Hi guys,

right now in HLSL I'm trying to implement specular lighting, but ran into an issue, first here's a code snippet:

                float3 reflection;
		float4 specular;

		// Initialize the specular color.
		specular = float4(0.0f, 0.0f, 0.0f, 0.0f);

		// Calculate the amount of light on this pixel.
		float lightIntensity = saturate(dot(input.normal, -lightvec));

		if(lightIntensity > 0.0f)
		{
			//color += (ambientcol * lightIntensity);

			// Saturate the ambient and diffuse color.
			color = saturate(color);

			reflection = normalize(2 * lightIntensity * input.normal - (-lightvec)); 

			specular = pow(saturate(dot(reflection, input.viewDirection)), specularPower);
		}

		// Add the specular component last to the output color.
		color = saturate(color + specular);

Now all the alien variables are set correctly (debugged), but somehow the variable specular is NEVER correctly calculated.

Now this seams a bit vein, but this is all I got for now... But do you know why it happens?

Thank You

It may have something to do with the fact that your declaration of specular is a float4, while your other variables appear to be float3 (at least reflection is, I am assuming the others are too). Do you get any warnings when you compile the shader?

In any case, it is good practice to make sure your types all match and that you aren't depending on any default behavior.