diff --git a/src/renderers/shaders/ShaderChunk/fog_vertex.glsl b/src/renderers/shaders/ShaderChunk/fog_vertex.glsl
index 4ac023c0590d58..9d76892ecd11f6 100644
--- a/src/renderers/shaders/ShaderChunk/fog_vertex.glsl
+++ b/src/renderers/shaders/ShaderChunk/fog_vertex.glsl
@@ -1,4 +1,4 @@
 
 #ifdef USE_FOG
-fogDepth = -mvPosition.z;
+fogDepth = length(mvPosition);
 #endif
\ No newline at end of file