ray: libize raytracer core, introduces src/libs

This is the first step of breaking out all the core rendering stuffs
into reusable libraries and making modules purely compositional,
consumers of various included rendering/effects libraries.

Expect multiple modules leveraging libray for a variety of scenes and
such.  Also expect compositions mixing the various libraries for more
interesting visuals.

1 files changed, 33 insertions, 0 deletions

diff --git a/src/libs/ray/ray_euler.h b/src/libs/ray/ray_euler.h
new file mode 100644
index 0000000..39da17e
--- /dev/null
+++ b/src/libs/ray/ray_euler.h
@@ -0,0 +1,33 @@
+#ifndef _RAY_EULER_H
+#define _RAY_EULER_H
+
+#include <math.h>
+
+#include "ray_3f.h"
+
+/* Desired order to apply euler angle rotations */
+typedef enum ray_euler_order_t {
+	RAY_EULER_ORDER_PYR,
+	RAY_EULER_ORDER_YRP,
+	RAY_EULER_ORDER_RPY,
+	RAY_EULER_ORDER_PRY,
+	RAY_EULER_ORDER_RYP,
+	RAY_EULER_ORDER_YPR,
+} ray_euler_order_t;
+
+/* euler angles are convenient for describing orientation */
+typedef struct ray_euler_t {
+	ray_euler_order_t	order;	/* order to apply rotations in */
+	float			pitch;	/* pitch in radiasn */
+	float			yaw;	/* yaw in radians */
+	float			roll;	/* roll in radians */
+} ray_euler_t;
+
+
+/* convenience macro for converting degrees to radians */
+#define RAY_EULER_DEGREES(_deg) \
+	(_deg * (2 * M_PI / 360.0f))
+
+void ray_euler_basis(const ray_euler_t *e, ray_3f_t *forward, ray_3f_t *up, ray_3f_t *left);
+
+#endif