Method for producing bump mapping effect for a three dimensional object of a computer graphic
View Patent ↗A method is for producing the bump mapping effect for a 3D object in a computer graphic. First, a shading vector is produced at one point of the surface of the 3D object. A shift coordinate with respect to this point is determined, according to the shading vector. According to the shift coordinate, a rotational calculation matrix is set up. Then, a diffuse color value with respect to this point is computed, which is equal to the difference between an adjacent rotation color value to this point and an averaged color value, wherein the averaged color value is defined as the sum and average of the color channels for R, G, and B with respect to this point, and the adjacent rotation color value is defined as a sum of the averaged color value with respect to a number of the adjacent points and the coefficient product with respect to the adjacent points in the rotational calculation matrix. Then, the emboss image value at this point is computed. The color channels of R, G, and B of the emboss image value are respectively equal to the product of the color channels of R, G, and B at this point being subtracted by the diffuse color value and the coefficient of the emboss effect. By repeating the foregoing steps, the emboss image value at each point of the surface of the 3D object is computed.
1. A method for producing the bump mapping effect for a 3D object in a computer graphic, the method comprising:
producing a shading vector at a point on a surface of the 3D object;
determining a shift coordinate with respect to the point, wherein the shift coordinate is equal to a product of the components of the shading vector on a X-Y plane and a coefficient of an emboss radius;
setting up a rotational calculation matrix, wherein the rotational calculation matrix includes a plurality of coefficient quantities for the matrix, and the coefficient quantities of the matrix are determined by the shift coordinate;
calculating a diffuse color value with respect to the point, wherein the diffuse color value is equal to a difference between an adjacent rotation color value to the point and an averaged color value, wherein the averaged color value is defined as a sum and average of the color channels for R, G, and B with respect to the point, and the adjacent rotation color value is defined as a sum of the averaged color value with respect to a plurality of adjacent points and a coefficient product with respect to the adjacent points in the rotational calculation matrix;
calculating an emboss image value at the point, wherein the color channels of R, G, and B of the emboss image value are respectively equal to a product of the color channels of R, G, and B at the point being subtracted by the diffuse color value, and a coefficient for an emboss effect; and
repeating the foregoing steps, so as to calculate the emboss image value at each point of the surface of the 3D object.
2. The method as recited in claim 1 , wherein the shading vector includes a normal vector at the point.
3. The method as recited in claim 1 , wherein the shading vector is a normal vector of a polygon, on which the point is located.
4. The method as recited in claim 1 , wherein the shading vector includes a cross product of a light source vector and a normal vector of a polygon, on which the point is located.
5. The method as recited in claim 1 , wherein between the step of producing the shading vector and the step of determining the shift coordinate, the method further comprises the step of:
normalizing the shading vector.
6. The method as recited in claim 1 , wherein the shift coordinate is in a format of (dOffx, dOffy), wherein the coefficients (w00, w01, w10, w11) of the rotational calculation matrix can be (1-w01-w10-w11, (┌dOffx┐-dOffx)* (dOffy-└dOffy┘), (dOffx-└dOffy┘) *(┌dOffy┘dOffy), (dOffy-└dOffy┘) *(dOffx-└dOffy┘)), in which a sum of w00, w01, w10, and w11 is equal to 1.
7. The method as recited in claim 1 , wherein the coefficient of the emboss effect is a parameter of visual depth.
8. The method as recited in claim 1 , wherein the coefficient of the emboss effect is a parameter of light intensity.