mbrot-mt

annotate src/mbrot-mt.c @ 0:e9ae6289e14f

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initial commit
author John Tsiombikas <nuclear@member.fsf.org>
date Fri, 07 Mar 2014 07:42:48 +0200
parents
children 3a893f9831ac
rev   line source
nuclear@0 1 #include <stdio.h>
nuclear@0 2 #include <complex.h>
nuclear@0 3 #include <SDL/SDL.h>
nuclear@0 4
nuclear@0 5 void display(void);
nuclear@0 6 int mandelbrot(float x, float y, int max_iter, int *iter);
nuclear@0 7 int handle_event(SDL_Event *ev);
nuclear@0 8
nuclear@0 9 static SDL_Surface *fbsurf;
nuclear@0 10 static int win_width, win_height;
nuclear@0 11 static float win_aspect;
nuclear@0 12 static float xoffs, yoffs, zoom = 1.0;
nuclear@0 13 static int max_iter = 64;
nuclear@0 14
nuclear@0 15 int main(void)
nuclear@0 16 {
nuclear@0 17 win_width = 800;
nuclear@0 18 win_height = 600;
nuclear@0 19 win_aspect = (float)win_width / (float)win_height;
nuclear@0 20
nuclear@0 21 SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER);
nuclear@0 22 if(!(fbsurf = SDL_SetVideoMode(win_width, win_height, 32, SDL_SWSURFACE | SDL_RESIZABLE))) {
nuclear@0 23 fprintf(stderr, "failed to create framebuffer\n");
nuclear@0 24 return 1;
nuclear@0 25 }
nuclear@0 26
nuclear@0 27 SDL_WM_SetCaption("Mandelbrot", 0);
nuclear@0 28
nuclear@0 29 for(;;) {
nuclear@0 30 SDL_Event ev;
nuclear@0 31
nuclear@0 32 while(SDL_PollEvent(&ev)) {
nuclear@0 33 if(handle_event(&ev) == -1) {
nuclear@0 34 goto done;
nuclear@0 35 }
nuclear@0 36 }
nuclear@0 37
nuclear@0 38 display();
nuclear@0 39 }
nuclear@0 40
nuclear@0 41 done:
nuclear@0 42 SDL_Quit();
nuclear@0 43 return 0;
nuclear@0 44 }
nuclear@0 45
nuclear@0 46 void display(void)
nuclear@0 47 {
nuclear@0 48 unsigned char *fbuf, *pixptr;
nuclear@0 49 int i, j, xsz, ysz;
nuclear@0 50
nuclear@0 51 if(SDL_MUSTLOCK(fbsurf)) {
nuclear@0 52 SDL_LockSurface(fbsurf);
nuclear@0 53 }
nuclear@0 54 fbuf = fbsurf->pixels;
nuclear@0 55 xsz = fbsurf->w;
nuclear@0 56 ysz = fbsurf->h;
nuclear@0 57
nuclear@0 58 pixptr = fbuf;
nuclear@0 59 for(i=0; i<ysz; i++) {
nuclear@0 60 float y = 2.0 * (float)i / (float)ysz - 1.0;
nuclear@0 61 for(j=0; j<xsz; j++) {
nuclear@0 62 float x = (2.0 * (float)j / (float)xsz - 1.0) * win_aspect;
nuclear@0 63
nuclear@0 64 int iter, r, g, b;
nuclear@0 65 int inset = mandelbrot((x - xoffs) * zoom, (y - yoffs) * zoom, max_iter, &iter);
nuclear@0 66 if(!inset) {
nuclear@0 67 r = iter * 256 / max_iter;
nuclear@0 68 g = 0;
nuclear@0 69 b = 0;
nuclear@0 70 } else {
nuclear@0 71 r = g = b = 0;
nuclear@0 72 }
nuclear@0 73
