87 lines
1.7 KiB
C
87 lines
1.7 KiB
C
/*----------------------------------------------------------------------+
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| gfxbrot.c -- demonstrate fractal in gfx / quick and dirty |
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+----------------------------------------------------------------------*/
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// Standard includes
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#include <limits.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <assert.h>
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#include <string.h>
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#include <math.h>
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#include <gigatron/console.h>
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#include <gigatron/sys.h>
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#define HEIGHT 120
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#define WIDTH 160
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#define SCALE 1.6
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#define YSTEP 1
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#define XSTEP 1
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int mandelbrot(float x, float y) {
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float zz;
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float a;
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float b;
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float a2;
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float b2;
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float atemp;
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int i;
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a = 0;
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b = 0;
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i = 0;
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while (i < 15)
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{
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a2 = a * a;
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b2 = b * b;
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zz = a2 + b2;
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if(zz > 4) break;
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atemp = a2 - b2 + x;
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b = 2.0 * a * b + y;
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a = atemp;
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i++;
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}
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return i;
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}
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void drawPixel(int x, int y, int color)
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{
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screenMemory[y][x] = color;
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}
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void main(void) {
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int x, y, data;
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int col[16];
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float sx, sy;
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col[0] = 0x01;
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col[1] = 0x02;
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col[2] = 0x03;
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col[3] = 0x07;
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col[4] = 0x0b;
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col[5] = 0x0f;
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col[6] = 0x0e;
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col[7] = 0x0d;
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col[8] = 0x0c;
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col[9] = 0x3c;
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col[10] = 0x38;
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col[11] = 0x34;
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col[12] = 0x30;
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col[13] = 0x20;
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col[14] = 0x10;
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col[15] = 0x00;
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for(y = 0; y < HEIGHT; y = y + YSTEP ) {
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for(x = 0; x < WIDTH; x = x + XSTEP ) {
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sx = -0.7 + (SCALE * (WIDTH/2.0 - x) / (WIDTH/2.0))*(-1);
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sy = (SCALE * (HEIGHT/2.0 - y) / (HEIGHT/2.0))*(-0.75);
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data = mandelbrot(sx, sy);
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drawPixel(x,y,col[data]);
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}
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}
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}
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