semilagranianfluidvelo.fp

PDE simulator on GPU.

!!FP1.0
#2d FLUID Diffuse for Density or Velocity or Pressure
DECLARE TexPARA = {0,0,0,0};
#TEX0 -- OldValue
#TEX1 -- NewValue
ADD R0, f[WPOS].xyxy, {1,0,-1,0};
ADD R1, f[WPOS].xyxy, {0,1,0,-1};

#U(i+1,j)-->R2
TEX R2, R0.xyww, TEX1, RECT;
#U(i-1,j)-->R3
TEX R3, R0.zwww, TEX1, RECT;
#U(i,j+1)-->R4
TEX R4, R1.xyww, TEX1, RECT;
#U(i,j-1)-->R5
TEX R5, R1.zwww, TEX1, RECT;

ADD R6, R2, R3;
ADD R6, R6, R4;
ADD R6, R6, R5;
MUL R6, R6, TexPARA.xxzz;

TEX R0, f[WPOS], TEX0, RECT;
ADD R0, R6, R0;
MUL R0, R0, TexPARA.yyww;

#Tex2 --BoundaryConditionTexID--Obstacle
TEX R1, f[WPOS], TEX2, RECT;

#Tex3- Texture offset for boundary condition
TEX R2, f[WPOS], TEX3, RECT;
ADD R2, R2, f[WPOS].xyxy;
#for u component
TEX R3.x, R2.xyww, TEX1, RECT;
#for v component
TEX R3.y, R2.zwww, TEX1, RECT;

LRP o[COLR], R1, R0, -R3;

END