The projection tag has no wiki summary.
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1answer
26 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 ...
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1answer
41 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 ...
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0answers
27 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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3answers
99 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 ...
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0answers
33 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 ...
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3answers
770 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. ...
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0answers
70 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
85 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()
{
...
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1answer
197 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 ...
1
vote
1answer
110 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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2answers
173 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 ...
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0answers
59 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 ...
-1
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1answer
161 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 ...
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0answers
88 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 ...
2
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1answer
84 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?
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2answers
130 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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1answer
59 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 ...
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0answers
84 views
Premultiplying matrices with Perspective destroys them
If I apply world_to_camera, perspective and camera_to_screen to my mesh, everything is okay. But if I premultiply given matrices (i.e. transform = world_to_camera * perpective * camera_to_screen) ...
0
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1answer
89 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 ...
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1answer
196 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
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1answer
130 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
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2answers
146 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) ...
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3answers
112 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
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0answers
58 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 ...
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0answers
117 views
Uses for vector projection? [on hold]
My previous question was solved by vector projection. Thus I spent some time studying it (Few helpful links: Interactive projection, short video and a longer video.).
There were plenty of sites that ...
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1answer
127 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
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2answers
264 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 ...
0
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1answer
135 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
236 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 ...
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0answers
110 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 ...
5
votes
1answer
132 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 ...
2
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2answers
223 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 ...
2
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1answer
166 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 ...
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0answers
724 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 ...
1
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1answer
437 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 ...
2
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2answers
298 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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3answers
1k 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 ...
12
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1answer
307 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 ...
4
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2answers
654 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 ...
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1answer
147 views
Scanline filling of polygons that share edges and vertices
In this picture (a perspective projection of an icosahedron), the scanline (red) intersects that vertex at the top. In an icosahedron each edge belongs to two triangles. From edge a, only one triangle ...
0
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1answer
175 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 ...
1
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1answer
150 views
Orthogonal projection and world transform
I'm reading about projection matrix. Needs of perspective projection is obvious, but I'm not sure about orthogonal projection. Because orthogonal projection effect looks possible with only world ...
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1answer
396 views
Off center projection
I'm trying to implement the code that was freely given by a very kind developer at the following link:
...
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3answers
506 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.: ...
5
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2answers
514 views
Draw a 3D object at specific coordinates on the screen
I'm creating an application which allows the user to manipulate 3D models.
I would like to draw 3 axis representing the world coordinate system in 3D in order to give the user an idea where he is. ...
0
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0answers
244 views
Map 3D space to 2D screen space?
Could some one help me to understand this code and explain it?
It's about converting from 3D space to 2D position, so that I can use it in another Effects (.fx) files, but I am a bit confused.
float ...
1
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1answer
442 views
Trouble with SAT style vector projection in C#/XNA
Simply put I'm having a hard time working out how to work with XNA's Vector2 types while maintaining spatial considerations. I'm working with separating axis theorem and trying to project vectors onto ...
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3answers
212 views
Understanding how to go from a scene to what's actually rendered to screen in OpenGL?
I want something that explains step by step how, after setting up a simple scene I can go from that 'world' space, to what's finally rendered on my screen (ie, actually implement something). I need ...
3
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1answer
364 views
Silly question about perspective correct texture mapping
OK, I'll admit, the math on a perspective projection matrix is quite hairy for me, but I get the general gist of it: morph the object so that it looks... perspective-ish.
But there is one thing which ...
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0answers
124 views
What is the connection between an isometric angle and scale
I am trying to work out an isometric projection matrix for a custom angle.
In the engine I'm using there's a projection matrix defined like so:
projection.rotate(45 * (Math.PI / 180) );
scale = ...
