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circle_recursive.c
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circle_recursive.c
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/* Author: NagaChaitanya Vellanki */
#include <GLFW/glfw3.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
static float PI = 3.14159265358979323846;
static float RADIUS = 300.0f;
void draw_circle(float x, float y, float radius) {
glColor4f(0.5f, 1.0f, 0.0f, 1.0f);
glPointSize(2.0f);
glBegin(GL_POINTS);
for (int radian = 0; radian < 360; radian++)
{
float degree = radian * (PI / 180.0);
glVertex2f(x + radius * cosf(degree), y + radius * sinf(degree));
}
glEnd();
if(radius > 10.0f) {
draw_circle(x + radius, y, radius / 2);
draw_circle(x - radius, y, radius / 2);
draw_circle(x, y + radius, radius / 2);
draw_circle(x, y - radius, radius / 2);
}
}
static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
glfwSetWindowShouldClose(window, GL_TRUE);
}
int main(int argc, char *argv[]) {
GLFWwindow* window;
if(!glfwInit()) {
return -1;
}
GLFWmonitor* monitor = glfwGetPrimaryMonitor();
const GLFWvidmode* vidmode = glfwGetVideoMode(monitor);
window = glfwCreateWindow(vidmode->width, vidmode->height, "Circle Recursive", monitor, NULL);
if(!window) {
glfwTerminate();
return -1;
}
glfwSetKeyCallback(window, key_callback);
glfwMakeContextCurrent(window);
int width, height;
glfwGetFramebufferSize(window, &width, &height);
float x = width / 2;
float y = height / 2;
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0f, width, 0.0f, height, 0.0, 1.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
while(!glfwWindowShouldClose(window)) {
glClear(GL_COLOR_BUFFER_BIT);
draw_circle(x, y, RADIUS);
glfwSwapBuffers(window);
glfwPollEvents();
}
glfwTerminate();
return 0;
}