Genny and 3D

[Stef]

So you cannot push the pixels closer together on Stef's code ?

Cant give u definitely answer right now As i understand, Stef's bitmaps routines are fast, because they treat pixels as bytes instead of nibble (8 bit, instead of 4 bit) - so because of this bitmap is "vertically interlaced" on screen. But to be true i didnt looked into his routines very closely... I may be completely wrong! But even if i right, probably, here is some way to switch it to 4bit mode... If Stef read this, and its not difficult for him, he may comment on this issue.

Actually the bitmap engine use 4 packed pixel as the MD does.
So you can easily double pixel by writing c | (c<<4) to the buffer.
I modified the drawSlice method this way :

Code: Select all

inline void drawSlice( u8 screenX, SLICE *slice )
{
        if( slice->sliceHeight == 0 ) return;

        u8 offsetY   = ( slice->sliceHeight >  64 ) ? ( 0 ) : ( 32 - ( slice->sliceHeight >> 1 ) );
        u8 overflowY = ( slice->sliceHeight <= 64 ) ? ( 0 ) : ( ( slice->sliceHeight - 64 ) >> 1 );

        register u8 heightY   = ( slice->sliceHeight >  64 ) ? ( 64 ) : ( slice->sliceHeight );
        register u16 textureInc = divlut[slice->sliceHeight];
        register u16 textureY =  ( overflowY * textureInc );
        register u16 *texturePtr = &textures[ slice->textureId ][ slice->textureOffset ];
        register u8 *screenBuffer = &bmp_buffer_write[screenX + ((offsetY + 16) * BMP_PITCH)];

        while( heightY )
        {
            register u16 c = texturePtr[ textureY & ~63 ];
            *screenBuffer = c | (c << 4);
            screenBuffer += BMP_PITCH;
            textureY += textureInc;
            heightY--;
        }
}

It's almost as fast and draw doubled pixel

[peekpoke]

It's almost as fast and draw doubled pixel

Thank you very much!

[Chilly Willy]

Treating each pixel as a byte also allows you to do some pseudo-dithering for more colors... you could store (c | c<<4), or you could store c1c2, where that is two colors chosen to make a different color. On composite video, this works pretty well, and is a common affect in many MD games for more color.

[Nitro]

How much performance it will costs to build the game around sectors like Build Engine does?

Seems like a good choice -- you just stick with portals one room with
another.

http://msx.gnu-linux.net/doomlike/doomlike.html And what can you say about this article? It's covers 8-bit computer, imagine what Genesis could pull off.