Basically I am trying to compile cg shader file with DX. A char* pointer is used to store the name of a variable in cg. But, here is the question, I don't know why I have to type "$modelViewProj" instead of "modelViewProj". Otherwise the function constanttable->SetValue() will not success. In the cg file that variable's name is just modelViewProj as

void vertextransform(float4 position : POSITION,
float3 Normal : NORMAL,
float2 texCoord : TEXCOORD0,
out float4 oPosition : POSITION,
out float2 otexCoord : TEXCOORD0,
uniform float4x4 modelViewProj)
{
// Transform position from object space to clip space
oPosition = mul(modelViewProj, position);
Normal= float3(0,0,-1);
otexCoord = texCoord;
}

Thanks in advance

Jerry

So the question is: Why do I need to use the dollar sign?

There is already a global input named modelViewProj.

The people who wrote the system decided that when the same name comes from both sources, the function parameter would be prepended with $ to avoid duplicate names.


So:
modelViewProj is the global input
$modelViewProj is the parameter.

So:
modelViewProj is the global input

But I did not write any input named modelViewProj, or it is just default input written by program?

The people who wrote the system decided that when the same name comes from both sources

What do both sources mean here? global input and parameter?
What if I put uniform float4x4 modelViewProj out of the funcion as an global input, I would only need "modelViewProj"?