From a41edc31ce81daf69157a345525933ca6c560004 Mon Sep 17 00:00:00 2001
From: Brian Paul <brian.paul@tungstengraphics.com>
Date: Wed, 9 May 2001 20:02:28 +0000
Subject: [PATCH] check for tiny values in dir[] vector in calcposobjs(),
 prevents FP underflows later

---
 progs/demos/fire.c    | 7 +++++++
 progs/demos/ipers.c   | 7 +++++++
 progs/demos/ray.c     | 7 +++++++
 progs/demos/terrain.c | 7 +++++++
 progs/demos/tunnel.c  | 7 +++++++
 progs/demos/tunnel2.c | 7 +++++++
 6 files changed, 42 insertions(+)

diff --git a/progs/demos/fire.c b/progs/demos/fire.c
index e895b0e6a0a..e4492cbc161 100644
--- a/progs/demos/fire.c
+++ b/progs/demos/fire.c
@@ -257,6 +257,13 @@ calcposobs(void)
    dir[2] = cos(alpha * M_PI / 180.0) * sin(beta * M_PI / 180.0);
    dir[1] = cos(beta * M_PI / 180.0);
 
+   if (dir[0] < 1.0e-5 && dir[0] > -1.0e-5)
+      dir[0] = 0;
+   if (dir[1] < 1.0e-5 && dir[1] > -1.0e-5)
+      dir[1] = 0;
+   if (dir[2] < 1.0e-5 && dir[2] > -1.0e-5)
+      dir[2] = 0;
+
    obs[0] += v * dir[0];
    obs[1] += v * dir[1];
    obs[2] += v * dir[2];
diff --git a/progs/demos/ipers.c b/progs/demos/ipers.c
index d38c4d1ae88..029de000898 100644
--- a/progs/demos/ipers.c
+++ b/progs/demos/ipers.c
@@ -205,6 +205,13 @@ calcposobs(void)
    dir[1] = cos(alpha * M_PI / 180.0) * sin(beta * M_PI / 180.0);
    dir[2] = cos(beta * M_PI / 180.0);
 
+   if (dir[0] < 1.0e-5 && dir[0] > -1.0e-5)
+      dir[0] = 0;
+   if (dir[1] < 1.0e-5 && dir[1] > -1.0e-5)
+      dir[1] = 0;
+   if (dir[2] < 1.0e-5 && dir[2] > -1.0e-5)
+      dir[2] = 0;
+
    obs[0] += v * dir[0];
    obs[1] += v * dir[1];
    obs[2] += v * dir[2];
diff --git a/progs/demos/ray.c b/progs/demos/ray.c
index aede3d8edbd..44289b7f965 100644
--- a/progs/demos/ray.c
+++ b/progs/demos/ray.c
@@ -102,6 +102,13 @@ calcposobs(void)
    dir[1] = cos(alpha * M_PI / 180.0) * sin(beta * M_PI / 180.0);
    dir[2] = cos(beta * M_PI / 180.0);
 
+   if (dir[0] < 1.0e-5 && dir[0] > -1.0e-5)
+      dir[0] = 0;
+   if (dir[1] < 1.0e-5 && dir[1] > -1.0e-5)
+      dir[1] = 0;
+   if (dir[2] < 1.0e-5 && dir[2] > -1.0e-5)
+      dir[2] = 0;
+
    obs[0] += v * dir[0];
    obs[1] += v * dir[1];
    obs[2] += v * dir[2];
diff --git a/progs/demos/terrain.c b/progs/demos/terrain.c
index 2fe1df3a071..5b5ad3e1f7a 100644
--- a/progs/demos/terrain.c
+++ b/progs/demos/terrain.c
@@ -81,6 +81,13 @@ calcposobs(void)
    dir[2] = cos(alpha * M_PI / 180.0) * sin(beta * M_PI / 180.0);
    dir[1] = cos(beta * M_PI / 180.0);
 
+   if (dir[0] < 1.0e-5 && dir[0] > -1.0e-5)
+      dir[0] = 0;
+   if (dir[1] < 1.0e-5 && dir[1] > -1.0e-5)
+      dir[1] = 0;
+   if (dir[2] < 1.0e-5 && dir[2] > -1.0e-5)
+      dir[2] = 0;
+
    alpha1 = alpha + FOV / 2.0;
    v1[0] = sin(alpha1 * M_PI / 180.0);
    v1[1] = cos(alpha1 * M_PI / 180.0);
diff --git a/progs/demos/tunnel.c b/progs/demos/tunnel.c
index d495b31b4f6..f0faa61a0bf 100644
--- a/progs/demos/tunnel.c
+++ b/progs/demos/tunnel.c
@@ -164,6 +164,13 @@ calcposobs(void)
    dir[1] = cos(alpha * M_PI / 180.0) * sin(beta * M_PI / 180.0);
    dir[2] = cos(beta * M_PI / 180.0);
 
+   if (dir[0] < 1.0e-5 && dir[0] > -1.0e-5)
+      dir[0] = 0;
+   if (dir[1] < 1.0e-5 && dir[1] > -1.0e-5)
+      dir[1] = 0;
+   if (dir[2] < 1.0e-5 && dir[2] > -1.0e-5)
+      dir[2] = 0;
+
    obs[0] += v * dir[0];
    obs[1] += v * dir[1];
    obs[2] += v * dir[2];
diff --git a/progs/demos/tunnel2.c b/progs/demos/tunnel2.c
index 8d662484109..048cd6d8e7c 100644
--- a/progs/demos/tunnel2.c
+++ b/progs/demos/tunnel2.c
@@ -162,6 +162,13 @@ calcposobs(void)
    dir[1] = cos(alpha * M_PI / 180.0) * sin(beta * M_PI / 180.0);
    dir[2] = cos(beta * M_PI / 180.0);
 
+   if (dir[0] < 1.0e-5 && dir[0] > -1.0e-5)
+      dir[0] = 0;
+   if (dir[1] < 1.0e-5 && dir[1] > -1.0e-5)
+      dir[1] = 0;
+   if (dir[2] < 1.0e-5 && dir[2] > -1.0e-5)
+      dir[2] = 0;
+
    obs[0] += v * dir[0];
    obs[1] += v * dir[1];
    obs[2] += v * dir[2];
-- 
2.30.2