Making a camera semi-orthographic

Questions & Answers
1

Hello unity community, I am asking if it is possible to make only the bottom of a perspective camera orthographic, in Unity Free. Here why,

I am creating a 2D game, and today was the first day of development and i already encounter an issue that has no easy fix. I want to add a scrolling like background in my game, like what is scene in unity. The issue is that to get the effect right, i need to use a perspective camera. However, this type of camera has a nasty feature, the bottom view goes down. This i bad because every layer has to be slightly lower than the other, and its really frustrating trying to fix it

One way i have thought about to fix it is possibly making the bottom of the camera straight, like orthographic, unfortunately I don’t know if its possible and if it is, how do i do it?, so that is why i am posting this question.

EDIT: This is what i am wishing to achieve

6757-answerquestion01.png

2

You need to make changes to your camera’s projection matrix.

Projection matrices is hard stuff. The internet has lots of resources; I can’t give any specifics. It’s been way too long since basic 3D graphics class :slight_smile:

3

What you are looking for is an off-axis projection where the optical axis is “shifted” from the center of the screen to the bottom. You can accomplish that by setting the element m[1,2] of a regular projection matrix to 1 instead of 0. (usually denoted as “b”, for example here. Instead of top=1 and bottom=-1, you need to use top=2 and bottom=0, the new vertical “distances” of your screen corners from the optical axis. this results in B=1).