diff --git a/files/shaders/CMakeLists.txt b/files/shaders/CMakeLists.txt
index 31db4a3eb..0738b5783 100644
--- a/files/shaders/CMakeLists.txt
+++ b/files/shaders/CMakeLists.txt
@@ -11,6 +11,7 @@ set(SHADER_FILES
     terrain_vertex.glsl
     terrain_fragment.glsl
     lighting.glsl
+    parallax.glsl
 )
 
 copy_all_files(${CMAKE_CURRENT_SOURCE_DIR} ${DDIR} "${SHADER_FILES}")
diff --git a/files/shaders/parallax.glsl b/files/shaders/parallax.glsl
new file mode 100644
index 000000000..52ea0d2cc
--- /dev/null
+++ b/files/shaders/parallax.glsl
@@ -0,0 +1,8 @@
+#define PARALLAX_SCALE 0.04
+#define PARALLAX_BIAS -0.02
+
+vec2 getParallaxOffset(vec3 eyeDir, mat3 tbn, float height)
+{
+    vec3 TSeyeDir = normalize((vec4(normalize(tbn * eyeDir),0)).xyz);
+    return TSeyeDir.xy * ( height * PARALLAX_SCALE + PARALLAX_BIAS );
+}
diff --git a/files/shaders/terrain_fragment.glsl b/files/shaders/terrain_fragment.glsl
index e1b519932..14f00a2e1 100644
--- a/files/shaders/terrain_fragment.glsl
+++ b/files/shaders/terrain_fragment.glsl
@@ -25,12 +25,11 @@ varying vec3 passViewPos;
 varying vec3 passNormal;
 
 #if @parallax
-#define PARALLAX_SCALE 0.04
-#define PARALLAX_BIAS -0.02
 uniform mat4 osg_ViewMatrixInverse;
 #endif
 
 #include "lighting.glsl"
+#include "parallax.glsl"
 
 void main()
 {
@@ -53,9 +52,7 @@ void main()
 #if @parallax
     vec3 cameraPos = osg_ViewMatrixInverse[3].xyz;
     vec3 eyeDir = normalize(cameraPos - (osg_ViewMatrixInverse * vec4(passViewPos, 1)).xyz);
-    vec3 TSeyeDir = normalize((vec4(normalize(tbn * eyeDir),0)).xyz);
-
-    adjustedUV += TSeyeDir.xy * ( normalTex.a * PARALLAX_SCALE + PARALLAX_BIAS );
+    adjustedUV += getParallaxOffset(eyeDir, tbn, normalTex.a);
 
     // update normal using new coordinates
     normalTex = texture2D(normalMap, adjustedUV);