/*******************************************************************************
* Function Name : StepLight
* Inputs : *pLight
* Description : Advance one step in the light rotation.
*******************************************************************************/
void OGLESLighting::StepLight(SLightVars &Light)
{
PVRTMat4 RotationMatrix, RotationMatrixX, RotationMatrixY, RotationMatrixZ;
// Increase rotation angles
Light.vRotation.x += Light.vRotationStep.x;
Light.vRotation.y += Light.vRotationStep.y;
Light.vRotation.z += Light.vRotationStep.z;
while(Light.vRotation.x > 360.0f) Light.vRotation.x -= 360.0f;
while(Light.vRotation.y > 360.0f) Light.vRotation.y -= 360.0f;
while(Light.vRotation.z > 360.0f) Light.vRotation.z -= 360.0f;
// Create three rotations from rotation angles
RotationMatrixX = PVRTMat4::RotationX(Light.vRotation.x * (PVRT_PIf / 180.0f));
RotationMatrixY = PVRTMat4::RotationY(Light.vRotation.y * (PVRT_PIf / 180.0f));
RotationMatrixZ = PVRTMat4::RotationZ(Light.vRotation.z * (PVRT_PIf / 180.0f));
// Build transformation matrix by concatenating all rotations
RotationMatrix = RotationMatrixZ * RotationMatrixY * RotationMatrixX;
// Transform light with transformation matrix, setting w to 1 to indicate point light
PVRTTransformArray((PVRTVec3*)&Light.Position, &Light.vPosition, 1, &RotationMatrix);
Light.Position.w = 1.0f;
}
/*!***************************************************************************
@Function PVRTTransformArrayBack
@Output pTransformedVertex
@Input pVertex
@Input nNumberOfVertices
@Input pMatrix
@Description Transform all vertices in pVertex by the inverse of pMatrix
and store them in pTransformedVertex.
- pTransformedVertex is the pointer that will receive transformed vertices.
- pVertex is the pointer to untransformed object vertices.
- nNumberOfVertices is the number of vertices of the object.
- pMatrix is the matrix used to transform the object.
*****************************************************************************/
void PVRTTransformArrayBack(
PVRTVECTOR3 * const pTransformedVertex,
const PVRTVECTOR3 * const pVertex,
const int nNumberOfVertices,
const PVRTMATRIX * const pMatrix)
{
PVRTMATRIX mBack;
PVRTMatrixInverse(mBack, *pMatrix);
PVRTTransformArray(pTransformedVertex, pVertex, nNumberOfVertices, &mBack);
}
