Hi,
I’m having a bit of a problem with the main shader for my game.
Using DirectX, my main shader needs to be able to do the following things :
 Texture mapping
 Ambient, diffuse, and specular lighting
 Normal mapping
 Shadows using a shadow map
 Reflections using a cubemap
Now because most of the work will be done in the pixel shader, my vertex shader output is becoming too crowded. I had to move on to shader model 5, because 4.9.3 was giving me an error saying that the max number of output (8) had been reached.
Here are my current VS outputs :
struct InstancingVSoutput
{
float4 Position : POSITION0;
float2 TexCoord : TEXCOORD0;
float3 View : TEXCOORD3;
float3 Reflection : TEXCOORD4;
float4 WorldPos : TEXCOORD5;
float4 HighlightColor : TEXCOORD6;
float3x3 WorldToTangentSpace : TEXCOORD7;
};
Here is what each output is for :

View :
This is a precalculation for specular lighting. The formula is :
output.View = normalize(float4(EyePosition, 1.0)  worldPosition); 
Reflection :
This is the reflection vector. Its formula is :
reflect(normalize(worldPosition  EyePosition), normalize(output.WorldToTangentSpace[2])); 
WorldPos :
This is the “real world” position of my vertex. I need this for my shadow calculations 
HighlightColor :
I am using hardware instancing the draw a bunch of the same model at once, each model is being shaded with a different tint. Since the coloring is happening in the pixel shader, I need to pass the tint color to it. 
WorldToTangentSpace :
This is the normal, binormal, and tangent Vectors used by my normal mapping
Now I am aware there are a few things I could cut. For starters, I could cut the tangent vector, since it’s the cross product of my normal and binormal vectors. Also, the reflection and view vectors seem similar enough that only one is needed, and the other could be calculated in the pixel shader.
But I am wondering if there is a better way to approach this? With my main shader getting bigger and bigger, it seems that I am bound to encounter this problem again in the future. I have no experience with multi pass shaders, but it seems like they could help me in this situation?
Thank you for your help