MOved hemisphere transformation stuff out of ray.c

1 files changed, 30 insertions, 0 deletions

diff --git a/ctranslate.h b/ctranslate.h
new file mode 100644
index 0000000..a2cc9b2
--- /dev/null
+++ b/ctranslate.h
@@ -0,0 +1,30 @@
+#ifndef CTRANS_H
+#define CTRANS_H
+
+#include "vector.h"
+
+// Used to create a sort of "virtual" coordinate system where up is defined by a given vector
+// Implemented from https://www.scratchapixel.com/lessons/3d-basic-rendering/global-illumination-path-tracing/global-illumination-path-tracing-practical-implementation
+// These methods assume y is up
+
+typedef struct {
+	vector_t *up;
+
+	// These are calculated from the given up vector
+	vector_t ax;
+	vector_t az;
+} csystem_t;
+
+// Inits the given csystem_t with a given up vector.
+// Will overwrite everything in cs
+void csystem_init(csystem_t *cs, vector_t *up);
+
+// Translates the inside coordinates to real and saves them in real.
+// Will overwrite real
+void csystem_calc_real(csystem_t *cs, vector_t *inside, vector_t *real);
+
+// Writes the inside coordinates of a random direction in the upper hemisphere, and saves in out
+// One must provide random numbers r1 and r2 between 0 and 1
+void csystem_hemisphere_random(csystem_t *cs, COORD_T r1, COORD_T r2, vector_t *out);
+
+#endif