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/**
* lensdraw.c - source file for trying things with SDL2.
*
* Copyright (C) 2025 https://optics-design.com
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* See the COPYING file for the full license text.
*/
#include <SDL.h>
#include <math.h>
#define SCREEN_WIDTH 800
#define SCREEN_HEIGHT 600
void draw_circle(SDL_Renderer *renderer, int cx, int cy, int r) {
for (int x = -r; x <= r; x++) {
int y = sqrt(r * r - x * x);
SDL_RenderDrawPoint(renderer, cx + x, cy + y);
SDL_RenderDrawPoint(renderer, cx + x, cy - y);
}
}
void draw_lens(SDL_Renderer *renderer, int cx, int cy, int r) {
SDL_SetRenderDrawColor(renderer, 0, 200, 255, 255); // Light blue color for lens
for (int x = 0; x <= r; x++) {
int y1 = sqrt(r * r - x * x);
int y2 = -y1;
for (int y = y2; y <= y1; y++) {
SDL_RenderDrawPoint(renderer, cx + x, cy + y);
}
}
}
int main(int argc, char* argv[]) {
SDL_Init(SDL_INIT_VIDEO);
SDL_Window *window = SDL_CreateWindow("Spherical Lens", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
SDL_Renderer *renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255); // Black background
SDL_RenderClear(renderer);
draw_lens(renderer, SCREEN_WIDTH / 2, SCREEN_HEIGHT / 2, 100); // Draw lens
SDL_RenderPresent(renderer);
SDL_Delay(5000); // Show for 5 seconds
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}
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