Fix terrain normal/displacement mapping

Author: wareya

files/shaders/compatibility/terrain.vert

@@ -46,7 +46,7 @@ void main(void)
     normalToViewMatrix = gl_NormalMatrix;
 
 #if @normalMap
-    mat3 tbnMatrix = generateTangentSpace(vec4(1.0, 0.0, 0.0, -1.0), passNormal);
+    mat3 tbnMatrix = generateTangentSpace(vec4(1.0, 0.0, 0.0, 1.0), passNormal);
     tbnMatrix[0] = -normalize(cross(tbnMatrix[2], tbnMatrix[1])); // our original tangent was not at a 90 degree angle to the normal, so we need to rederive it
     normalToViewMatrix *= tbnMatrix;
 #endif