From c7cd23ac587b970fb1ec9d55508a8d4bba21096f Mon Sep 17 00:00:00 2001
From: Patrick Hull <patrick.d.hull@gmail.com>
Date: Sat, 20 Oct 2012 10:38:45 -0700
Subject: [PATCH] opengl life from the past

---
 .gitignore |   2 +
 life.c     | 152 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 makefile   |  10 ++++
 3 files changed, 164 insertions(+)
 create mode 100644 .gitignore
 create mode 100755 life.c
 create mode 100755 makefile

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..2dbc176
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.o
+life
diff --git a/life.c b/life.c
new file mode 100755
index 0000000..0c54922
--- /dev/null
+++ b/life.c
@@ -0,0 +1,152 @@
+#include <GLUT/glut.h>
+#include <OpenGL/glu.h>
+#include <OpenGL/gl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#define RETURN 13
+#define ESCAPE 27
+#define SPACE  32
+#define P      112
+
+int window;
+int size = 1000;
+int current[1000][1000];
+int next[1000][1000];
+
+void initBoard(int *board, int n) {
+  int i, j;
+  for(i=0; i < n; i++)
+    for(j = 0; j < n; j++)
+      board[i*n + j] = 0;
+}
+
+void randomize(int *board, int n) {
+  int i, j;
+  for(i = 0; i < n; i++)
+    for(j = 0; j < n; j++)
+      board[n*i + j] = random() % 2;
+}
+
+void getNext(int *board, int *next, int n) {
+  int i, j;
+  int count;
+  for(i = 1; i < n-1; i++) {
+    for(j = 1; j < n-1; j++) {
+      count = 0;
+      if(board[n*(i-1)+j])
+        count++;
+      if(board[n*(i-1)+(j-1)])
+        count++;
+      if(board[n*(i-1)+(j+1)])
+        count++;
+      if(board[n*i + (j-1)])
+        count++;
+      if(board[n*i + (j+1)])
+        count++;
+      if(board[n*(i+1) + (j-1)])
+        count++;
+      if(board[n*(i+1) + j])
+        count++;
+      if(board[n*(i+1) + (j+1)])
+        count++;
+      if(board[n*i + j]) {
+        if(count < 2 || count > 3)
+          next[n*i + j] = 0;
+        else
+          next[n*i + j] = 1;
+      } else {
+        if(count == 3)
+          next[n*i + j] = 1;
+        else
+          next[n*i + j] = 0;
+      }
+    }
+  }
+  memcpy(board, next, sizeof(int) * n * n);
+}
+
+void initGL() {
+  glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+  glClearDepth(1.0);
+  glEnable(GL_DEPTH_TEST);
+  glDepthFunc(GL_LEQUAL);
+  glShadeModel(GL_SMOOTH);
+}
+
+void resizeGL(int w, int h) {
+  if(h == 0) { h=1; }
+  glViewport(0, 0, w, h);
+  glMatrixMode(GL_PROJECTION);
+  glLoadIdentity();
+  gluPerspective(45.0f, (GLfloat)w/h, 0.1f, 200.0f);
+  glMatrixMode(GL_MODELVIEW);
+}
+
+float randomf() {
+  float mmm = 2147483647;
+  return rand()/mmm;
+}
+
+void drawBoard() {
+  int i, j;
+  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+  glLoadIdentity();
+  glTranslatef(-40.0, -40.0, -50.0);
+  glPushMatrix();
+  glPointSize(3.0f);
+  glBegin(GL_POINTS);
+  for(i=0; i < size; i++) {
+    for(j=0; j < size; j++) {
+      if(current[i][j]) {
+        glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
+      }
+      else {
+        glColor4f(0.0f, 0.0f, 0.0f, 1.0f);
+      }
+      glVertex3f(i*(0.5f), j*(0.5f), -6.0f);
+    }
+  }
+  glEnd();
+  glPopMatrix();
+  glutSwapBuffers();
+}
+
+void update() {
+  getNext(*current, *next, size);
+  drawBoard();
+}
+
+void keyPressed(unsigned char key, int x, int y) {
+  usleep(100);
+  if(key == ESCAPE) {
+    glutDestroyWindow(window);
+    exit(0);
+  }
+  if(key == SPACE)
+    randomize(*current, size);
+  if(key == RETURN)
+    getNext(*current, *next, size);
+}
+
+int main(int argc, char **argv) {
+  glutInit(&argc, argv);
+  glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH);
+  glutInitWindowSize(800, 600);
+
+  window = glutCreateWindow("life");
+
+  initBoard(*current, size);
+  randomize(*current, size);
+
+  glutDisplayFunc(&drawBoard);
+  glutIdleFunc(&update);
+  glutReshapeFunc(&resizeGL);
+  glutKeyboardFunc(&keyPressed);
+
+  initGL();
+  glutMainLoop();
+  return 1;
+}
diff --git a/makefile b/makefile
new file mode 100755
index 0000000..d8c1c44
--- /dev/null
+++ b/makefile
@@ -0,0 +1,10 @@
+INCLUDE = -I/usr/include/
+LIBRARY = -L/usr/X11R6/lib
+
+COMPILERFLAGS = -Wall
+CC = gcc
+CFLAGS = $(COMPILERFLAGS) $(INCLUDE)
+LIBRARIES = -framework GLUT -framework OpenGL
+
+life : life.o
+	$(CC) $(CFLAGS) -o $@ $(LIBDIR) $< $(LIBRARIES)