Use cone rotation, not point of base, for vectors

2 files changed, 24 insertions, 16 deletions

diff --git a/include/xas/spatial.h b/include/xas/spatial.h
index 6ad2675..db04ceb 100644
--- a/include/xas/spatial.h
+++ b/include/xas/spatial.h
@@ -14,7 +14,7 @@ typedef struct _xas_spatial_coord {
 
 typedef struct _xas_spatial_cone {
     xas_spatial_coord apex,
-                        base;
+                        rotation;
 
     float angle;
 } xas_spatial_cone;
diff --git a/src/spatial.c b/src/spatial.c
index 9885418..654ef0b 100644
--- a/src/spatial.c
+++ b/src/spatial.c
@@ -78,15 +78,23 @@ static void rotate(xas_spatial_coord rotation,
 
 static int within_cone(xas_spatial_coord coord,
                        xas_spatial_cone cone) {
-    xas_spatial_coord apex_to_x_vect,
-                        axis_vect;
-
-    diff(&apex_to_x_vect, cone.apex, coord);
-    diff(&axis_vect,      cone.apex, cone.base);
-
-    return dotf(apex_to_x_vect, axis_vect)
-         / magnf(apex_to_x_vect)
-         / magnf(axis_vect) > cosf(cone.angle / 2.0f);
+    xas_spatial_coord apex_to_point_vect,
+                        axis_vect,
+                        rotated  = cone.apex,
+                        opposite = {
+                            .x = cone.rotation.x * -2.0f,
+                            .y = cone.rotation.y * -2.0f,
+                            .z = cone.rotation.z * -2.0f
+                        };
+
+    rotate(opposite, &rotated);
+
+    diff(&apex_to_point_vect, cone.apex, coord);
+    diff(&axis_vect,          cone.apex, rotated);
+
+    return dotf(apex_to_point_vect, axis_vect)
+         / magnf(apex_to_point_vect)
+         / magnf(axis_vect) <= cosf(cone.angle / 2.0f);
 }
 
 static int buffer_realloc(xas_spatial_scene *scene,
@@ -178,13 +186,13 @@ ssize_t scene_fill(xas_spatial_scene *scene,
     int16_t *dest = (int16_t *)(scene->buffer + 1);
 
     xas_spatial_cone cone_l = {
-        .apex  = scene->speaker_l,
-        .base  = { scene->speaker_l.x - 20.0f, scene->speaker_l.y, scene->speaker_l.z },
-        .angle = M_PI / 4.0f
+        .apex     = scene->speaker_l,
+        .rotation = { 0.0f, M_PI * 1.5f, 0.0f },
+        .angle    = M_PI / 4.0f
     }, cone_r = {
-        .apex  = scene->speaker_r,
-        .base  = { scene->speaker_r.x + 20.0f, scene->speaker_r.y, scene->speaker_r.z },
-        .angle = M_PI / 4.0f
+        .apex     = scene->speaker_r,
+        .rotation = { 0.0f, M_PI * 0.5f, 0.0f },
+        .angle    = M_PI / 4.0f
     };
 
     buffer_zero(buffer, count);