# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1400858862 -10800
# Node ID 3d541da6e48cdc72354bcff63abf8c5b2421d167
# Parent  68db0e456733ef8514bb73a0d73f0fb9a42bed1e
lalalala

diff -r 68db0e456733 -r 3d541da6e48c grav.sln
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/grav.sln	Fri May 23 18:27:42 2014 +0300
@@ -0,0 +1,24 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 2013
+VisualStudioVersion = 12.0.30501.0
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "grav", "grav.vcxproj", "{C45C3601-EB97-417C-B3F8-9F02529BE312}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{0CE743CE-21C9-408E-AE91-4BA9F74D931D}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Win32 = Debug|Win32
+		Release|Win32 = Release|Win32
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{C45C3601-EB97-417C-B3F8-9F02529BE312}.Debug|Win32.ActiveCfg = Debug|Win32
+		{C45C3601-EB97-417C-B3F8-9F02529BE312}.Debug|Win32.Build.0 = Debug|Win32
+		{C45C3601-EB97-417C-B3F8-9F02529BE312}.Release|Win32.ActiveCfg = Release|Win32
+		{C45C3601-EB97-417C-B3F8-9F02529BE312}.Release|Win32.Build.0 = Release|Win32
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+EndGlobal
diff -r 68db0e456733 -r 3d541da6e48c grav.vcxproj
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/grav.vcxproj	Fri May 23 18:27:42 2014 +0300
@@ -0,0 +1,90 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="12.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{C45C3601-EB97-417C-B3F8-9F02529BE312}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>grav</RootNamespace>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v120</PlatformToolset>
+    <CharacterSet>MultiByte</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>v120</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>MultiByte</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <LinkIncremental>true</LinkIncremental>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <LinkIncremental>false</LinkIncremental>
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>
+      </PrecompiledHeader>
+      <WarningLevel>Level3</WarningLevel>
+      <Optimization>Disabled</Optimization>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;_LIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <AdditionalDependencies>glut32.lib;libvmath.lib;%(AdditionalDependencies)</AdditionalDependencies>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <PrecompiledHeader>
+      </PrecompiledHeader>
+      <Optimization>MaxSpeed</Optimization>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;_LIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+      <AdditionalDependencies>glut32.lib;libvmath.lib;%(AdditionalDependencies)</AdditionalDependencies>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ClCompile Include="src\main.cc" />
+    <ClCompile Include="src\sim.cc" />
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="src\sim.h" />
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
\ No newline at end of file
diff -r 68db0e456733 -r 3d541da6e48c grav.vcxproj.filters
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/grav.vcxproj.filters	Fri May 23 18:27:42 2014 +0300
@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <Filter Include="Source Files">
+      <UniqueIdentifier>{4FC737F1-C7A5-4376-A066-2A32D752A2FF}</UniqueIdentifier>
+      <Extensions>cpp;c;cc;cxx;def;odl;idl;hpj;bat;asm;asmx</Extensions>
+    </Filter>
+    <Filter Include="Header Files">
+      <UniqueIdentifier>{93995380-89BD-4b04-88EB-625FBE52EBFB}</UniqueIdentifier>
+      <Extensions>h;hh;hpp;hxx;hm;inl;inc;xsd</Extensions>
+    </Filter>
+    <Filter Include="Resource Files">
+      <UniqueIdentifier>{67DA6AB6-F800-4c08-8B7A-83BB121AAD01}</UniqueIdentifier>
+      <Extensions>rc;ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe;resx;tiff;tif;png;wav;mfcribbon-ms</Extensions>
+    </Filter>
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="src\main.cc">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="src\sim.cc">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="src\sim.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+  </ItemGroup>
+</Project>
\ No newline at end of file
diff -r 68db0e456733 -r 3d541da6e48c src/main.cc
--- a/src/main.cc	Fri May 23 03:13:47 2014 +0300
+++ b/src/main.cc	Fri May 23 18:27:42 2014 +0300
@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <assert.h>
 #include <GL/glut.h>
 #include "sim.h"
 
