Tagged Questions

An array of numbers, symbols or expressions, arranged in row and columns. The numbers, symbols or expressions themselves are called elements or entries.

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8
votes
1answer
527 views

Downprojecting an imaginary 4D mesh to the screen

As a mental exercise, I'm trying to imagine projecting an arbitrary 4D mesh onto the screen (2D). I'm guessing a single 4D triangle would still consist of only 3 points, however each of those 3 ...
1
vote
1answer
196 views

Mesh to world vector translation

Suppose I have a world defined in typical OpenGL coords.. then the up vector defined for this space is (0,1,0). Now, if I load a model that is defined with (0,0,1) as its up vector, what are the ...
2
votes
1answer
169 views

Integration of homogenous wave

I have a 2D matrix; each of its elements describes a homogenous coordinate in 3D wave (the values of wave coordinates are changed in time). The wave rendering is done with texture. I need to make an ...
6
votes
2answers
886 views

What is eigenvalue decomposition and why would it be useful in games?

In various math libraries developed for game engines, I see 2x2 and 3x3 square matrices having this function (along with some helper functions). I tried to find information regarding it but did not ...
5
votes
2answers
444 views

Is a dynamic enviroment map using pincushion curvilinear perspective projection possible?

I'm wondering if it is possible to generate a dynamic spherical environment map using a single frame render using a pincushion curvilinear perspective projection matrix (phew, that's a mouthful)? ...
6
votes
1answer
5k views

Help understanding gluLookAt()

I am fairly new to openGL( 3 months ) and am asking for assistance in understanding the fundamentals behind gluLookAt(). Currently I have spent most of my time with openGL modeling scenes with fixed ...
1
vote
1answer
168 views

Is there a memory read/write or performance difference when applying affine transformations on a movieclip rather basic elementary math

I am using Actionscript 3.0 to make games and I fall into the category of programmers who use ball.x+=5; ball.y+=5; in order to move a ball by 5 pixels horizontally and vertically. Well, now i seem ...
0
votes
1answer
320 views

Conversion from matrix defining rotation and position to camera matrix

I have a matrix that defines the rotation and translation of an object, relative to (0, 0, 0). Assuming that the identity matrix defines the camera to be at (0, 0, 0) pointing at (0, 0, 1), how would ...
7
votes
2answers
542 views

Portal Projection

Ok ok I admit, I'm bored and toying with a portal script like the one on steam. I've figured out the following: relative positioning of the mirrored cameras render to texture for the portal (the ...
5
votes
1answer
700 views

Problem with DirectX scene-graph

I'm trying to implement a basic scene graph in DirectX using C++. I am using a left child-right sibling binary tree to do this. I'm having trouble updating each node's world transformation relative to ...
4
votes
3answers
4k views

Inverting matrix in HLSL

I've got an object in HLSL and I'm using hardware instancing to render multiple copies. But I've come a bit of a cropper when it comes to the vertex normals. Currently I am not using normal mapping ...
2
votes
2answers
1k views

How do I calculate an offset from an Object based on the Objects Rotation rather than the World Space

I have a Matrix of a player & I want to create a second location a set distance away from the first location but I want the second matrix to be set a set distance based on the rotation of the ...
3
votes
1answer
355 views

Is there are a good double-precision small matrix SIMD library for x86?

I'm looking for a SIMD library focused small (4x4) matrix operations for graphics. There's lots of single precision ones out there, but I need to support both single and double precision. I've looked ...
12
votes
6answers
5k views

Math topics for 3D graphics programming

I understand that the following math topics are required for 3D graphics programming. I have started doing some of them in my math course. Can someone point me in the direction of a resource that ...
4
votes
1answer
514 views

Managing Game Entity coordinates

In my Game I'm currently have "Scene Coordinates" which are the X,Y coordinates relative to a Game Scene. In that Scene there are Game Entities, let's say there's a GameEntity A in x=100.0, y=100.0 ( ...
4
votes
4answers
1k views

