6 replies to this topic

[Retsu90]

Hi!
I'm trying to understand how to flip/mirror a model, but after hours of researches and tries I didn't get any solution.
The engine that I'm developing is a tile engine in a 3D space (i'm using D3DFVF_XYZ | D3DFVF_TEX1 as vertex), I'm using D3DXMatrixOrthoOffCenterLH(&matProjection, 0.0f, f_viewWidth, -f_viewHeight, 0.0f, 1.0f, 100.0f) to get a good view space for a 2D game.
Currently, when I need to flip the tiles, I set on a vertex created, drawed and deleted every frame, I set TU and TV from x+width to x (for not-flipped tiles I set it from x to x+width). The effect that I get with this is very bad:


I tried also to uses D3DSAMP_ADDRESSU and D3DSAMP_ADDRESSV but with bad results and when I trying to do rotation with matrix, the window is totally empty.
Any idea?

[Retsu90]

UP
I didn't resolve the problem yet >_<

[Tispe]

Try this

D3DXMATRIX MirrorX(-1.0f,0,0,0,  0, 1.0f,0,0,  0,0, 1.0f,0,  0,0,0,1.0f);
D3DXMATRIX MirrorY( 1.0f,0,0,0,  0,-1.0f,0,0,  0,0, 1.0f,0,  0,0,0,1.0f);
D3DXMATRIX MirrorZ( 1.0f,0,0,0,  0, 1.0f,0,0,  0,0,-1.0f,0,  0,0,0,1.0f);

D3DXVECTOR4 VertexPos;
//Set VertexPos.x .y. z from source vertex, .w = 1.0f;


//Flip Vertex over X axis
D3DXVec4Transform(&VertexPos,&VertexPos,&MirrorX);

[Retsu90]

Try this

It doesn't work, the tiles won't show anymore when I negate X or Y.
Basically I need to do a 180° Y rotation to have the mirror effect and a 180° Z rotation to have flip effect right? But there are two questions: to have the mirror effect I need to create another square back to the front square? And to have the flip effect I need to set the center position of the current tile but how? When I try to rotate it, it takes as center coord 0, 0 that in my viewport is the top-left pixel... Basically I can set the position to -width/2 and -height/2, to place the center of the image to 0, 0 do a rotation for example of 45 degree in Z and place the model to x and y but I don't know how. I tried to multiply the transformation matrix (the one that set the center of the sprite in 0,0) with the rotation matrix and with the position matrix, but the result is likes that transformation matrix is not multiplied =\

[Tispe]

SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);

see if it shows now

[Retsu90]

SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);

see if it shows now

AWESOME!!! Finally X and Y rotation works!!! What cull mode do exactly?
Oh, I resolved also the rotation's center problem:

D3DXMATRIX matrixFinal;
D3DXMATRIX matrixTemp;
D3DXMATRIX matrixPosition;
D3DXMATRIX matrixBlockCenter;
D3DXMatrixTranslation(&matrixBlockCenter, width/-2, height/-2, z);
D3DXMatrixTranslation(&matrixPosition, x, y, z);
D3DXMatrixMultiply(&matrixTemp, &matrixBlockCenter, &matrix_WorldRotation);
D3DXMatrixMultiply(&matrixFinal, &matrixTemp, &matrixPosition);
d3dd->SetTransform(D3DTS_WORLD, &matrixFinal);

EDIT:
Mmm seems that when I do the rotation, the TU and TV are altered:
http://dl.dropbox.co...5489/before.png
http://dl.dropbox.co...95489/after.png
All the vertex uses the same texture and a single square has texture coordinates that are multiples of 1.0f/textureWidth*tileDimension and the rotation seems to move the TU/TV by 1.0f/textureWidth/tileDimension (so if the TU goes from 0.01 to 0.05, when I rotate the model using transformation, the final TU is something likes 0.06 to 0.02). It's a bug? A limitation of D3D or simply a bad use of rotation?

Edited by Retsu90, 15 February 2012 - 04:17 PM.

[Retsu90]

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