Add lots of comments, and some code fixes discovered in the process.

13 files changed, 65 insertions, 39 deletions

diff --git a/libdimension/dimension/array.h b/libdimension/dimension/array.h
index d0693fc..0af4406 100644
--- a/libdimension/dimension/array.h
+++ b/libdimension/dimension/array.h
@@ -18,14 +18,14 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
-#ifndef DIMENSION_ARRAY_H
-#define DIMENSION_ARRAY_H
-
 /*
  * Simple thread-safe generalized arrays, for returning variable-length arrays
  * from functions, and other fun stuff.
  */
 
+#ifndef DIMENSION_ARRAY_H
+#define DIMENSION_ARRAY_H
+
 #include <pthread.h> /* For pthread_rwlock_t */
 #include <stdlib.h>  /* For size_t */
 
@@ -37,24 +37,26 @@ typedef struct {
   pthread_rwlock_t *rwlock;
 } dmnsn_array;
 
+/* Array allocation never returns NULL - if dmnsn_new_array, it succeeded */
 dmnsn_array *dmnsn_new_array(size_t obj_size);
 void dmnsn_delete_array(dmnsn_array *array);
 
+/* Thread-safe atomic array access */
+
 void dmnsn_array_push(dmnsn_array *array, const void *obj);
 void dmnsn_array_pop(dmnsn_array *array, void *obj);
-
 void dmnsn_array_get(const dmnsn_array *array, size_t i, void *obj);
 void dmnsn_array_set(dmnsn_array *array, size_t i, const void *obj);
 
 size_t dmnsn_array_size(const dmnsn_array *array);
 void   dmnsn_array_resize(dmnsn_array *array, size_t length);
 
-/* Manual locking */
-
+/* Non-atomic operations for manual locking */
 void *dmnsn_array_at(dmnsn_array *array, size_t i);
 size_t dmnsn_array_size_unlocked(const dmnsn_array *array);
 void dmnsn_array_resize_unlocked(dmnsn_array *array, size_t length);
 
+/* Manual locking */
 void dmnsn_array_rdlock(const dmnsn_array *array);
 void dmnsn_array_wrlock(dmnsn_array *array);
 void dmnsn_array_unlock(const dmnsn_array *array);
diff --git a/libdimension/dimension/camera.h b/libdimension/dimension/camera.h
index 95b36fa..9b06359 100644
--- a/libdimension/dimension/camera.h
+++ b/libdimension/dimension/camera.h
@@ -18,13 +18,13 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
-#ifndef DIMENSION_CAMERA_H
-#define DIMENSION_CAMERA_H
-
 /*
  * A camera.
  */
 
+#ifndef DIMENSION_CAMERA_H
+#define DIMENSION_CAMERA_H
+
 /* Forward-declare dmnsn_camera */
 typedef struct dmnsn_camera dmnsn_camera;
 
@@ -47,7 +47,6 @@ void dmnsn_delete_camera(dmnsn_camera *camera);
 /* A perspective camera, at the origin, looking at (0, 0, 1).  The feild of view
    is the section of the plane z = 1 from (-0.5, -0.5) to (0.5, 0.5).  Rays are
    transformed by the transformation matrix `trans'. */
-
 dmnsn_camera *dmnsn_new_perspective_camera(dmnsn_matrix trans);
 void dmnsn_delete_perspective_camera(dmnsn_camera *camera);
 
diff --git a/libdimension/dimension/canvas.h b/libdimension/dimension/canvas.h
index f05264b..50cc612 100644
--- a/libdimension/dimension/canvas.h
+++ b/libdimension/dimension/canvas.h
@@ -18,14 +18,15 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+/*
+ * A canvas which is rendered to.
+ */
+
 #ifndef DIMENSION_CANVAS_H
 #define DIMENSION_CANVAS_H
 
