JPS63163683A - Three-dimensional display device - Google Patents

Abstract

PURPOSE:To attain the area fill processing at high speed by obtaining an increment of a color intensity in advance as to the scanning line of the maximum length in a triangle being an object of area fill and using the increment obtained in advance as the increment on an object scan line in the area fill of each scan line. CONSTITUTION:In applying area fill of plural triangles approximating a three- dimensional object at each triangle, the scan line having the maximum length in a triangle being an object of area fill is detected by a detection means 11. Then, the increment of the color intensity is obtained by an increment calculating means 12 when the horizontal direction coordinate (X coordinate) on the maximum length scan line by one element and the horizontal coordinate is incremented by one picture element to apply area fill at each scan line in the triangle being the object of area fill, the value of the color intensity of the preceding picture element on the corresponding scan line added with the color intensity increment calculated by the increment calculation means 12 is generated as the color intensity of the next picture element. Thus, the area fill processing is quickened.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention approximates a three-dimensional object with a set of triangles in a three-dimensional space, and performs a filling process for each triangle to create a three-dimensional object. The present invention relates to a three-dimensional display device that performs original display.

(Prior Art) In recent computer systems, graphic processing technology for displaying three-dimensional objects on color display monitors using the Rusk scan method has become very important.

This process basically proceeds as follows.

(a) A three-dimensional object is approximated by a set of triangles in three-dimensional space. (b) Determine the coordinate values and color intensity of each vertex of the triangle. (c) Fill each triangle with glow shading. This filling process is performed by the three-dimensional display device in the following procedure.

Now, the coordinates (XA) of each vertex A, B, and C of the triangle to be filled (ΔABC) shown in FIG.

YA, ZA), (XB, YB, ZB), (XC.

YC, ZC) and color intensities IA, IB, IC are ``1
The information on each vertex (coordinates and color intensity) is sorted in descending order of Y coordinate, A, B .

It is assumed that they are arranged in the order of C. Now, here, the triangle to be filled in ΔABC is divided into two monogons ΔPBC and ΔAPB along a horizontal line passing through the apex B, and each of the divided triangles is filled in. The procedure for filling in the lower triangle ΔPBC will be described below. In addition,
The same applies to the upper triangle ΔAPB.

■ First, regarding side PC and side BC of triangle ΔPBC,
X, Z when Y increases by 1 (unit length).

■ Find the rate of increase (unit increment). Here, the unit increment of X, Z, I with respect to side PC (that is, the unit increment of X, Z, I with respect to side AC) is Δx pc.

ΔZ PC, ΔI PC, X, Z, regarding side BC,
If the unit increments of I are ΔX BC, ΔZ BC, and ΔIBC, these are as shown in the following equations.

ΔXPC-(XA-XC)/(YA-YC)ΔZ
PC-(ZA-ZC')/(YA-YC)ΔIP
C-CIA-IC')/(YA-YC)ΔXBC
−(XB −XC)/(YB −YC)ΔZBC−(
ZB - ZC) / (YB - YC) ΔIBC - (IB
-IC”)/ (YB -YC)■ Y coordinate value is Yl
The X, Z coordinate values of the left end of the scan line (first scan line) Li are X si, Z si and intensity 1
st, the X and Z coordinate values X ai and Z ei of the right end, and the color intensity Iei. These are as shown in the following formula.

X si = X 5 (i-1) + ΔXPCZ si −
Z 5 (1-1) + ΔZPC1sl = I 5 (1-1
)+ΔI PCX cl −X e(+−1)+ΔXB
CZ el = Z e (,1-1) + ΔZBCI c
i=I c(1-1)+113G However, YC≦Y1
≦YB Also, for the first scan line where Yi is Yl (-YC), The first scan line with points (Y-Y
It is sufficient to fill in each scan line from the (YB - YC+1)th scan line (Y-Yl - Yl3).

■ Once the coordinates and color intensities of both end points of the first scan line Li are determined, based on these coordinates and color intensities, approximate coordinate values and color intensities of each pixel on the i-th scan line Li are calculated from the first pixel. occur in sequence. At this time, Z, I when X increases by 1 (unit length) on the i-th scan line Li
The rate of increase (unit increment) ΔZl and ΔIi are determined in advance.

These ΔZi and ΔII are as shown by the following equations.

