potree/src/Features.js

WebGL point cloud viewer - WORK IN PROGRESS

Potree.Features = (function () {
	var ftCanvas = document.createElement('canvas');
	var gl = ftCanvas.getContext('webgl') || ftCanvas.getContext('experimental-webgl');
	if (gl === null)		{ return null; }

	// -- code taken from THREE.WebGLRenderer --
	var _vertexShaderPrecisionHighpFloat = gl.getShaderPrecisionFormat(gl.VERTEX_SHADER, gl.HIGH_FLOAT);
	var _vertexShaderPrecisionMediumpFloat = gl.getShaderPrecisionFormat(gl.VERTEX_SHADER, gl.MEDIUM_FLOAT);
	// Unused: var _vertexShaderPrecisionLowpFloat = gl.getShaderPrecisionFormat(gl.VERTEX_SHADER, gl.LOW_FLOAT);

	var _fragmentShaderPrecisionHighpFloat = gl.getShaderPrecisionFormat(gl.FRAGMENT_SHADER, gl.HIGH_FLOAT);
	var _fragmentShaderPrecisionMediumpFloat = gl.getShaderPrecisionFormat(gl.FRAGMENT_SHADER, gl.MEDIUM_FLOAT);
	// Unused: var _fragmentShaderPrecisionLowpFloat = gl.getShaderPrecisionFormat(gl.FRAGMENT_SHADER, gl.LOW_FLOAT);

	var highpAvailable = _vertexShaderPrecisionHighpFloat.precision > 0 && _fragmentShaderPrecisionHighpFloat.precision > 0;
	var mediumpAvailable = _vertexShaderPrecisionMediumpFloat.precision > 0 && _fragmentShaderPrecisionMediumpFloat.precision > 0;
	// -----------------------------------------

	var precision;
	if (highpAvailable) {
		precision = 'highp';
	} else if (mediumpAvailable) {
		precision = 'mediump';
	} else {
		precision = 'lowp';
	}

	return {
		SHADER_INTERPOLATION: {
			isSupported: function () {
				var supported = true;

				supported = supported && gl.getExtension('EXT_frag_depth');
				supported = supported && gl.getParameter(gl.MAX_VARYING_VECTORS) >= 8;

				return supported;
			}
		},
		SHADER_SPLATS: {
			isSupported: function () {
				var supported = true;

				supported = supported && gl.getExtension('EXT_frag_depth');
				supported = supported && gl.getExtension('OES_texture_float');
				supported = supported && gl.getParameter(gl.MAX_VARYING_VECTORS) >= 8;

				return supported;
			}

		},
		SHADER_EDL: {
			isSupported: function () {
				var supported = true;

				supported = supported && gl.getExtension('EXT_frag_depth');
				supported = supported && gl.getExtension('OES_texture_float');
				supported = supported && gl.getParameter(gl.MAX_VARYING_VECTORS) >= 8;

				return supported;
			}

		},
		precision: precision
	};
}());