 #include <pthread.h>
 
-/*
- * A canvas which is rendered to.
- */
 typedef struct {
   unsigned int x, y;
 
diff --git a/libdimension/dimension/color.h b/libdimension/dimension/color.h
index ab6efa3..f1964c3 100644
--- a/libdimension/dimension/color.h
+++ b/libdimension/dimension/color.h
@@ -18,13 +18,13 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
-#ifndef DIMENSION_COLOR_H
-#define DIMENSION_COLOR_H
-
 /*
  * Types to represent color.
  */
 
+#ifndef DIMENSION_COLOR_H
+#define DIMENSION_COLOR_H
+
 /* Internally, we use CIE 1931 XYZ color. */
 typedef struct {
   double X, Y, Z;
diff --git a/libdimension/dimension/cube.h b/libdimension/dimension/cube.h
index e7f2b90..e55ec74 100644
--- a/libdimension/dimension/cube.h
+++ b/libdimension/dimension/cube.h
@@ -18,13 +18,13 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
-#ifndef DIMENSION_CUBE_H
-#define DIMENSION_CUBE_H
-
 /*
  * A cube, axis-aligned, from (-1, -1, -1) to (1, 1, 1)
  */
 
+#ifndef DIMENSION_CUBE_H
+#define DIMENSION_CUBE_H
+
 dmnsn_object *dmnsn_new_cube();
 void dmnsn_delete_cube(dmnsn_object *cube);
 
diff --git a/libdimension/dimension/error.h b/libdimension/dimension/error.h
index 3204cb2..cd7dd81 100644
--- a/libdimension/dimension/error.h
+++ b/libdimension/dimension/error.h
@@ -18,23 +18,26 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
-#ifndef DIMENSION_ERROR_H
-#define DIMENSION_ERROR_H
-
 /*
- * Error handling.
+ * Error handling.  Errors are reported at a given severity by the dmnsn_error()
+ * macro at a given severity, which prints a warning if it is below the set
+ * resilience, or prints an error and exits if it's at or above the set
+ * resilience.
  */
 
+#ifndef DIMENSION_ERROR_H
+#define DIMENSION_ERROR_H
+
 typedef enum {
   DMNSN_SEVERITY_LOW,    /* Only die on low resilience */
   DMNSN_SEVERITY_MEDIUM, /* Die on low or medium resilience */
   DMNSN_SEVERITY_HIGH    /* Always die */
 } dmnsn_severity;
 
-/* Use this to report an error */
-#define dmnsn_error(severity, str)                                            \
-  dmnsn_report_error((dmnsn_severity)severity, __PRETTY_FUNCTION__, __LINE__, \
-                     str)
+/* Use this macro to report an error */
+#define dmnsn_error(severity, str)                                             \
+  dmnsn_report_error((dmnsn_severity)(severity), __PRETTY_FUNCTION__, __LINE__,\
+                     (str))
 
 /* Called by dmnsn_error() - don't call directly */
 void dmnsn_report_error(dmnsn_severity severity,
diff --git a/libdimension/dimension/geometry.h b/libdimension/dimension/geometry.h
index 95692c6..c635fd9 100644
--- a/libdimension/dimension/geometry.h
+++ b/libdimension/dimension/geometry.h
@@ -19,7 +19,7 @@
  *************************************************************************/
 
 /*
- * Core geometric types like scalars, vectors, and rays.
+ * Core geometric types like vectors, matricies, and rays.
  */
 
 #ifndef DIMENSION_GEOMETRY_H
@@ -73,6 +73,6 @@ dmnsn_line   dmnsn_matrix_line_mul(dmnsn_matrix lhs, dmnsn_line rhs);
 /* A point on a line, defined by x0 + t*n */
 dmnsn_vector dmnsn_line_point(dmnsn_line l, double t);
 /* Solve for the t value such that x0 + t*n = x */
-double       dmnsn_line_index(dmnsn_line l, dmnsn_vector x);
+double dmnsn_line_index(dmnsn_line l, dmnsn_vector x);
 
 #endif /* DIMENSION_GEOMETRY_H */
diff --git a/libdimension/dimension/object.h b/libdimension/dimension/object.h
index 589ac29..d18f426 100644
--- a/libdimension/dimension/object.h
+++ b/libdimension/dimension/object.h
@@ -18,13 +18,13 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
-#ifndef DIMENSION_OBJECT_H
-#define DIMENSION_OBJECT_H
-
 /*
  * Objects.
  */
 