@@ -10,8 +11,12 @@
 static void idle();
 static void reshape(int x, int y);
 static void keyb(unsigned char key, int x, int y);
+static void mouse(int bn, int st, int x, int y);
+static void motion(int x, int y);
+static void draw_grid(float sz, int nlines, float alpha);
 
 static SimWorld sim;
+static float cam_theta, cam_phi = 25, cam_dist = 8;
 
 int main(int argc, char **argv)
 {
@@ -24,16 +29,177 @@
 	glutIdleFunc(idle);
 	glutReshapeFunc(reshape);
 	glutKeyboardFunc(keyb);
+	glutMouseFunc(mouse);
+	glutMotionFunc(motion);
+
+	if(!init()) {
+		return 1;
+	}
+	atexit(cleanup);
+
+	glutMainLoop();
+	return 0;
 }
 
 
 static bool init()
 {
+	glEnable(GL_DEPTH_TEST);
+	glEnable(GL_CULL_FACE);
+	glEnable(GL_LIGHTING);
+	glEnable(GL_LIGHT0);
+
+	Particle p;
+	p.mass = 10.0;
+	sim.add_particle(p);
+	return true;
 }
 
-static void cleanup();
-static void update(long tmsec);
-static void display();
-static void idle();
-static void reshape(int x, int y);
-static void keyb(unsigned char key, int x, int y);
+static void cleanup()
+{
+}
+
+static void update(long tmsec)
+{
+	static long prev_upd;
+	long interval = tmsec - prev_upd;
+
+	if(interval >= 1000 / 60) {
+		prev_upd = tmsec;
+
+		float dt = (float)interval / 1000.0f;
+		sim.step(dt);
+	}
+}
+
+static void display()
+{
+	unsigned int msec = glutGet(GLUT_ELAPSED_TIME);
+	update(msec);
+
+	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+	glMatrixMode(GL_MODELVIEW);
+	glLoadIdentity();
+	glTranslatef(0, 0, -cam_dist);
+	glRotatef(cam_phi, 1, 0, 0);
+	glRotatef(cam_theta, 0, 1, 0);
+
+	sim.draw();
+
+	draw_grid(10, 10, 1);
+
+	glutSwapBuffers();
+	assert(glGetError() == 0);
+}
+
+static void generate()
+{
+	Particle p;
+	p.mass = (float)rand() / (float)RAND_MAX + 0.25;
+
+	p.pos.x = ((float)rand() / (float)RAND_MAX - 0.5) * 10.0;
+	p.pos.y = ((float)rand() / (float)RAND_MAX - 0.5) * 10.0;
+	p.pos.z = ((float)rand() / (float)RAND_MAX - 0.5) * 10.0;
+
+	p.vel.x = ((float)rand() / (float)RAND_MAX - 0.5) * 1.0;
+	p.vel.y = ((float)rand() / (float)RAND_MAX - 0.5) * 1.0;
+	p.vel.z = ((float)rand() / (float)RAND_MAX - 0.5) * 1.0;
+
+	sim.add_particle(p);
+}
+
+static void idle()
+{
+	glutPostRedisplay();
+}
+
+static void reshape(int x, int y)
+{
+	glMatrixMode(GL_PROJECTION);
+	glLoadIdentity();
+	gluPerspective(50.0, (float)x / (float)y, 0.5, 1000.0);
+
+	glViewport(0, 0, x, y);
+}
+
+static void keyb(unsigned char key, int x, int y)
+{
+	switch(key) {
+	case 27:
+		exit(0);
+
+	case ' ':
+		generate();
+		break;
+	}
+}
+
+static bool bnstate[16];
+static int prev_x, prev_y;
+
+static void mouse(int bn, int st, int x, int y)
+{
+	prev_x = x;
+	prev_y = y;
+	bnstate[bn - GLUT_LEFT_BUTTON] = st == GLUT_DOWN;
+}
+
+static void motion(int x, int y)
+{
+	int dx = x - prev_x;
+	int dy = y - prev_y;
+	prev_x = x;
+	prev_y = y;
+
+	if(!dx && !dy) return;
+
+	if(bnstate[0]) {
+		cam_theta += dx * 0.5;
+		cam_phi += dy * 0.5;
+
+		if(cam_phi < -90) cam_phi = -90;
+		if(cam_phi > 90) cam_phi = 90;
+	}
+	if(bnstate[2]) {
+		cam_dist += dy * 0.1;
+		if(cam_dist < 0.0) cam_dist = 0.0;
+	}
+}
+
+static void draw_grid(float sz, int nlines, float alpha)
+{
+	float hsz = sz / 2.0;
+	float offs = sz / (float)nlines;
+
+	glPushAttrib(GL_ENABLE_BIT);
+	glDisable(GL_LIGHTING);
+	glDisable(GL_TEXTURE_2D);
+
+	glLineWidth(2.0);
+	glBegin(GL_LINES);
+	glColor4f(1, 0, 0, alpha);
+	glVertex3f(-hsz, 0, 0);
+	glVertex3f(hsz, 0, 0);
+	glColor4f(0, 0, 1, alpha);
+	glVertex3f(0, 0, -hsz);
+	glVertex3f(0, 0, hsz);
+	glEnd();
+
+	glLineWidth(1.0);
+	glBegin(GL_LINES);
+	glColor4f(0.5, 0.5, 0.5, alpha);
+	for(int i=0; i<nlines / 2; i++) {
+		float dist = (float)(i + 1) * offs;
+		for(int j=0; j<2; j++) {
+			float sign = j > 0 ? -1.0 : 1.0;
+			glVertex3f(-hsz, 0, dist * sign);
+			glVertex3f(hsz, 0, dist * sign);
+			glVertex3f(dist * sign, 0, -hsz);
+			glVertex3f(dist * sign, 0, hsz);
+		}
+	}
+	glEnd();
+
+	glPopAttrib();
+}
\ No newline at end of file
diff -r 68db0e456733 -r 3d541da6e48c src/sim.cc
--- a/src/sim.cc	Fri May 23 03:13:47 2014 +0300
+++ b/src/sim.cc	Fri May 23 18:27:42 2014 +0300
@@ -1,4 +1,4 @@
-#include <GL/gl.h>
+#include <GL/glut.h>
 #include "sim.h"
 
