Questions tagged [projection]

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3D projection, Similar to SceneCapture2D

I would appreciate some help, I was wondering if it was possible in UE4 to do a "3D projection" of a scene, Similar to what SceneCapture2D does, but the viewer can see a 3D scene (with a ...
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27 views

How to make a multiplayer game for multiple screen sizes?

I am making a 2d multiplayer game for Android, targeted to run on every device. How do I calculate the common position of an asset, independent of screen size? What size map should I assume is a ...
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0answers
60 views

Approximate doom/heretic-style freelook distortion with modern graphics APIs

Currently working on a doom-like engine with fewer technical limitations, and looking into rendering techniques. I'm aware doom's a raycaster, and I want to capture a similar look but with modern ...
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0answers
23 views

Perspective of a Point Light

I'm trying to calculate shadows by projecting the silhouette of each object seen by the light source. (The shadows are just going to go on planes.) To get each silhouette I take a snapshot from the ...
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4answers
4k views

How to determine if a 2D image represents what player sees in 3D game world?

I'm working on a game idea where the player is shown a 2D image (say, a "photo") and the player must find a spot in a 3D world where the view is about equivalent to that photo - not ...
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1answer
71 views

Find projecting triangle for UV mapping in RuneScape model format

I am using an old Runescape model format, also used by Thief and Quake. In this format, instead of specifying UV coordinates for each vertex ABC, we specify a second trio of vertices PMN. Those ...
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1answer
90 views

Need help projecting 2D projectile motion in 2.5/isometric 2D game

So I’ve been researching this a lot and have hit a road block. I’ve read pretty much every thread on here regarding this and while I understand the concept I don’t understand how to implement it. For ...
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1answer
35 views

Convert Global Space 3D Location to Local object space?

I'm trying to find a formula that could convert my 3D global coordinates into local object space. Here are the inputs I have ...
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2answers
215 views

How to project a 3D circle/ellipse to 2D?

The 3D ellipse is represented by its center and the vectors for its major and minor axes and the 2D ellipse by its center, the length of the major and minor axes and the angle between the major axis ...
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0answers
59 views

How to add a falloff (transparency) to projector shader in Unity?

I am new to Unity shaders and I was wondering if it was possible to add a falloff variable to control the transparency of the projected color. Here is the shader code : ...
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0answers
17 views

Projector making the scene objects grey in Unity

Everytime I enable my projector, it makes all the overlapping elements look entirely grey. The shadows also disapear. I tryed a couple of other shaders found on the internet but the issue still ...
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0answers
144 views

Deferred shading - g-buffer positions, world or view space?

So, i am doing this for the first time. I have a lodded terrain that i would like shade deferred. I have built the g-buffer with positions/normals/albedo/depth and render vertices like I did before ...
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1answer
104 views

How to convert from frag position to UV coordinates when my viewport doesn't cover the screen?

So, I'm implementing SSAO as part of my rendering pipeline using OpenGL/GLSL. It works pretty well when I have a camera that takes up the entire screen. However, when my camera is smaller than the ...
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1answer
59 views

Isometric tiles on wrong positions if the mouse points at a negative world coordinate

I am using this approach: http://clintbellanger.net/articles/isometric_math/ Basically, you can calculate the iso coordinates based on the screen coordinates. What I am doing is, getting the actual ...
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1answer
197 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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0answers
311 views

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
262 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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0answers
29 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 ...
3
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1answer
216 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
495 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 ...
3
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0answers
197 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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0answers
44 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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1answer
139 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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0answers
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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0answers
241 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
171 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
1k 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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0answers
65 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
29 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
150 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
2k 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
46 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
2k 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
122 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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0answers
87 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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0answers
36 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, ...
0
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1answer
235 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
2k 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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0answers
56 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
341 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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0answers
751 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 ...
2
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2answers
201 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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0answers
892 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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0answers
202 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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0answers
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
635 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 ...
2
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1answer
465 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
667 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 ...
1
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1answer
310 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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