KR19980035727A - How to create sprite animation - Google Patents

Abstract

The present invention relates to a graphics processing apparatus, and more particularly, to a sprite animation method for expressing a movement of an arbitrary two-dimensional sprite more quickly, comprising: a step of initializing the number of residual sprites N to be left; Initializing the previous sprite index j; Comparing the difference i-j of the previous sprite index from the current sprite index with the residual image sprite number N; A fourth step of deleting the corresponding j-th previous sprite if the index difference value (i-j) is greater than the number of residual sprites (N); 5 steps of increasing the index j of the previous sprite by one; A sixth step of drawing a current sprite after the fifth step or when the comparison result of the second step has an index difference value (i-j) smaller than the number of residual sprites (N); Storing seven memory locations of the current sprite; The present invention consists of 8 steps of increasing the index (i) of the current sprite by 1 and repeatedly performing the above steps. This can be used wherever necessary or when a blurring effect is especially needed.

Description

Generating method of sprite animation

The present invention relates to a graphics processing device, and more particularly, to a sprite animation method for expressing a movement of an arbitrary two-dimensional sprite more quickly.

Recently, as the automation progresses and the information society progresses, the application fields of computer graphics are rapidly expanding, and the development of animation processing technology that processes two-dimensional and three-dimensional graphics in real time is being actively developed. This graphics processing technology requires a high resolution display (1280 × 1024) to create realistic and lively images. When performing transformations and color calculations for more than one million pixels, Calculation is required.

1 is a configuration diagram showing an example of a general graphics system, which is connected to the system bus 1 and performs a general program (CPU) 2 that performs an overall program, and is connected to the system bus 1 while being centrally processed. It consists of a system memory (3) that stores the data needed by the device, a graphics board (4) connected to the system bus to handle graphics, and a monitor (5) to display video signals from the graphics board. It is.

The graphics board 4 is composed of a graphics dedicated processor 4-1, a graphics processor memory 4-2, a frame buffer 4-3, and a video processor 4-4.

The graphics only processor 4-1 collectively performs a processor related to graphics processing.

The graphic processor memory 4-2 stores various data and programs required by the graphic processor.

The frame buffer 4-3 stores data for display processed by the graphic processor.

The video processor 4-4 signals the data stored in the frame buffer to be displayed on the monitor 5.

2 is a view showing an example of a process of displaying the data of the frame buffer on a monitor, wherein the frame buffer has 8 bits per pixel, and 8 bits store pixel values of actual pixels (look-up table). ) Will be the address. Therefore, the palette has 256 colors and 4 bits are allocated to red, green, and blue, respectively, and as shown in FIG. 2, the pixel value (100110100001) of the pixel is displayed on the monitor according to the address (67: 01000011) of the frame buffer. Will be displayed.

On the other hand, animation is a life-giving work that takes pictures of moving scenes and shows them at high speed, using the effect that the object is actually moving due to the optical illusion of the eyes. For example, a cartoon film is drawn at 24 frames per second and a TV is 30 frames per second. Depending on the speed of a moving object, the number of frames to be drawn per second is handled differently to enhance the effect.

In the case of animation using a computer, the processing speed of the computer becomes a problem, and a faster processing speed is required to process a large number of frames per second. In particular, since the animation at that time is changed according to the input speed of the user moving the object, a processing method for this is needed.

In particular, to express animation effects, an animation technique that can express the movement of an object by hardware may be referred to as 'sprite animation', where a sprite resides in a frame buffer that stores video level data. Points to less memory. The position of this sprite is always specified in the register of the frame buffer, and the value of this register is changed by the movement of the sprite on the screen.

Here, the term 'sprite' was first used by Apple in the 1970s, and is widely used not only to mean a small amount of memory in the frame buffer but also to directly refer to a 'moving object' that penetrates a background screen.

The concept of sprites used here refers to a form in which a part except the drawing area is visible even if it is overlaid on another picture (background), such as a picture on a glass plate, and is used as the latter meaning (moving object).

Computers with sprite engines that provide sprite processing directly from hardware are being manufactured. On the other hand, IBM PC models do not have hardware to provide sprites.

When the sprite is implemented through software, the data structure of the sprite is mapped to the one-dimensional structure because the data structure of the sprite has the same length and width as the screen structure, or because the memory is a one-dimensional structure. , NOT, XOR) to change the pixel value.

