ray: introduce a rudimentary ray tracer

My first ray tracer, it only has spheres, planes, and point light sources.

No texture mapping, no soft shadows, no global illumination.

This is all very basic right now, the camera movement is simple and boring, but
sufficient for further development and optimization.

I made some effort to support multiple CPUs, it should detect the number of
CPUs in the system and use enough pthreads to keep them busy.

Jacco Bikker's tutorial on flipcode was the original impetus to do this, and
definitely served as a guide early on.

1 files changed, 45 insertions, 0 deletions

diff --git a/modules/ray/ray_euler.h b/modules/ray/ray_euler.h
new file mode 100644
index 0000000..86f5221
--- /dev/null
+++ b/modules/ray/ray_euler.h
@@ -0,0 +1,45 @@
+#ifndef _RAY_EULER_H
+#define _RAY_EULER_H
+
+#include <math.h>
+
+#include "ray_3f.h"
+
+
+/* euler angles are convenient for describing orientation */
+typedef struct ray_euler_t {
+	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))
+
+
+/* produce basis vectors from euler angles */
+static inline void ray_euler_basis(ray_euler_t *e, ray_3f_t *forward, ray_3f_t *up, ray_3f_t *left)
+{
+	float	cos_yaw = cosf(e->yaw);
+	float	sin_yaw = sinf(e->yaw);
+	float	cos_roll = cosf(e->roll);
+	float	sin_roll = sinf(e->roll);
+	float	cos_pitch = cosf(e->pitch);
+	float	sin_pitch = sinf(e->pitch);
+
+	forward->x = sin_yaw;
+	forward->y = -sin_pitch * cos_yaw;
+	forward->z = cos_pitch * cos_yaw;
+
+	up->x = -cos_yaw * sin_roll;
+	up->y = -sin_pitch * sin_yaw * sin_roll + cos_pitch * cos_roll;
+	up->z = cos_pitch * sin_yaw * sin_roll + sin_pitch * cos_roll;
+
+	left->x = cos_yaw * cos_roll;
+	left->y = sin_pitch * sin_yaw * cos_roll + cos_pitch * sin_roll;
+	left->z = -cos_pitch * sin_yaw * cos_roll + sin_pitch * sin_roll;
+}
+
+#endif