According to the book I have on HLSL, you can make if statements all you want. However, most shader models can only support static branching (if you had a bunch of bools that go into the function this would be ok, as it would cause those branches to NOT execute).

However, only shader model 3.0 has true dynamic branching, all the other models just end up having both the if and else executed and the shader chosing the part you wanted. So in effect, it is not giving you a performance boost in the same way regular code would if you blocked it off with an if.

This is the real difference between optimizing shaders and optimizing regular code.

and xXxGuitar511; totally valid, I failed to realize that he was making a global effect. It should definately be a local material per mesh. That would make the effect significantly easier.

well, some time ago i created this shader (postprocess) which wouldnt be possible on a per model base:


imagine you want your whole scene toon like, but u use standard shaders (normal mapping, reflections and others) per model and in the end you give the whole scene a toon touch. thats a case of postprocessing

Okay, so would I still be able to calculate the dot product with a post-processing effect? Maybe with a vertex shader?

Wait! I finally got the right equation! I was trying to change only the red green or blue value based on how much of each was present, but I needed to multiply them all by one universal fraction! Here's my results (by the way I wasn't really looking for an outline):


And the code:

Code:

---

 material mat_rgb 
{	
	effect = "		
	sampler2D g_samSrcColor;

	float4 MyShader( float2 Tex : TEXCOORD0 ) : COLOR0
	{
		float4 Color;
		int Color_all;
		float multiplyer;
		Color = tex2D( g_samSrcColor, Tex.xy);
		Color_all = ((Color.r + Color.g + Color.b)/3)/.167;
		multiplyer = (Color_all * .167)/((Color.r + Color.g + Color.b)/3);
		Color.r = (Color.r * multiplyer);
		Color.g = (Color.g * multiplyer);
		Color.b = (Color.b * multiplyer);
		return Color;
	}


	technique PostProcess
	{
		pass p1
		{
			VertexShader = null;
			PixelShader = compile ps_2_0 MyShader();
		}

	}
	";
} 

---