Δ Zi −(Zal−Zsi)/(Xai−X
sDΔ I i = (Iel −1st)/
(Xel-Xsl) Now, if the leftmost pixel of the i-th scan line Li is the first pixel (first pixel), then the Y coordinate value Yij,X of the first pixel (first pixel) on the i-th scan line Li The coordinate value Xlj, the Z coordinate value Zij, and the color intensity 11j are as shown in the following equation.

Y Ij-Y l X1j turtle
1(j-1>+Δ■1However, ″X il −Xs!, Z if −Z si,
I if −1si1≦j≦(Xai −Xsi+ 1
)■ When the coordinate values Xij, Ylj, ZIj and color intensity 11j of the first pixel of the i-th scan line Lj 1- are generated, the Z buffer for storing the Z coordinate value is set to the address by the coordinate values Xij, Yij. The Z value of the specified address 1u can be read out. Then, this Z value (old Z value) - and Z[j (new Z value) are compared. If the new Zfif'1 (Zij) is closer to the old Z value, the old Z value is updated to the new Z value (Z Ij), and the color intensity I addressed by the coordinate values X ij, Y ij is The I value (old I value), which is the storage content of the storage frame buffer, is updated to Ilj. On the other hand, if the new Z value (Z ij) is located behind the old Z value, the old Z value and the internal frame buffer value are saved. This is the so-called hidden surface processing.

(2) The above operations are repeated while sequentially increasing the X value by 1, and when the above operations are performed for the pixel whose X value matches Xcl, the filling shading for the i-th scan line Li is completed. Then, the next scan line indicated by YL-Yi +1 is filled in using the same procedure as last time.

The above operation is repeated, and when the filling of the scan line passing through point B (Y value is YB) is completed, the third
The filling of the triangle (ΔPBC) below the triangle (ΔABC) in the figure is completed.

Next, the 1-side triangle (ΔAPB) is filled in in the same manner as the lower triangle, thereby completing the filling of the triangle (ΔABC).

In the above-mentioned conventional three-dimensional display device, as mentioned in ①, division processing to obtain ΔZI and ΔIi is required for each scan line, making it difficult to speed up the filling process. .

(Problems to be Solved by the Invention) As described above, conventionally, in order to sequentially generate the coordinate values and color intensities of each pixel of a triangle in three-dimensional space for each scan line, It is necessary to calculate the Z coordinate value and the increase in color intensity by 1 when the X value increases by 1, and there is a problem in that filling processing for three-dimensional display requires time.

This invention was made in view of the above circumstances, and its purpose is to increase the color intensity l required when sequentially generating the coordinate values and color intensities of each pixel on a triangle in three-dimensional space for each scan line. minutes, i.e. the X value (water - r
The increase in color intensity I when the t-direction coordinate value) increases by one pixel, and the increase in the Z-coordinate value (depth direction coordinate value),
It is an object of the present invention to provide a three-dimensional display device that does not require calculation for each scan line.

[Structure of the Invention] (Means and Operations for Solving the Problems) This invention provides the following features: when filling in triangles with a number of steps that approximate a three-dimensional object for each triangle, the maximum length within the triangle to be filled is The detection means detects the scan line that becomes
The increment in color intensity when the horizontal coordinate value (X coordinate value) increases by one pixel on this maximum fill scan line is determined by the increment calculation means, and the fill is performed for each scan line within the triangle to be filled. When increasing the horizontal coordinate value by one pixel, the color intensity of the next pixel is calculated by adding the color intensity increment calculated by the above increment calculation means to the color intensity of the preceding pixel on the relevant scan line. This is so that it occurs as follows. The color intensity increment on the maximum length scan line is the same as the color intensity increment on any other scan line in the triangle, and therefore,
When filling in scan lines other than the maximum co-scan line, correct color intensity can also be determined using the color intensity increment on the maximum co-scan line. Similarly,
When the horizontal coordinate value (X coordinate value) increases by one pixel on the maximum co-scan line, the increment in the depth coordinate value (Z coordinate value) is the same as the increase in the depth coordinate value (Z coordinate value) on any other scan line within the triangle. It is the same as the depth coordinate value increment, and therefore,
In filling scanlines other than the maximum co-scanline, the maximum co-scanline! The iE depth direction coordinate value can also be determined using the depth direction coordinate value increment at -.

(Embodiment) FIG. 1 shows a block configuration of a three-dimensional display device according to an embodiment of the present invention. In the following explanation, the vertices of the triangle to be filled are assumed to be A, B, and C, as in FIG.
Its three-dimensional coordinates are (XA).

YA, ZA), (XB, 'l, ZB), (XC.

YC, ZC), and the color intensities are IA, In, and IC.

