Hi everyone. I have a sphere model in .x format with normals, prooven by opening the directX viewer. I have loaded the model into a D3D9 Mesh using just D3DXLoadMeshFromX() and have also tried to clone the mesh with a defined vertex declaration. But I cant get my diffuse lighting to work.

//my models only need Normals, UV and position.

D3DVERTEXELEMENT9 tempElem[4]=

{

{0, 0, D3DDECLTYPE_FLOAT3, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_POSITION, 0},

{0, 12, D3DDECLTYPE_FLOAT3, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_NORMAL , 0},

{0, 24, D3DDECLTYPE_FLOAT2, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 0},

D3DDECL_END()

};

meshSys->CloneMesh(D3DXMESH_SYSTEMMEM,tempElem,m_D3DDevice,&m_mesh);

/******************************************************STRUCTURES**********************/
struct VS_INPUT
{
	float4 Position : POSITION;
	float3 Normal 	: NORMAL;
	float2 UV 		: TEXCOORD0;
};

struct VS_OUTPUT
{
	float4 Position 	 : POSITION;
	float2 UV 	         : TEXCOORD0;
	float4 WorldPos 	 : TEXCOORD1;
	float4 WorldNormal  	 : TEXCOORD2;
	
};
/****************************************************************************************/


/****************************************************SHADERS**********************/
VS_OUTPUT vs_default(VS_INPUT In)
{
	VS_OUTPUT Out;
	
	//TRANSFORM VERTEX INFO
	Out.Position = mul( In.Position, gWVP );
	Out.WorldPos = mul( In.Position, gWorldMatrix);
	Out.WorldNormal = mul(float4(In.Normal,0.0), gWorldMatrix);
	Out.UV = In.UV;
	
	return Out;
}

float4 ps_default(VS_OUTPUT In) : COLOR0
{
	//////////////////////////////////////////////
	//CALCULATE LIGHT AMOUNT
	//////////////////////////////////////////////
	
	//PIXEL TO LIGHT POSITION
	float3 PixelToLightVec = gLightPosition - In.WorldPos;
	//COMPUTE SQUARED DISTANCE
	float LenSq = dot( PixelToLightVec, PixelToLightVec );
	PixelToLightVec = normalize(gLightPosition - In.WorldPos);
	float3 WorldNormal = normalize(In.WorldNormal.xyz);
	

	float3 LightAmount   = gRange * saturate( dot( WorldNormal, PixelToLightVec ) ) * gLightColour *(gLightFalloff * gLightFalloff) / LenSq;
	float3 reflection     = normalize((PixelToLightVec + gCameraPos) * 0.5);
	float3 LightSpecular  = LightAmount * pow( max( dot(WorldNormal, reflection), 0.0000001 ), gSpecularPower );

	//////////////////////////////////////////////
	//CALCULATE DIRECTIONAL LIGHT AMOUNT
	/////////////////////////////////////////////
	
	float3 DirectionalLight    = gDirectionalLightColour * max( dot(WorldNormal,   normalize(gDirectionalLight)), 0.0 );
	reflection         	   = normalize((gDirectionalLight + gCameraPos) * 0.5);
	float3 DirectionalSpecular = DirectionalLight * pow( max( dot(WorldNormal, reflection), 0.0000001 ), gSpecularPower );
	
	//////////////////////////////////////////////
	//TOTAL LIGHT = RETURNED COLOUR
	//////////////////////////////////////////////
	
	float3 DiffuseLight  = gAmbientColour + DirectionalLight + LightAmount;
	float3 SpecularLight = DirectionalSpecular + LightSpecular;
	
	float4 colour       = (tex2D(DiffuseSampler, In.UV) * float4(DiffuseLight,1.0f)) + (gSpecularMaterial * float4(SpecularLight,1.0f));
	return colour;	
}
/**************************************************************************************/

There is the shader which I use. The lights are in world space and so I transform the normal and the position into world space. I am only rotating and translating the mesh so I thought I didnt require the transpose inverse matrix. The problem is the sphere appears with ambient lighting only. I have entered a vector where 'WorldNormal' is, manually in the DP calculations and this can brighten the sphere so the problem must be with the normals passed in from the mesh or the transformation from Vertex Shader, not the lights or their calculations. Any ideas.

Thank you

	Out.WorldNormal = mul(float4(In.Normal,0.0), gWorldMatrix);

Not an expert here, but does this cause your normal to become degenerate? I would guess the w component would need to be 1.0 or else the matrix mul will scale it to zero, and then when you try to normalize it, you can't.

Ok good idea. I'll give it a go. thanks

Well the sphere is grey when I transform the normals but multicoloured (as expected) when I just render the normal as it came in the model. So it's something to do with the transformation for sure. I am going to try and use the transpose inverse matrix of the world matrix instead, even though I just thought that was necessary with non-uniform scaling.

Worked straight away. Case closed. Do these forums have like a topic finished option or anything.

Well i create a matrix using MatrixScaling(x,y,z) SCALING

then have world as

(SCALING * TRANSFORMATION)

so the only problem I could think of is that the w value of a normal is not scaled. But that confuses me a little.

Normal is something like a "direction vector". usually when you want to transform direction vectors you need to set 'w' component to 0 so that translation part of transformation matrix isn't included into output. Position is, well position (point in space) and you set 1 to include translation part.

float3 normal = mul( float4( v.normal, 0.0f ), World ).xyz;
or
float3 normal = mul( v.normal, float3x3(World) );