compute_acc_vis.cg.bak

来自「游戏编程精粹６第中关于粒子的实时流体仿真系统,对入门的游戏开发者很有帮助．」· BAK 代码 · 共 137 行

#include "sph.cg"

float3 compute_pres_vis(float3 p_i, float3 v_i, float2 dp_i, 
						float3 p_j, float3 v_j, float2 dp_j,
						float h_r)
{
	return 45*m/(PI*h*h*h*h*h*h)*h_r*((dp_i.y + dp_j.y)*0.5*h_r*(pos_i - pos_j)/r + mu*(v_j - v_i))*dp_j.x*dp_i.x;
}

/*
void main(float pindex : TEXCOORD0,
uniform samplerRECT attr_rect : TEXUNIT0,
//uniform samplerRECT tri_rect  : TEXUNIT1,
uniform float4x4 mat_col,
uniform float4x4 mat_inv_col,
out float3 result : COLOR)*/
void collision_glass(float3 pos_i,
					 float3 vel_i,
					 float4x4 mat_col, 
					 float4x4 mat_inv_col,
					 out float3 result)
{
	float stiff = 30000.0;
	float damp = 128.0;
	//float k = 10000.0;
	//float k = 40000.0;
	float radius = 0.004;
	const float GLASS_R = 0.05;
	const float GLASS_BOTTOM = -0.08;
	const float GLASS_TOP = 0.08;
	const float EPSILON = 0.000001f;

	float4 pp = float4(pos_i, 1);
//	float3 vel = mul((float3x3)mat_col, f3texRECT(attr_rect, float2(pindex, 1)));
	float3 vel = mul((float3x3)mat_col, vel_i);//f3texRECT(attr_rect, float2(pindex, 1)));

	float3 pos = mul(mat_col, pp).xyz;

	float dist = GLASS_R - sqrt(dot(pos.xy, pos.xy));
	//	float dist = GLASS_R - distance(pos.xy);//sqrt(dot(pos.xy, pos.xy))
	float diff = 2.0*radius - dist;

	float3 col_force = float3(0, 0, 0);
	if (diff > EPSILON)
	{
		float3 n = -normalize(float3(pos.x, pos.y, 0.0));
		float vel0 = dot(vel, n);
		col_force += (stiff*diff - damp*vel0)*n;
		//		col_force += max(k*diff - 64.0*vel0, 0.0)*n;
	}

	diff = 2.0f*radius - (pos.z - GLASS_BOTTOM);
	//	diff = 2.0f*radius - pos.z;// - GLASS_BOTTOM);

	if (diff > EPSILON)
	{
		float3 n = float3(0, 0, 1);
		float vel0 = dot(vel, n);//vec3_dot(&n, &sph->vel[i]);

		col_force += (stiff*diff - damp*vel0)*n;
	}


	diff = 2.0f*radius - (GLASS_TOP - pos.z);
	if (diff > EPSILON)
	{
		float3 n = float3(0, 0, -1);
		float vel0 = dot(vel, n);
		col_force += (stiff*diff - damp*vel0)*n;
	}

	result = mul((float3x3)mat_inv_col, col_force);
}

void main(float index : TEXCOORD0,  // subject particle index
		  uniform samplerRECT attr_rect      : TEXUNIT0,  // attributes of particles
		  uniform samplerRECT neighbour_rect : TEXUNIT1,  // neighbour list
		  uniform float mass,
		  uniform float smoothlen,
		  uniform float viscosity,
		  uniform float timestep,
		  uniform float4x4 mat_col,
		  uniform float4x4 mat_inv_col,
		  uniform int n_neighbours, // num. of neighbours
		  out float3 result : COLOR // acceleration
		  )
{
	float h = smoothlen;//SMOOTHING_LENGTH;
	float m = mass;
	//	float mu = VISCOSITY;
	float mu = viscosity;

	//	float neighbour_index = f1texRECT(neighbour_rect, sn_coord + float2(1, 0));

	float3 pos_i = f3texRECT(attr_rect, float2(index, GPU_ATTR_POS));
	float3 v_i = f3texRECT(attr_rect, float2(index, GPU_ATTR_VEL));
	/** do you need this velosity **/


	float2 dp_i = f2texRECT(attr_rect, float2(index, GPU_ATTR_DP));

	result = float3(0, 0, 0);

	for (int i = 1; i < n_neighbours; i++)
	{
		float neighbour_index = f1texRECT(neighbour_rect, float2(i, index));

		//if (neighbour_index == 3000)
		//		break;

		float3 pos_j = f3texRECT(attr_rect, float2(neighbour_index, GPU_ATTR_POS));
		float r = distance(pos_i, pos_j);

		float h_r = h - r;

		//	h_r = max(h_r, 0.0); 

		if (h_r > 0.0)
		{
			float3 v_j = f3texRECT(attr_rect, float2(neighbour_index, GPU_ATTR_VEL));
			float2 dp_j = f2texRECT(attr_rect, float2(neighbour_index, GPU_ATTR_DP));
			//		result = 15*m/(PI*h*h*h*h*h*h)*h_r*((dp_i.y + dp_j.y)*0.5*h_r*h_r*(pos_i - pos_j) + 3*mu*(v_j - v_i))*dp_j.x;///dp_j.x;
			//		result = 45*m/(PI*h*h*h*h*h*h)*h_r*((dp_i.y + dp_j.y)*0.5*h_r*(pos_i - pos_j)/r + mu*(v_j - v_i))*dp_j.x;
			result += 45*m/(PI*h*h*h*h*h*h)*h_r*((dp_i.y + dp_j.y)*0.5*h_r*(pos_i - pos_j)/r + mu*(v_j - v_i))*dp_j.x*dp_i.x;

			//result.xy = sn_coord.xy - 100;
		}
	}

	float3 col_force;
	float3 vel_i_half = f3texRECT(attr_rect, float2(index, GPU_ATTR_VELHALF));
	pos_i += timestep*vel_i_half;
	collision_glass(pos_i, v_i, mat_col, mat_inv_col, col_force);
	result += col_force;
		//result.xy = unpack_2ushort(neighbour_index)*65536;

}