An array of numbers, symbols or expressions, arranged in row and columns. The numbers, symbols or expressions themselves are called elements or entries.
0
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0answers
44 views
OpenGL, objects disappear at a certain z distance
I'm writing a managed OpenGL library in C++, and I'm having a pretty annoying problem. Whenever I set an objects position to -2.0 or lower, the object disappears. And at distances 0 through -1.9, it ...
3
votes
1answer
52 views
How to make an object stay relative to another object
In the following example there is a guy and a boat. They have both a position, orientation and velocity.
The guy is standing on the shore and would like to board. He changes his position so he is ...
1
vote
0answers
31 views
Extract derived 3D scaling from a 3D Sprite to set to a 2D billboard
I am trying to get the derived position and scaling of a 3D Sprite and set them to a 2D Sprite.
I have managed to do the first part like this:
var p:Point = sprite3d.local3DToGlobal(new ...
2
votes
2answers
92 views
Rotating a child shape relative to its parent's orientation
When rotating a shape using a quaternion value I also wish rotate its child shape.
The parent and child shapes both start with different orientations but their relative orientations should always be ...
0
votes
1answer
55 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 ...
2
votes
1answer
56 views
Camera closes in on the fixed point
I've been trying to create a camera that is controlled by the mouse and rotates around a fixed point (read: (0,0,0)), both vertical and horizontal. This is what I've come up with:
camera.Eye = ...
0
votes
1answer
60 views
What's the standard location of a 3D clipping box?
The way I understand 3D rendering, polygons are transformed using several matrices, and they are then clipped if they are not inside a certain box, before projecting the box onto the screen. Before ...
2
votes
1answer
112 views
Does XNA 4 support 3D affine transformations for 2D images?
Looooong story short I'm essentially trying to code Mode 7 in XNA. Before I continue bashing my brains out in research and various failed matrix math equations; I just want to make sure that XNA ...
3
votes
1answer
84 views
D3DXMatrixDecompose gives different quaternion than D3DXQuaternionRotationMatrix
In trying to solve this problem, I tracked down the problem to the conversion of the rotation matrix to quaternion. In particular, consider the following matrix:
-0.02099178 0.9997436 -0.008475631 0
...
3
votes
2answers
117 views
How to derive euler angles from matrix or quaternion?
Currently working on steering behavior for my AI and just hit a little mathematical bump.
I'm in the process of writing an align function, which basically tries to match the agent's orientation with ...
2
votes
1answer
34 views
Problem with D3DXMatrixReflect
Currently I am trying to reflect a sky sphere into a flat piece of geometry which is acting as water. The sphere is very small, it follows the camera on all 3 axis and the z-buffer is turned off so it ...
0
votes
1answer
94 views
Correct Rotation and Translation with a 4x4 matrix
I am using a 4x4 matrix to transform verts in a shader. I multiply an identity matrix by a rotation matrix by a translation matrix. I am trying to first rotate the verts and then translate them, ...
3
votes
2answers
89 views
Rotating voxels in 3d space amongst the x axis
I have a very simple voxel engine and so far it works based on coordinates, e.g. x, y, z. I was wondering if there is a formula for rotating groups of voxels/coordinates from the x axis(e.g. [0, 1, ...
0
votes
2answers
72 views
get coordinates of origin of coordinate system in second coordinate system by knowin matrices of one point in bith systems
Situation, two coordinate systems A, B. origins Oa, Ob. I have one point, for which i know modelview matrix (translatoin/orientation) in both systems. And what i need to get is modelview matrix of Ob ...
1
vote
1answer
85 views
Can't work out how matrix is applied to 2D vertices
I have a texture, some 2D vertices, and a matrix. The matrix is used to calculate the texture coordinates for each vertex, but the problem is that the matrix comes with absolutely no documentation and ...