 Particle::Particle()
@@ -6,9 +6,9 @@
 	mass = 1.0;
 }
 
-void Particle::impulse(const Vector3 &imp)
+void Particle::add_force(const Vector3 &force)
 {
-	accel += imp;
+	accel += force;
 }
 
 void Particle::step(float dt)
@@ -18,6 +18,7 @@
 	vel += accel * dt;
 	accel.x = accel.y = accel.z = 0.0;
 
+	prev_pos = pos;
 	pos = npos;
 }
 
@@ -40,7 +41,21 @@
 
 void SimWorld::step(float dt)
 {
-	std::list<Particle>::iterator it = particles.begin();
+	for(size_t i=0; i<particles.size(); i++) {
+		for(size_t j=0; j<particles.size(); j++) {
+			if(i == j) continue;
+
+			// calculate amount of force applied by particle[j] to particle[i]
+			Vector3 gdir = particles[j].pos - particles[i].pos;
+			float len = gdir.length();
+			if(len > 0.0) {
+				gdir /= len;
+				particles[i].add_force(gdir * particles[j].mass / (len * len));
+			}
+		}
+	}
+
+	std::vector<Particle>::iterator it = particles.begin();
 	while(it != particles.end()) {
 		Particle *p = &*it;
 		p->step(dt);
@@ -58,16 +73,22 @@
 	glBlendFunc(GL_ONE, GL_ONE);
 	glEnable(GL_BLEND);
 
-	glBegin(GL_POINTS);
 	glColor3f(0.5, 0.6, 0.7);
 
-	std::list<Particle>::const_iterator it = particles.begin();
-	while(it != particles.end()) {
-		const Particle *p = &*it++;
+	for(size_t i=0; i<particles.size(); i++) {
+		const Particle *p = &particles[i];
+
+		glPushMatrix();
+		glTranslatef(p->pos.x, p->pos.y, p->pos.z);
+		glutSolidSphere(p->mass * 0.1, 12, 6);
+		glPopMatrix();
+
+		glBegin(GL_LINES);
+		glNormal3f(0, 0, 1);
 		glVertex3f(p->pos.x, p->pos.y, p->pos.z);
+		glVertex3f(p->prev_pos.x, p->prev_pos.y, p->prev_pos.z);
+		glEnd();
 	}
 
-	glEnd();
-
 	glDisable(GL_BLEND);
 }
diff -r 68db0e456733 -r 3d541da6e48c src/sim.h
--- a/src/sim.h	Fri May 23 03:13:47 2014 +0300
+++ b/src/sim.h	Fri May 23 18:27:42 2014 +0300
@@ -1,24 +1,25 @@
 #ifndef SIM_H_
 #define SIM_H_
 
-#include <list>
+#include <vector>
 #include <vmath/vmath.h>
 
 class Particle {
 public:
 	float mass;
 	Vector3 pos, vel;
+	Vector3 prev_pos;
 	Vector3 accel;
 
 	Particle();
 
-	void impulse(const Vector3 &imp);
+	void add_force(const Vector3 &force);
 	void step(float dt);
 };
 
 class SimWorld {
 private:
-	std::list<Particle> particles;
+	std::vector<Particle> particles;
 	float radius_sq;
 
 public: