131 lines
3 KiB
NASM
Executable file
131 lines
3 KiB
NASM
Executable file
; $Id: tmap_flt.asm,v 1.1.1.1 2006/03/17 19:59:59 zicodxx Exp $
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;THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
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;SOFTWARE CORPORATION ("PARALLAX"). PARALLAX, IN DISTRIBUTING THE CODE TO
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;END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
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;ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
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;IN USING, DISPLAYING, AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
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;SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
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;FREE PURPOSES. IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
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;CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES. THE END-USER UNDERSTANDS
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;AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
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;COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION. ALL RIGHTS RESERVED.
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;
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;
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; Flat shader derived from texture mapper (kind of slow)
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;
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;
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[BITS 32]
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global _asm_tmap_scanline_flat
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global asm_tmap_scanline_flat
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[SECTION .data]
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%include "tmap_inc.asm"
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[SECTION .text]
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; --------------------------------------------------------------------------------------------------
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; Enter:
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; _xleft fixed point left x coordinate
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; _xright fixed point right x coordinate
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; _y fixed point y coordinate
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;**; _pixptr address of source pixel map
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; for (x = (int) xleft; x <= (int) xright; x++) {
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; _setcolor(read_pixel_from_tmap(srcb,((int) (u/z)) & 63,((int) (v/z)) & 63));
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; _setpixel(x,y);
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;
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; z += dz_dx;
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; }
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align 4
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_asm_tmap_scanline_flat:
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asm_tmap_scanline_flat:
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pusha
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; Setup for loop: _loop_count iterations = (int) xright - (int) xleft
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;**; esi source pixel pointer = pixptr
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; edi initial row pointer = y*320+x
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; set esi = pointer to start of texture map data
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;** mov esi,_pixptr
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; set edi = address of first pixel to modify
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mov edi,[_fx_y]
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cmp edi,[_window_bottom]
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ja near _none_to_do
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imul edi,[_bytes_per_row]
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mov eax,[_fx_xleft]
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test eax, eax
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jns eax_ok
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sub eax,eax
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eax_ok:
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add edi,eax
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add edi,[_write_buffer]
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; set _loop_count = # of iterations
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mov eax,[_fx_xright]
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cmp eax,[_window_right]
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jl eax_ok1
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mov eax,[_window_right]
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eax_ok1: cmp eax,[_window_left]
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jg eax_ok2
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mov eax,[_window_left]
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eax_ok2:
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mov ebx,[_fx_xleft]
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sub eax,ebx
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js _none_to_do
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cmp eax,[_window_width]
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jbe _ok_to_do
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mov eax,[_window_width]
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dec eax
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_ok_to_do:
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mov ecx,eax
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; edi = destination pixel pointer
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cmp dword [_tmap_flat_cthru_table], 0
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jne do_flat_cthru
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mov al,[_tmap_flat_color]
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; word align
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inc ecx
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test edi,1
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je edi_even
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mov [edi],al
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inc edi
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dec ecx
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je _none_to_do
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edi_even: shr ecx,1
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je _no_full_words
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mov ah,al
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rep stosw
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_no_full_words: adc ecx,ecx ; if cy set, then write one more pixel (ecx == 0)
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rep stosb ; write 0 or 1 pixel
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_none_to_do: popa
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ret
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do_flat_cthru:
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mov esi, [_tmap_flat_cthru_table]
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xor eax, eax
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cmp ecx, 0
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je _none_to_do
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; edi = dest, esi = table, ecx = count
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flat_cthru_loop:
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mov al, [edi] ; get already drawn pixel
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mov al, [eax+esi] ; xlat thru cthru table
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mov [edi],al ; write it
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inc edi
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dec ecx
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jnz flat_cthru_loop
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popa
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ret
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