Beginning in Qt with OpenGL

Dinesh Balu · wrote on 24 May 2011, 07:21

[quote author="Chuck.Gao" date="1306221357"]I can build it on both Desktop(also simulator) and Symbian device, but it’ll crash some where.
[/quote]

You mean the application that I sent you will crash somewhere,...

[quote author="Chuck.Gao" date="1306221357"]Qt will use OpenGL ES automatically if you build Symbian based application.
[/quote]

Then why is it not working.... I got the simulator window opened but the triangle is not drawn on the screen...

ZapB · wrote on 24 May 2011, 07:27

That's for you to debug. It's your app. Run it in the debugger and see why it crashes.

Dinesh Balu · wrote on 24 May 2011, 07:37

When I started debugging...
A Warning is shown..
It says..

bq. The preferred debugger engine for debugging binaries of type 'x86-windows-msvc2008-pe-32bit' is not available.
The debugger engine 'Gdb engine' will be used as a fallback.
Details:There is no CDB binary available for binaries in format 'x86-windows-msvc2008-pe-32bit'

What does that mean?

ZapB · wrote on 24 May 2011, 07:40

Which build are you trying to debug? Desktop/simulator/symbian? I would try getting it working on the desktop first.

Dinesh Balu · wrote on 24 May 2011, 07:46

[quote author="ZapB" date="1306222858"]Which build are you trying to debug? Desktop/simulator/symbian? I would try getting it working on the desktop first.[/quote]

That was Qt Simulator -> N900 simulator

I tried that with desktop simulator,... It says Debugging starts..
It does nothing...

No window appears... no output...

This is a Qt Mobile application...

ZapB · wrote on 24 May 2011, 07:56

Can you try building your app for the desktop target (not the desktop mobile simulator) and debugging that. You should have all the tools needed to debug that.

Dinesh Balu · wrote on 24 May 2011, 08:07

That was the desktop target...

This is the report when I interrupt debugging...

bq. Debugging starts
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x0 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x0 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)
(Internal error: pc 0x4 in read in psymtab, but not in symtab.)

if you don't mind of testing my app yourself, I can mail you the project.... do you?

Dinesh Balu · wrote on 24 May 2011, 11:42

Guys I got it .....

I didn't use show function... now only i did...

Thanks for all your help..... :D

Dinesh Balu · wrote on 25 May 2011, 05:17

I have one more problem...

In this project , I'm drawing a triangle in center of the screen...

The project clears the screen with the color I specified , but it doesn't draw the triangle...

Here is the code...

@GamePlay::GamePlay(QWidget *parent) :
QGLWidget(parent)
{
setFormat(QGLFormat(QGL::DoubleBuffer | QGL::DepthBuffer));
}

void GamePlay::initializeGL()
{
qglClearColor(Qt::green);

}

void GamePlay::resizeGL(int width,int height)
{
glViewport(0,0,width,height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
GLfloat x = GLfloat(width) / height;
glFrustum(-x, x, -1.0, 1.0, 4.0, 15.0);
glMatrixMode(GL_MODELVIEW);
}
void GamePlay::paintGL()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
draw();
}

void GamePlay::draw()
{
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0,0,-10.0f);
glBegin(GL_TRIANGLES);
qglColor(Qt::red);
glVertex3f(-0.5f,-0.5f,0);
glVertex3f(0,-0.5f,0);
glVertex3f(0.5f,-0.5f,0);
glEnd();
}@

zester · wrote on 11 Jun 2011, 10:41

First strait OpenGL isn't trivial and isn't for most people, just knowing how to program in C/C++ and the OpenGL api isn't enough you need a background in advanced mathematics. Also if your doing things in the wrong order or if your not in the right mode at the correct time you will end up with a different result than what you expected. When programming in OpenGL you have to think of it in a procedural mind set. Post a link to your complete source code if you want help.