3D Translations.... almost got it

Started by Nibbles November 26, 2001 02:51 AM

7 comments, last by Nibbles 23 years, 2 months ago

Author

569

November 26, 2001 02:51 AM

Hi, for the translation matrix: 1 0 0 0 0 1 0 0 0 0 1 0 tx ty tz 1 how do i get values for tx, ty, tz based on the pitch, yaw, and roll? thanks, Scott ------------------------------------------------------------ Email Website
"If you try and don''t succeed, destroy all evidence that you tried." ------------------------------------------------------------

Stellar Sprites - Unity 2D Procedural Spaceship and Planets

Scott Wojtowicz - [http://scottw.comli.com/wp_dev/]

siaspete

208

November 26, 2001 03:15 AM

Pitch, yaw and roll are rotations, so wouldn''t appear in a translation matrix.

- Pete

Saurus Games, home of the Independent Game Engine

Nibbles

Author

569

November 26, 2001 03:47 AM

ah, okie...

then how do/and from what do I get values for tx, ty, tz?

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Email
Website

"If you try and don''t succeed, destroy all evidence that you tried."
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Stellar Sprites - Unity 2D Procedural Spaceship and Planets

Scott Wojtowicz - [http://scottw.comli.com/wp_dev/]

Fruny

1,658

November 26, 2001 04:13 AM

In OpenGL

double modelview[16], projection[16]glGetDoublev( GL_MODELVIEW_MATRIX, modelview );glGetDoublev( GL_PROJECTION_MATRIX, projection );

I don''t do DX.

"Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it." — Brian W. Kernighan

henryx

128

November 26, 2001 10:51 AM

in DX,

D3DXMatrixTranslation(&MatrixT, XPosition, YPosition, ZPosition);

produces translation matrix MatrixT

henry

HenryLecturer in Computer Games TechnologyUniversity of Abertay DundeeScotlandUK

grhodes_at_work

1,385

November 26, 2001 11:34 AM

I''m not sure the question was stated clearly. If this is a question about OpenGL or DirectX, it belongs in a different forum. Please state the question more clearly and specifically.

Graham Rhodes
Senior Scientist
Applied Research Associates, Inc.

Graham Rhodes Moderator, Math & Physics forum @ gamedev.net

Nibbles

Author

569

November 26, 2001 01:44 PM

well, i''m using OpenGL, but I didn''t think it matter which API i was using. Anywho, Tx, Ty and Tz are the distances along the x, y and z axis that we want to translate right? So how do get that vector? I''m not sure how to convert the 3 Angles to a vector, assuming that''s what I need to do.

Thanks,
Scott

Sorry for the lack of info, I probably left more out too

------------------------------------------------------------
Email
Website

"If you try and don''t succeed, destroy all evidence that you tried."
------------------------------------------------------------

Stellar Sprites - Unity 2D Procedural Spaceship and Planets

Scott Wojtowicz - [http://scottw.comli.com/wp_dev/]

grhodes_at_work

1,385

November 26, 2001 05:54 PM

quote:
Original post by wojtos
well, i''m using OpenGL, but I didn''t think it matter which API i was using. Anywho, Tx, Ty and Tz are the distances along the x, y and z axis that we want to translate right? So how do get that vector? I''m not sure how to convert the 3 Angles to a vector, assuming that''s what I need to do.

I didn''t think the API was part of your question,

.

So now I think I understand your question. You are representing your translation axis in terms of a pitch, yaw, and roll. And you would like to convert that axis into a vector whose components are (tx, ty, tz).

The order of application of roll, pitch, yaw is important. Assuming you first apply roll about the x axis, followed by pitch about y axis, and lastly yaw about the z axis then you can generate a rotation matrix (yes, matrix) as:

  cr = cos(roll)sr = sin(roll)cp = cos(pitch)sp = sin(pitch)cy = cos(yaw)sy = sin(yaw)    [cy*cp    (cy*sp*sr - sy*cr)    (cy*sp*cr + sy*sr)]R = |sy*cp    (sy*sp*sr + cy*cr)    (sy*sp*cr - cy*sr)|    [ -sy            cp*sr                 cy*cr      ]

Then, one of the columns of this matrix will define your vector (tx, ty, tz). Which column will depend on which axis points to the front of your object (i.e., if the object''s x axis points to the front, choose the first column).

So you may have to adjust the matrix if your pitch, roll, yaw are applied in a different order (just rename things in my matrix to match your order), and choose a different column to be your (tx, ty, tz) depending on which axis points to the front of your object.

Hope that helps.

Graham Rhodes
Senior Scientist
Applied Research Associates, Inc.

Graham Rhodes Moderator, Math & Physics forum @ gamedev.net

Nibbles

Author

569

November 26, 2001 08:16 PM

Um, maybe i'm really messed up, i'm getting some really weird results. What are the correct, or one of the various correct order of methods? My code looks like this:

For one thing, it rapidly accelerates, and i'm not sure where to add the velocity (or magnitude?).

the matrices i'm using look are order by row:
[ 00 01 02 03 ]
| 10 11 12 13 |
| 20 21 22 23 |
[ 30 31 32 33 ]

    void move(){  float x, y, z;  float cr, sr, cp, sp, cy, sy;   cMatrix temp;   cr = cosf(Cam.zr);  sr = sinf(Cam.zr);  cp = cosf(Cam.xr);  sp = sinf(Cam.xr);  cy = cosf(Cam.yr);  sy = sinf(Cam.yr);   tx = ((cy*sp*cr) + (sy*sr));  ty = ((sy*sp*cr) - (cy*sr));  tz = (cy*cr);    // add the new values of tx, ty, tz into the translation matrix  setTranslationMatrix();    // multiply the translation matrix by the x rotation matrix  temp = mulMatrix(translate, rotateX);  // multiply result by the t rotation matrix  temp = mulMatrix(temp, rotateY);  // and so on  temp = mulMatrix(temp, rotateZ);    x = (temp.m[0][0] * Cam.x) + (temp.m[1][0] * Cam.y) + (temp.m[2][0] * Cam.z) + temp.m[3][0];  y = (temp.m[0][1] * Cam.x) + (temp.m[1][1] * Cam.y) + (temp.m[2][1] * Cam.z) + temp.m[3][1];  z = (temp.m[0][2] * Cam.x) + (temp.m[1][2] * Cam.y) + (temp.m[2][2] * Cam.z) + temp.m[3][2];    Cam.x = x;  Cam.y = y;  Cam.z = z;}

Thanks, I really appreciate it
Scott

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Edited by - wojtos on November 26, 2001 9:18:29 PM

Stellar Sprites - Unity 2D Procedural Spaceship and Planets

Scott Wojtowicz - [http://scottw.comli.com/wp_dev/]

3D Translations.... almost got it

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