PSPGL and DepthTesting problem.

LarryTM · Post by **LarryTM** » Wed Jul 05, 2006 1:02 am

Hi,

I've enabled gl_depth_test, gl_cull_face, disabled blending, and when i try to display few objects placed one after another i have no depth testing at all. Here is the screenshot :

Why? Here is my code :

Code: Select all

glEnable&#40;GL_LIGHTING&#41;;
	glEnable&#40;GL_DEPTH_TEST&#41;;
	glEnable&#40;GL_CULL_FACE&#41;;
	glShadeModel&#40;GL_FLAT&#41;;	

	glColor4f&#40;1,1,1,1&#41;;
	glDepthFunc&#40;GL_LESS&#41;;
	glDisable&#40;GL_BLEND&#41;;
	glBindTexture&#40;GL_TEXTURE_2D,mojetekstury&#91;4&#93;&#41;;	
	
	glPushMatrix&#40;&#41;;		
		glRotatef&#40;ile,0,0,1&#41;;
		glColor4f&#40;1,1,1,1&#41;;		
		glPushMatrix&#40;&#41;;
			glTranslatef&#40;0,2,0&#41;;
			glRotatef&#40;-ile*4,1,0,0&#41;;	
			for &#40;float a=0;a<10;a++&#41;
			&#123;
			glPushMatrix&#40;&#41;;				
				glRotatef&#40;360.0 * float&#40;a&#41; / 10.f,1,0,0&#41;;	
				glTranslatef&#40;0,2,0&#41;;
				Tube01&#40;&#41;;
			glPopMatrix&#40;&#41;;
			&#125;
		glPopMatrix&#40;&#41;;
	glPopMatrix&#40;&#41;;

Tube01() is just a object drawing rutine (object converted with polytrans to opengl code).

Can anyone knows why i dont have eny depth testing?

/lar

ffelagund · Post by **ffelagund** » Wed Jul 05, 2006 2:59 am

Hello,

Have you cleared the depth buffer at the beginning of each frame?
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

LarryTM · Post by **LarryTM** » Wed Jul 05, 2006 3:12 am

Yes, and i've noticed another strange problem :

When i display an object - everything looks fine, but when i rotate this object (about 180 degrees) it looks very messy - like when the gl_cull_face is disabled.

/lar

memon · Post by **memon** » Wed Jul 05, 2006 3:37 am

Do you set glDepthMask? Try setting it to GL_TRUE.

LarryTM · Post by **LarryTM** » Wed Jul 05, 2006 4:31 am

yes, that did nothing. :(

/lar

ffelagund · Post by **ffelagund** » Wed Jul 05, 2006 5:22 am

I dont know if this is implemented in PSPGL, but try: glGetIntegerv(GL_DEPTH_BITS,&a); to see if you truly have a depth buffer.

LarryTM · Post by **LarryTM** » Wed Jul 05, 2006 5:51 am

glGetIntegerv(GL_DEPTH_BITS,&a) returns 16;

edit: I've rotated all the objects (in 180 degrees) and now it looks good - with depth testing, but thats doesnt solve the problem with cullfacing. :/ maybe its something with normals? but on PC (radeon 9800 pro) those objects looks fine.

/lar

Jim · Post by **Jim** » Wed Jul 05, 2006 7:54 am

Is Tube01() using GL_QUADS with more than one quad between glBegin and glEnd? GL_QUADS isn't supported properly.

Jim

LarryTM · Post by **LarryTM** » Wed Jul 05, 2006 9:17 am

No, its uses olny GL_TRIANGLES.

/lar

ffelagund · Post by **ffelagund** » Wed Jul 05, 2006 5:41 pm

I think that the error should be in the Tube01 function, because the rest seems to be ok. Could you paste here that func? (it is not neccesary to paste the data arrays)

LarryTM · Post by **LarryTM** » Thu Jul 06, 2006 12:29 am

Ok, here is test source file with one rotating object - compiled & src. Its the same error with cull facing.

http://www.temporary.art.pl/test.zip

/lar

LarryTM · Post by **LarryTM** » Thu Jul 06, 2006 11:46 pm

Anyone? Please - its very important to me.

/lar

ffelagund · Post by **ffelagund** » Fri Jul 07, 2006 3:30 am

Sorry LarryTM, currently I lost my RHEL4 partition (viva linux!) due a filesystem corruption error, so I cant test your app. Now I'm installing cygwin and the pspsdk (again). As soon as I have the dev environment running, I'll check your sources.

LarryTM · Post by **LarryTM** » Fri Jul 07, 2006 3:34 am

I will be very thankful to you.

edit: I think i solved the problem.

I have bad gluPerspective definition :

gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.0f,100.0f);

the correct one is

gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f);

Anyway - thanks for your support and help.

/lar

dot_blank · Post by **dot_blank** » Sat Jul 08, 2006 11:19 am

also note you have 1000000 constants
for your tube