raycastings

• Python3 (+pygame as 2D graphics lib)
• C
• JavaScript

addtional feature: I implemented a custom collison system with only using math & program logic.

How my custom collison system works?

here's the specific code:

#storing the previous values of the player's x & y coordinates
prev_x = player_x
prev_y = player_y

#movment code here

#the collison system
for ang in range(0,360,STEP):
  a = radians(ang)
  row = int((player_y-(RADIUS+0.5)*sin(a))/LENGTH)
  col = int((player_x-(RADIUS+0.5)*cos(a))/LENGTH)
  if MAP[row][col] == 1:
    player_x = prev_x
    player_y = prev_y

this is the whole collsion system code.
in actual code at line number:
81-82 & 98-102

What Exactly Is It Doing?

It is essentially tracking specific points along the circumference. When these points overlap with any coordinates on the "wall", the player's X and Y coordinates are reverted to their previous positions.

Defining Points

To define the points, I implemented a for-loop that iterates from 0 to 360, covering every possible angle in a circle, with a specified "step". In this code and example, the "step" is set to 45 degrees. Therefore, the angles it will iterate through are 0, 45, 90, 135, 180, 225, 270, and 315 degrees.

Assuming the player's (X, Y) represents the center point of the circle, you can calculate the coordinates of the points along the circumference as follows:
XPoint = X - (radius + variance) * cos(angle-in-radians)
YPoint = Y - (radius + variance) * sin(angle-in-radians)

The diagram below illustrates all the points on a circle, starting from 0 degrees and incrementing by 45 degrees.

that's how points can be defined and then check if they overlaped.

Pros:

• The lesser the step value the more delicate it gets as it will track more points. Even though currently step is set to 45 degrees it still does very well job at detecting collsion.
• Pretty Errorless.

Cons:

• Can be CPU intensive if tracking more and more points.

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Great thanks to monkey_see_monkey_do I understood his video on raycasting only a bit, but his final code that I referred was pretty good and also made me understood a lot.

Some videos that did good job explaining raycasting are as follows:

• Building a Raycasting Engine in Python - Gpopcorn
• Make Your Own Raycaster Part 1 - 3DSage
• DDA Line Drawing Algorithm - Computer Graphics - Abdul Bari

(To be honest I didn't really watched/read much of these for making this project. I learned about it through the proccess of making it. Which can get painfull sometimes but thinking from scratch is like inventing it.)
(I might make a video on it, explaining it in my own way)