Multiple light source simulation in computer graphics
AssigneesVolkswagon AG, Audi AG
InventorGeorge Allen Khorasani
Life of this patent
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Abstract
Light sources are simulated by using a surface normal perturbation method. A mesh representing the surface of an object and containing surface normals is provided. A light source vector representing the orientation of the surface toward a light source is generated. Based on light intensity adjustments input by a user, the surface normals are perturbed in a lighting equation to simulate a change in light intensity on the surface without rotating the surfaces relative to the scene.
Claims15
A system for simulating multiple light sources in a computer image comprising:
- one or more processors operatively coupled to one or more non-transitory storage devices on which is stored executable computer code, which when executed by the one or more processors causes the system to modify the lighting on a surface in a scene without adding or removing light sources, wherein the surface is represented as a mesh containing surface normals;
- a display operatively connected to at least one of the one or more processors for displaying the scene;
- and
- a means for simulating a change in light intensity on the surface, without rotating the surface relative to the scene, by perturbing a surface normal in a lighting equation, the means for simulating a change in light intensity configured to:
- act upon a selected delineated mesh portion of the surface to simulate light intensity modification of the delineated mesh portions;
- generate a light source vector originating at a point coincident with the surface normal and directed toward a light source, the light source vector representing the orientation of the surface in the scene toward a light source;
- perturb the surface normal for a delineated portion of the mesh by a selected angular amount toward or away from the light source vector based on user input of a chosen light intensity modification value;
- calculate the cosine of the angle between the perturbed surface normal and the light source vector;
- adjust light intensity based on the calculated cosine to simulate an adjusted orientation of the surface, thereby modifying the lighting of the surface;
- and
- render the surface with the simulated light intensity modification;
- wherein the display displays the scene with the simulated light intensity change.
A method of simulating multiple light sources carried out by one or more processors configured with executable instructions, the method comprising:
- providing a surface representation in the form of a mesh with portions delineated for light intensity adjustment simulation, the mesh including surface normals;
- selecting a mesh portion;
- generating a light source vector originating at points coincident with the surface normal and directed toward a light source, the light source vector representing the orientation of the surface toward a light source;
- inputting a chosen light intensity modification value;
- perturbing the surface normal for a delineated portion of the mesh by a selected angular amount toward or away from the light source vector to achieve the chosen light intensity modification value;
- calculating the cosine of the angle between the perturbed surface normal and the light source vector to obtain the light intensity modification;
- multiplying the cosine by the surface color to obtain an adjusted color, thereby simulating modified lighting of the surface;
- and
- rendering the surface with the simulated lighting modification.
A non-transitory computer-readable storage medium on which is stored computer code, which when executed on one or more processors causes a computer system to perform the computer graphics light modification method of:
- receiving a surface representation in the form of a mesh with portions delineated for light intensity adjustment simulation, the mesh including surface normals;
- receiving a mesh portion selection;
- generating a light source vector originating at points coincident with the surface normal and directed toward a light source, the light source vector representing the orientation of the surface toward a light source;
- receiving a chosen light intensity modification value;
- perturbing the surface normal for the selected portion of the mesh by a selected angular amount toward or away from the light source vector to achieve the chosen light intensity modification value;
- calculating the cosine of the angle between the perturbed surface normal and the light source vector to obtain the light intensity modification;
- multiplying the cosine by the surface color to obtain an adjusted color, thereby simulating modified lighting of the surface;
- and
- rendering the surface with the simulated lighting modification.
Dependencies are inferred from the claim text.