nuclear@0 74 pixptr[0] = b;
nuclear@0 75 pixptr[1] = g;
nuclear@0 76 pixptr[2] = r;
nuclear@0 77 pixptr[3] = 255;
nuclear@0 78 pixptr += 4;
nuclear@0 79 }
nuclear@0 80 }
nuclear@0 81
nuclear@0 82 if(SDL_MUSTLOCK(fbsurf)) {
nuclear@0 83 SDL_UnlockSurface(fbsurf);
nuclear@0 84 }
nuclear@0 85 SDL_Flip(fbsurf);
nuclear@0 86 }
nuclear@0 87
nuclear@0 88 int mandelbrot(float x, float y, int max_iter, int *iter)
nuclear@0 89 {
nuclear@0 90 int i;
nuclear@0 91 complex float c = x + y * I;
nuclear@0 92 complex float z = c;
nuclear@0 93
nuclear@0 94 for(i=0; i<max_iter; i++) {
nuclear@0 95 float re = creal(z);
nuclear@0 96 float im = cimag(z);
nuclear@0 97 if(re * re + im * im > 4) {
nuclear@0 98 if(iter) *iter = i;
nuclear@0 99 return 0;
nuclear@0 100 }
nuclear@0 101
nuclear@0 102 z = z * z + c;
nuclear@0 103 }
nuclear@0 104
nuclear@0 105 return 1;
nuclear@0 106 }
nuclear@0 107
nuclear@0 108 int handle_event(SDL_Event *ev)
nuclear@0 109 {
nuclear@0 110 static int prev_x, prev_y;
nuclear@0 111 static int bnstate[32];
nuclear@0 112
nuclear@0 113 switch(ev->type) {
nuclear@0 114 case SDL_KEYDOWN:
nuclear@0 115 if(ev->key.keysym.sym == SDLK_ESCAPE) {
nuclear@0 116 return -1;
nuclear@0 117 }
nuclear@0 118
nuclear@0 119 case SDL_MOUSEBUTTONDOWN:
nuclear@0 120 prev_x = ev->button.x;
nuclear@0 121 prev_y = ev->button.y;
nuclear@0 122 bnstate[ev->button.button - SDL_BUTTON_LEFT] = 1;
nuclear@0 123 break;
nuclear@0 124
nuclear@0 125 case SDL_MOUSEBUTTONUP:
nuclear@0 126 bnstate[ev->button.button - SDL_BUTTON_LEFT] = 0;
nuclear@0 127 break;
nuclear@0 128
nuclear@0 129 case SDL_MOUSEMOTION:
nuclear@0 130 {
nuclear@0 131 int dx = ev->button.x - prev_x;
nuclear@0 132 int dy = ev->button.y - prev_y;
nuclear@0 133 prev_x = ev->button.x;
nuclear@0 134 prev_y = ev->button.y;
nuclear@0 135
nuclear@0 136 if(!dx && !dy) break;
nuclear@0 137
nuclear@0 138 if(bnstate[0]) {
nuclear@0 139 xoffs += win_aspect * 2.0 * (float)dx / (float)win_width;
nuclear@0 140 yoffs += 2.0 * (float)dy / (float)win_height;
nuclear@0 141 }
nuclear@0 142 if(bnstate[2]) {
nuclear@0 143 zoom += (float)dy / (float)win_height;
nuclear@0 144 if(zoom < 1e-6) zoom = 1e-6;
nuclear@0 145 }
nuclear@0 146 }
nuclear@0 147 break;
nuclear@0 148
nuclear@0 149 case SDL_VIDEORESIZE:
nuclear@0 150 win_width = ev->resize.w;
nuclear@0 151 win_height = ev->resize.h;
nuclear@0 152 win_aspect = (float)win_width / (float)win_height;
nuclear@0 153 break;
nuclear@0 154
nuclear@0 155 default:
nuclear@0 156 break;
nuclear@0 157 }
nuclear@0 158 return 0;
nuclear@0 159 }