I'm currently working on a ray-casting engine in Java and I can't figure out what's wrong with my code.
For the learning and theory I use:
The permadi tutorial: ( https://permadi.com/1996/05/ray-casting-tutorial-12/ ) When I started having problems with floor-casting I found this: ( https://www.allegro.cc/forums/thread/374305 )
I was happy becaues my implementation was 90% the same as the second code snippet on the linked Allegro.cc page. I added the x and y calculation to my code and I tried, but it didn't work. I tried exactly the same solution from the page but it didn't work.
The interesting fact that my code seems to "work" sometimes and sometimes not.
Furthermore, if I start walking then the floor moves to the wrong direction, sometimes backward for example.
In the beginning of implementing the engine I used the example code from the permadi tutorial too to correct my misunderstandings and so and it worked out well so far.
In this implementation 60° = planewidth. Every other degree is based upon this. Even the toRad function uses ANGLE180 (planeWidth*3) for the calculation.
I think I may not understand something in the math or I don't know, I just couldn't find where the error is.
I looked for the solution on other sites as well but it didn't help.
(Sorry if my english was bad.)
int x,y;
double floorPointDistance;
for(int i = floorCastingStartPixel; i < planeHeight; i++) {
floorPointDistance = ( ( PLAYERHEIGHT * playerPaneDist ) / ( (planeHeight>>1) - i ) ) / (Math.sin(((double)toRad(angle+rayAngle))));
// almost good
x = (int) Math.abs( (-floorPointDistance * sinTable[rayAngle]) + (playerX) ) % 64;
y = (int) Math.abs( (floorPointDistance * cosTable[rayAngle]) + (playerY) ) % 64;
screenBuffer.setRGB(raysCasted, i, Texture.floor.texture.getRGB(x,y));
}
Something very strange is happenning here:
But now it seems to be fine...mostly:
UPDATE
Success!!!!
I just "ruin" the equations a little bit and it's got better. I corrected the wrong floor-move direction by removing the "-" from the x equation. And I noticed the floor was very rotated, rotated into each other (you can see that "anomaly" in the previous pictures), I removed the cos part from the distance formula and it's got better.
int floorCastingStartPixel = planeHeight>>1;
int x,y;
for (int i=floorCastingStartPixel; i<=planeHeight-1; i++) {
distance = (float) (((float)PLAYERHEIGHT / (i-(planeHeight>>1)) )* playerPaneDist );
x = ( (int) (distance * (cosTable[rayAngle])) ) + playerX;
y = ( (int) (distance * (sinTable[rayAngle])) ) + playerY;
screenBuffer.setRGB(raysCasted, i, addFogEffect(Texture.floor.texture.getRGB(x&63,y&63),distance));
}
The current state:
I did the ceil-casting by "reversing" the for loop (loop variable = 0 and incrementing till it's planeHeight>>1).
UPDATE #2
I just realized that my ceiling don't move correctly...not always.
UPDATE #3
Tried other texture, now seems to move ok, so it could have been just seom optical effect.
And...I noticed thath the floor and ceiling has a little hyperbolic(?) curve. And I just realized that it's like the fisheye-effect.
You have to do fish-eye correction on the floor and ceil distance too!!!!
