1 files changed, 104 insertions, 0 deletions
diff --git a/balls.cpp b/balls.cpp
new file mode 100644
index 0000000..555b192
--- /dev/null
+++ b/balls.cpp
@@ -0,0 +1,104 @@
+#include <stdlib.h>
+#include <GL/glut.h>
+#include <oneapi/tbb.h>
+
+using namespace std;
+
+enum window { WIDTH = 800, HEIGHT = 600 };
+enum keys { KEY_QUIT = 'q' };
+enum { CIRCLE_SEGS = 32 };
+
+typedef struct {
+	double x, y;
+} Point;
+
+typedef struct {
+	Point min, max;
+} Rectangle;
+
+void keyboard(unsigned char key, int x, int y);
+void display(void);
+void drawBg(void);
+void drawCircle(double radius, Point p);
+void reshape(int w, int h);
+
+const static Rectangle bounds = {{-1.5, -1.0}, {1.5, 1.0}};
+
+int
+main(int argc, char *argv[]) {
+	glutInit(&argc, argv);
+	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
+	glutInitWindowSize(WIDTH, HEIGHT);
+	glutCreateWindow("Balls");
+
+	glutKeyboardFunc(keyboard);
+	glutDisplayFunc(display);
+	glutReshapeFunc(reshape);
+
+	glClearColor(1.0, 1.0, 1.0, 1.0);
+
+	glutMainLoop();
+
+	return 1;
+}
+
+void
+keyboard(unsigned char key, int x, int y) {
+	if (key == KEY_QUIT)
+		glutDestroyWindow(glutGetWindow());
+}
+
+void
+display(void) {
+	static Point p = {0.35, 0.35};
+
+	glClearColor(0, 0, 0, 1);
+	glClear(GL_COLOR_BUFFER_BIT);
+	drawBg();
+	drawCircle(0.25, p);
+
+	glutSwapBuffers();
+}
+
+void
+drawBg(void) {
+	glColor3f(1, 1, 1);
+	glBegin(GL_QUADS);
+		glVertex2f(bounds.min.x, bounds.min.y);
+		glVertex2f(bounds.max.x, bounds.min.y);
+		glVertex2f(bounds.max.x, bounds.max.y);
+		glVertex2f(bounds.min.x, bounds.max.y);
+	glEnd();
+}
+
+void
+drawCircle(double radius, Point p) {
+	int i;
+	double theta, x, y;
+
+	glColor3f(0.1, 0.6, 0.8);
+	glBegin(GL_TRIANGLE_FAN);
+		glVertex2f(p.x, p.y);
+		for (i = 0; i <= CIRCLE_SEGS; i++) {
+			theta = 2.0 * M_PI * i / CIRCLE_SEGS;
+			x = radius * cosf(theta);
+			y = radius * sinf(theta);
+			glVertex2f(x+p.x, y+p.y);
+		}
+	glEnd();
+}
+
+void
+reshape(int w, int h) {
+	double ratio;
+
+	glViewport(0, 0, w, h);
+	glMatrixMode(GL_PROJECTION);
+	glLoadIdentity();
+	ratio = (double) w / (double) h;
+	if (ratio >= 1.0)
+		glOrtho(-ratio, ratio, -1, 1, -1, 1);
+	else
+		glOrtho(-1, 1, -1.0/ratio, 1.0/ratio, -1, 1);
+	glMatrixMode(GL_MODELVIEW);
+}