Moved instance creation into its own class

To clean up main.cpp

Author: pkivolowitz

instance.cpp

@@ -0,0 +1,31 @@
+#include "instance.h"
+
+using namespace std;
+using namespace glm;
+
+inline float Random(float min, float max)
+{
+	return float(rand()) / float(RAND_MAX) * (max - min) + min;
+}
+
+void Instance::DefineInstances(vector<Instance> & instances, int n)
+{
+	float d = 8.0f;
+
+	for (int i = 0; i < n; i++)
+	{
+		mat4 m = rotate(mat4(), Random(0.0f, pi<float>() * 2.0f), vec3(0.0f, 1.0f, 0.0f));
+		m = rotate(m, Random(0.0f, pi<float>() * 2.0f), vec3(1.0f, 0.0f, 0.0f));
+		float z = Random(-8.0f, 8.0f);
+		z += (z > 0) ? 2.0f : -2.0f;
+
+		vec4 p = m * vec4(0.0f, 0.0f, z, 1.0f);
+
+		vec3 diffuse(Random(0.2f, 1.0f), Random(0.2f, 1.0f), Random(0.2f, 1.0f));
+		instances.push_back(Instance(
+			vec3(p),
+			Random(0.0f, pi<float>() * 2.0f),
+			Random(-360.0f, 360.0f),
+			diffuse));
+	}
+}

instance.h

@@ -0,0 +1,18 @@
+#pragma once
+#include <vector>
+#include <glm/glm.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+#include <glm/gtc/type_ptr.hpp>
+#include <glm/gtc/constants.hpp>
+
+class Instance
+{
+public:
+	Instance(glm::vec3 p, float o, float r, glm::vec3 d) : position(p), offset(o), rate(r), diffuse(d) {};
+	static void DefineInstances(std::vector<Instance> & instances, int n = 32);
+
+	glm::vec3 position;
+	float offset;
+	float rate;
+	glm::vec3 diffuse;
+};