THIS program is designed to show how one picture can be transformed into another with a smooth transition. Of course, the easiest way would be to simply flick between the two frames, but this is hardly smooth, and definitely not pleasing to the eye. What is needed is a series of frames to go in between the originals, using a technique called tweening to create a smooth animation sequence. The first frame we draw needs to be split up into its component lines and re-assembled as the second frame. One way of doing this would be to use a conventional art package to draw each frame by hand. This would be immensely time consuming and not very mathematical. The method Metamorphosis adopts is to assume that each line in the first frame has a partner in the second. Of course, if this were literally true we would have the limitation of both frames needing an identical number of lines, which would make life very difficult. To get around this, the computer makes the frame with the most lines Frame I and the other Frame II. Each line in Frame I is given a partner in Frame II. When all the lines in Frame II have been used up, the computer goes back to the start of this frame again. In practice, all this means is that some lines appear to converge on the same spot. Once this process has been completed it is just a matter of building up the frames in between. Metamorphosis uses a complete cycle of eight frames. Therefore the distance between the two points of a line and its partner is calculated and divided by eight. This gives us a series of numbers that are added on repeatedly to build up the individual frames. This may all seem very complicated, but it is completely transparent to the user. The only details you are required to supply are the starting and finishing frames. On running the listing you will be presented with a six-option menu:
- Create Design: Used for drawing your two frames. Move the crosshairs with the cursor keys and press the spacebar to plot the start and end of each line. When you are satisfied with your creation, press F and repeat the process for the second frame. At any time you can return to the main menu by pressing Q. This will not corrupt the current design in memory, but will abort the frames you were working on. Each frame may consist of up to 64 lines.
- Animate Design: Once you've completed option one, or loaded a previously saved design, you can select this option. Your current design will be animated before your very eyes at medium speed. To see just what the program is capable of, press 3 to select fast speed. If you want to study the frames more closely press 1 for slow speed. To return to the main menu press Q.
- Load design: Type in the filename - up to eight characters - and press Return. The computer will then attempt to load this saved design.
- Save design: Can be used to save your current design to tape or disc, which can be recalled later with option three. Again, the filename can be up to eight characters long.
- Catalogue disc: Shows all the designs on the disc in the current drive. Not available for tape.
- Exit Program: Returns the user to Basic. Note that the Escape key is disabled throughout the program. To get a feel for the program, draw something very simple the first time - say a square at bottom left for Frame I and a square at top right for Frame II.
The machine code data at line 2650 sets up two bar commands, |STORE and. |RECALL. The (bar) character before these commands is typed by holding down Shift and pressing the (a key. which you'll find just to the right of the P key.ACU #8903 | ★ AMSTRAD CPC ★ DOWNLOAD ★ |
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CPCrulez[Content Management System] v8.7-desktop/c
Page créée en 499 millisecondes et consultée 1574 foisL'Amstrad CPC est une machine 8 bits à base d'un Z80 à 4MHz. Le premier de la gamme fut le CPC 464 en 1984, équipé d'un lecteur de cassettes intégré il se plaçait en concurrent du Commodore C64 beaucoup plus compliqué à utiliser et plus cher. Ce fut un réel succès et sorti cette même années le CPC 664 équipé d'un lecteur de disquettes trois pouces intégré. Sa vie fut de courte durée puisqu'en 1985 il fut remplacé par le CPC 6128 qui était plus compact, plus soigné et surtout qui avait 128Ko de RAM au lieu de 64Ko. |
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