sqrt( a*a+b*b )

examples/jsm/postprocessing/SSRPass.js

@@ -220,7 +220,7 @@ var SSRPass = function ( { renderer, scene, camera, width, height, selects, enco
 
 	this.ssrMaterial = new ShaderMaterial( {
 		defines: Object.assign( {}, SSRShader.defines, {
-			MAX_STEP: Math.sqrt( this.width * this.width + this.height + this.height ).toFixed(1)
+			MAX_STEP: Math.sqrt( this.width * this.width + this.height * this.height ).toFixed(1)
 		} ),
 		uniforms: UniformsUtils.clone( SSRShader.uniforms ),
 		vertexShader: SSRShader.vertexShader,