Method calcProjection

src/cinder/Camera.cpp:289–350

}

void CameraPersp::calcProjection() const
{
	mFrustumTop		=  mNearClip * math<float>::tan( (float)M_PI / 180.0f * mFov * 0.5f );
	mFrustumBottom	= -mFrustumTop;
	mFrustumRight	=  mFrustumTop * mAspectRatio;
	mFrustumLeft	= -mFrustumRight;

	// perform lens shift
	if( mLensShift.y != 0.0f ) {
		mFrustumTop = ci::lerp<float, float>(0.0f, 2.0f * mFrustumTop, 0.5f + 0.5f * mLensShift.y);
		mFrustumBottom = ci::lerp<float, float>(2.0f * mFrustumBottom, 0.0f, 0.5f + 0.5f * mLensShift.y);
	}

	if( mLensShift.x != 0.0f ) {
		mFrustumRight = ci::lerp<float, float>(2.0f * mFrustumRight, 0.0f, 0.5f - 0.5f * mLensShift.x);
		mFrustumLeft = ci::lerp<float, float>(0.0f, 2.0f * mFrustumLeft, 0.5f - 0.5f * mLensShift.x);
	}

	mat4 &p = mProjectionMatrix;
	p[0][0] =  2.0f * mNearClip / ( mFrustumRight - mFrustumLeft );
	p[1][0] =  0.0f;
	p[2][0] =  ( mFrustumRight + mFrustumLeft ) / ( mFrustumRight - mFrustumLeft );
	p[3][0] =  0.0f;

	p[0][1] =  0.0f;
	p[1][1] =  2.0f * mNearClip / ( mFrustumTop - mFrustumBottom );
	p[2][1] =  ( mFrustumTop + mFrustumBottom ) / ( mFrustumTop - mFrustumBottom );
	p[3][1] =  0.0f;

	p[0][2] =  0.0f;
	p[1][2] =  0.0f;
	p[2][2] = -( mFarClip + mNearClip ) / ( mFarClip - mNearClip );
	p[3][2] = -2.0f * mFarClip * mNearClip / ( mFarClip - mNearClip );

	p[0][3] =  0.0f;
	p[1][3] =  0.0f;
	p[2][3] = -1.0f;
	p[3][3] =  0.0f;

	mat4 &m = mInverseProjectionMatrix;
	m[0][0] =  ( mFrustumRight - mFrustumLeft ) / ( 2.0f * mNearClip );
	m[1][0] =  0.0f;
	m[2][0] =  0.0f;
	m[3][0] =  ( mFrustumRight + mFrustumLeft ) / ( 2.0f * mNearClip );

	m[0][1] =  0.0f;
	m[1][1] =  ( mFrustumTop - mFrustumBottom ) / ( 2.0f * mNearClip );
	m[2][1] =  0.0f;
	m[3][1] =  ( mFrustumTop + mFrustumBottom ) / ( 2.0f * mNearClip );

	m[0][2] =  0.0f;
	m[1][2] =  0.0f;
	m[2][2] =  0.0f;
	m[3][2] = -1.0f;

	m[0][3] =  0.0f;
	m[1][3] =  0.0f;
	m[2][3] = -( mFarClip - mNearClip ) / ( 2.0f * mFarClip*mNearClip );