Added limits to t.

olbender · Dec 7, 2018 · bdc2d3b · bdc2d3b
1 parent 2dd826d
commit bdc2d3b
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Showing 2 changed files with 36 additions and 2 deletions.
diff --git a/splinetoolbox.hpp b/splinetoolbox.hpp
@@ -36,6 +36,12 @@ namespace splinetoolbox {
  */
 inline double catmullrom(double p0, double p1, double p2, double p3, double t) noexcept
 {
+  if (t > 1.0) {
+    t = 1.0;
+  }
+  if (t < 0.0) {
+    t = 0.0;
+  }
   return p1 + 0.5 * (p2 - p0) * t + 0.5 * (4 * p2 + 2 * p0 - p3 - 5 * p1) * t * t + 0.5 * (3 * p1 + p3 - p0 - 3 * p2) * t * t * t;
 }
 
@@ -44,6 +50,12 @@ inline double catmullrom(double p0, double p1, double p2, double p3, double t) n
  */
 inline double catmullrom_d(double p0, double p1, double p2, double p3, double t) noexcept
 {
+  if (t > 1.0) {
+    t = 1.0;
+  }
+  if (t < 0.0) {
+    t = 0.0;
+  }
   return 0.5 * (p2 - p0) + (4 * p2 + 2 * p0 - p3 - 5 * p1) * t + 1.5 * (3 * p1 + p3 - p0 - 3 * p2) * t * t;
 }
 
@@ -52,6 +64,12 @@ inline double catmullrom_d(double p0, double p1, double p2, double p3, double t)
  */
 inline double catmullrom_dd(double p0, double p1, double p2, double p3, double t) noexcept
 {
+  if (t > 1.0) {
+    t = 1.0;
+  }
+  if (t < 0.0) {
+    t = 0.0;
+  }
   return (4 * p2 + 2 * p0 - p3 - 5 * p1) + 3 * (3 * p1 + p3 - p0 - 3 * p2) * t;
 }
 

diff --git a/test/test-splinetoolbox.cpp b/test/test-splinetoolbox.cpp
@@ -27,6 +27,22 @@
 
 #include "splinetoolbox.hpp"
 
-TEST_CASE("Some test") {
-  REQUIRE(true);
+TEST_CASE("Catmull-Rom tests") {
+  REQUIRE(splinetoolbox::catmullrom(1, 2, 3, 4, -0.0) == Approx(2.0));
+  REQUIRE(splinetoolbox::catmullrom(1, 2, 3, 4, 0.0) == Approx(2.0));
+  REQUIRE(splinetoolbox::catmullrom(1, 2, 3, 4, 0.6) == Approx(2.6));
+  REQUIRE(splinetoolbox::catmullrom(1, 2, 3, 4, 1.0) == Approx(3.0));
+  REQUIRE(splinetoolbox::catmullrom(1, 2, 3, 4, 1.1) == Approx(3.0));
+
+/*
+  REQUIRE(splinetoolbox::catmullrom_d(1, 2, 3, 4, -0.1) 
+      == Approx(splinetoolbox::catmullrom_d(1, 2, 3, 4, 0.0)));
+  REQUIRE(splinetoolbox::catmullrom_d(1, 2, 3, 4, 1.0) 
+      == Approx(splinetoolbox::catmullrom_d(1, 2, 3, 4, 1.1)));
+  
+  REQUIRE(splinetoolbox::catmullrom_dd(1, 2, 3, 4, -0.1) 
+      == Approx(splinetoolbox::catmullrom_d(1, 2, 3, 4, 0.0)));
+  REQUIRE(splinetoolbox::catmullrom_dd(1, 2, 3, 4, 1.0) 
+      == Approx(splinetoolbox::catmullrom_d(1, 2, 3, 4, 1.1)));
+      */
 }