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1answer
132 views

OpenGL ES, orthopgraphics projection and viewport

I want to make some simple 2D game on iOS to familiarize myself with OpenGL ES. I started with Ray Wenderlich tutorial (How To Create A Simple 2D iPhone Game with OpenGL ES 2.0 and GLKit). That ...
0
votes
1answer
68 views

Perspective projection computation

I'm learning OpenGL from arcsynthesis and I don't understand something about perspective projection (http://www.arcsynthesis.org/gltut/Positioning/Tut04%20Perspective%20Projection.html). When the ...
1
vote
2answers
171 views

projected textures not appear on the “back” of the mesh as well?

I want to create blood wounds on my character's bodies by using projected textures. I've watched some commentaries on games like Left 4 Dead and they say they use projected textures for the blood. But ...
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vote
2answers
195 views

Orthographic Zooming with 0,0 at top/left

I'm trying to implement zooming on my 2D game. Since it's using orthographic projection, I thought it would be easy to implement zooming. After looking around the internet, I found a bunch of ...
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0answers
57 views

Rasterizing euclidean planes

I'd like to visualize a BSP tree. To do this, I need to project an arbitrary euclidean plane onto a projection plane. I was thinking about calculating the intersections of the plane with the viewing ...
1
vote
1answer
93 views

Using gluUnProject to transform mouse position to world coordinates (LWJGL)?

I have a little LWJGL application and I have been trying to figure out how to successfully use the GLU.gluUnProject function in order to transform a given point on the screen (mouse position) to world ...
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1answer
59 views

Why are there different ways of building projection matrices?

Matrix.PerspectiveFovLH documentation page says that this method uses the following formula to build a perspective projection matrix. [w, 0, 0, 0] [0, h, 0, 0] [0, 0, zFar/(zFar - zNear), 1] [0, 0, ...
1
vote
1answer
102 views

Where is the error in my perspective projection implementation?

My question is not really a game development question, but since it's based on 3D programming, I thought it would fit best here. I've got a line made out of Point3D objects where the value of x, y, ...
2
votes
1answer
102 views

Minimal Projection Matrix

i hope you can help me. I'm currently stuck at the creation process for projection matrices used by shadow maps. The problem is the following: I got the spot/directional light ...
2
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4answers
2k views

2D camera perspective projection from 3D coordinates — HOW?

I am developing a camera for a 2D game with a top-down view that has depth. It's almost a 3D camera. Basically, every object has a Z even though it is in 2D, and similarly to parallax layers their ...
1
vote
1answer
49 views

Why does everything appear backwards when using orthographic projection?

I may not be calculating my orthographic projection matrix properly. What can I do to ensure that my scene renders correctly when using orthographic projection? The rendering order appears to be ...
2
votes
1answer
116 views

Is it bad-practice using left-handed coordinate system in OpenGL eye-space?

In the engine I am currently programming I want to use a left-handed coordinate system for eye-space instead of the glFrustum standard right-handed one. Is that in anyway considered bad practice?
2
votes
2answers
81 views

Trying to project a point onto a cubemap

I've got a simple test program with a camera within a cubemap (skybox). You can look around, and it feels like you're in a 3D room, but really it's just a cubemap image. Now I want to draw a point ...
4
votes
1answer
166 views

How do I ensure that perspective and orthographic projection matricies show objects at the same size on the screen?

I am working on a 3d scene editor and would like to show the scene in orthographic projection. My current problem is that I am not sure how to calculate the orthographic projection matrix such that ...
0
votes
1answer
38 views

Rotate final image with projection matrix

I'm trying to use space in my shadow (depth) maps in a more efficient way. If I could freely rotate the final image I get with projection matrix I could save a lot of pixels, but I don't know if it is ...
2
votes
3answers
560 views

Game Engine which can provide 360 degree projection for PC [closed]

I'm searching Game engine which can provide 360 degree real-time projection. I've already achieved this by using VBS2 Game Engine. (Ref.: ...
0
votes
0answers
42 views

