );

		capabilities = new WebGLCapabilities( _gl, extensions, parameters );

		if ( ! capabilities.isWebGL2 ) {

			extensions.get( 'WEBGL_depth_texture' );
			extensions.get( 'OES_texture_float' );
			extensions.get( 'OES_texture_half_float' );
			extensions.get( 'OES_texture_half_float_linear' );
			extensions.get( 'OES_standard_derivatives' );
			extensions.get( 'OES_element_index_uint' );
			extensions.get( 'ANGLE_instanced_arrays' );

		}

		extensions.get( 'OES_texture_float_linear' );

		utils = new WebGLUtils( _gl, extensions, capabilities );

		state = new WebGLState( _gl, extensions, utils, capabilities );
		state.scissor( _currentScissor.copy( _scissor ).multiplyScalar( _pixelRatio ) );
		state.viewport( _currentViewport.copy( _viewport ).multiplyScalar( _pixelRatio ) );

		info = new WebGLInfo( _gl );
		properties = new WebGLProperties();
		textures = new WebGLTextures( _gl, extensions, state, properties, capabilities, utils, info );
		attributes = new WebGLAttributes( _gl );
		geometries = new WebGLGeometries( _gl, attributes, info );
		objects = new WebGLObjects( geometries, info );
		morphtargets = new WebGLMorphtargets( _gl );
		programCache = new WebGLPrograms( _this, extensions, capabilities, textures );
		renderLists = new WebGLRenderLists();
		renderStates = new WebGLRenderStates();

		background = new WebGLBackground( _this, state, objects, _premultipliedAlpha );

		bufferRenderer = new WebGLBufferRenderer( _gl, extensions, info, capabilities );
		indexedBufferRenderer = new WebGLIndexedBufferRenderer( _gl, extensions, info, capabilities );

		info.programs = programCache.programs;

		_this.context = _gl;
		_this.capabilities = capabilities;
		_this.extensions = extensions;
		_this.properties = properties;
		_this.renderLists = renderLists;
		_this.state = state;
		_this.info = info;

	}
Enables error checking and reporting when shader programs are being compiled
@type {boolean}