Method and apparatus for non-disturbed specular reflections on textured surfaces

• US 5,673,374 A
• Filed: 04/28/1993
• Issued: 09/30/1997
• Est. Priority Date: 04/28/1992
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kuwana, Toshiyuki, Fujita, Ryo, Sakaibara, Toru
• Primary Examiner(s): Zimmerman, Mark K.
• Application Number:
  US08/053,371
• Time in Patent Office: 1,616 Days
• Field of Search: 395/125, 395/126, 395/130
• US Class Current: 345/426
• CPC Class Codes: G06T 15/506 Illumination models

Abstract

Intensities of light reflected from a surface of an object to be displayed are calculated as to values of an ambient light reflection component, a diffuse light reflection component, and a specular reflection component. Judgement is made as whether the calculated value of the specular reflection component exceed a predetermined value. Texture data are blended with a sum of the calculated ambient light reflection component value and the calculated diffuse light reflection component value. If it is judged that the calculated specular reflection component value exceeds the predetermined value, the specular reflection component value is added to the blended value of the texture data with the sum of the calculated ambient light reflection component value and the calculated diffuse light reflection component value.

Claims

1. A display method in which intensities of light reflected from a plurality of portions on a surface of an object to be displayed are calculated, texture data of said object to be displayed are blended with values of the calculated intensities of the reflected light, and an image of said object is displayed on the basis of the blended values of the texture data with the calculated intensities of the reflected light, said method comprising the steps of:

calculating an ambient light reflection component value on each of a plurality of vertexes of a primitive forming said object to be displayed, a diffuse light reflection component value on each vertex, and a specular reflection component value of intensity of the reflected light on each vertex, based upon direction vectors toward a light source and a viewpoint, a light source intensity, an ambient light intensity, and an ambient reflection coefficient, a diffuse reflection coefficient, a specular reflection coefficient, and a specular-reflection exponent of said each of said vertexes of said primitive;

summing up the calculated ambient light reflection component value and the calculated diffuse light reflection component value on each vertex of said primitive;

interpolating between at least two of the summed up component values of said vertexes to calculate an interpolated intensity value of each pixel laying between said vertexes;

modifying said interpolated intensity value of each of said pixels by the value of said texture data on a corresponding pixel;

judging whether or not the calculated value of said specular reflection component exceeds a predetermined value;

interpolating between at least two of the calculated values of the specular reflection components on the vertexes of said primitive, to calculate an interpolated specular reflection value of each pixel lying between said vertexes, when said calculated specular reflection component value of at least one of said vertexes of said primitive exceeds said predetermined value, in said judging step; and

adding the calculated interpolated specular reflection value to the modified interpolated intensity value of said each pixel.

2. A display method according to claim 1, wherein said interpolating step for the intensity values and the interpolating step for the specular reflection values are executed by a device for interpolation, at different times.

3. A display apparatus which displays an image of an object to be displayed on the basis of calculated values of intensities of light reflected from a plurality of portions on a surface of said object to be displayed and texture data of said object to be displayed, said apparatus comprising:

means for calculating an ambient light reflection component value of each of at least two vertexes of a primitive forming said object to be displayed, a diffuse light reflection component value of said each vertex, and a specular reflection component value of intensity of reflected light of said each vertex, based upon direction vectors toward a light source and a viewpoint, a light source intensity, an ambient light intensity, and an ambient reflection coefficient, a diffuse reflection coefficient, a specular reflection coefficient, and specular reflection exponent of said each vertex of said primitive;

means for summing up the calculated ambient light reflection component value and the calculated diffuse light reflection component value on each vertex of said primitive;

means for interpolating between at least two of the summed up component values of said vertexes to calculate an interpolated intensity value of each pixel lying between said at least two vertexes;

means for modifying said interpolated intensity value of said each pixel by the value of said texture data on a corresponding pixel;

means for judging whether or not the calculated value of said specular reflection component exceeds a predetermined value;

means for interpolating between at least two of the calculated values of the specular reflection components on the vertexes of said primitive, to calculate an interpolated specular reflection value of each pixel lying between said at least two vertexes, when said calculated specular reflection component value of at least one of said vertexes of said primitive exceeds said predetermined value, by said judging means; and

means for adding the calculated interpolated specular reflection value to the modified interpolated intensity value of said each pixel.

4. A display apparatus according to claim 3, wherein said interpolating means for the intensity values and said interpolating means for the specular reflection component values are the same apparatus used separately in time series.

5. A display apparatus which displays an image of an object to be displayed on the basis of calculated values of intensities of light reflected from a plurality of portions on a surface of said object to be displayed and texture data of said object to be displayed, said apparatus comprising:

means for calculating an ambient light reflection component value of each of at least two vertexes of a primitive forming said object to be displayed, a diffuse light reflection component value of said each vertex, and a specular reflection component value of intensity of reflected light of said each vertex, based upon direction vectors toward a light source and a viewpoint, a light source intensity, an ambient light intensity, and an ambient reflection coefficient, a diffuse reflection coefficient, a specular reflection coefficient, and a specular reflection exponent of said each vertex of said primitive;

means for summing up the calculated ambient light reflection component value and the calculated diffuse light reflection component value on each vertex of said primitive;

means for interpolating between at least two of the summed up component values of said vertexes to calculate an interpolated intensity value of each pixel lying between said at least two of said vertexes;

means for modifying said interpolated intensity value of said each pixel by the RGB intensity values of said texture data on a corresponding pixel;

means for judging whether or not the calculated value of said specular reflection component exceeds a predetermined value;

means for interpolating through said device, between at least two of the calculated values of the specular reflection components on the vertexes of said primitive, to calculate interpolated specular reflection value of each pixel lying between said at least two vertexes, when said calculated specular reflection component value of at least one of said vertexes of said primitive exceeds said predetermined value, by said judging means; and

means for adding the calculated interpolated specular reflection value to the modified interpolated intensity value of said each pixel.