topic XML light examples in Intel® Embree Ray Tracing Kernels

XML light examples

jasonmerchant — Mon, 19 Mar 2012 09:13:27 GMT

I've been attempting to figure out the xml format of the lights to no avail, my adjustments to the values for the most part do nothing or have unexpected results.

I'm mainly interested indirectionallight,distantlight, andpointlight, but haven't been able to figure out any of them.

Any help on understanding how to create the lights for the xml files would be greatly appreciated.

Thanks

XML light examples

SvenW_Intel — Mon, 19 Mar 2012 11:42:02 GMT

Every light gets a transformation to position the light. In case of the spotlight, the spotlight is defined to shine in the z-direction of its local coordinate space.Try the following spotlight in the cornell_box_sphere.xml file as a starting point. It defines a spotlight shining into the negative y direction (3rd column of matrix is (0,-1,0)).

1 0 0 213

0 0 -1 508.77

0 1 0 227

5000000 5000000 5000000

Due to the quadratic falloff, point lights and spotlights need often a large intensity.The parameters to all lights can be found in the file app/importers/xml.cpp in the loadXXXLight functions.

XML light examples

jasonmerchant — Wed, 21 Mar 2012 22:20:59 GMT

Thanks so much! it's making more sense now, and I've gotten a couple lights working.

Would you be able to point me in the direction of where I could find what each number in the AffineSpace matrix is used for? I'm attempting to convert a light's rotation amount in degrees to this format.

XML light examples

SvenW_Intel — Thu, 22 Mar 2012 06:10:12 GMT

See theloadSpotLight function on app/importers/xml.cpp. Most of the included lights are very symmetric, thus ignore some components of this matrix. The spotlight for instance, only cares about the position and a direction.

XML light examples

profiled — Wed, 27 Jun 2012 14:37:18 GMT

Did you manage to modify the files? joc