[android-developers] is there any limitation on glTranslatef or vertex coordinate system?

[Jong Min Lee]

Hello~ comrade!

I am developing opengl based application.
something mysterious happened.
I've tested it with simple triangle.

I moved triangle's x coordinate and I also moved coordinate system
itself using glTranslatef
It looks well before triangle's x coordination approach around 8100..
But when x coordination over around 8100, triangle disappear.

this is strange.

is there any limitation on glTranslatef or vertex coordinate system?

Here is my code:.

....
        private float zoom=-8020.0f;

        private float xt=-8000.0f;

        private float yt=-8000.0f;

        private float prevTouchedX;

        private float prevTouchedY;

        private float xrot=0;

        private float yrot=0;




        public ModelRenderer(GLSurfaceView v, Model m) {
                this.m=m;
                this.v=v;
                this.c=v.getContext();
        }

        @Override
        public void onDrawFrame(GL10 gl) {

                int w = v.getWidth();
                int h = v.getHeight();

                gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);

                gl.glMatrixMode(GL10.GL_PROJECTION);
                gl.glLoadIdentity();
                gl.glViewport(0,0,w,h);
                GLU.gluPerspective(gl, 45.0f, ((float)w)/h, 1f, 1000f);

                gl.glMatrixMode(GL10.GL_MODELVIEW);
                gl.glLoadIdentity();

                xt-=1.0f;

                gl.glTranslatef(xt,yt,zoom);

                gl.glRotatef(xrot, 1, 0, 0);
                gl.glRotatef(yrot, 0, 1, 0);

                vertices[frame_ix].put(0,vertices[frame_ix].get(0)+1.0f);
                vertices[frame_ix].put(3,vertices[frame_ix].get(3)+1.0f);
                vertices[frame_ix].put(6,vertices[frame_ix].get(6)+1.0f);

                System.out.println(vertices[frame_ix].get(0));


                gl.glVertexPointer(3,GL10.GL_FLOAT, 0, vertices[frame_ix]);
                gl.glNormalPointer(GL10.GL_FIXED,0, normals);
                gl.glTexCoordPointer(2,GL10.GL_FIXED,0,texCoords);
                gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
                gl.glEnableClientState(GL10.GL_NORMAL_ARRAY);
                gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

                gl.glColor4f(1,0,0,1);
                gl.glBindTexture(GL10.GL_TEXTURE_2D, tex);
                gl.glBindTexture(GL10.GL_TEXTURE_2D, 0);
                gl.glDrawElements(GL10.GL_TRIANGLES, verts, 
GL10.GL_UNSIGNED_SHORT,
indices);

                frame_ix = (frame_ix+1)%m.getFrameCount();
        }

....

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