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# tutorial 10 camera code, problem

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Hi,
I used the tutorial 10 camera code in one of my project, as I started OpenGL 3 days ago I'm not sure about my Opengl INIT.

my problem is the following, if I only do translation or Y rotation everything looks fine.
But as soon as I do X rotation my sector get "seprarated"

this is my init
 private void initGL() { GL11.glEnable(GL11.GL_TEXTURE_2D);//texture mapping GL11.glShadeModel(GL11.GL_SMOOTH);//smooth shading GL11.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);//couleur de fond noire GL11.glClearDepth(1.0);//setup du buffer de profondeur GL11.glEnable(GL11.GL_DEPTH_TEST);//permet le test de profondeur GL11.glDepthFunc(GL11.GL_LEQUAL); //le type de test de profondeur a faire GL11.glMatrixMode(GL11.GL_PROJECTION);//selectrione la matrice de projection GL11.glLoadIdentity();//reset la matrice de projection // Calcul l'aspect ratio de la fenetre GLU.gluPerspective( 45.0f, (float) displayMode.getWidth() / (float) displayMode.getHeight(), 0.1f, 100.0f); GL11.glMatrixMode(GL11.GL_MODELVIEW);//selectionne la modelview Matrix GL11.glColor4f(1.0f,1.0f,1.0f,0.3f); // Full luminosité, 30% Alpha GL11.glBlendFunc(GL11.GL_SRC_ALPHA,GL11.GL_ONE); // Blending mode one // met les melleur parametre GL11.glHint(GL11.GL_PERSPECTIVE_CORRECTION_HINT, GL11.GL_NICEST); } 

any problem in it? (projection mode or something)

as for the rendering algorythm, I don't think that there is any problem with it.
it's quite simple.

I made a function that draw cube where I want (from the current position).
I have 16x256x16 sectors containing 65k cubes
a world is 9x9 sectors large.

I draw the world line by line

world top view
-z
^
|Sec Sec Sec <- World line 3
|Sec Sec Sec
|Sec Sec Sec <-World line 1
|------------------------>x

and a sector is drawed layer by lawer

 GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT); GL11.glLoadIdentity(); GL11.glRotatef(lookupdown,1.0f,0.0f,0.0f); GL11.glRotatef(sceneroty,0.0f,1.0f,0.0f); GL11.glTranslatef(xtrans, ytrans, ztrans); //starting position //drawing each sector for (int zsect=0 ; zsect < displayArea; zsect++) { for (int xsect=0 ; xsect < displayArea; xsect++){ chunk = world.getSector((short)xsect, (short)zsect); //drawing each layer for(int yc=0; yc<256; yc++){ for(int zc=0; zc<16;zc++){ for(int xc=0; xc<16; xc++){ chunk.drawCube(xc.yc.zc,0.5f) //0.5f is a x translation } GL11.glTranslatef(-16.0f, 0.0f, 1.0f); //goes where line+1 of the layer is starting } GL11.glTranslatef(0.0f, 1.0f, -16.0f); //goes where layer+1 is starting } GL11.glTranslatef(16.0f, -256.0f, 0.0f); //goes where the next chunk on the line is starting } GL11.glTranslatef(-(float)(displayArea*16.0f), 0.0f, 16.0f);//goes at the beginning of the next chunk line } 

video examples, chunk generation :

world generation

any idea?

thanks =D

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after several hours af tweaking I am still unsuccessful.

however since each chunk is drawed perfectly and the problem occurs just betwen them, I think the problem here is mathematical precision.

indeed, each chunk is drawed layer by layer, the cursor is only moved from 1f on Y betwen each layer.
but when you want to draw the next chunk you need to get down from 256f on Y.

since the camera is using sin, cos, a precalculation of 1/180*pi may be, a slight offset appears and screw with my grid positioning.

I don't really see how to solve that :/

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Hi,

I think the problem is the 1.0f in your glTranslatef calls. Remember that glTranslatef will translate your whole scene about the vector your plug in, and by calling it several times these translations are accumulated. So if you want to stay on one of your grid lines, you just advance x or z by 16, but leave all others 0.

Hope that helps even though we kept you waiting so long..

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thanks for your awnser, but I still don't get it =p

I have to make some 1.0f translation, because once the first layer of the chunk is displayed I have to draw the next one, wich is 1.0f above.