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https://github.com/rigreco/Runge-Kutta-Simulation.git
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134 lines
4.9 KiB
C
134 lines
4.9 KiB
C
/* ------------------------------------------------------------------------
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System : Manx Aztec C65 Version 3.2b
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MS-DOS cross-development environment
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Platform : Apple IIe 128K PRODOS 8
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Program : piclode.c
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Description : G2 Library Routine
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For Hi-Res Mode
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Written by : Bill Buckels
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Creation Date: June 5, 1991
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Revised : January 2013
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Licence : You may use this code for whatever you wish as long
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as you agree that Bill Buckels has no warranty or
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liability obligations whatsoever from said use.
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------------------------------------------------------------------------ */
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#include <fcntl.h>
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extern unsigned HB[];
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/* globals to override the load point for the image loader */
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char XPIC=0;
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char YPIC=0;
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int piclode(name)
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char *name;
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{
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int fh,y,y1=0,x1,bos,height,packet,c=-2;
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char tempchar[2];
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fh = open(name,O_RDONLY,0xc3); /* open a binary file */
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if (fh == -1)return -1;
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if (read(fh,tempchar,2)==2) {
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packet= (int)tempchar[0];
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height= (int)tempchar[1];
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/* special case for fullscreen images first
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always load from top left */
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if (packet == 40) XPIC = 0;
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if (height == 192) YPIC = 0;
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if (packet == 40 && height == 160) YPIC = 0; /* fullscreen mixed text */
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/* center the picture in the screen */
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if(XPIC>39)
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x1 = 20-(packet/2); /* break on even byte boundaries */
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else
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x1 = (int)XPIC;
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if((x1%2)!=0)x1--;
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if(YPIC>191)
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y1=96-(height/2);
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else
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y1=(int)YPIC;
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bos=y1+height;
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if (bos > 192)bos = 192;
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/* Unbuffered read of each scanline = 192 reads for a full screen.
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this may not be terribly efficient for full screen images
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from a disk access perspective but may work quicker for small image
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fragments than RAX format encoded images.
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Consider encoding larger images in the RAX format if disk space
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is the greatest consideration.
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Consider leaving full screen images in a bsaved format if the
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loading is too slow and if a venetian-blind effect is acceptable.
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Also consider using the following routine and the rag format for
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everything if code size creates a memory problem and you just want
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one routine to save available memory. It may be your best
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all-around option.
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Keep in mind that you can use an overlay design for your program
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and put each loader in a separate overlay. There are 3 downsides to
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doing so: 1. overlays can be lost when programs are copied
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by inexperienced users which will render your
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app useless.
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2. overlays need to be read from disk and the extra read
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required by their use may slow down your loader.
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3. the disk space that you save by reformatting a small
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number of images into multiple formats may be
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chewed-up by expanding your code size with multiple
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loaders and complicating your life further (whether
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you use overlays or just use multiple loaders).
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If you decide to use multiple loaders and you can avoid using
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overlays do so. Your program will run quicker and the bits and
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pieces (overlays) will not become hopelessly lost by some idiot
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which may even be you if you forget things like I do especially
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years later.
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A large non-trivial program like a paint program will likely
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need a number of overlays and support for multiple image
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formats. A trivial program like a slideshow or viewer will
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likely not need any overlays but will likely need mutiple
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format support.
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A final note. If you are using many images and image fragments
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take a look at the code in emsput which uses auxiliary memory
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to store RAG images that you preload when your program starts
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(or prior to viewing) and can be moved quickly directly to the screen.
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emsput can also be used to for sprite-like animation. RAX images
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can be expanded to RAG images and then stored in auxiliary memory
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and other neat stuff can be done like putting a bunch of
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concatanated RAG or RAX images into the auxiliary bank. Have a look at
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my ribcook program in the tools directory for some idea on
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how that can be done, and the code in emslode.c and the PLOGO.C code
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in Applex\SAMPLES\TIME for more information on how all this fits
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together.
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*/
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for(y=y1;y<bos;y++) {
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c = read(fh,(unsigned char *)(HB[y] + x1),packet); /* read each raster to the screen */
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if(c!=packet) break;
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}
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if (c != packet) c = -2;
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else c = 0;
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}
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close(fh);
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/* zero our globals each time */
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XPIC=0;
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YPIC=0;
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return c;
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}
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