   [c++]wild magic 4 phong
  Hy.I'm try to create a simple phong shader in wild magic 4 engine.I have tested the shader with fx composer , but when i'm insert a light in my scene wild magic add a default light effect and i wouldn't it.Another problem is how to send the light direction to the shader , i try to send a shader renderer constant as i do for matrixes (word , wordprojectonview ecc.c. i call they as string constant:WVPMatrix,VMatrixIT)so i choose the corrispondent constant : Light0ModelDirection but my mesh appear always black.This is the vertex shader:// Define inputs from application.struct appin{float4 Position : POSITION;float4 Normal : NORMAL;};// Define outputs from vertex shader.struct vertout{float4 HPosition : POSITION;float4 Color : COLOR;};vertout main(appin IN,uniform float4x4 WVPMatrix,uniform float4x4 VMatrixIT,uniform float4 Light0ModelDirection){vertout OUT;// Transform vertex position into homogenous clip-space.OUT.HPosition = mul(WVPMatrix, IN.Position);// Transform normal from model-space to view-space.float3 normalVec = normalize(mul(VMatrixIT,IN.Normal).xyz);// Store normalized light vector.float3 LIGHT0_MODEL_DIRECTION_N = normalize(Light0ModelDirection.xyz);// Calculate half angle vector.float3 eyeVec = float3(0.0, 0.0, 1.0);float3 halfVec = normalize(LIGHT0_MODEL_DIRECTION_N + eyeVec);// Calculate diffuse component.float diffuse = dot(normalVec, LIGHT0_MODEL_DIRECTION_N);// Calculate specular component.float specular = dot(normalVec, halfVec);// diffuse and specular values.float4 lighting = lit(diffuse, specular, 32);// Blue diffuse materialfloat3 diffuseMaterial = float3(0.0, 0.0, 1.0);// White specular materialfloat3 specularMaterial = float3(1.0, 1.0, 1.0);// Combine diffuse and specular contributions and// output final vertex color.OUT.Color.rgb = lighting.y * diffuseMaterial +lighting.z * specularMaterial;OUT.Color.a = 1.0;return OUT;}and this is the fragment shader(i use opengl)struct vertout{float4 HPosition : POSITION;float4 Color : COLOR;};struct PS_OUT{float4 Color : COLOR;};PS_OUT main(vertout input){PS_OUT output;output.Color =  input.Color; return output;}what can do?Thanks.   