In particular, the useful XOR technique uses the inversion of the random logic operation to convert the arbitrary pixel or the block pixel (set of pixels) to the new value by using the result of the exclusive logical sum of bits of the current pixel value in the frame buffer. Express.

That is, if an XOR operation of an arbitrary pixel value is stored twice in an empty frame buffer, the object is drawn in the first XOR operation, and then erased again in the second XOR operation. Here, if you move the position of the object to be redrawn a little, you feel like the object is moving.

Also, after an object is erased by performing an XOR operation (exclusive logical sum operation) on the object of the previous frame, the moving object may be expressed by performing an OR operation (logical sum operation) on the new frame to redraw the object.

This conventional technique is not enough to feel the fast speed because the sprites are moved to the previous frame every time the various sprites are moving on the screen, and the sprites are redrawn on the new frame.

Accordingly, the present invention has been made to solve the above-mentioned problems, and provides a method for generating a sprite animation by storing the position information on several previous frames and quickly displaying several previous frames as needed. Its purpose is to.

In order to achieve the above object, the method of the present invention comprises the steps of: initializing the residual number of sprites (N) to be left; Initializing the previous sprite index j; Comparing the difference i-j of the previous sprite index from the current sprite index with the residual image sprite number N; A fourth step of deleting the corresponding j-th previous sprite if the index difference value (i-j) is greater than the number of residual sprites (N); 5 steps of increasing the index j of the previous sprite by one; A sixth step of drawing a current sprite after the fifth step or when the comparison result of the second step has an index difference value (i-j) smaller than the number of residual sprites (N); Storing seven memory locations of the current sprite; It consists of eight steps of increasing the index (i) of the current sprite by one and repeatedly performing the above three steps.

1 is a block diagram showing an example of a general computer graphics system,

2 is a view illustrating a process of displaying data of the frame buffer;

3 is a flowchart illustrating a method of displaying an afterimage sprite in accordance with the present invention.

Hereinafter, the operation and effects of the present invention will be described in detail.

In order to achieve the above object, the method of the present invention is illustrated in FIG. 3.

Referring to the variable used in the flowchart of FIG. 3, N is a variable representing the number of frames of the sprite desired for the afterimage effect on the screen, i is an index of the current sprite showing the last movement, and j is a previous movement showing the intermediate movement. The index of the sprite.

As shown in FIG. 3, in the first step S1, the frame number N of the afterimage sprites to be left is initialized, and in the second step S2, the index j of the first drawn sprite is initialized to 1.

In the third step S3, the difference ij of the previous sprite index j from the current sprite index i is compared with the afterimage sprite number N, and in the fourth step S4, the third step S3. If the difference (ij) of the index is greater than the number of residual sprites (N), the jth previous sprite is deleted.

In the fifth step (S5), the index j of the previous sprite is increased by one, and in the sixth step (S6), the difference (ij) of the comparison result index after the fifth step (S5) or the second step (S2) is increased. If the number of afterimage sprites is less than N, the i-th current sprite is drawn.

In the seventh step S7, the memory location of the i-th current sprite is stored. In the eighth step S8, the index i of the current sprite is increased by one, and the process is repeated from the third step S3.

For example, a process of displaying on the screen assuming three afterimage sprites to be left in order to give a blurring or afterimage effect will be described.

Sprites that change their movement over time are stored in memory.

Here, the order in which the moving sprites are drawn is drawn from the smallest index of the sprite, after which the sprites of the next index are drawn.

The sprite index corresponding to real time t is the index of the current sprite frame, the current sprite index i is updated in register A, and the previous sprite index j is updated in register B.

In displaying the first sprite, when time t is 1, after determining the third step (S3), the sixth step (S6) is performed to perform OR operation on the bitmap of the current sprite to the destination register of the video RAM. Display on. Then, the location of the memory where the first sprite is stored is stored in the first-in first-out buffer (FIFO) (S7). Now, by increasing the register A value by 1, the current sprite index becomes 2, and as a result of the determination in the third step, the second sprite is displayed on the screen in the same manner as the display of the first sprite. It also stores the location of the memory where sprite 2 is stored in the first-in, first-out buffer.

Subsequently, the same process as for displaying the first sprite is performed until the register A value becomes 4.

