Eevee: Make Normal node interactive

Before it was triggering shader recompilation. Include small cleanup/opti.

source/blender/gpu/shaders/gpu_shader_material.glsl

@@ -468,16 +468,10 @@ void invert_z(vec3 v, out vec3 outv)
 	outv = v;
 }
 
-void normal(vec3 dir, vec3 nor, out vec3 outnor, out float outdot)
+void normal_new_shading(vec3 nor, vec3 dir, out vec3 outnor, out float outdot)
 {
-	outnor = nor;
-	outdot = -dot(dir, nor);
-}
-
-void normal_new_shading(vec3 dir, vec3 nor, out vec3 outnor, out float outdot)
-{
-	outnor = normalize(nor);
-	outdot = dot(normalize(dir), nor);
+	outnor = dir;
+	outdot = dot(normalize(nor), dir);
 }
 
 void curves_vec(float fac, vec3 vec, sampler1DArray curvemap, float layer, out vec3 outvec)

source/blender/nodes/shader/nodes/node_shader_normal.c

@@ -60,7 +60,7 @@ static void node_shader_exec_normal(void *UNUSED(data), int UNUSED(thread), bNod
 
 static int gpu_shader_normal(GPUMaterial *mat, bNode *node, bNodeExecData *UNUSED(execdata), GPUNodeStack *in, GPUNodeStack *out)
 {
-	GPUNodeLink *vec = GPU_constant(out[0].vec);
+	GPUNodeLink *vec = GPU_uniform(out[0].vec);
 	return GPU_stack_link(mat, node, "normal_new_shading", in, out, vec);
 }