compute_density.cg

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#include "kernel.cg"
#include "sph.cg"

void main(fixed2 sn_coord : TEXCOORD0,
		  /**
		  y  : subject particle index
		  xy : neighbour particle index
		  **/

		  uniform samplerRECT attr_rect      : TEXUNIT0,
		  uniform samplerRECT neighbour_rect : TEXUNIT1,
		  //uniform float smoothlen,
		  //uniform float mass,
		  //uniform float mu,
		  out float result : COLOR // density pressure
		  )
{
	float h = SMOOTHING_LENGTH;
	//float m = MASS;//mass;
	
	float neighbour_index = f1texRECT(neighbour_rect, sn_coord);

	float3 pos_i = f3texRECT(attr_rect, float2(sn_coord.y, GPU_ATTR_POS));
	float3 pos_j = f3texRECT(attr_rect, float2(neighbour_index, GPU_ATTR_POS));

	float3 diff = pos_i - pos_j;

	//float density = poly6_kernel(dot(diff, diff), h, MASS);
//	float h2_r2;
//	h2_r2 = max(h*h -dot(diff, diff), 0.0);

	float h2_r2;
	h2_r2 = h*h -dot(diff, diff);
	if (h2_r2 > 0.0)
		result = MASS*315.0f/(64.0f*PI*h*h*h*h*h*h*h*h*h)*pow(h2_r2, 3);
	else result = 0.0;

		//result = MASS*315.0f/(64.0f*PI*h*h*h*h*h*h*h*h*h)*h2_r2*h2_r2*h2_r2;
//		k = 315.0f/(64.0f*PI*pow(h, 9))*h2_r2*h2_r2*h2_r2;
	//else result = 0.0f;
}