130 lines
4.2 KiB
C++
130 lines
4.2 KiB
C++
#include <SDL2/SDL.h>
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#include <iostream>
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const int SCREEN_WIDTH = 750;
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const int SCREEN_HEIGHT = 750;
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const int CENTER_SCREEN_WIDTH = SCREEN_WIDTH/2;
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const int CENTER_SCREEN_HEIGHT = SCREEN_HEIGHT/2;
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const double ZOOM_FACTOR = 1.1;
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SDL_Window* createWindow(){
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if (SDL_Init(SDL_INIT_VIDEO) < 0) {
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std::cerr << "SDL could not initialize! SDL_Error: " << SDL_GetError() << std::endl;
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exit(-1);
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}
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SDL_Window* window = SDL_CreateWindow("Braindead Mandelbrot", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
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if (window == nullptr) {
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std::cerr << "Window could not be created! SDL_Error: " << SDL_GetError() << std::endl;
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SDL_Quit();
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exit(-1);
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}
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return window;
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}
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void handle_events(SDL_Event e, bool& quit, bool& cliqued, double* center_offset_x, double* center_offset_y, double* zoom, int* max_itter){
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int mouse_x, mouse_y;
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SDL_GetMouseState(&mouse_x, &mouse_y);
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while (SDL_PollEvent(&e) != 0) {
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if (e.type == SDL_QUIT) {
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quit = true;
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}
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if (e.type == SDL_MOUSEBUTTONDOWN) {
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if (e.button.button == SDL_BUTTON_LEFT) {
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*center_offset_y += (double) (mouse_y - CENTER_SCREEN_HEIGHT) / *zoom;
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*center_offset_x += (double) (mouse_x - CENTER_SCREEN_WIDTH) / *zoom;
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std::cout << "New center offset " << *center_offset_x << ", " << *center_offset_y << ")\n";
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}
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if (e.button.button == SDL_BUTTON_RIGHT) {
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*max_itter = (int)((double)*max_itter * 1.1);
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std::cout << "Increase max_itter :" << *max_itter << "\n";
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}
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if (e.button.button == SDL_BUTTON_MIDDLE) {
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*max_itter = (int)((double)*max_itter / 1.1);
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std::cout << "Decrease max_itter :" << *max_itter << "\n";
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}
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}
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else if (e.type == SDL_MOUSEWHEEL){
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if (e.wheel.y == 1){
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*zoom *= ZOOM_FACTOR;
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std::cout << "Increase zoom :" << *zoom << "\n";
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}
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else{
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*zoom /= ZOOM_FACTOR;
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std::cout << "Decrease zoom :" << *zoom << "\n";
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}
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}
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}
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}
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int mandelbrot_pixel(double cx, double cy, int max_itter){
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double ux = 0.0;
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double uy = 0.0;
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double temp_ux;
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for (int i = 0; i < max_itter; i++) {
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temp_ux = ux;
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ux = ux*ux - uy*uy + cx;
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uy = 2*uy*temp_ux + cy;
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if (ux*ux + uy*uy > 4) return i;
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}
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return 0;
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}
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void draw_mandelbrot(SDL_Renderer* renderer, double center_offset_x, double center_offset_y, double zoom, int max_itter) {
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double cx, cy;
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for (int y = 0; y < SCREEN_HEIGHT; ++y) {
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for (int x = 0; x < SCREEN_WIDTH; ++x) {
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cy = 4.0 * (y + center_offset_y * zoom) / SCREEN_HEIGHT - 2.0;
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cx = 4.0 * (x + center_offset_x * zoom) / SCREEN_WIDTH - 2.0;
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int mandelbrot_escape = mandelbrot_pixel(cx / zoom, cy / zoom, max_itter);
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if (mandelbrot_escape) {
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uint8_t r = mandelbrot_escape % 255;
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uint8_t g = (2*mandelbrot_escape) % 255;
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uint8_t b = (3*mandelbrot_escape) % 255;
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SDL_SetRenderDrawColor(renderer, r, g, b, 255);
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SDL_RenderDrawPoint(renderer, x, y);
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} else {
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SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
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SDL_RenderDrawPoint(renderer, x, y);
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}
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}
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}
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}
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int main() {
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SDL_Window* window = createWindow();
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SDL_Event e;
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bool quit = false;
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bool clicked = false;
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SDL_Renderer* renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
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double center_offset_y = 0.0;
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double center_offset_x = 0.0;
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double zoom = 1.0;
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int max_itter = 255;
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while (!quit) {
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handle_events(e, quit, clicked, ¢er_offset_x, ¢er_offset_y, &zoom, &max_itter);
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draw_mandelbrot(renderer, center_offset_x, center_offset_y, zoom, max_itter);
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SDL_RenderPresent(renderer);
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}
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SDL_DestroyWindow(window);
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SDL_Quit();
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return 0;
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}
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