From 09475f0100ac382eef60365fe58f1115baaca747 Mon Sep 17 00:00:00 2001
From: Akshay <nerdy@peppe.rs>
Date: Thu, 11 Nov 2021 12:53:28 +0530
Subject: add 3d serpinsky gasket

---
 flake.nix    |  2 +-
 src/1/main.c |  5 ++++
 src/2/main.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 98 insertions(+), 1 deletion(-)
 create mode 100644 src/2/main.c

diff --git a/flake.nix b/flake.nix
index 21b787c..1b6249f 100644
--- a/flake.nix
+++ b/flake.nix
@@ -10,7 +10,7 @@
     , nixpkgs
     }:
     let
-      allPrograms = [ 1 ];
+      allPrograms = [ 1 2 ];
       supportedSystems = [ "x86_64-linux" ];
       forAllSystems = f: nixpkgs.lib.genAttrs supportedSystems (system: f system);
       nixpkgsFor = forAllSystems (system:
diff --git a/src/1/main.c b/src/1/main.c
index f75eca5..ad35c47 100644
--- a/src/1/main.c
+++ b/src/1/main.c
@@ -1,3 +1,8 @@
+/* 2-d serpinski gasket
+ *
+ * Akshay Oppiliappan
+ */
+
 #include <GL/glut.h>
 #include <stdlib.h>
 #include <time.h>
diff --git a/src/2/main.c b/src/2/main.c
new file mode 100644
index 0000000..2d78d35
--- /dev/null
+++ b/src/2/main.c
@@ -0,0 +1,92 @@
+/* 3-d serpinsky gasket
+ *
+ * Akshay Oppiliappan
+ */
+
+#include <GL/glut.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+typedef float point[3];
+
+point tetra[4] = {
+    {0, 250, -250},
+    {0, 0, 250},
+    {250, -250, 250},
+    {-250, -250, -250},
+};
+
+void myInit() {
+    glClearColor(1.0, 1.0, 1.0, 1.0);
+    glOrtho(-300.0, 300.0, -300.0, 300.0, -300.0, 300.0);
+};
+
+void drawTriangle(point p1, point p2, point p3) {
+    glBegin(GL_TRIANGLES);
+    glVertex3fv(p1);
+    glVertex3fv(p2);
+    glVertex3fv(p3);
+    glEnd();
+}
+
+void drawTetra(point p1, point p2, point p3, point p4) {
+    glColor3f(1.0, 1.0, 0.0);
+    drawTriangle(p1, p2, p3);
+
+    glColor3f(0.0, 1.0, 0.0);
+    drawTriangle(p1, p3, p4);
+
+    glColor3f(1.0, 0.0, 0.0);
+    drawTriangle(p1, p4, p2);
+
+    glColor3f(0.0, 0.0, 1.0);
+    drawTriangle(p2, p3, p4);
+}
+
+void divideTetra(point p1, point p2, point p3, point p4, int iter) {
+    point mid[6];
+    int j;
+
+    if (iter > 0) {
+        for (j = 0; j < 3; j++)
+            mid[0][j] = (p1[j] + p2[j]) / 2;
+        for (j = 0; j < 3; j++)
+            mid[1][j] = (p1[j] + p3[j]) / 2;
+        for (j = 0; j < 3; j++)
+            mid[2][j] = (p1[j] + p4[j]) / 2;
+        for (j = 0; j < 3; j++)
+            mid[3][j] = (p2[j] + p3[j]) / 2;
+        for (j = 0; j < 3; j++)
+            mid[4][j] = (p3[j] + p4[j]) / 2;
+        for (j = 0; j < 3; j++)
+            mid[5][j] = (p2[j] + p4[j]) / 2;
+
+        divideTetra(p1, mid[0], mid[1], mid[2], iter - 1);
+        divideTetra(mid[0], p2, mid[3], mid[5], iter - 1);
+        divideTetra(mid[1], mid[3], p3, mid[4], iter - 1);
+        divideTetra(mid[2], mid[4], p4, mid[5], iter - 1);
+    } else {
+        drawTetra(p1, p2, p3, p4);
+    }
+}
+
+void display() {
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+    glBegin(GL_TRIANGLES);
+    divideTetra(tetra[0], tetra[1], tetra[2], tetra[3], 5);
+    glEnd();
+    glFlush();
+}
+
+int main(int argc, char *argv[]) {
+    glutInit(&argc, argv);
+    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
+    glutInitWindowSize(600, 600);
+    glutInitWindowPosition(0, 0);
+    glutCreateWindow("Sierpinski Gasket");
+    glutDisplayFunc(display);
+    glEnable(GL_DEPTH_TEST);
+    myInit();
+    glutMainLoop();
+}
-- 
cgit v1.2.3