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Cart #17535 | 2015-12-06 | Code ▽ | Embed ▽ | License: CC4-BY-NC-SA

This is a first attempt to render textured height maps in something close to real time. I guess these would be considered voxels?

I am casting rays from the screen and checking intersect with the floor plane to get an x,z coordinate. Then I load a pixel from the map for the color and a pixel from the map at an offset location to get a height value.

A neat feature is that shadows could be baked into the texture.

Code is ugly, buggy, and poorly optimized...

--In order to keep the frame rate up while moving, I had to double pixel size.
--Looking up a pixel on the map is very slow, but I want to be able to handle 512x512 height maps and this is the best way I can think of. (512x512 color map and 512x512 height map)
--tall vertical walls jump in and out of existence, especially when at a distance. Actually, this happens with all pixels. Rounding errors perhaps?

I'm going to look at Zep's Raycast demo and see if there is anything in there that I can borrow.


P#17537 2015-12-05 20:19 ( Edited 2016-02-02 20:18)


Was playing around with it and ever so slightly boosted the performance
Most/all of the performance issues come from get_map_pix and the rectfill

P#17560 2015-12-06 16:08 ( Edited 2015-12-06 21:08)

Hi Gamax92,

Thanks for the speed up!

local tile_y = shl(flr(shr(tile_number,4)),3)+y%8
local tile_y = band(shr(tile_number,1),0xfff8)+y%8

What does the binary AND do in this case? It definitely squeezes a little more speed out of things. I guess it combines one of the shift and floor operations?

Right now I am using two get_map_pix commands to find the color and the height of the pixel--I think I can combine these into one (and have the height map for a sprite just 8 pixels offset from the sprite) and shave a little more time. (Also this will make map editing easier and allow for larger spaces.)

The other thing that I am planning to change is the resolution with the rectfills. May just bite the bullet and switch to the 64x64 resolution screen hack.

P#17563 2015-12-06 17:21 ( Edited 2015-12-06 22:21)

the band is being used to cut off the last three bits, and the shr(, 1) is still there since the overall bit displacement was 1 to the right

P#17564 2015-12-06 17:27 ( Edited 2015-12-06 22:27)

I could see a terminal velocity type game being made with this! I don't think performance is good enough for it though.

P#18611 2016-02-02 11:37 ( Edited 2016-02-02 16:37)

Double Pixel size? Why not change the screen mode?
Screen Modes by sta64

For 64x64 resolution:

P#18613 2016-02-02 15:18 ( Edited 2016-02-02 20:18)

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