It is also assumed that YA≧YB≧YC. In FIG. 1, 11 is a scan line (parallel to the X axis) whose one end is vertex B, whose Y coordinate value is between those of the other two vertices among the three vertices of the triangle to be filled (ΔABC);
That is, ΔA B Cl has the maximum common scan line (hereinafter,
This is a representative scan line detection circuit that detects a line segment BP (referred to as a representative scan line) L (line segment BP). [2 is the coordinate value (XB, Y13.ZB) of both end points B and P of the representative scan line L detected by the representative scan line detection circuit 11.

(XP, YP, ZP) and color intensity 113. Based on IP, Z and I when X increases by 1 on scan line L
The rate at which the value increases (unit increment) ΔZ.

Scan line direction unit increment calculation circuit for calculating Δ■, 1
3 is the rate of increase in X when Y increases by 1 (unit length) for each side of the triangle to be filled (ΔABC) (C11th increment) ΔX AC, ΔX BC.

ΔXAB, unit increment of Z when Y increases by 1 ΔZ A
Lit increment of color intensity l when C, Δz nc, ΔZAB and Y increase by 1 ΔI AC, ΔI BC, Δ
This is a Y-direction unit increment calculation circuit that calculates IAB. 14 is a unit increment of Z and I with respect to X of the representative scan line L calculated by the scan line direction unit increment calculation circuit 12;
Y of each side calculated by the Y direction ilj increment calculation circuit 13
unit increment of X, Z, I for , and X of vertices B, C given by the -1- position processor.

X, Y of each pixel within the triangle (ΔABC) in response to the Y, Z coordinate values as well as the color intensity and the Y coordinate value of vertex A.

Fill circuit for generating Z coordinate value and color intensity I, 1
A frame buffer 5 stores the color intensity I generated by the fill circuit 14, and a Z buffer 16 stores the Z coordinate value generated by the fill circuit 14.

Next, regarding the operation of the configuration shown in FIG. 1, the magnitude relationship of the X coordinate values XB and
The case where XP≦XB as shown in FIG. 2(a) and the case where XP>XB as shown in FIG. 2(b) will be explained.

Now, each vertex A, B of one triangle (ΔABC) among the tji number of triangles that approximate the three-dimensional object to be displayed.

Three-dimensional coordinate values of C (XA, YA, ZA), (XP3゜Y
I3. ZB), (XC, YC, ZC) and color intensity IA
, IB, IC, or a higher-level processor. The representative scan line detection circuit 11 detects each vertex A, B,
Receiving the coordinate value and color intensity of C, vertices B and Y on side AC
Coordinate values XP, YP (-YB'), ZP and color intensity I of the point P (Figures 2 and 3) where the coordinate values are equal
Find P. Then, the representative scan line detection circuit 11 detects the coordinate values and color intensities of points B and P, that is, the X and Z coordinate values (XB) of both end points B and P of representative scan line L.

ZB), (XP, ZP) and color intensities IB and IP are supplied to the scan line h° direction Il1st increment calculation circuit 12. The representative scan line detection circuit 11 also supplies the X coordinate value XP of the point P to the Y direction unit increment calculation circuit 13.

The scan line direction unit increment calculation circuit 12 calculates points P and B.
X coordinate value XP, XB, Z coordinate value zp.

Based on ZB and color intensity IP, 113, ΔZ (i.e., unit increment of Z with respect to X on representative scan line L) and Δ1 (i.e., 11-fold position of ■ with respect to X on representative scan line L) are calculated as follows. Calculate according to the following formula.

ΔZ-(ZB-ZP)/(XB-XP)ΔI
The scan line direction unit increment calculating circuit 12 calculates ΔZ and ΔI and supplies them to the filling circuit 14 .

On the other hand, the Y direction unit increment calculation circuit 13 receives the vertices A and B of the triangle (ΔABC) from the upper processor.

Three-dimensional coordinate values of C (XA, YA, ZA), (XB.

YB, ZB), (XC, YC, ZC) and color intensity IA
, IB, and IC are generated, each side AC.

Unit increment of X with respect to Y on BC, AB- ΔX AC
.

Find ΔX BC and ΔXAB according to the following formula.

ΔXAC-(XA-XC)/(YA-YC)ΔX
BC-(XB-XC)/(YB-YC)ΔX,A
B-(XA-XB) / (YA-YB
) Furthermore, the Y-direction unit increment calculation circuit 13 compares the X coordinate value XB of the point B with the X coordinate value XP of the point P supplied from the representative scan line detection circuit 11. If XP≦X like the triangle (ΔABC) shown in Figure 2 (a),
In the case of B, the Y direction unit increment calculation circuit 13 calculates the side AC
Unit increment of Z, I with respect to Y above ΔZ AC, ΔIA
C is determined according to the following formula.

