iOS OpenGLES 2.0 and a 3D scene

[Chirone]

I'm trying to make a 3D scene with opengles 2.0 by rendering multiple models

the problem i'm having is that the models appear on top of each other like it's 2D

so.. if in the code a cube is drawn after a cone then the cube is drawn on top of the cone even though the cube's coordinates have it behind the cone

how do i render a 3D scene in opengles 2.0? i've enabled Depth_Test like i would if it were opengles 1 but that didn't help.

 

[gandrakar]

Hye,

Did you find any solutions ? I have exactly the same problem.
As for me , I just can't draw a simple square.

Here is the result :

 

[Chirone]

no.

when i added this code:

    if (USE_DEPTH_BUFFER) {
        glGenRenderbuffers(1, &depthRenderbuffer);
        glBindRenderbuffer(GL_RENDERBUFFER, depthRenderbuffer);
        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, backingWidth, backingHeight);
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthRenderbuffer);
    }

which is meant to enable the depth buffer nothing happened... i just got a black screen, yet it worked for other people
is there something in the apple template that's missing to make this work?

edit: whoops, i accidentally killed two lines in the draw method that binds the frame buffer and color buffer

things show up if Depth_Test isn't enabled, but otherwise nothing shows up....




gandrakar: is that meant to be a cube? looks like you've something funny going on inside your shader or whatever stores the coordinates of the verts of the cube, or you've funny matrix math

 

[softwareguy256]

As an experienced 3D guy, there are too many possibilities:
incorrect depth function
bad z values in vertices
incorrect clearing of depth values
depth buffer not created attached correctly
etc...

read the redbook and find an example and go line by line

 

[Chirone]

so if nothing is showing up only when glEnable(GL_Depth_Test) is on what does that tell you?

 

[Chirone]

i seem to get something if i go like this:

glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_ALWAYS);
// drawing code
glDisable(GL_DEPTH_TEST);

i just tried different depth functions

edit: oh wait, things just show up as if depth_test wasnt enabled

 

[gandrakar]

Chirone as for the matrix wrongness you were wright.

I have few mistakes in matrix multiplication. However I always have the depth buffer problem.

 

[gandrakar]

Hye,

Chirone did you think about the glEnable(GL_CULL_FACE); option.

It solve a problem for me.