diff --git a/docs/05 Advanced Lighting/05 Parallax Mapping.md b/docs/05 Advanced Lighting/05 Parallax Mapping.md
index 434e716..8b62883 100644
--- a/docs/05 Advanced Lighting/05 Parallax Mapping.md	
+++ b/docs/05 Advanced Lighting/05 Parallax Mapping.md	
@@ -143,7 +143,7 @@ void main()
 vec2 ParallaxMapping(vec2 texCoords, vec3 viewDir)
 { 
     float height =  texture(depthMap, texCoords).r;    
-    vec3 p = viewDir.xy / viewDir.z * (height * height_scale);
+    vec2 p = viewDir.xy / viewDir.z * (height * height_scale);
     return texCoords - p;    
 }
 ```
@@ -302,4 +302,4 @@ return finalTexCoords;
 ## 附加资源
 
 - [Parallax Occlusion Mapping in GLSL](http://sunandblackcat.com/tipFullView.php?topicid=28)：sunandblackcat.com上的视差贴图教程。
-- [How Parallax Displacement Mapping Works](https://www.youtube.com/watch?v=xvOT62L-fQI)：TheBennyBox的关于视差贴图原理的视频教程。
\ No newline at end of file
+- [How Parallax Displacement Mapping Works](https://www.youtube.com/watch?v=xvOT62L-fQI)：TheBennyBox的关于视差贴图原理的视频教程。