W2S, worldtoscreen from Projection Matrix and View Matrix

After a couple of days of tremendous trial and error coding, I must give up: I have a simple 3d program that I'm adding a visual layer to. Basically, I want to draw 2d icons and text over 3d objects ...
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vote
3answers
182 views

Orthographic Projection with variable FOV

We are building agame with orthographic view. The problem we face is the fact that with different resolution you can see different area of the game world. E.g. if you have higher resolution you can ...
12
votes
3answers
846 views

Camera for 2.5D Game

I'm hoping someone can explain this to me like I'm 5, because I've been struggling with this for hours and simply cannot understand what I'm doing wrong. I've written a Camera class for my 2.5D game. ...
2
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0answers
99 views

Unproject considering parallax depth

How can I take screen coordinates (or alternatively world coordinates on the 'primary' parallax plane) and find out what world coordinates they translate into when taking parallax depth into account? ...
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0answers
102 views

Screen space to world space revisited

I am revisiting some code that I thought I understood, but have found that I do not quite understand it. I put together a test to see what was going on. Here's the code: [Fact] public void wtf() { ...
1
vote
1answer
249 views

Project location to perspective fake 3D view

I am trying to implement a perspective view in a 2D soccer game, such like Nintendo World Cup. In this case, the soccer pitch will look like a isosceles trapezoid, but not a rectangle in real. Here ...
2
votes
2answers
320 views

Unproject mouse position to tile — extremely jumpy position?

I'm trying to unproject the mouse position to get the position on the X-Z plane of a ray cast from the mouse. The camera is fully controllable by the user. Right now, the algorithm I'm using is... ...
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vote
2answers
257 views

What is the camera direction vector for an isometric view?

What values correspond to a 3D vector for screen-normal from within an isometric game? It needs to be in game coordinates. It is a standard isometric where tiles are rotated 45 degrees and half ...
-1
votes
1answer
169 views

Pinhole matrix problem

I made a program to represent a 3D world. I use the projection matrix we can find on wikipedia. For viewing a scene it's very nice but when I straff in the scene, everything behind the camera go on ...
2
votes
0answers
104 views

Stereo 3D: drawing 2D elements at apparent screen depth

I'm developing an application making use of DirectX11's stereoscopic features. At such I am not relying on nVidia's automatic implementation. That means I have to replicate a way to render 2d elements ...
3
votes
1answer
140 views

Shear transformation in the projection matrix?

I am trying to understand what the shear transformation (l+r/r-l & b+t/t-b) is actually doing in the projection matrix? The only thing I got till now is headache :) Can you please help?
0
votes
1answer
65 views

XNA Rendering vertices that only appear within the cameras view

I'm making a game in XNA and I recall hearing that professionally made games use a technique to only render the polygons that appear within the cameras projection. I've been trying to find something ...
0
votes
1answer
101 views

Which is the right way to build a OpenGL Projection Matrix

This time I'm trying to learn the core of matrix transformations. I dont like the idea to using a Math library and dont understand what is hapening on background, because this I'm having some ...
0
votes
1answer
227 views

Projecting world coordinates to screen coordinates issue - points disappear when origin not in view

I am trying to implement a 2d line drawing effect on a 3d mesh using Ogre. In order to do so, I perform silhouette detection on the lines of the object (this works) and then project these lines from ...
1
vote
1answer
165 views

XNA draw 3d graphics in 2d game

I am programming a simple pool game in XNA. I am using Farseer for simple 2d physics but I want to use 3d graphics. My problem is I can't get the rendering to work. I have one model for the ball and ...
3
votes
2answers
155 views

What kind of projection is ScreenX=X/Z, ScreenY=Y/Z?

I have an existing class which transforms 3D vectors and projects them on a 2D plane (Camera). The code is all written in C without help from an external library. To project a single vector (X,Y,Z) ...
0
votes
3answers
132 views

Keeping raycast on the same level

I want my raycast to end at certain height(red line). But as the game is 3D and the camera rotates I can't use a fixed magnitude. What I thought was a stroke of genius, I figured I'd project the ...
2
votes
0answers
64 views

uniform z slices in clip-space

1) Context I'm using a regular OpenGL perspective projection matrix created with GLM (glm::perspective) and taking the inverse (glm::inverse) to transform clip-space back into view space (and world ...
0
votes
1answer
170 views

Ways to “invert Z-axis” in shader-based core-profile OpenGL?

