fisheye | Easily create a fisheye effect

I'm working on a project for school where I need to implement a fisheye shader, and I'm struggling with the process for determining the depth values of the vertices. I know that for a point in space P1 = (x, y, z, w) that P * my projection matrix should result in a new point P2 = (a, b, c, d) where for any point between the near and far clipping planes P2.c/P2.d results in a number between 0 and 1.

My hlsl vertex shader contains this code where input.Position is the raw Vertex Position

What is the difference between these two functions provided in OpenCV?

Why is there cv2.fisheye.calibrate() function we need?

I tried using cv2.calibrateCamera() for barrel distorted images and I think it is giving me good results, so why would I want to use fisheye.calibrate()?

I am writing a raycaster using SDL's C API. I have spent weeks trying to fix the notorious fisheye effect to no avail. According to this source, I can multiply my calculated distance by the cosine of half of the FOV to fix it. That has not worked for me. I still have the cosine correction in my code nonetheless.

Here are two images demonstrating the distortion:

I think a core problem of my code may be that my angle increment is constant, while the increment should be smaller as I'm closer to the screen borders. Unfortunately, I don't know how to start implementing this.

If possible, could anyone please take a look at my code and give me a tip on how to remove the fisheye? To move in any direction, use the arrow keys. Use the 'a' and 's' keys to turn left and right respectively.

This is how I'm compiling: clang `pkg-config --cflags --libs sdl2` raycaster.c

I am writing a raycaster using the SDL library with C. I have been dealing with the fisheye effect for many weeks now. For a field of view like 60 degrees, I multiply the distance to the wall by the cosine of the relative angle (ranging from -30 to 30), but still, I get the same fisheye. Here's what that looks like:

I don't know what to do at this point, given that so many sources have recommended cosine correction and it just does not fix the distortion in my case.

• I am compiling like this: clang `pkg-config --cflags --libs sdl2` raycaster.c
• To go forward and back, press the up and down keys. Press left and right to strafe. You can use the a and s keys to turn left and right respectively.

My code is below if you want to take a look. If you manage to figure out why I am getting a warped perspective in my engine, please let me know.

This project is taking pictures for the sky and then it's going to mask the clouds, so there will be two pictures, one is the original and the other is the masked one.

I just want to upload every picture taken by the camera pi to Dropbox.

Here is the main code:

I am looking for a fast way to interpolate a 3 channel image on a grid of x-y points. I have a functioning code using map_coordinates. As you can see, i am doing 3 times the same thing, I would like a faster way that can do at least the 3 channels at the same time.

I am using cytoscape js with react cytoscape and cytoscape undoRedo and cytoscape expand collapse. On first render I want to have layout by preset(I have all node's positions). It works well but when i perform api.collapseAll() it looks like nodes does not have these positions. Even though groupped nodes have the same position as parent. On expand I want to use cose bilkent layout. Is there a way to do it?

What does cv2.remap(img, map1, map2, interpolation=cv2.INTER_LINEAR) do when the map1 has a shape (h,w,2) and map2 a shape (h,w). These maps come as an output to the cv2.fisheye.initUndistortRectifyMap but the documentation is not very clear. If I change the map2 variable for a numpy.array([],dtype=np.int16) it will still give me a output that looks close to the one without omitting map2 but there are differences.

Does cv2.remap change the data type of img during this process?

I've got a CG shader which scrolls a sprite in a SpriteRenderer in Unity, like so:

https://imgur.com/a/yxV4BRq

The problem is that there's no "bending" on the edges of the sprite, so it doesn't look like the bowling ball is rolling. I'd like to add a fisheye effect. I see there is a simple fisheye effect shader here:

http://www.michaelbibby.co.uk/2017/10/05/simple-fish-eye-post-process-shader/

which I am trying to add to my scrolling effect by taking the frag shader function and putting it in my shader. But when I do, it tells me that the v2f called i in the frag shader doesn't have a .uv property. I don't understand this problem, because there doesn't seem to be a definition for a struct of type v2f in my shader, though there is in the fisheye effect one.

Here's my starting point, which is the scrolling shader being used in the video. Can anyone advise me on how to add the fisheye effect?