1 files changed, 41 insertions, 0 deletions
diff --git a/src/population.h b/src/population.h
new file mode 100644
index 0000000..14c9b77
--- /dev/null
+++ b/src/population.h
@@ -0,0 +1,41 @@
+#pragma once
+
+namespace population {
+
+constexpr unsigned d = 3;
+constexpr unsigned q = 19;
+
+constexpr int velocity[q][d] = {
+	{ 0, 1, 1}, {-1, 0, 1}, { 0, 0, 1}, { 1, 0, 1}, { 0,-1, 1},
+	{-1, 1, 0}, { 0, 1, 0}, { 1, 1, 0}, {-1, 0, 0}, { 0, 0, 0}, { 1, 0, 0}, {-1,-1, 0}, { 0,-1, 0}, { 1,-1, 0},
+	{ 0, 1,-1}, {-1, 0,-1}, { 0, 0,-1}, { 1, 0,-1}, { 0,-1,-1}
+};
+
+unsigned opposite(unsigned iPop) {
+	return q - 1 - iPop;
+}
+
+std::ptrdiff_t offset(const Cuboid& c, int iX, int iY, int iZ) {
+	return iX*c[1]*c[2] + iY*c[2] + iZ;
+}
+
+std::ptrdiff_t offset(const Cuboid& c, unsigned iPop) {
+	return offset(c, velocity[iPop][0], velocity[iPop][1], velocity[iPop][2]);
+}
+
+std::ptrdiff_t max_offset(const Cuboid& c) {
+	std::ptrdiff_t padding = 0;
+	for (unsigned iPop=0; iPop < q; ++iPop) {
+		padding = std::max(padding, std::abs(offset(c, iPop)));
+	}
+	return padding;
+}
+
+}
+
+namespace stage {
+
+struct pre_collision { };
+struct post_collision { };
+
+}