In my hobbyist shader-based (non-FFP) GL (3.2+ core) "engine", everything in world-space and model-space is by design "left-handed" (and to stay that way), so X-axis goes from -1 ("left") to 1 ...
5
votes
2answers
300 views

Calculate new coords of camera after a 90 degree rotation in an isometric 2D projection

I made a 2D isometric renderer. It works fine but now I want to show my scene from 4 different points of view (NE NW SE SW) but, on a 90° rotation, my camera cannot keep the center of my scene on ...
5
votes
1answer
146 views

Composite 3-D and 2-D using Anamorphic Projection?

I'm working on a game which takes place on a two dimensional grid similar to the fluid background grid in Geometry Wars. It is implemented as a procedurally drawn spring system which may have force ...
6
votes
3answers
853 views

Arbitrary projection matrix from 6 arbitrary frustum planes

A projection matrix represent a tranformation from the camera view space to the rendering system clip space. In other words, it defines the transormation between a 6-sided frustum to the clip cube. ...
0
votes
1answer
156 views

Simulating flight dynamics in two dimensions

I have decided that in order to improve my math skills and game programming skills I am going to work on a two-dimensional space simulator. The view of the player or camera will be from inside the ...
3
votes
1answer
269 views

How to do perspective projection “parallax” but without changing the scale or offset of objects?

Hello everyone I have this problem that I have tried everything I could think of. The problem: I am making a 2D game with parallax effect but I am using 3d space so am not simulating the parallax but ...
0
votes
3answers
252 views

Project rendering onto a polygon in the scene

I have a function that renders a simple OpenGL scene. I want to display this scene on a polygon within another scene, without the function having to know about it. For example, to display the scene on ...
15
votes
1answer
592 views

Keystone Correction using 3D-Points of Kinect

With XNA, I am displaying a simple rectangle which is projected onto the floor. The projector can be placed at an arbitrary position. Obviously, the projected rectangle gets distorted according to the ...
0
votes
0answers
129 views

Drawing Projected Vertices/Faces In Order

I recently created a 3d engine, and have gotten to what is (as I've found) the hardest part so far. I need to sort the objects and then draw them. I've looked at sorting algorithms, but my case is ...
2
votes
2answers
228 views

What kind of projection is used here?

Tibia is a 2d game, but it's sprites are drawn using certain kind of orthographic projection that is not the same I'm used to: I'm trying to figure out what projection is used here. I've guessed ...
1
vote
0answers
878 views

Black Screen: How to set Projection/View Matrix

I have a Windows Phone 8 C#/XAML with DirectX component project. I'm rendering some particles, but each particle is a rectangle versus a square (as I've set the vertices to be positions equally offset ...
2
votes
1answer
184 views

Coordinate spaces and transformation matrices

I'm trying to get an object from object space, into projected space using these intermediate matrices: The first matrix (I) is the one that transforms from object space into inertial space, but since ...
1
vote
1answer
491 views

How to do geometric projection shadows?

I have decided that since my game world is mostly flat I don't need better shadows than geometric projections - at least for now. The only problem is I don't even know how to do those properly - that ...
13
votes
1answer
368 views

Orthographic unit translation mismatch on grid (e.g. 64 pixels translates incorrectly)

I am looking for some insight into a small problem with unit translations on a grid. Update and Solved I solved my own issue. See below for details. Everything in this part of the post turned out to ...
0
votes
1answer
229 views

Greiner-Hormann clipping problem

I have a set of planar polygons in 3D space defined by their vertices in counterclockwise order. Let's define the 'positive face' as being the face of the 3D polygon such as when observed, the ...
4
votes
2answers
698 views

If I project a sphere in 3D will it be a circle?

Assuming I have infinite vertices to represent the sphere, if I project the sphere from any position/scale in 3D to 2D, will it be a circle? I know it will not be a circle on the screen, because of ...