Method CalculateProjectionMatrix

trinity/Eve/EveCamera.cpp:602–639

------------------------------------------------------------- Description: Sets up and assigns the desired projection to the matrix provided and passes it on to the projection if it's provided. Arguments: mat - the transform matrix that stores the result aspectRatio - the aspect ratio for this projection matrix fov - the desired field of view centerOffset - camera projection offset(horizontal offs

//   projection - the TriProjection matrix to store the resulting matrix
// -------------------------------------------------------------
void EveCamera::CalculateProjectionMatrix( Matrix* mat, float aspectRatio, float fov, float offsetX, float offsetY, float front, float back, TriProjection* projection )
{
	if( !aspectRatio || !IsFinite( aspectRatio ) )
	{
		aspectRatio = 1;
	}
	if( !fov || !IsFinite( fov ) )
	{
		fov = 1;
	}

	// TODO: update TriProjection to do all this for us, having the aspect ratio correction as a value on the
	// TriProjection itself rather than transmogrifying the matrix here.
	float dX = aspectRatio * front * tan( fov / 2 );
	float dY = front * tan( fov / 2 );

	if( aspectRatio > 1.6f )
	{
		// The field of view in x is now too warped so we switch things around and
		// adjust the matrix so that the fov in x doesn't go beyond what it would be
		// at a 1.6 aspect ratio.  Note that 1920/1200 = 1.6.
		float adjustment = aspectRatio / 1.6f;
		dX /= adjustment;
		dY /= adjustment;
	}
	float left = -dX + dX * offsetX;
	float right = dX + dX * offsetX;
	float top = dY + dY * offsetY;
	float bottom = -dY + dY * offsetY;
	*mat = PerspectiveOffCenterMatrix( left, right, bottom, top, front, back );

	if( projection )
	{
		// TODO: as per comment at the top here. Should call something like
		// projection->OffCenterAspectAdjust(left, right, -dy, dy, front, back, aspectClamp(1.6 in this case))
		projection->CustomProjection( (Matrix)*mat );
	}
}


// -------------------------------------------------------------