Questions tagged [projection]

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(XNA) Pseudo-3D Buildings/Hills (like Road Rash)

So I was doing a pseudo-3d game in FNA (XNA) like roadrash or outrunners. The road is built from quads using 'UserIndexedPrimitives' and 'BasicEffect' which are calculated using pseudo-3d perspective ...
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1answer
41 views

Reversing plane projection texture mapping algorithm

I found this algorithm in some old codebase, it takes two triangles from a mesh ABC and PMN, where ABC is the triangle that will be rendered and PMN is an extra triangle that is only used to generate ...
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Unity custom camera projection only working in scene editor

I've found this article on Gamasutra on a custom camera projection to make 3D look more 2D and decided to implement it to make some gameplay tests. I had to make some changes to make it work on URP(on ...
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2answers
83 views

How to render a field of view of over 180 degrees?

In most 3D renderings, a view frustum is used. This has the problem, that things get stretched out towards the edges. At "normal" fov (field of view) of about 60 degrees, the effect is not ...
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33 views

Game Maker - Raycasting from camera in orthographic projection

I have been trying to figure out how to click on 3D objects in Game Maker Studio 2. I am using an orthographic projection. I know the basic idea is to calculate a ray that comes from the camera ...
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Does Unity provide access to a camera's Viewport Rect in a shader?

If I, for example, set a camera's Viewport Rect to W:0.5 H:0.5, is there some way to access that in a shader? Is there some way to extract it from unity_CameraProjection? I thought about comparing ...
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25 views

Projecting Coordinates from one Space into another, but with “twisting”

i'm trying to generate a decal mesh kinda like this: http://blog.wolfire.com/2009/06/how-to-project-decals/ but instead of projecting the decal with a box, i need to project it with a sort of ...
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1answer
144 views

Why when I do an isometric projection do I get a “dimmetric” view?

First of all I would like to apologize for my poor English. It is not my native language. I have some doubts about isometric projection that perhaps I do not know how to describe them and I would ...
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1answer
87 views

Perspective projection and ultrawide resolution

The problem I'm going to describe did not occur to me until very recently, when I got a super ultra-wide monitor (32:9 aspect ratio) and tried playing videogames on it. TL;DR: the scenery is ...
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71 views

How to convert screen to world coordinates while using gluLookAt / gluPerspective or similar matrix transforms?

I am just starting an adventure in looking under the hood of graphics for a game project I've been working on for a while, and I could use some guidance. I am using Python/Kivy (though that is not ...
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27 views

Libnoise bounding box - from spherical to planar

I'm trying to convert a bounding box inside a spherical map (equirectangular image as a result of Libnoise/c++) into a planar projection, but I can't find the correct algorithm for it and I'm not good ...
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22 views

Map an equirectangular square slice inside cubemap

I'm trying to map a square slice of an equirectangular image inside a cubemap with 6 faces, without distortion. The point is that I'm dealing with huge array sizes if I try to project the whole ...
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1answer
77 views

Tiles on sphere - check visibility

I have a sphere with tiles. I need to heck if tile is visible or not. See the image. Tiles are red squares, "screen" is represented by yellow quad. Currently, I calculate coordinates of tile in ...
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39 views

Confused on graphics rendering

Implementing a viewport is just a rectangular space on the back buffer usually a 2d texture set to the size of the client window that we render to. However in direct3d when we describe the viewport ...
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215 views

How to set the camera projectionmatrix so that it's 4 rays always exactly hit the corners of a defined plane?

I have a camera, and I have a plane. The plane has 4 corner points. I need to find out how to change the projection-matrix of the camera so that the projection-rays of the camera always hit the ...
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2answers
105 views

z ordering in directx11

Hi recently i am trying to implement z ordering system into my directx framework. So every object will have z order property(int), and this value will have higher priority than depth checking for ...
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1answer
746 views

Unity3d: Get a direction vector parallel to plane

I need to send a raycast from my camera which is parallel to the plane (Ground) and in the same direction of its forward vector (Represented by the black color vector) I cant use world space ...
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60 views

Why projection window is between -1 and 1

Is it a convetion ? What we achieve with this ? I am reading about how the perspective and orthographic matrix is getting calculated and everyone is trying to normalize the homogenous coordinates to [...
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1answer
26 views

How can spotlights be implemented with a perspective projection?

I was reading Shadow Mapping with Directional Lights and noted that spotlights are implemented by rendering with the perspective projection, stating that the spotlight worked just like the camera. ...
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1answer
78 views

What is the alternative (new) 3d projection called that solves the stretching / zooming at sides of monitor?

I understand about camera's and projections etc, such that we have distortion and zooming when at the sides of the screen (exacerbated on 21:9 monitors), however a few years ago, in a Unity forum ...
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3answers
854 views

How to render top-down perspective in a tile-based RPG?

My question is specifically about the type of perspective that GBA Pokemon games like Fire Red/Leaf Green have: I'm not sure of the correct terms for what I'm trying to achieve. I am using SDL2 and ...
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1answer
43 views

Z rotation matrix inverting object

I'm currently creating a 3d game where I need to rotate shapes. To do se, I created a rotation matrix for each axis, X, Y and Z. X and Y are giving me expected results, but not Z who kind of "inverts ...
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1answer
866 views

3d isometric projection matrix?

I have 3d vectors that I want to project as 2d vectors to draw my shapes. I got a 3d vector cameraPosition, a 3d vector cameraDirection, a float renderDistance. I need to create an orthogonal / ...
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1answer
97 views

Can we flip znear and zfar so that positive z values increase away from the viewer?