ΔZAC-(ZA -ZC) / (YA -YC)Δ
I AC- (IA, -IC) / (YA -YC) On the other hand, as shown in the triangle (ΔABC) shown in Figure 2 (b),
In the case of P > XB, the 111th position increment calculation circuit I in the Y direction
3 is the unit increment Δ of Z with respect to Y on sides AB, BCI-
Z AB, ΔZ DC, and unit increments of l (color intensity) with respect to Y, ΔI An, ΔI BC, are determined according to the following equations.

ΔZAB-(ZA-ZB)/(YA-YB)
ΔIA[3-(IA-In)/(YA-Yi3
)ΔZBC-(l1l-ZC)/(YB-Y
C) Δl13C-(IB-IC') / (YB-Y
C) The calculation result of the Y-direction unit increment calculation circuit 13 is supplied to the filling circuit 14.

The filling circuit 14 fills the inside of the triangle (ΔABC) based on the coordinate values and color intensity generated by the host processor and the calculation results of the representative scan line unit increment calculation circuit 12 and the Y direction unit increment calculation circuit 13. Let's do it. To fill in ΔABC, it is sufficient to fill in each scan line from the first scan line where the Y coordinate value is YC (-Yl) to the (YA - YC + 1) scan line where the Y coordinate value is YA. . here,
The first (1≦i≦YA
-YC+1) scan line, that is, Y coordinate force <Yi
If the scan line of (-Y('+1-1) is defined as the i-th scan line, then the i-th scan line is filled in as follows.

(a) X and Z coordinate values of the left end of the i-th scan line
si, Z s [and intensity 1si, and Xe at the right end
Find i. This method of determination is roughly divided into two depending on the magnitude of the X coordinate values XP and XB of both end points P and B of the representative scan line L.

(a-1) When XP≦xn As shown in Figure 2 (a), when XP≦XB, Xsi,
Zsi, Isi and Xei are such that Yi is YC≦
It is determined as follows depending on whether Yl≦YI3 or YF3×YI≦YA.

Range of YC≦Yl≦YB
Z 5 (1-1) + ΔZACI si -15 (1-1
)+ΔIACX cl −X c(1-1)+ΔXl3
C However, for the first scan line where yi is Yl (-YC'), si=
Z 5 (1-1) + Δ ZACI sl= I
5(1-1) ten Δ-IACX ci=X e(1-
1) +ΔXAr5(a-2) When XP > XB As shown in Figure 2 (b), when XP > XB, Xsl
, Zsi, Isl and Xei are Yl is YC
It is determined as follows depending on whether ≦YL≦YB or YB<Yi≦YA.

Range X si = X 5 (i-1) + ΔXBCZ sl = YC≦Yi ≦YI3
Z 5 (i-1) + ΔZBCI sl = I 5 (1-
1)+Δll3GX ei = X e(i-1)+Δ
XACHowever, for the first scan line where yt is Yl (-YC), si-
Z 5 (i-1) + ΔZABI si -15 (1-1
) 10ΔIABX ai −X c(1-1)+ΔXAC
(b) When the left end X, Z coordinate values X si, Z sl, color intensity Isi, and right end X coordinate value Xel of the i-th scan line are determined by the process in (a) above,
Approximate coordinate values and color intensities for each pixel on the first scan line are generated in order from the first pixel. Here, if the leftmost pixel of the first scan line is the first pixel (first pixel), then the Y
The coordinate value Ylj, the X coordinate value Xlj, the Z coordinate value ZIj, and the color intensity 1ij are determined as follows.

1j-Yi Ztl-Zsl, 1it-1
s11≦j≦(Xcl−Xsi+1) As described above, in this embodiment, in order to obtain the Z coordinate value Zij and color intensity 11j of the first pixel on the i-th scan line, Yi3-YC+
1) Unit increments ΔZ and ΔI of Z and I with respect to X on the scan line are used.

This is based on the fact that on all scan lines in a three-dimensional triangle, the +1 increments of Z and I relative to X are constant.

