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Amiga ACS 1998 #6
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texmap
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tmap_16g.asm
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Assembly Source File
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1998-06-08
|
5KB
|
215 lines
;THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
;SOFTWARE CORPORATION ("PARALLAX"). PARALLAX, IN DISTRIBUTING THE CODE TO
;END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
;ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
;IN USING, DISPLAYING, AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
;SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
;FREE PURPOSES. IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
;CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES. THE END-USER UNDERSTANDS
;AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
;COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION. ALL RIGHTS RESERVED.
;
; $Source: f:/miner/source/texmap/rcs/tmap_16g.asm $
; $Revision: 1.4 $
; $Author: mike $
; $Date: 1994/11/30 00:56:37 $
;
; inner loop of rgb lighted linear texture mapper for 16 bits/pixel
;
; $Log: tmap_16g.asm $
; Revision 1.4 1994/11/30 00:56:37 mike
; optimization.
;
; Revision 1.3 1994/11/12 16:39:23 mike
; jae to ja.
;
; Revision 1.2 1993/11/22 10:24:28 mike
; *** empty log message ***
;
; Revision 1.1 1993/09/08 17:29:17 mike
; Initial revision
;
;
;
.386
option oldstructs
.nolist
include psmacros.inc
.list
public asm_tmap_scanline_lin_rgb_16g_
include tmap_inc.asm
_DATA SEGMENT DWORD PUBLIC USE32 'DATA'
extd _fx_u
extd _fx_v
extd _fx_du_dx
extd _fx_dv_dx
extd _fx_y
extd _fx_xleft
extd _fx_xright
extd _pixptr
extd _x
extd _loop_count
extd _fx_rgb,_fx_drgb_dx
extd _fx_r,_fx_g,_fx_b,_fx_dr_dx,_fx_dg_dx,_fx_db_dx
align 4
_DATA ENDS
DGROUP GROUP _DATA
_TEXT SEGMENT PARA PUBLIC USE32 'CODE'
ASSUME DS:_DATA
ASSUME CS:_TEXT
; --------------------------------------------------------------------------------------------------
; Enter:
; _xleft fixed point left x coordinate
; _xright fixed point right x coordinate
; _y fixed point y coordinate
; _pixptr address of source pixel map
; _u fixed point initial u coordinate
; _v fixed point initial v coordinate
; _du_dx fixed point du/dx
; _dv_dx fixed point dv/dx
; for (x = (int) xleft; x <= (int) xright; x++) {
; _setcolor(read_pixel_from_tmap(srcb,((int) (u/z)) & 63,((int) (v/z)) & 63));
; _setpixel(x,y);
;
; u += du_dx;
; v += dv_dx;
; z += dz_dx;
; }
align 4
asm_tmap_scanline_lin_rgb_16g_:
pusha
; Setup for loop: _loop_count iterations = (int) xright - (int) xleft
; esi source pixel pointer = pixptr
; edi initial row pointer = y*320+x
; set esi = pointer to start of texture map data
mov esi,_pixptr
; set edi = address of first pixel to modify
mov edi,_fx_y
cmp edi,_window_bottom
ja _none_to_do
sub edi,_window_top
imul edi,_bytes_per_row
mov eax,_fx_xleft
sar eax,16
jns eax_ok
sub eax,eax
eax_ok:
sub eax,_window_left
add edi,eax
add edi,eax
add edi,write_buffer
; set _loop_count = # of iterations
mov eax,_fx_xright
sar eax,16
cmp eax,_window_right
jb eax_ok1
mov eax,_window_right
eax_ok1: cmp eax,_window_left
ja eax_ok2
mov eax,_window_left
eax_ok2:
mov ebx,_fx_xleft
sar ebx,16
sub eax,ebx
js _none_to_do
cmp eax,_window_width
jbe _ok_to_do
mov eax,_window_width
_ok_to_do:
mov _loop_count,eax
; edi destination pixel pointer
; shift up all light values and deltas so that the highest 5 bits are the integer portion
shl _fx_r,11
shl _fx_g,11
shl _fx_b,11
shl _fx_dr_dx,11
shl _fx_dg_dx,11
shl _fx_db_dx,11
; ---------------------------------------------------------------------------------------------------------------------
mov eax,_fx_g
mov edx,_fx_b
mov ebx,_fx_r
mov ebp,_fx_dr_dx
mov esi,_fx_dg_dx
; register usage:
; eax _fx_g
; ebx _fx_r
; ecx work
; edx _fx_b
; ebp _fx_dr_dx
; esi _fx_dg_dx
; edi write address
; do the regular texture mapper linear interpolation to get the pixel from the source bitmap
_loop1:
mov ecx,ebx ; light value in high 5 bits
shr ecx,27 ; shift out all but light value
shld ecx,eax,5
shld ecx,edx,5
; now %ecx = r|g|b, each 5 bits, bit #15 clear, write the pixel
mov [edi],cx
add edi,2
; now add the deltas
add ebx,ebp
add eax,esi
add edx,_fx_db_dx
dec _loop_count
jns _loop1
; ---------------------------------------------------------------------------------------------------------------------
_none_to_do: popa
ret
; -- Code to get rgb 5 bits integer, 5 bits fraction value into 5 bits integer (for each gun)
; suitable for inverse color lookup
;**__test:
;** int 3
;**; rrrrrfffffrrrrrfffffxxbbbbbfffff
;** mov eax,11111001001010101110101101110111b
;** and eax,11111000001111100000001111100000b
;** shld ebx,eax,15
;** or bx,ax
_TEXT ends
end