TECHNIQUES FOR REPRESENTING 3D SCENES USING FIXED POINT DATA

• US 20080186309A1
• Filed: 04/11/2008
• Published: 08/07/2008
• Est. Priority Date: 11/21/2003
• Status: Active Grant

• Current Assignee: International Business Machines Incorporated (International Business Machines Corporation)
• Original Assignee: International Business Machines Incorporated (International Business Machines Corporation)
• Inventors: D'Amora, Bruce David
• Granted Patent: US 7,656,401 B2
• Time in Patent Office: Days
• US Class Current: 345/419
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects
• CPC Class Codes: G06T 2210/12 Bounding box
• CPC Class Codes: G06T 2210/32 Image data format
• CPC Class Codes: G06T 2210/61 Scene description

Abstract

A quantization transform, corresponding to a geometric object, is determined. The geometric object represents at least a portion of an object in a three-dimensional scene. The quantization transform is suitable for converting a floating point space to a fixed point space, where the floating point space contains floating point data corresponding to the geometric object. The quantization transform is used to convert floating point data to fixed point data. The floating point data is typically vertices corresponding to the geometric object. Additionally, a quantization transform corresponding to a geometric object is determined. The geometric object represents at least a portion of the three-dimensional scene. The quantization transform is suitable for converting a floating point space to a fixed point space, and the fixed point space contains one or more fixed point data corresponding to the geometric object. The floating point space defines at least the portion of the three-dimensional scene. At least the quantization transform is applied to the one or more fixed point data.

Claims

1. A method for representing a three-dimensional scene using fixed point data, the method comprising the steps of:

determining a quantization transform corresponding to a geometric object, the geometric object representing at least a portion of the three-dimensional scene, the quantization transform useable for converting a floating point space to a fixed point space, wherein the floating point space contains one or more floating point data corresponding to the geometric object; and

converting, by using the quantization transform, the one or more floating point data to one or more fixed point data.

2. The method of claim 1, wherein the geometric object represents at least a portion of an object in a three-dimensional scene.

3. The method of claim 1, wherein the step of converting further comprises the steps of:

multiplying the quantization transform and the one or more floating point data to create temporary data in floating point; and

converting the temporary data to fixed point whole numbers.

4. The method of claim 1, wherein the step of determining a quantization transform further comprises the step of determining a bounding sphere defining extents of the floating point space represented by the geometric data in the three-dimensional scene, and wherein the one or more floating point data are contained within the bounding sphere and wherein the step of determining a quantization transform further comprises the steps of:

determining extents of the bounding sphere; and

mapping the extents of the bounding sphere to data having values falling between first and second integer values.

5. The method of claim 1, wherein quantization transform comprises a scale factor and a translate factor.

6. The method of claim 1, further comprising the steps of:

computing a first transform comprising one or more of scale, rotate, and translate data;

computing an inverse of the first transform;

computing an inverse of the quantization transform;

concatenating the inverse of the quantization transform and the inverse of the first transform to create a second transform.

7. The method of claim 6, wherein the first transform is a ModelView transform or a concatenation of more than one ModelView transform.

8. The method of claim 6, further comprising the steps of:

converting one or more normals corresponding to the geometric object from floating point data to fixed point data; and

combining textures associated with the geometric object into a single texture map.

9. The method of claim 6, further comprising the steps of:

storing the one or more fixed point data in a quantized scene file; and

storing the second transform in the quantized scene file.

10. The method of claim 1, wherein the floating point data are vertices corresponding to the geometric object.

11. The method of claim 1, wherein the geometric object corresponds to a Geometry node of a scene graph.

12. An apparatus for representing a three-dimensional scene using fixed point data, the apparatus comprising:

one or more memories; and

one or more processors coupled to the one or more memories, the one or more processors configured;

to determine a quantization transform corresponding to a geometric object, the geometric object representing at least a portion of the three-dimensional scene, the quantization transform useable for converting a floating point space to a fixed point space, wherein the floating point space contains one or more floating point data corresponding to the geometric object; and

to convert, by using the quantization transform, the one or more floating point data to one or more fixed point data.

13. An article of manufacture for representing a three-dimensional scene using fixed point data, the article of manufacture comprising:

a computer readable medium containing one or more programs which when executed implement the steps of;

determining a quantization transform corresponding to the geometric object, the geometric object representing at least a portion of a three-dimensional scene, the quantization transform useable for converting a floating point space to a fixed point space, wherein the floating point space contains at least a portion of the three-dimensional scene; and

converting, by using the quantization transform, the one or more floating point data to one or more fixed point data.

14. A method for representing a three-dimensional scene using fixed point data, the method comprising the steps of:

determining a quantization transform corresponding to a geometric object, the geometric object representing at least a portion of the three-dimensional scene, the quantization transform suitable for converting a floating point space to a fixed point space, wherein the fixed point space contains one or more fixed point data corresponding to the geometric object and the floating point space defines at least the portion of the three-dimensional scene; and

applying at least the quantization transform to the one or more fixed point data.

15. The method of claim 14, wherein the step of determining a quantization transform further comprises the step of reading the quantization transform from a file, wherein the file comprises the quantization transform and the one or more fixed point data corresponding to the geometric object.

16. The method of claim 14, wherein the step of determining a quantization transform further comprises the step of determining a bounding sphere defining extents of the floating point space represented by the geometric data in the three-dimensional scene.

17. The method of claim 16, wherein the step of determining a quantization transform further comprises the steps of:

determining extents of the bounding sphere; and

mapping the extents of the bounding sphere to data having values falling between first and second integer values.

18. The method of claim 17, wherein the step of determining extents of the bounding sphere further comprises the step of computing at least one minimum vertex value and at least one maximum vertex value for all geometric objects in at least the portion of the three-dimensional scene.

19. The method of claim 17, where the step of mapping uses a radius of the bounding sphere, a center of the bounding sphere, and maximum and minimum short integer values.

20. An apparatus for representing a three-dimensional scene using fixed point data, the apparatus comprising:

one or more memories; and

one or more processors coupled to the one or more memories, the one or more processors configured;

to determine a quantization transform corresponding to a geometric object, the geometric object representing at least a portion of the three-dimensional scene, the quantization transform suitable for converting a floating point space to a fixed point space, wherein the fixed point space contains one or more fixed point data corresponding to the geometric object and the floating point space defines at least the portion of the three-dimensional scene; and

to apply at least the quantization transform to the one or more fixed point data.