(C) Coordinate value X of the first pixel on the i-th scan line
ij, Y lj, Z ij and color intensity 11j
is generated by the filling circuit 14, the coordinate value X ij
, Y ij addresses the Z buffer 16, and the Z value at that address position is read. The filling circuit 14 compares this Z value (old Z value) and 21j (new Z value), and if the new Z value (Zij) is closer than the old Z value, it changes the old Z value to the new Z value ( At the same time, update the l value (old I value) which is the memory content of the frame buffer 15 addressed by the coordinate values Xij and Yij to Iij
Update to. On the other hand, the new Z value (Z ij) is the same as the old Z
If it is on the back side of the value, the fill circuit 14 uses Z buffer 1
6 and frame buffer 15 are not performed. As a result, the old Z value and 11-11 value mentioned above are preserved. This is the so-called hidden surface processing. If this hidden surface processing is not required, the generation of Zlj and the Z buffer 1B are unnecessary, and each time the coordinate values X ij, Y Ij and the color intensity 11j are generated, the coordinate values X ij,
An operation is performed to update the ■ value (old l value) in the frame buffer 15 specified by Y ij to Ilj.

(d) The filling circuit 14 repeats the above operation while sequentially incrementing the X value by 1. Then, when the above operation is performed for the pixel whose X coordinate value matches Xe1, the i-th
Filling and shading of the scan line is completed. The filling circuit 14 is now Yj
For the next scan line denoted by −Yl +1,
Fill in the area using the same procedure as last time.

This is the filling process for one scan line. The filling circuit 14 includes (a) to (d)
) from i-1 to imYA -YC+1 (i.e., from the first scan line where the Y coordinate value is YC to the first scan line whose Y coordinate value is YC).
This is repeated until the (YA-YC+1)th scan line, which is A). Then, when the filling of the (YA - YC+ 1.)th scan line is completed, the triangle (ΔAB
Filling in C) is complete.

[Effects of the Invention] As described in detail above, according to the present invention, in any scan line of a triangle, the color intensity ( Focusing on the fact that the increment of (and depth direction coordinate value) is constant, this increment is determined in advance for the longest scan line within the triangle to be filled, and this predetermined increment is used to fill in each scan line. Since it is used as an increment on the target scan line, there is no need to calculate the increment in color intensity (and depth direction coordinate value) for each scan line, and it is possible to speed up the filling process.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of a three-dimensional display device according to an embodiment of the present invention, FIG. 2 is a diagram showing types of triangles to be filled and representative scan lines, and FIG. 3 is a diagram showing triangles to be filled and scan lines to be filled. FIG. 11...Representative scan line detection circuit, I2...Scan line direction 11j increment calculation circuit, 13...Y
Direction and position increment calculation circuit, 14... Filling circuit,
15...Frame buffer, 1B...Z buffer, L
...Representative scan line. Applicant's agent Patent attorney Takehiko Suzue Figure 1 (Xc, Yc, Zc) jc
(Xc, Yc, Zcllc(a)
(b) Figure 2

Claims (2)

[Claims] (1) In a three-dimensional display device in which a three-dimensional object is approximated by a plurality of triangles in a three-dimensional space, and each triangle is filled in by filling in each scan line within each triangle, the maximum length within the triangle to be filled is a detection means for detecting a scan line with the maximum length, an increment calculation means for calculating an increment in color intensity when the horizontal coordinate value increases by one pixel on the maximum length scan line detected by the detection means, and the fill-in A filling means that calculates the color intensity of the corresponding pixel while increasing the horizontal coordinate value by one pixel for each scan line in order to fill each scan line in the target triangle. 3. A three-dimensional display device, comprising: a filling means for determining the color intensity of the next pixel by adding the color intensity increment calculated by the increment calculation means to the color intensity of the pixel. (2) In a three-dimensional display device in which a three-dimensional object is approximated by a plurality of triangles in a three-dimensional space, and each triangle is filled in by filling in each scan line within each triangle, the maximum length within the triangle to be filled is a detection means for detecting a scan line, and an increment in color intensity and an increment in depth direction coordinate value when the horizontal direction coordinate value increases by one pixel on the maximum length scan line detected by the detection means; In order to fill in each scan line within the triangle to be filled, the color intensity and depth coordinate value of the corresponding pixel are calculated by increasing the horizontal coordinate value by one pixel for each scan line. The filling means to calculate the color intensity of the next pixel by adding the color intensity increment calculated by the increment calculation means to the color intensity of the preceding pixel on the corresponding scan line, and and a filling means for calculating the depth direction coordinate value of the next pixel by adding the depth direction coordinate value increment calculated by the increment calculation means to the depth direction coordinate value of the preceding pixel. A three-dimensional display device.