/* ****************************************

2nd step of force calc for render-to-texture
water simulation.

Adds the 4th & final neighbor point to the 
force calc..

Bias and scale the values so 0 force is 0.5, 
  full negative force is 0.0, and full pos is
  1.0

******************************************* */


#include "PixelConstants.h"


; Declare pixel shader version
ps.1.1



; t0 = velocity field
; t1 = forces          
;  or
;  t0 = height & t1 = velocity


def c7,  0.33333, 0.33333, 0.33333, 1.0


tex t0      // prev vel
tex t1      // force texture - sample at offset of 0,0


; Bias the force back to 0 = 0.0 and negative = negative.
;   Too bad we can't store signed values in the velocity and
;   force textures!

 mov r0, t1_bias


//mul  r0, c7, t1_bias
//mad  r0, c7, t2_bias, r0
//mad  r0, c7, t3_bias, r0



; add force * scale and output
mad  r0, r0, c[PCN_MULTFACTOR_1], t0