Shadows for inserted content

1. A method comprising:

determining a location to insert content within an image, the content including a polygonal mesh defined in part by a skeleton that has a plurality of joints;

selecting a plurality of selected joints form the plurality of joints;

generating a shadow polygon;

determining shadow contributions values for the plurality of selected joints for pixels of the shadow polygon;

combining the shadow contribution values from the selected joints to generate shadow magnitude values for the pixels;

rendering the shadow polygon using the shadow magnitude values; and

overlaying the inserted content on the rendered shadow polygon.

2. The method of claim 1 , wherein the selecting the plurality of selected joints comprises selecting joints based on a data structure associated with the content.

3. The method of claim 1 , wherein the selecting the plurality of selected joints includes selecting joints based on distance to a surface plane that is identified based on the image.

4. The method of claim 3 , wherein the selecting the plurality of selected joints includes selecting a threshold percentage of the plurality of joints that are closest to the surface plane.

5. The method of claim 3 , further comprising assigning fade-out values to the plurality of selected joints based on distance to the surface plane.

6. The method of claim 1 , wherein the shadow contribution value for a specific joint from the plurality of selected joints for a specific pixel of the shadow polygon is based on a distance from the specific pixel to the specific joint.

7. The method of claim 6 , wherein the shadow contribution value for the specific joint for the specific pixel is based on an overhead angle between the specific pixel and the specific selected joint.

8. The method of claim 1 , wherein the combining the shadow contribution values includes selecting a maximum shadow contribution value.

9. The method of claim 1 , further comprising combining the rendered shadow polygon with an additional shadow polygon.

10. A non-transitory computer-readable storage medium comprising instructions stored thereon that, when executed by at least one processor, are configured to cause a computing system to at least:

capture an image with a camera assembly;

identify a surface plane within the image;

determine a location to insert content, the content including a polygonal mesh defined in part by a skeleton that has a plurality of joints;

select a plurality of selected joints form the plurality of joints;

assign fade-out values to the plurality of selected joints;

generate a shadow polygon based on the content;

determine shadow contributions values for the plurality of selected joints for pixels of the shadow polygon;

combine the shadow contribution values from the selected joints to generate shadow magnitude values for the pixels;

normalize the shadow magnitude values to generate normalized shadow magnitude values;

apply a radial falloff to the normalized shadow magnitude values to generated adjusted shadow magnitude values;

render the shadow polygon using the adjusted shadow magnitude values; and

overlay the inserted content on the rendered shadow polygon.

11. The non-transitory computer-readable storage medium of claim 10 , wherein the instructions that cause the system to select the plurality of selected joints include instructions that cause the system to select joints based on a data structure associated with the content.

12. The non-transitory computer-readable storage medium of claim 11 , wherein the data structure includes a joint blacklist and the instructions that cause the system to select the plurality of selected joints include instructions that cause the system to select joints that are not in the joint blacklist.

13. The non-transitory computer-readable storage medium of claim 10 , wherein the selecting the plurality of selected joints includes selecting joints based on distance to a surface plane that is identified based on the image.