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kolibrios/programs/demos/3dsheart/trunk/3dmath.asm

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x3d equ 0
y3d equ 2
z3d equ 4
vec_x equ 0
vec_y equ 4
vec_z equ 8
; 3d point - triple integer word coordinate
; vector - triple float dword coordinate
;----------------------in: --------------------------------
;------------------------ esi - pointer to 1st 3d point ---
;------------------------ edi - pointer to 2nd 3d point ---
;------------------------ ebx - pointer to result vector --
;---------------------- out : none ------------------------
make_vector:
fninit
fild word[edi+x3d] ;edi+x3d
fisub word[esi+x3d] ;esi+x3d
fstp dword[ebx+vec_x]
fild word[edi+y3d]
fisub word[esi+y3d]
fstp dword[ebx+vec_y]
fild word[edi+z3d]
fisub word[esi+z3d]
fstp dword[ebx+vec_z]
ret
;---------------------- in: -------------------------------
;--------------------------- esi - pointer to 1st vector --
;--------------------------- edi - pointer to 2nd vector --
;--------------------------- ebx - pointer to result vector
;---------------------- out : none
cross_product:
fninit
fld dword [esi+vec_y]
fmul dword [edi+vec_z]
fld dword [esi+vec_z]
fmul dword [edi+vec_y]
fsubp ;st1 ,st
fstp dword [ebx+vec_x]
fld dword [esi+vec_z]
fmul dword [edi+vec_x]
fld dword [esi+vec_x]
fmul dword [edi+vec_z]
fsubp ;st1 ,st
fstp dword [ebx+vec_y]
fld dword [esi+vec_x]
fmul dword [edi+vec_y]
fld dword [esi+vec_y]
fmul dword [edi+vec_x]
fsubp ;st1 ,st
fstp dword [ebx+vec_z]
ret
;----------------------- in: ------------------------------
;---------------------------- edi - pointer to vector -----
;----------------------- out : none
normalize_vector:
fninit
fld dword [edi+vec_x]
fmul st, st
fld dword [edi+vec_y]
fmul st, st
fld dword [edi+vec_z]
fmul st, st
faddp st1, st
faddp st1, st
fsqrt
ftst
fstsw ax
sahf
jnz @f
fst dword [edi+vec_x]
fst dword [edi+vec_y]
fstp dword [edi+vec_z]
ret
@@:
fld st
fld st
fdivr dword [edi+vec_x]
fstp dword [edi+vec_x]
fdivr dword [edi+vec_y]
fstp dword [edi+vec_y]
fdivr dword [edi+vec_z]
fstp dword [edi+vec_z]
ret
;------------------in: -------------------------
;------------------ esi - pointer to 1st vector
;------------------ edi - pointer to 2nd vector
;------------------out: ------------------------
;------------------ st0 - dot-product
dot_product:
fninit
fld dword [esi+vec_x]
fmul dword [edi+vec_x]
fld dword [esi+vec_y]
fmul dword [edi+vec_y]
fld dword [esi+vec_z]
fmul dword [edi+vec_z]
faddp
faddp
ret