Added a generator for polygons to make the init easier

Makefile

@@ -11,7 +11,7 @@ CXXFLAGS=-Wall -g -O2 $(PROFILING_CFLAGS) $(GTK_CFLAGS)
 LIBS=$(GTK_LIBS) -lm
 
 PROGS=balls
-OBJS=balls.o c_index.o game.o gravity.o spaceship.o main.o polygons.o
+OBJS=balls.o c_index.o game.o gravity.o spaceship.o main.o polygons.o polygon_generator.o
 
 # dependencies (gcc -MM *.cc)
 balls.o: balls.cc game.h balls.h vec2d.h gravity.h
@@ -21,6 +21,9 @@ gravity.o: gravity.cc gravity.h balls.h vec2d.h game.h
 main.o: main.cc game.h balls.h vec2d.h c_index.h gravity.h spaceship.h
 spaceship.o: spaceship.cc balls.h vec2d.h game.h
 stats.o: stats.cc
+polygons.o: polygons.cc polygons.h vec2d.h polygon_generator.h
+polygon_generator.o: polygon_generator.cc polygon_generator.h
+
 
 .PHONY: run
 run: balls

polygon_generator.cc

@@ -0,0 +1,29 @@
+#include "polygon_generator.h"
+
+#include <cassert>
+#include <cmath>
+
+#define PI 3.141592653589793238462643323
+
+static double to_rad(double angle_in_deg) {
+    static double PI_180 = PI / 180;
+    return angle_in_deg * PI_180;
+}
+
+polygon poly_generate::rectangle(double width, double height) {
+    assert(width > 0);
+    assert(height > 0);
+    return polygon{
+        {0, 0}, 0, {{0, 0}, {width, 0}, {width, height}, {0, height}}};
+}
+
+polygon poly_generate::triangle(double side1, double side2, double angle) {
+    assert(side1 > 0);
+    assert(side2 > 0);
+    return polygon{{0, 0},
+        0,
+        {{0, 0},
+            {side1, 0},
+            {side2 * std::cos(to_rad(angle)),
+                side2 * std::sin(to_rad(angle))}}};
+}

polygon_generator.h

@@ -0,0 +1,20 @@
+#ifndef POLYGON_GENERATOR_H_INCLUDED
+#define POLYGON_GENERATOR_H_INCLUDED
+
+#include "polygons.h"
+
+#include <cassert>
+
+namespace poly_generate {
+
+    polygon rectangle(double width, double height);
+
+    inline polygon square(double width) {
+        assert(width > 0);
+        return rectangle(width, width);
+    };
+
+    polygon triangle(double side1, double side2, double angle);
+
+}; // namespace poly_generate
+#endif

polygons.cc

@@ -1,26 +1,28 @@
 #include "polygons.h"
 
+#include "polygon_generator.h"
+
 #include <iostream>
 
 polygon* polygons = nullptr;
-uint n_polygons = 1;
+uint n_polygons = 3;
 
 void polygons_init_state() {
     polygons = new polygon[n_polygons];
 
-    polygon poly =
+    polygons[0] = poly_generate::triangle(200, 200, 30).set_center({300, 200});
-        polygon{{400, 400}, 0, {{-50, -50}, {50, -50}, {50, 50}, {-50, 50}}};
+    polygons[1] = poly_generate::square(200).set_center({100, 400});
-    polygons[0] = poly;
+    polygons[2] = poly_generate::rectangle(200, 100).set_center({400, 400});
 }
 
 void polygon::draw(cairo_t* cr) const {
-    polygon& poly = polygons[0];
+    const vec2d& center = this->center;
-    vec2d& center = poly.center;
     cairo_set_source_rgb(cr, 1, 1, 1);
 
-    for (auto& point : poly.points)
+    for (auto& point : this->points)
         cairo_line_to(cr, center.x + point.x, center.y + point.y);
-    cairo_line_to(cr, center.x + poly.points[0].x, center.y + poly.points[0].y);
+    cairo_line_to(
+        cr, center.x + this->points[0].x, center.y + this->points[0].y);
     cairo_stroke(cr);
 }