Hi, thanks. I got it, with the difference that I have a different diffuse and ambient material.
Part of the lighting calculation (diffuse light) is done in te Vertex shader, the rest in the pixel shader.

The working result now is:
 

float4 PS_function(VS_OUTPUT input): COLOR0
{
    float4 textureColor = tex2D(textureSampler, input.TexCoord);
    textureColor.a = 1;

    return saturate((input.Color * MatDiff + AmbientColor * AmbientIntensity * MatAmb) * textureColor);
}

The only thing I don't understand is that splitting the formula up, doesn't give the correct result.
I tried it like this:

float amb = AmbientColor * AmbientIntensity * MatAmb
float diff = input.Color * MatDiff
return saturate(diff + amb) * textureColor

This doesn't work though, resulting pixels are black/ not as expected.
I tried to fund this by doing a pseudo formula:

return saturate((input.Color * MatDiff + AmbientColor * AmbientIntensity * MatAmb) * textureColor);
equals
result = ((A * B + C * D * E) * F)

amb = C * D * E
diff = A * B

result = (A + B) * F

When I fill in fictive numbers for A though F, I get the same result calculating it in one formula as when I do it in with the amb/diff step in between.
Strange? or am I missing something

Hi, thanks. I got it, with the difference that I have a different diffuse and ambient material.

Part of the lighting calculation (diffuse light) is done in te Vertex shader, the rest in the pixel shader.

The working result now is:

float4 PS_function(VS_OUTPUT input): COLOR0
{
    float4 textureColor = tex2D(textureSampler, input.TexCoord);
    textureColor.a = 1;

    return saturate((input.Color * MatDiff + AmbientColor * AmbientIntensity * MatAmb) * textureColor);
}

The only thing I don't understand is that splitting the formula up, doesn't give the correct result.

I tried it like this:

float amb = AmbientColor * AmbientIntensity * MatAmb

float diff = input.Color * MatDiff

return saturate(diff + amb) * textureColor

This doesn't work though, resulting pixels are black/ not as expected.

I tried to fund this by doing a pseudo formula:

return saturate((input.Color * MatDiff + AmbientColor * AmbientIntensity * MatAmb) * textureColor);

equals

result = ((A * B + C * D * E) * F)

amb = C * D * E

diff = A * B

result = (A * B) * F

When I fill in fictive numbers for A though F, I get the same result calculating it in one formula as when I do it in with the amb/diff step in between.

Strange? or am I missing something