screen.h: Factor out the minimal graphics stuff, implement a dumb VT1…

…00 mode for POSIX

And clang-format and detab.
And add a Makefile.
And fix all -W -Wall warnings from Clang.

.clang-format

@@ -0,0 +1,7 @@
+BasedOnStyle: LLVM
+Standard: Cpp11
+IndentWidth: 4   
+UseTab: Never 
+AccessModifierOffset: -4
+AllowShortBlocksOnASingleLine: Never
+AllowShortFunctionsOnASingleLine: None

Collision.cpp

@@ -1,11 +1,10 @@
 #include <iostream>
+#include <cmath>
 #include <cstdlib>
 #include <ctime>
 #include "screen.h"
 #include "vec2.h"
 
-#define M_PI 3.14159265358979323846
-
 constexpr float G=3.0f;
 
 struct Body
@@ -34,8 +33,7 @@ struct Body
 		acc=0;
 	}
 
-	Body(float m,float r)
-	:m(m),r(r)
+	Body(float m,float r) : r(r), m(m)
 	{
 		pos=0;
 		vel=0;
@@ -66,9 +64,6 @@ struct Body
 
 void Plot(const Body& body, Screen& scr)	//render the body
 {
-	vec2 O=body.pos;
-	vec2 X=body.pos + 0.5f*body.vel;
-
 	scr.PlotCircle(body.pos.x,body.pos.y,body.r);
 }
 
@@ -81,12 +76,10 @@ int main()
 {
 	srand (static_cast <unsigned> (time(0)));
 
-	setup();
 	Screen scr(0,0,5);
 
 	const int n=20000;
 	constexpr float dt=1.0/40.0f;
-	constexpr float r=3.5f,R=30.0f;
 
 	/* Initializing first galaxy */
 	Body Centre1(2000.0f,2.5f);

Makefile

@@ -0,0 +1,17 @@
+CXXFLAGS=-std=c++17
+
+all: ThreeBody Sun-Earth-Moon Collision
+
+ThreeBody: ThreeBody.cpp screen.h vec2.h
+	$(CXX) $(CXXFLAGS) ThreeBody.cpp -o $@
+
+Sun-Earth-Moon: Sun-Earth-Moon.cpp screen.h vec2.h
+	$(CXX) $(CXXFLAGS) Sun-Earth-Moon.cpp -o $@
+
+Collision: Collision.cpp screen.h vec2.h
+	$(CXX) $(CXXFLAGS) Collision.cpp -o $@
+
+clean:
+	rm -f ThreeBody Sun-Earth-Moon Collision
+
+.PHONY: clean

Sun-Earth-Moon.cpp

@@ -27,8 +27,7 @@ struct Body
 		acc=0;
 	}
 
-	Body(float m,float r)
-	:m(m),r(r)
+	Body(float m,float r) : r(r), m(m)
 	{
 		pos=0;
 		vel=0;
@@ -60,15 +59,11 @@ struct Body
 
 void Plot(const Body& body, Screen& scr)
 {
-	vec2 O=body.pos;
-	vec2 X=body.pos + 0.5f*body.vel;
-
 	scr.PlotCircle(body.pos.x,body.pos.y,body.r);
 }
 
 int main()
 {
-	setup();
 	Screen scr(0,0,10);
 
 	constexpr float dt=1.0/100.0f;

ThreeBody.cpp

@@ -27,8 +27,7 @@ struct Body
 		acc=0;
 	}
 
-	Body(float m,float r)
-	:m(m),r(r)
+	Body(float m,float r) : r(r), m(m)
 	{
 		pos=0;
 		vel=0;
@@ -94,7 +93,6 @@ void Plot(const Body& body, Screen& scr)
 
 int main()
 {
-	setup();
 	Screen scr(0,0,200);
 
 	constexpr float dt=1.0/100.0f;