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#ifdef _WIN32 // грубый способ определения; на деле разница не в ОС, а в компиляторe
#include <SDL.h>
#include <SDL_image.h>
#include <SDL_timer.h>
#else
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <SDL2/SDL_timer.h>
#endif
#include <time.h>
#include <math.h>
#define SCALE 1
#define BOIDNUM 30
#define SPEED 1
#define CRANGE 30
#define WIDTH 1280
#define HEIGHT 640
#define PI 3.1415926535
struct boid { double x, y, dx, dy, th; };
typedef struct vec { float x, y; } vector;
struct boid B[BOIDNUM];
char color[3] = {0, 255, 0};
int init()
{
srand(time(NULL));
for(int i = 0; i<BOIDNUM; i++) {
B[i].x = WIDTH/2 + rand() % 128 - 64;
B[i].y = HEIGHT/2 + rand() % 128 - 64;
B[i].th = rand() / (float)RAND_MAX * (PI/3) - PI/6;
B[i].dx = SPEED * cos(B[i].th);
B[i].dy = SPEED * sin(B[i].th);
// printf("%f",B[i].th);
}
return 0;
}
int processEvents(SDL_Window *window)
{
SDL_Event event;
while(SDL_PollEvent(&event))
{
switch(event.type)
{
case SDL_WINDOWEVENT_CLOSE:
if(window)
{
SDL_DestroyWindow(window);
window = NULL;
return 1;
}
break;
case SDL_KEYDOWN:
switch(event.key.keysym.sym) {
case SDLK_ESCAPE:
return 1;
}
}
}
return 0;
}
void render(SDL_Renderer *renderer)
{
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255); // фон
SDL_RenderClear(renderer);
SDL_Vertex arrow[BOIDNUM][3];
for(int i = 0; i<BOIDNUM; i++) {
arrow[i][0].position.x = (B[i].x+7 *cos(B[i].th-PI/2))/SCALE;
arrow[i][0].position.y = (B[i].y+7 *sin(B[i].th-PI/2))/SCALE;
arrow[i][1].position.x = (B[i].x+7 *cos(B[i].th+PI/2))/SCALE;
arrow[i][1].position.y = (B[i].y+7 *sin(B[i].th+PI/2))/SCALE;
arrow[i][2].position.x = (B[i].x+20*cos(B[i].th)) /SCALE;
arrow[i][2].position.y = (B[i].y+20*sin(B[i].th)) /SCALE;
for(int j = 0; j<3; j++) {
arrow[i][j].color.r = color[0];
arrow[i][j].color.g = color[1]+j*25;
arrow[i][j].color.b = color[2];
arrow[i][j].color.a = 255;
}
SDL_RenderGeometry(renderer, NULL, arrow[i], 3, NULL, 0);
}
SDL_RenderPresent(renderer);
}
float geomdist(int i, int j)
{
return sqrt(pow( B[i].x - B[j].x, 2 ) + pow( B[i].y - B[j].y, 2 ));
}
vector cohesion(int n, int factor)
{
vector sum = {0, 0};
for(int b = 0; b < BOIDNUM; b++) {
if(geomdist(n, b) > CRANGE) {continue;}
if(b == n) {continue;}
sum.x += B[b].x;
sum.y += B[b].y;
}
sum.x /= BOIDNUM - 1;
sum.y /= BOIDNUM - 1;
sum.x -= B[n].x;
sum.y -= B[n].y;
sum.x /= factor;
sum.y /= factor;
return sum;
}
vector separation(int n, float dist, int factor)
{
vector c = {0, 0};
c.x = 0;
c.y = 0;
for(int b = 0; b < BOIDNUM; b++) {
if(geomdist(n, b) > CRANGE) {continue;}
if(b == n) {continue;}
if(geomdist(n, b) < dist) {
c.x -= B[b].x - B[n].x;
c.y -= B[b].y - B[n].y;
}
}
c.x /= factor;
c.y /= factor;
return c;
}
vector alignment(int n, int factor)
{
vector pv = {0, 0};
for(int b = 0; b < BOIDNUM; b++) {
if(geomdist(n, b) > CRANGE) {continue;}
if(b == n) {continue;}
pv.x += B[b].dx;
pv.y += B[b].dy;
}
pv.x /= BOIDNUM - 1;
pv.y /= BOIDNUM - 1;
pv.x -= B[n].dx;
pv.y -= B[n].dy;
pv.x /= factor;
pv.y /= factor;
return pv;
}
int updatePos(SDL_Renderer *renderer) {
vector v[3];
for(int i = 0; i<BOIDNUM; i++) {
B[i].x += B[i].dx;
B[i].y += B[i].dy;
// B[i].th += PI/72;
if(B[i].x > WIDTH)
B[i].x -= WIDTH;
// B[i].dx = 0;
if(B[i].y > HEIGHT)
B[i].y -= HEIGHT;
// B[i].dy = 0;
if(B[i].x < 0)
B[i].x += WIDTH;
// B[i].dx = 0;
if(B[i].y < 0)
B[i].y += HEIGHT;
// B[i].dy = 0;
v[0] = cohesion(i, 40);
v[1] = separation(i, 20, 200);
// v[0].x = 0;
// v[0].y = 0;
v[2] = alignment(i, 80);
// v[2].x = 0;
// v[2].y = 0;
for(int j = 0; j<3; j++) {
if(i == 0) {
SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
SDL_RenderDrawLine(renderer, B[i].x, B[i].y, B[i].x-v[j].x, B[i].y - v[j].y);
SDL_RenderPresent(renderer);
printf("|vx = %f, vy = %f", v[j].x, v[j].y);
}
B[i].dx += v[j].x / 1000;
B[i].dy += v[j].y / 1000;
}
// if (B[i].dx > sqrt(50)) B[i].dx = sqrt(50);
// if (B[i].dy > sqrt(50)) B[i].dy = sqrt(50);
B[i].th = acos(B[i].dx / sqrt(B[i].dx * B[i].dx + B[i].dy * B[i].dy) + 0.0001);
// if(i == 0) {
// printf("%f|", B[i].th);
// }
}
return 0;
}
int main(int argc, char *argv[])
{
SDL_Window *window = NULL;
SDL_Renderer *renderer = NULL;
init();
SDL_Init(SDL_INIT_VIDEO);
window = SDL_CreateWindow("Boids",
SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED,
WIDTH,
HEIGHT,
0);
renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
while(1) {
if(processEvents(window) == 1)
break;
render(renderer);
updatePos(renderer);
SDL_Delay(10);
}
return 0;
}
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