From camera coordinates to world coordinates

I want to calculate world coordinates from camera coordinates. However, I seem to have problems with my understandings of how matrices in HLSL work. From world to camera is clear: cameraPosition = ...
5
votes
1answer
312 views

Realistic damage

I'm looking for a good way to simulate damage, for example a weapon firing at a ship it would calculate the damage depending on layer type, weapon type, angle and similar what i need is a way to to ...
2
votes
1answer
266 views

Why doesn't the y Axis work with SuperBible frame reference or GluLookAt

I'm currently trying to understand how to use the GLFrame Class in the superbible book, and acording to the 4th edition of the book, the camera matrix derived from the Frame of reference class should ...
1
vote
2answers
419 views

opengl rotations for a human

I currently can rotate around a pivot point by first translating to the pivot point then performing the rotation and finally translating back to the origin. I do that easily enough for the shoulder in ...
4
votes
1answer
3k views

How to create a perspective field of view matrix?

Hey, hello. I am learning a little of WebGL (OpenGL ES 2.0) through the http://learningwebgl.com tutorials, but it uses a third party library to create the View, Projection and transformation matrices ...
4
votes
1answer
258 views

Projecting onto different size screens by cropping

I am building a phone application which will display a shape on screen. The shape should look the same on different screen sizes. I Decided the best way to do this is to show more of the background on ...
1
vote
1answer
1k views

Converting to and from local and world 3D coordinate spaces?

I've been following a guide I found here (http://knol.google.com/k/matrices-for-3d-applications-view-transformation) on constructing a matrix that will allow me to 3D coordinates to an object's local ...
1
vote
1answer
1k views

Restoring projection matrix

I am learning to use FBOs and one of the things that I need to do when rendering something onto user defined FBO, I have to setup the projection, modelview and viewport for it. Once I am done ...
4
votes
2answers
6k views

View matrix in opengl

Sorry for my clumsy question. But I don't know where I am wrong at creating view matrix. I have the following code: createMatrix(vec4f(xAxis.x, xAxis.y, xAxis.z, dot(xAxis,eye)), vec4f( ...
2
votes
3answers
1k views

Interpolating Matrices

Apologies if I am missing something very obvious (likely!) but is there anything wrong with interpolating between two matrices by: float d = (float)(targetTime.Ticks - keyframe_start.ticks) / ...
13
votes
5answers
640 views

Is there a common word that encompasses handling of position, rotation, and scale together?

I'm looking for a name for my class that manipulates 4x4 matrices that handle position, rotation, and scale. Is there a common word that encompasses all three? (I'm splitting the matrix math into its ...
1
vote
0answers
293 views

How can I draw a model perpendicular to a sloped surface? [duplicate]

Possible Duplicate: How do I find rotation in 3D based on a vector/normal? My models are axis-aligned. I know the normal of the surface I want to draw them on. How do I compute the ...
3
votes
3answers
1k views

Basic tutorial/introduction for 3d matrices, idealy in c++, without openGl or directX

I am wondering if there is a simple tutorial that covers the basics of how to initialize rotation, translation and projection matrices, and how to multiply them, and how to get the screen coordinates ...
1
vote
2answers
647 views

How do I have to take into account the direction in which the camera is facing when creating a first person strafe (left/right) movement

This is the code I am currently using, and it works great, except for the strafe always causes the camera to move along the X axis which is not relative to the direction in which the camera is ...
8
votes
1answer
1k views

2D Skeletal Animation Transformations

I have been trying to build a 2D skeletal animation system for a while, and I believe that I'm fairly close to finishing. Currently, I have the following data structures: struct Bone { Bone ...
3
votes
2answers
490 views

When constructing an orientation matrix, are the rows of the matrix the axis?

When constructing an orientation matrix, are the rows of the matrix the axis? The matrix is row-major and I'm multiplying vectors on the right (Mv). So, the matrix looks like r0c0 r0c1 r0c2 r1c0 ...