i am using directx11 , and i create light source ( parallel light source )and scene ( loaded from obj file ) , and every thing look correct but when i rotate some object in the scene , my light rotate too with the object , and i don't wont to rotate the light and keep it fixed .

i try to fix the problem by do something like this , but i fail :




hlsl code


cbuffer LIGHT
{
float4 light_color ;
float3 Direction ;
float3 Position ;
float3 attribute ;
float Power ;
float range ;
float spotpower ;


};

cbuffer CAMERA
{
float4x4 view ;
float4x4 world ;
float4x4 proj ;
};

cbuffer local
{
float3 eye;
float4x4 localworld ;

};
Texture2D texture_obj ;
SamplerState Texture_sampler ;
/* diffuse texture */
float4 Get_Texture (float2 uv )

{
return texture_obj.Sample (Texture_sampler , uv );

}

/* light calc */
float4 Parrallel (float3 eye ,float3 Position ,float3 Normal , MTRL mtrl )
{

float3 lightvec = normalize(-Direction) ;

float4 LitColor = float4(0.0f , 0.0f ,0.0f ,0.0f );

float diff_factor = dot(lightvec , Normal );
float4 diff = light_color * mtrl.Diffuse_Mtrl ;

if (diff_factor > 0.0f )
{
float4 amb = light_color * mtrl.Ambient_Mtrl ;

float3 view = normalize(eye - Position) ;


float3 rf = normalize(reflect (Direction , Normal )) ;



float4 Spec_Fac = pow ( max ( dot (rf , view ) , 0.0f ) , max (1.0f ,Power ));
float4 Spec = light_color * mtrl.Specular_Mtrl ;

LitColor += ( diff *diff_factor) + (Spec_Fac*Spec) + (amb*diff_factor) ;
}
return LitColor ;

}

struct VS_INPUT
{
float4 Pos :POSITION ;
float3 Normal : NORMAL0 ;
float2 UV : TEXCOORD0 ;
};


struct VS_OUT
{
float4 Pos :SV_Position ;
float4 Posw : POSITION ;
float4 Normal : TEXCOORD1 ;
float2 UV : TEXCOORD0 ;


};



VS_OUT VS (VS_INPUT input)
{
VS_OUT v ;





v.Pos = mul ( input.Pos , localworld );
v.Pos = mul (v.Pos , world );
v.Pos = mul (v.Pos , view );
v.Pos = mul (v.Pos , proj );


v.Posw = mul ( input.Pos, localworld );

v.UV = input.UV ;

v.Normal = mul (float4(input.Normal , 0.0f) ,world );

return v ;
}


float4 PS (VS_OUT ps):SV_Target
{

MTRL y ;
y.Diffuse_Mtrl = Get_Texture (ps.UV);
y.Ambient_Mtrl = y.Diffuse_Mtrl /8 ;
y.Specular_Mtrl = float4 ( 0.5f , 0.5f , 0.5f , 0.0f );
float4 licolor = Parrallel ( eye , (float3)ps.Posw , (float3)ps.Normal ,y ) ;


return licolor ;
}



technique11 tech2
{
pass P0
{
SetVertexShader( CompileShader( vs_5_0, VS() ) );
SetPixelShader( CompileShader( ps_5_0, PS() ) );
}