PMREMGenerator: Use highp precision in GGX VNDF shader (#32225)

Author: mrdoob

src/extras/PMREMGenerator.js

@@ -36,7 +36,7 @@ const EXTRA_LOD_SIGMA = [ 0.125, 0.215, 0.35, 0.446, 0.526, 0.582 ];
 const MAX_SAMPLES = 20;
 
 // GGX VNDF importance sampling configuration
-const GGX_SAMPLES = 512;
+const GGX_SAMPLES = 256;
 
 const _flatCamera = /*@__PURE__*/ new OrthographicCamera();
 const _clearColor = /*@__PURE__*/ new Color();
@@ -817,8 +817,8 @@ function _getGGXShader( lodMax, width, height ) {
 
 		fragmentShader: /* glsl */`
 
-			precision mediump float;
-			precision mediump int;
+			precision highp float;
+			precision highp int;
 
 			varying vec3 vOutputDirection;