That is, the first sprite is displayed when t = 1, the first and second sprites are displayed when t = 2, and the first, second and third sprites are displayed when t = 3, and the first when t = 4. , Sprites 2, 3 and 4 are displayed. The positions of the frames stored in the first-in, first-out buffer (FIFO) are the memory locations of sprites 4, 3, 2, and 1.

Now, when the register A value is 5 and the register B value is 1 when t = 5, the difference value of the previous sprite index from the current sprite index (ij = 5-1 = 4) as a result of the determination in the third step S3. Since the number of afterimages is greater than 3 (= N), the fourth step S4 is performed to erase the first sprite by XORing the previous sprite bitmap one time in the destination register of the video RAM.

Here, the location of the first sprite can be extracted from the first-in first-out buffer to find and erase the location. Then, the fifth step S5 is performed to increase the previous sprite index j by one, so that the register B value becomes two. After performing the sixth step S6, the bitmap of the current sprite 5 is ORed in the destination register of the video RAM and displayed on the screen, and the memory location of the current sprite 5 is stored in the first-in first-out buffer.

At this time, the frame positions stored in the first-in, first-out buffer are the memory positions of the sprites 5, 4, 3, and 2.

The eighth step S8 is performed to increase the current sprite index i by one, so that the register A value is six, and the third step S3 is repeated.

Now, when the register A value is 6 and the register B value is 2 when t = 6, the difference value of the previous sprite index from the current sprite index (ij = 6-2 = 4) as a result of the determination in the third step S3. Since the number of afterimages is greater than 3 (= N), the fourth step is performed to delete the second sprite by XORing the previous two sprite bitmaps in the destination register of the video RAM.

Here, the position of the second sprite can be extracted from the first-in, first-out buffer to find and erase the position. Then, the fifth step S5 is performed to increase the previous sprite index j by one, so that the register B value becomes three. After performing the sixth step (S6) to display on the screen by OR-operating the bitmap of the current six sprites to the destination register of the video RAM, the memory location of the current sixth sprite is stored in the first-in first-out buffer.

At this time, the frame positions stored in the first-in, first-out buffer are memory locations of sprites 6, 5, 4, and 3.

The above operations are shown in a table with the sprites displayed over time.

t i (current sprite) j (formerly sprite) FIFO Displayed Sprite One One One #One One 2 2 One # 2, # 1 1,2 3 3 One # 3, # 2, # 1 1,2,3 4 4 One # 4, # 3, # 2, # 1 1,2,3,4 5 5 2 # 5, # 4, # 3, # 2 2,3,4,5 6 6 3 # 6, # 5, # 4, # 3 3,4,5,6 7 7 4 # 7, # 6, # 5, # 4 4,5,6,7

As shown in the above table, t = 1 to t = 4 continues to draw the current sprite, and from t = 5 it erases the remaining sprites from the current frame except for the previous three frames, which results in four successive shots. To display the sprite.

Here, the position information on the previous frame to be erased uses a first-in, first-out buffer, and in this embodiment, four (= N + 1) shift registers are sufficiently implemented.

You can also track the trajectory of the overall movement by increasing the number of residual images you want to leave in the moving sprite.

With the above operation, the second hand or minute hand rotates quickly on the watch, or when the car or train is passing by at high speed and needs to be faintly drawn, leaving a trace of the sprite. If you perform blurring, you will feel a sense of speed.

As described above, according to the present invention, the current stripe is displayed along with the previous stripe to continuously display the movement, and thus, the present invention can be effectively used when the speed is required during the animation generation process or when the blurring effect is particularly needed.

Claims (1)

In the animation generating method that brings the speed and blurring effect of the sprite, A first step S1 of initializing the residual number of sprites N to be left; Step S2 of initializing the previous sprite index j; Step S3 of comparing the difference i-j of the previous sprite index from the current sprite index with the afterimage sprite number N; A fourth step (S4) of deleting the corresponding j-th previous sprite when the index difference value (i-j) is larger than the number of residual sprites (N); Step S5 of increasing the index j of the previous sprite by one; A sixth step (S6) of drawing the current sprite after the fifth step or when the comparison result index difference value (i-j) of the second step is smaller than the number of residual sprites (N); Step 7 (S7) of storing the memory location of the current sprite; And increasing the index (i) of the current sprite by one and performing eight steps (S8) which are repeatedly performed from the three steps.