vs.1.1              	; version instruction

; Get the x and z index, from -32768 to 32767 and add 32768 to bring back to 0 - 65535
add r1.xyzw, v1.xzyz, c[16].wywy	; r1.xyzw = (x 0 z 0) + (32768.0f 1.0 32768.0f 1.0)
mov r1.y, v0.x              		; Get the terrain height for that vertex from v0

; Bring r1 in world space multiplying by terrain square size.
mul r1.xyz, r1.xyz, c[16].xyz

// Transform the vertex position
dp4 oPos.x, r1, c[0]      ; Matrix multiply row 0
dp4 oPos.y, r1, c[1]      ; Matrix multiply row 1
dp4 oPos.z, r1, c[2]      ; Matrix multiply row 2
dp4 oPos.w, r1, c[3]      ; Matrix multiply row 3

//mov r0, -v0
sub r0, r1, c[5]            ; r0 = vertex position - shadow center
//add r0, c[5], v0          ; r0 = vertex position - shadow center
mul r0, r0, c[6]            ; r0 = r0 / shadow radius
//sub r0, c[8], r0
add r0, r0, c[7]            ; r0 = r0 + 0.5
mov oT0.xyz, r0.xzy

// Apply lighting to the vertex color
mov oD0, c[4]     			; Diffuse