Buzz #13 12 февраля 1998

Ассемблер     Программирование

Assembler - Procedures: Stretch texture engine, Texture mapping engine, Texture mapping + gourauds hading engine, Gouraudmapping engine for Z80.

                  RULEZ!


   We continue to print ultra faaaaast algorithms by Exploder /
MegaCode / Extreme.

 +------------------------------------------------- -----------+
 | - Stretch texture engine for Z80 CPU - |
 | - Last n'joyment date: 11-JUL-97 - |
 +------------------------------------------------- -----------+

And now ...
Ultra faaaaast stretch texture algorythm

ver_1:

        POP HL; Read XY shifts

        ADD HL, BC; Increase YX pos in texture

        LD A, (HL); Read texel from texture

        LD (DE), A; Write texel to chunky buffer

        INC E;

About 39 takts of CPU power

Really needed:

        SP = Pointer to shifts-tab

        BC = YX-increase

        DE = Pointer to destination chunky buffer

ver_2:

        LD HL, # 0000; XY shifts data

        ADD HL, BC; Increase YX pos in texture

        LD D, (HL); Read texel from texture

        LD HL, # 0000; XY shifts data

        ADD HL, BC; Increase YX pos in texture

        LD E, (HL); Read texel from texture

        PUSH DE; Write 2texels to chunky buffer

About 67 takts of CPU power

Really needed:

        BC = YX-increase

        SP = Pointer to destination chunky buffer

ver_3: with light map mix

        POP HL; Read XY shifts

        ADD HL, BC; Increase YX pos in texture

        LD L, (HL); Read texel from texture

        LD H, (IX + # 00); Read light tab pointer

        LD (DE), A; Write texel to chunky buffer

        INC E;

About 58 takts of CPU power

Really needed:

        SP = Pointer to shifts-tab

        BC = YX-increase

        DE = Pointer to destination chunky buffer

        IX = Pointer to light tab

ver_4: with light map mix

        LD HL, # 0000; XY shifts data

        ADD HL, BC; Increase YX pos in texture

        LD L, (HL); Read texel from texture

        LD H, # 00; Light pointer data

        LD D, (HL); Read mixed texel

        LD HL, # 0000; XY shifts data

        ADD HL, BC; Increase YX pos in texture

        LD L, (HL); Read texel from texture

        LD H, # 00; Light pointer data

        LD E, (HL); Read mixed texel

        PUSH DE; Write 2texels to chunky buffer

About 93 takts of CPU power

Really needed:

        BC = YX-increase

        SP = Pointer to destination chunky buffer


   Is the fastest stretch texture code for Z80. Nothing else.

 +------------------------------------------------- -----------+
 | - Texturemapping engine for Z80 CPU - |
 | - Last n'joyment date: 25-NOV-97 - |
 +------------------------------------------------- -----------+

And now ...
Ultra faaaaast texturemapped algorythm


        LD A, H;

        ADD HL, BC; Increase Y-pos in texture

        EXX;

        LD D, A; Set Y-pos

        LD E, H; Set X-pos

        LD A, (DE); Get texel from texture

        ADD HL, BC; Increase X-pos in texture

        EXX;

        LD (DE), A; Write texel to chunky buffer

        INC E;

About 60 takts of CPU power

Really needed:

        HL = Y-position on texture

        BC = Y-increase

        DE = Pointer to destination chunky buffer

        HL '= X-position on texture

        BC '= X-increase



   Is the fastest texturemapping code for Z80. Nothing else.

 +------------------------------------------------- -----------+
 | - Texturemapping + gouraudshading engine for Z80 CPU - |
 | - Last n'joyment date: 06-DEC-1997 - |
 +------------------------------------------------- -----------+

And now ...
Ultra faaaaast tmap + gouraudshading algorythm


        LD A, H;

        ADD HL, BC; Increase Y-pos in texture

        EXX;

        LD D, A; Set Y-pos

        LD E, H; Set X-pos

        LD A, (DE); Get texel from texture

        LD HL, BC; Increase X-pos in texture

        LD E, A;

        LD D, (IX + # 00); Get shading pointer

        LD A, (DE); Get shaded texel

        EXX;

        ADD IX, DE; Increase shading-table pointer

        LD (IY + # 00), A; Write shaded texel to buffer

About 113 takts of CPU power

Really needed:

        HL = Y-position on texture

        BC = Y-increase

        IX = Pointer to shading-table

        DE = Shading-increase

        HL '= X-position on texture

        BC '= X-increase

        IY = Pointer to destination chunky buffer

 Is the fastest tmap + gouraudshading code for Z80. Nothing 
else. 

 +------------------------------------------------- -----------+
 | - Gouraudmapping engine for Z80 CPU - |
 | - Last n'joyment date: 05-DEC-1997 - |
 +------------------------------------------------- -----------+

And now ...
Ultra faaaaast gouraudmapping algorythm

ver_1: extra fast

        LDI; Write shaded pixel to buffer

        ADD HL, BC; Increase shading-table pointer

About 27 takts of CPU power

ver_2: full correctly

        LD A, (HL); Read data from shading-table

        LD (DE), A; Write shaded pixel to buffer

        INC E

        ADD HL, BC; Increase shading-table pointer

About 29 takts of CPU power

Really needed:

        HL = Pointer to shading-table

        BC = Shading-increase

        DE = Pointer to destination chunky buffer


   Is the fastest gouraudmapping code for Z80. Nothing else.

 +----------------------------------------* Exploder / Extreme 
*-- +  | - Exploder_xtm@usa.net - - +7 (0922) 29-04-25 - |

 +-------------------------------------------< ZX128, A1200> - 
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