Author Topic: how to set my opengl es 3D projection to jpct-es  (Read 2533 times)

Offline Davi

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how to set my opengl es 3D projection to jpct-es
« on: October 29, 2011, 05:25:45 pm »
         I have opengl es code as blew:     
             
Code: [Select]
                gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glPushMatrix();
gl.glLoadMatrixf(ProjectionBuff);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glPushMatrix();
gl.glLoadMatrixf(Transform);
             
      I want to know how to set jpct-es like this?

Offline Davi

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Re: how to set my opengl es 3D projection to jpct-es
« Reply #1 on: October 30, 2011, 03:11:44 am »
anybody here,can help me? :-\

Offline EgonOlsen

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Re: how to set my opengl es 3D projection to jpct-es
« Reply #2 on: October 30, 2011, 07:51:47 pm »
The projection matrix is implicitly created by the engine based on the current fov settings and the far and near clipping plane. There's no way to set it directly from the outside. The model view matrix in OpenGL is a combination of object space->world space and world space->camera space transformations. The matrix itself is set by the engine based on an object's transformation and the camera rotation and position. You can't take some random GL code and just extract the matrices to feed them into jPCT-AE. You have to understand what the code does and rebuild it's behaviour by using the means that the engine offers.
« Last Edit: October 30, 2011, 07:54:14 pm by EgonOlsen »

Offline Davi

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Re: how to set my opengl es 3D projection to jpct-es
« Reply #3 on: October 31, 2011, 09:49:12 am »
Thank you very much ;D

Offline Davi

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Re: how to set my opengl es 3D projection to jpct-es
« Reply #4 on: October 31, 2011, 11:17:12 am »
Code: [Select]

onDrawFrame(GL10 gl) {

matrixTrans=new Matrix();
matrixTrans.translate(a,b,c)
model.setTranslationMatrix(matrixTrans);

//doAnim(); 
world.renderScene(fb);
world.draw(fb);
fb.display();
}
   
 a,b,c is my dynamic value,it can control my model moved by my marker correctly before using jpct-ae. But with jpct, it seems can't be transformed correctly,at least not entirely correct. eg.when my marker is away from my device camera,it can be scaled correctly.but when I move my marker from up to down or from left to right,it can not moved to right place,but the  orientation is right.I don't know it is effected by wold or camra of jpct-ae. please?

Offline EgonOlsen

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Re: how to set my opengl es 3D projection to jpct-es
« Reply #5 on: October 31, 2011, 01:17:25 pm »
I'm not 100% sure, what you are trying to do here, but keep in mind that jPCT uses this coordinate system: http://www.jpct.net/wiki/index.php/Coordinate_system

Maybe you have adjust your a,b,c values to this.

Offline Davi

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Re: how to set my opengl es 3D projection to jpct-es
« Reply #6 on: November 21, 2011, 04:16:05 am »
The projection matrix is implicitly created by the engine based on the current fov settings and the far and near clipping plane. There's no way to set it directly from the outside. The model view matrix in OpenGL is a combination of object space->world space and world space->camera space transformations. The matrix itself is set by the engine based on an object's transformation and the camera rotation and position. You can't take some random GL code and just extract the matrices to feed them into jPCT-AE. You have to understand what the code does and rebuild it's behaviour by using the means that the engine offers.
how can I understand what the code does,can you give me some open source code about that?

Offline EgonOlsen

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Re: how to set my opengl es 3D projection to jpct-es
« Reply #7 on: November 21, 2011, 07:58:32 am »
I wasn't taking about the jPCT code. You have to understand what the OpenGL code does that you are going to port. jPCT just does the usual transformation stuff. I can post this part (6 lines or so...), but i don't see how this would help in any way. All it does is to tranform the world space transformation matrix to OpenGL's coordinate system, multiply with the camera's matrix and apply the camera's translation. Nothing special at all.

Offline Davi

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Re: how to set my opengl es 3D projection to jpct-es
« Reply #8 on: November 21, 2011, 02:21:53 pm »
please post me that part (6 lines or so...), may be that can help me ;D

Offline EgonOlsen

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Re: how to set my opengl es 3D projection to jpct-es
« Reply #9 on: November 21, 2011, 02:26:03 pm »
I don't see how, but here you go:

Code: [Select]
mo.setTo(transBuffer);
mat.setTo(cam.getBack());
mat.transformToGL();
mo.translate(-cam.backBx, -cam.backBy, -cam.backBz);
mo.matMul(mat);

mo is a Matrix that contains the final result, mat is a temp matrix, transBuffer contains the world transformation of that object.

Offline Davi

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Re: how to set my opengl es 3D projection to jpct-es
« Reply #10 on: November 21, 2011, 03:47:49 pm »
"-cam.backBx, -cam.backBy, -cam.backBz",how to get them? :-[

Offline EgonOlsen

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Re: how to set my opengl es 3D projection to jpct-es
« Reply #11 on: November 21, 2011, 04:23:53 pm »
That's simply the camera's position.