From d32d6bffa25633fc1060e30c88b7739ed93f87ed Mon Sep 17 00:00:00 2001
From: Luke Lau <luke_lau@icloud.com>
Date: Fri, 20 Mar 2020 22:46:31 +0000
Subject: [PATCH] Clouds WIP

---
 clouds.cpp | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 clouds.hpp |  9 +++++++++
 2 files changed, 61 insertions(+)
 create mode 100644 clouds.cpp
 create mode 100644 clouds.hpp

diff --git a/clouds.cpp b/clouds.cpp
new file mode 100644
index 0000000..5fe2bb8
--- /dev/null
+++ b/clouds.cpp
@@ -0,0 +1,52 @@
+#include "clouds.hpp"
+#include <cmath>
+#include <GL/glew.h>
+
+float w(int i, int j, int k) { return 1; }
+
+const float metaballR = 1;
+float metaballField(float r) {
+	if (r > metaballR) return 0;
+	const float a = r / metaballR;
+	return (-4.f/9.f * powf(a, 6)) + (17.f/9.f * powf(a, 4)) - (22.f/9.f * powf(a, 2)) + 1;
+}
+
+const float normalizationFactor = 748.f / 405.f * M_PI * metaballR;
+
+void calcContDist(Clouds *clds, float t) {
+	const int i0 = 2, j0 = 2, k0 = 2, t0 = 2;
+	const float divisor = 1.f / 
+					((2 * t0 + 1) *
+					 (2 * k0 + 1) *
+					 (2 * j0 + 1) *
+					 (2 * i0 + 1));
+	float sum = 0;
+	for (int i = 0; i < CLOUD_DIM; i++) {
+		for (int j = 0; j < CLOUD_DIM; j++) {
+			for (int k = 0; k < CLOUD_DIM; k++) {
+
+
+				// inner sums
+				/* for (int tp = -t0, tp < t0; tp++) { */
+					for (int ip = -i0; ip < i0; ip++) {
+						for (int jp = -j0; jp < j0; jp++) {
+							for (int kp = -k0; kp < k0; kp++) {
+
+
+								sum += w(ip, jp, kp) * (float)clds->cld[i + ip][j + jp][k + kp];
+
+							}
+						}
+					}
+				/* } */
+
+				clds->contDist[i][j][k] = sum / divisor;
+
+			}
+		}
+	}
+}
+
+void renderBillboard() {
+	
+}
diff --git a/clouds.hpp b/clouds.hpp
new file mode 100644
index 0000000..1a8496d
--- /dev/null
+++ b/clouds.hpp
@@ -0,0 +1,9 @@
+static const int CLOUD_DIM = 16;
+struct Clouds {
+	char cld[CLOUD_DIM][CLOUD_DIM][CLOUD_DIM];
+	float contDist[CLOUD_DIM][CLOUD_DIM][CLOUD_DIM];
+};
+
+
+// calculate continuous distribution
+void calcContDist(Clouds *clds);
-- 
2.30.2