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Simple graphics running very slow

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Started by holtaf July 06, 2011 05:13 PM

15 comments, last by holtaf 12 years, 9 months ago

holtaf

100

Author

July 06, 2011 05:13 PM

Hi guys! I have some problems while trying to display some simple graphics( I am using OpenGL and c++ ).
I have this simple code :



glBegin( GL_QUADS );

 glTexCoord2f( 0.0, 0.0 ); glVertex2f( -1.0, -1.0 );

 glTexCoord2f( 0.0, 1.0 ); glVertex2f( -1.0,  1.0 );

 glTexCoord2f( 1.0, 1.0 ); glVertex2f(  1.0,  1.0 );

 glTexCoord2f( 1.0, 0.0 ); glVertex2f(  1.0, -1.0 ); 

glEnd();

I want to apply texture on whole screen and It runs veeery slow( with 4~10 fps )! Whats the problem ???

Thanks in advice
-holtaf

holtaf

100

Author

July 06, 2011 06:08 PM

Any suggestions ????

JTippetts

13,307

July 06, 2011 06:11 PM

First step is to ensure your video card drivers are up-to-date and that you're not defaulting to OpenGL 1.1. Check the values returned for glGetString(GL_VENDOR), and glGetString(GL_VERSION). If you get something like "Microsoft Corp.", and "1.1.0" for vendor/version, you need to update drivers, since the default GL drivers on Windows are slooooow.

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holtaf

100

Author

July 06, 2011 06:33 PM

First : I'm running on GNU/Linux ( Ubuntu 10.10 );
Second : When I draw smaller quads it's running ok, with 30~40 fps;
Third : Thanks for reply

gsamour

141

July 06, 2011 06:47 PM

What do you mean you want to "apply texture to the whole screen" ? You mean draw ONE quad that covers the whole screen? Because from your next post it sounds like you're drawing many quads. Or what exactly are you doing? Can you post more code or the full drawing code?

holtaf

100

Author

July 06, 2011 06:53 PM

Yes I want do draw one quad to whole screen. Sorry I can't post my whole code it's very big!

_Unicron_

438

July 06, 2011 06:54 PM

Yes I want do draw one quad to whole screen. Sorry I can't post my whole code it's very big!

We don't need your entire code, but an outline of the loop that runs every frame and your rendering function will help us to help you

gsamour

141

July 06, 2011 06:59 PM

Some suggestions:

1. check that you're not loading the texture every frame (or doing something every frame that can be done once in initialization)
2. check if the texture size is bigger than the desired quad size. If so, reduce it. (what size is the texture?)

holtaf

100

Author

July 06, 2011 07:13 PM

Ok I'll post some code

Here is Initialization :

 

        glEnable( GL_TEXTURE_2D );

	glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );

	glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );





	glGenTextures( 16, &texture.m_textureIds[0] );





	m_mapTextureId	     = texture.loadTexture( "map.bmp");

	m_playerTextureId      = texture.loadTexture( "player.bmp");

Here is render function





void Game::render(){



	glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);



	switch ( m_sceneId ) {



		case SCENE_MENU : 

			//menu.render();

			break;

		case SCENE_GAME : 

			texture.setActiveTexture( m_mapTextureId );

	     	map.draw();

			texture.setActiveTexture( m_playerTextureId );

			player.draw();

			break;

	}







	glXSwapBuffers( m_pDisplay, m_Window );

}

And here is map.draw() function



void Map::draw() {

	glPushMatrix();

	glColor3f( 1.0, 1.0, 1.0 );

	glBegin( GL_QUADS );

		glTexCoord2f( 0.0, 0.0 ); glVertex2f( -1.0, -1.0 );

  		glTexCoord2f( 0.0, 1.0 ); glVertex2f( -1.0,  1.0 );

   		glTexCoord2f( 1.0, 1.0 ); glVertex2f(  1.0,  1.0 );

    		glTexCoord2f( 1.0, 0.0 ); glVertex2f(  1.0, -1.0 ); 

	glEnd();

	glPopMatrix();

}

Note : texture.setActiveTexture( int ) is only binding the current texture, and you can avoid the player.draw() because it's draws a tiny square.

SuperVGA

1,303

July 06, 2011 07:16 PM

Are you certain that you don't have an expensive fragment shader enabled? That would explain the obvious decrease in performance with larger quads...

Simple graphics running very slow

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