OpenGL Camera

OpenGL OpenGL: Basic Coding
1

Hi,

I’m new to OpenGL and I have some 3d shapes and such drawn on my screen. Now this is great but I want to be able to move around. I know that there is no actual camera and such but that you have to move the whole scene.

I already have a fuction that sets the camera orientaion and rotation according to keypress and mouse movement. I currently sets some variables called x, y, z, rx and ry.

So how can I translate these values to change the camera? I was looking up on gluLookAt but was wondering if this is the right function to use and how it would fit in.

Thanks,

James

2

gluLookAt is exactly right (especially if your not using core profile).
First 3 parameters are the camera position in world space and the next 3 are where you want the camera to look at. The last 3 are the orientation of the camera which is usually 0 1 0.
If you are using the core profile you’ll have to build the camera (aka modelview matrix) yourself.

3

Hi,

I have the camera looking up, down, left and right now using gluLookAt. But when i use WASD to move the camera it spins out of control. Now, I understand that this is because although the camera is moving it is still looking at the same point. How can I make my camera move normally (like in any 3d game)?

Here is my code:

Called once per frame:


keychecker();
gluLookAt(x, y, z, ry, -rx, 1.0f, 0.0f, 1.0f, 0.0f);

keychecker


void keychecker()
{
    if (w_pressed)
    {
        // Move forward
		x -= sinf( degToRad( ry ) ) * cosf( -degToRad( rx ) );
		y -= sinf( -degToRad( rx ) );
		z -= cosf( degToRad( ry ) ) * cosf( -degToRad( rx ) );
    }

    if(s_pressed)
	{
		// Move backward
		x += sinf( degToRad( ry ) ) * cosf( -degToRad( rx ) );
		y += sinf( -degToRad( rx ) );
		z += cosf( degToRad( ry ) ) * cosf( -degToRad( rx ) );
	}

	if(a_pressed)
	{
		// Strafe left
		x += sinf( degToRad( ry - 90) );
		z += cosf( degToRad( ry - 90 ) );
	}

	if(d_pressed)
	{
		// Strafe right
		x += sinf( degToRad( ry + 90 ) );
		z += cosf( degToRad( ry + 90 ) );
	}

}

Move move events:


void mouseMoveEvent( float dX, float dY )
{
	// Look left/right
	ry -= dX / 100 * 30;

	// Look up/down but only in a limited range
	rx += dY / 100 * 30;
	if( rx > 90 ) rx = 90;
	if( rx < -90 ) rx = -90;
}

void GLFWCALL mouseMoveListener( int x, int y )
{
	if( !running )
	{
		mx0 = x; my0 = y;
		return;
	}

	mouseMoveEvent( (float)(x - mx0), (float)(my0 - y) );
	mx0 = x; my0 = y;
}

DegToRad converts from degrees to radians. This code used to work when using Horde3D.

Thanks,

James