// spot_tex makes a spotlight pattern to be projected
// $Revision: #1 $ 

#ifndef _H_SPOT_TEX
#define _H_SPOT_TEX

#ifndef SPOT_TEX_SIZE
#define SPOT_TEX_SIZE 64
#endif /* SPOT_TEX_SIZE */

#ifndef SPOT_TEX_INSIDE
#define SPOT_TEX_INSIDE 0.4
#endif /* SPOT_TEX_INSIDE */

// function used to fill texture
float4 spot_texel(float2 P : POSITION,float2 dP : PSIZE) : COLOR
{
	//adjust so the outer rows and columns are ALWAYS black
	float2 rad = float2(0.5,0.5) - dP;
	float2 v = P - float2(0.5,0.5);
	float d = length(v)/rad.x;	// for now simple case of (dP.x==dP.y)
	float s = 1.0 - smoothstep(SPOT_TEX_INSIDE,1,d);
    return s.xxxx;
}

texture SpotTex  <
    string TextureType = "2D";
    string function = "spot_texel";
    string UIWidget = "None";
    int width = SPOT_TEX_SIZE, height = SPOT_TEX_SIZE;
>;

// samplers
sampler SpotSamp = sampler_state 
{
    texture = <SpotTex>;
	MinFilter = LinearMipMapLinear;
	MagFilter = Linear;
    WrapS = Clamp;
    WrapT = Clamp;
};

#endif /* _H_SPOT_TEX */