The projection tag has no wiki summary.
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1answer
69 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
110 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
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3answers
83 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
40 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
52 views
Uses for vector projection?
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 ...
0
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1answer
66 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 ...
0
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1answer
62 views
Problems projecting a point to screen [closed]
In my game I'm trying to implement an equivalent of gluProject, my problem is that the code only seems to work if the camera has no rotation. Even turning left and right affects the vertical position ...
5
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2answers
155 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
100 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 ...
2
votes
1answer
180 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
89 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
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1answer
111 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
204 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 ...
0
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0answers
88 views
Camera Projection back Into 3D world, offset error
I'm using XNA to simulate a robot in a 3D world and then do image analysis on what the camera sees.
I have my camera looking down in front of the direction that the robot is going, and I have the ...
2
votes
1answer
140 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
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0answers
475 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
273 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 ...
1
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0answers
87 views
Numerically stable(ish) method of getting Y-intercept of mouse 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...
...
1
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3answers
685 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
195 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
votes
2answers
581 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 ...
0
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1answer
133 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
131 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 ...
0
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0answers
168 views
Unity3D - Projection matrix camera frustum
I've used off centre projection to create a custom projection matrix for my camera.
When I run the game I can see the scene correctly in the game view but in the editor view the camera frustum is not ...
1
vote
1answer
132 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 ...
-1
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1answer
264 views
Off center projection
I'm trying to implement the code that was freely given by a very kind developer at the following link:
...
3
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2answers
405 views
Game Engine which can provide 360 degree projection for PC
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
444 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
213 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
313 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 ...
0
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3answers
196 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 ...
2
votes
1answer
308 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 ...
0
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0answers
94 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 = ...
0
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1answer
337 views
Easy way to project point onto triangle (or plane)
I have a mesh of triangles (navigation mesh), and a point in 3d space. This point should be "over" one of the triangles all the times. I'm trying to determine which triangle is the one the point is ...
3
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1answer
235 views
How to compute the 2D equations of 3D circular arcs?
I'd like to obtain these equations for the ellipses produced by the perspective projections of (3-dimensionally transformed) circles.
This is useful for rendering in 2D contexts which provide curve ...
1
vote
2answers
603 views
How would I achieve diablo like 2D isometric projection?
I am in the process of coming up with an idea for a game, and I would like it to be isometric like Diablo. The problem is I have no idea how it achieves the effect of height like in the following ...
3
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2answers
340 views
Draw a projection of a mesh on a surface
I have a mesh looking almost like a cylinder, the cylinder goes through a mesh and continues on the other side. What I want to do is to draw the projection of the cylinder on the mesh. So if you look ...
15
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1answer
454 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 ...
1
vote
1answer
129 views
Finding furthermost point in game world
I am attempting to find the furthermost point in my game world given the player's current location and a normalized direction vector in screen space. My current algorithm is:
convert player world ...
8
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1answer
1k views
Screen space to world space
I am writing a 2D game where my game world has x axis running left to right, y axis running top to bottom, and z axis out of the screen:
Whilst my game world is top-down, the game is rendered on a ...
0
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3answers
224 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 ...
5
votes
3answers
616 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.
...
3
votes
1answer
776 views
How do I create a decal system?
I'm currently given the task to design & create a simple decal-system in C++/DirectX.
Does anybody know a great tutorial, article or paper to start with? (Especially the part about 2D-texture to ...
3
votes
1answer
278 views
Does the projection matrix flip winding order in right handed systems?
I am using a right handed coordinate system for my world coordinates (so, positive x goes right, y is up, and z is towards you).
However, after projection and the w divide, nomalised device ...
3
votes
1answer
404 views
Perspective projection with 90 degrees between X-Y axis?
I'm trying to create a game that mimics Tibia's projection style:
,
As you can see, a 3d point is mapped to 2d like this:
So I've downloaded Three.JS and a lib to create a Orthographic Camera. But ...
5
votes
3answers
648 views
What's a pre-multiplied 4x4 matrix?
I'm using a 3d game engine, that uses a 4x4 matrix to modify the camera projection.
The matrix is in the regular 4x4 format:
r r r x
r r r y
r r r z
- - - zoom
The description for the ...
2
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1answer
339 views
How to calculate FOV with four-walled tiles?
I'm working on a 2D tile-based game. I'm trying to calculate FOV and I've implemented walls so they don't take up an entire tile. Instead, they just take up a side of each tile. Similar to:
class ...
4
votes
3answers
295 views
How can I calculate where my camera can be to avoid showing something outside a region?
I have a landscape model, which goes from the coordinate -45, -45 to 90, 90.
The edge of the model just cuts off and i would like to somehow stop the screen from ever passing these points. Basically ...
2
votes
1answer
253 views
Shader issues when creating projection using CreateOrthographicOffCenter instead of CreateOrthographic
Pre. Having these matrix transformations:
var scale = Matrix.CreateScale(50f);
var eye = new Vector3(0, 0, 10.0f);
var view = Matrix.CreateLookAt(eye, Vector3.Zero, Vector3.Up);
var projection = ...
3
votes
1answer
1k views
Can a 4x4 matrix describe a camera's perspective?
I'm working with a closed-source 3D engine, and it only allows you to set the view projection via a 4x4 matrix. Can this matrix describe the camera's translation, rotation & perspective?
I turned ...