I am confused about the projection matrix in OpenGL. i have a habit of writing the code as follows. ...
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74 views

Perspective projection matrix with a non-orthogonal near plane

I'm trying to figure out a way to provide such a perspective projection matrix to a shader that the "near" plane wouldn't necessarily be orthogonal to the camera vector. More specifically, I'm ...
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33 views

Camera LookAt position with fixed screen position

I have a perspective "lookAt-type" camera. I'm trying to compute specific focus point of the camera, which should be placed in the middle of the screen: I also have a custom 3d point in world space, ...
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1answer
183 views

OpenGL orthographic projection rendering quarter of screen

I'm trying to set up an orthographic projection so I can draw a rectangle using screen coordinates, but even if I draw a rectangle using the width/height of the window, it only fills a quarter of the ...
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1answer
922 views

Difference between two perspective projection representations

When researching perspective projections on the web, I've come across two different representations. One is unrelated to OpenGL and the other is strictly associated with it. What is the relation of ...
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52 views

Why does this work in the fragment shader but not in the vertex shader?

I'm doing some model view and projection transforms in the vertex shader and I want to determine whether the current vertex will end up on the viewport or not. After searching a bit I found that ...
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3answers
308 views

Figuring out if two objects overlap on screen

I want to figure out if 2 3D models overlap on screen. My general idea is: Compute the bounding box of each model Transform the bounding box to the View Volume using the ViewProjection matrix Check ...
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457 views

2.5D UI, perspecitve view, distort objects by angle but not position

Instead of thousand words, a few pictures to explain what I want to achieve How do I get the merit of UI objects rotation in perspective projection, but ignore the position of an object(as in Overlay ...
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2answers
124 views

Custom Camera View Fustrum in Unity

Is it possible in Unity to make some sort of bounding box (with a running application) within the current viewpoint of the actual screen? Let me explain: I'm working on a project which uses a ...
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693 views

Screen-space shadows?

Is there such a thing as screen-space shadows? I know that most shadow projection comes from rendering the world from the viewpoint of the light source, projecting the shadows onto a large square ...
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147 views

How to implement a pannini projection in opengl?

I have read about the pannini projection, which involves (I think) projecting a scene onto a cyclinder instead of a rectangle. How can I implement this projection in a vertex shader? Blinky is using ...
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20 views

How do I change x,y,z coordinates if I want to make a perspective projection?

How do I supposed to modify x,y,z coordinates to make the perspective projection? I'm talking not about matrix, could you explain me each coodinate specifically? Like, x =... y=... z=... I'm asking ...
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1answer
524 views

Project 360 video on the inside of a iso sphere / polygon sphere

I'm creating a game in Unity. I have a iso sphere or polygon sphere, and I want to project a 360 video on the inside of the polygon sphere. I've learned thow to put a 360 video on the inside of a ...
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2answers
2k views

Finding the normals of the planes of a View Frustum

Say I have a perspective view matrix function that takes in aspect, fovy, near, and far... Transforming the view into a frustum. Typical OpenGL stuff, right. But say then, that I would like to find ...
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1answer
317 views

Project 2D texture onto a cubemap

I'm looking to take a 2D texture (previously rendered from the user's perspective), and overlay it overtop of a cubemap. Since a cubemap has 6 textures, I need to run a shader over top of all 6, and ...
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1answer
560 views

Camera and multiple shaders

What is the best way to handle a moving camera inside many shader programs? I believe most games need to have one common projection matrix inside all shader programs to use a moving camera. Currently ...
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1answer
242 views

How do I project the Earth globe on a flat plane with minimal distortion?

I want to build a game where the game map is the planet Earth. The game map needs to be on a 2d plane, with the Earth texture projected on it If the player walks endelessly in one direction, it should ...
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2answers
224 views

Rendering a 2D tree in WebGL

Assume a tree of objects that need to be rendered, each with their own x/y coordinates. Now let's say I could crawl through the tree and give each element a "z" coordinate, before rendering. Is ...
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1answer
70 views

MonoGame ortho projection axis direction

I have perfect square screen and I want to capture everything between -1000.0f and 1000.0f, so I create projection matrix like that: ...
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1answer
280 views

OpenGL Orthographic projection questions

I'm studying now about projections with OpenGL and I've some questions: Is there importance for the viewer's location? I know if I move forward/backward it won't mind, but what if I move upward with ...
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4answers
1k views

Why are 3d projections on a 2d screen not like what the human eye sees?

Firstly, I'm sorry if this question doesn't make much sense or is poorly written - I have almost no experience with programming, and none at all with game development. I'm also not sure it's an ...
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2answers
253 views

How can I draw the “cone of view” of a camera in a flat 2D minimap?

I have a 3D world with some model in it (the XZ-plane grid, some gray boxes and a red box). In the upper-left corner I'm trying to draw a minimap that should represents the whole world in 2D (flat). ...
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0answers
32 views

How to change a shape project when obstructed by object

I have a customized shape (mesh) in 3D as shown below: Now that customized shape projection will change when there are several obstacles located in front of the customized shape. I expect the result ...
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1answer
2k views

Deproject Screen To World Coordinates (Unreal Engine 4.15)

I am working on a small game in Unreal Engine 4.15 using blueprints only and encountered a behaviour I don't understand. The game is based on the Top Down Example. As I'd like to teleport an actor ...
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1answer
453 views

Left-handed version of the reversed depth projection with infinite far plane

Let's say that I have standard left-handed WorldToView and ViewToScreen row-major matrices in the same vein as the DirectX ...
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1answer
238 views

How to calculate a projection of 360° equirectangular slides?

My goal is to have a light source inside of a transparent sphere that has an equirectangular texture to act as a 360°-slide. I want to get the projection on arbitrary objects as a texture image on ...
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1answer
276 views

Move an object to a point relative to the second camera

I have two cameras, one for the UI, one for the 3d objects. The UI camera is just a simple, perspective camera. The ...

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