add specific transform 4d file, with basic helper function

1 files changed, 12 insertions, 0 deletions

diff --git a/src/4dvecops/transform4d.cpp b/src/4dvecops/transform4d.cpp
new file mode 100644
index 0000000..91f0d8c
--- /dev/null
+++ b/src/4dvecops/transform4d.cpp
@@ -0,0 +1,12 @@
+#include "raytracer/raytracer.h"
+
+// this is used to transform a 4d point by a 4d matrix and its associated translation
+// this is motivated by the fact that glm does not support 5d matrices, so we cannot define a mat5 to encapsulate both the rotation and translation in one matrix
+// therefore, we break the 5d transformation into a 4d rotation and a 4d translation
+glm::vec4 transformPoint4(glm::vec4 point4,  glm::mat4 transformDirectionMatrix, glm::vec4 translationPointVector) {
+    // do the translation first
+    point4 -= translationPointVector;
+    // do the rotation and scaling
+    point4 = transformDirectionMatrix * point4;
+    return point4;
+}
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