Post by TNJGames in Simple Racing Engine (3D + 2D) comments

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A lot of fun.
Spent the past few days checking it out.
If you want to go off road you can, with some extra steps
Under car physics removing
w = clamp(w,-1,1)
You can go anywhere.
Issue is the only thing with a 'height map' is the road generated from the Paths.

You can create a global 2D Array to store a height map and capture points during the 'stage_model_create' phase.

1. get the length of the total grass line

2. divide it by the grid size for the height map. so a 96 width line with a 32 pixel grid gives us 3 'segments'

3. find the total z-depth by taking the known Z of the track (max) and the known z-depth of the ground (min). So a zdpeth of 100 would be 100 -0

4. we know we need to descend 100 pixels in 3 segments. or 100/33 (33)

5. for each segment calculate the point of the road to each segmented point.

basically doing

100-33 = 77 z depth

100-66 = 44

100-99 = 1

Pseudo code

...

var newXForInBetweenWall = txx + lengthdir_x(Dist,Dir);

var newYForInBetweenWall = tyy + lengthdir_y(Dist,Dir);

// round to our grid for height map

newXForInBetweenWall = round(newXForInBetweenWall/spacings)*spacings;

newYForInBetweenWall = round(newYForInBetweenWall/spacings)*spacings;

.....

global.heightm[newXForInBetweenWall, newYForInBetweenWall] = (zz/totalSegmentsOfWall) * (wallCtr);

Yal2 years ago

One of the reasons I stop you from going offroad is because it removes the need to worry about the player taking big shortcuts by skipping parts of the track, you'll probably want to add walls (or e.g. clamp w to -2,2 instead and programmatically create different walls at that point) to avoid that becoming a problem.

TNJGames2 years ago

yea that makes sense.
Could keep the road pathing system for walls, or zones similar to mario kart where something puts you back on course.
Could reduce speed based on clamp distance to not necessarily stop the players from going off course, but have no advantage for it.free roaming like wave racers was a lot of fun.
do you have any tutorials on doing water / changing textures on the d3d models?

Yal2 years ago

Water is kinda tricky, doing waves the "regular" way (a dynamic 3D primitive that gets resubmitted every step) is slow - you can speed it up by having a special shader (the vertex shader moves each vertex up/down using a wave equation) but doing that means you need to make a lot of evenly spaced triangles instead of using a single 2-triangle plane with a repeated texture.

The gist of it is relatively simple, at least: each "corner" moves up and down using a sinewave function, whose argument is a sum of x coordinate * horizontal speed + y coordinate * vertical speed + time. For the texture you'd just add those speeds to the texture coordinate. Some games sample the water texture multiple times at different resolution (and different scroll speeds per resolution) and then add them together, to simulate there being multiple "layers" to the water.

itch.io

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