US 2019/0057544 A1Published application

Device and method to compute shadow in a 3d scene

AssigneeThomson Licensing

InventorsPascal LECOCQ, Jean-Eudes Marvie, Arthur Dufay

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Abstract

Shadow is computed in a lighted 3D scene, based on a depth map. For each depth map element, following geometric information is stored: depth value, coordinates of vertices and local depth variation of a surface element. Also, ray intersection is tested for a pixel with the surface element having depth computed from the depth and local depth variation, taking into account the coordinates of vertices. A minimum depth associated with the surface element is further computed from the geometric information, with which the depth of a pixel is compared. The pixel is classified as lit if the depth is lower than the minimum depth, and as shadowed if the depth is greater and if a ray intersection is found for the pixel with the surface element from the ray intersection testing. The invention can provide a fast solution for high-quality shadow.

Claims24

Dependent claims

A graphics processing device configured to compute shadow in a three-dimensional scene lighted by at least one light source, based on at least one depth map comprising a plurality of elements, said depth map being associated with a two-dimensional bounded space adapted to render an image of the scene according to a point of view of said light source, said graphics processing device comprising at least one processor configured for:

storing information representative of a depth consisting in the distance between said point of view and a closest visible surface from said point of view for each of said depth map elements;
storing in each element of at least part of said depth map, coordinates of vertices of at least one surface element of said closest visible surface, the coordinates being expressed in the space of said depth map;
storing in each element of said part of said depth map, information representative of local depth variation of said at least one surface element in the space of said depth map;
testing ray intersection in said part of said depth map for at least one pixel of said image, with said at least one surface element having depth computed for said pixel from said information representative of depth and of local depth variation, taking into account said coordinates of vertices;
computing at least one minimum depth associated with said at least one surface element for each element of said at least part of said depth map, said minimum depth being computed from said coordinates of vertices and said information representative of depth and of local depth variation;
comparing depth associated with at least one pixel of said image, located in said depth map element, with said minimum depth associated with said depth map element and with said at least one surface element;
classifying said pixel as lit if the depth associated with said pixel is lower than said minimum depth;
classifying said pixel as shadowed if the depth associated with said pixel is greater than said minimum depth, and if a ray intersection is found for said pixel with said at least one surface element from said ray intersection testing.

5 more elements

A method for graphics processing adapted to compute shadow in a three-dimensional scene lighted by at least one light source, based on at least one depth map comprising a plurality of elements, said depth map being associated with a two-dimensional bounded space adapted to render an image of the scene according to a point of view of said light source, said graphics processing method comprising:

storing information representative of a depth consisting in the distance between said point of view and a closest visible surface from said point of view for each of said depth map elements;
storing in each element of at least part of said depth map, coordinates of vertices of at least one surface element of said closest visible surface, the coordinates being expressed in the space of said depth map;
storing in each element of said part of said depth map, information representative of local depth variation of said at least one surface element in the space of said depth map;
testing ray intersection in said part of said depth map for at least one pixel of said image, with said at least one surface element having depth computed for said pixel from said information representative of depth and of local depth variation, taking into account said coordinates of vertices;
computing at least one minimum depth associated with said at least one surface element for each element of said at least part of said depth map, said minimum depth being computed from said coordinates of vertices and said information representative of depth and of local depth variation;
comparing depth associated with at least one pixel of said image, located in said depth map element, with said minimum depth associated with said depth map element and with said at least one surface element;
classifying said pixel as lit if the depth associated with said pixel is lower than said minimum depth;
classifying said pixel as shadowed if the depth associated with said pixel is greater than said minimum depth, and if a ray intersection is found for said pixel with said at least one surface element from said ray intersection testing.

5 more elements

Dependencies are inferred from the claim text.