+#ifndef DIMENSION_OBJECT_H
+#define DIMENSION_OBJECT_H
+
 /* Forward-declare dmnsn_object */
 typedef struct dmnsn_object dmnsn_object;
 
@@ -46,6 +46,7 @@ struct dmnsn_object {
   dmnsn_object_inside_fn        *inside_fn;
 };
 
+/* Allocate a dummy object */
 dmnsn_object *dmnsn_new_object();
 void dmnsn_delete_object(dmnsn_object *object);
 
diff --git a/libdimension/dimension/png.h b/libdimension/dimension/png.h
index 05ff79a..858f79f 100644
--- a/libdimension/dimension/png.h
+++ b/libdimension/dimension/png.h
@@ -18,6 +18,10 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+/*
+ * Support for exporting/importing canvases to/from PNG files
+ */
+
 #ifndef DIMENSION_PNG_H
 #define DIMENSION_PNG_H
 
diff --git a/libdimension/dimension/progress.h b/libdimension/dimension/progress.h
index a865c8f..7958ab9 100644
--- a/libdimension/dimension/progress.h
+++ b/libdimension/dimension/progress.h
@@ -18,6 +18,13 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+/*
+ * An interface for asynchronous tasks.  *_async() versions of functions
+ * return a dmnsn_progress* object which can indicate the progress of the
+ * background task, and wait for task completion.  The task's return value
+ * is returned as an int from dmnsn_finish_progress().
+ */
+
 #ifndef DIMENSION_PROGRESS_H
 #define DIMENSION_PROGRESS_H
 
@@ -43,6 +50,7 @@ typedef struct {
 } dmnsn_progress;
 
 dmnsn_progress *dmnsn_new_progress();
+/* For failed returns from *_async() functions */
 void dmnsn_delete_progress(dmnsn_progress *progress);
 
 /* This joins the worker thread and returns it's integer return value in
@@ -50,10 +58,14 @@ void dmnsn_delete_progress(dmnsn_progress *progress);
 int dmnsn_finish_progress(dmnsn_progress *progress);
 
 double dmnsn_get_progress(const dmnsn_progress *progress);
+/* Wait for the progress to be >= prog, in a better way than spinlocking */
 void dmnsn_wait_progress(const dmnsn_progress *progress, double prog);
 
+/* Create a new level of loop nesting */
 void dmnsn_new_progress_element(dmnsn_progress *progress, unsigned int total);
+/* Increment the progress counter; should only be called from innermost loop */
 void dmnsn_increment_progress(dmnsn_progress *progress);
-void dmnsn_progress_done(dmnsn_progress *progress);
+/* Instantly complete the progress */
+void dmnsn_done_progress(dmnsn_progress *progress);
 
 #endif /* DIMENSION_PROGRESS_H */
diff --git a/libdimension/dimension/raytrace.h b/libdimension/dimension/raytrace.h
index a69bb72..b58a39b 100644
--- a/libdimension/dimension/raytrace.h
+++ b/libdimension/dimension/raytrace.h
@@ -18,6 +18,10 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+/*
+ * Render a scene by raytracing
+ */
+
 #ifndef DIMENSION_RAYTRACE_H
 #define DIMENSION_RAYTRACE_H
 
diff --git a/libdimension/dimension/scene.h b/libdimension/dimension/scene.h
index a6f2e5d..35087a7 100644
--- a/libdimension/dimension/scene.h
+++ b/libdimension/dimension/scene.h
@@ -18,13 +18,13 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
-#ifndef DIMENSION_SCENE_H
-#define DIMENSION_SCENE_H
-
 /*
  * A scene.
  */
 
+#ifndef DIMENSION_SCENE_H
+#define DIMENSION_SCENE_H
+
 typedef struct {
   dmnsn_color background;
   dmnsn_array *objects;
diff --git a/libdimension/dimension/sphere.h b/libdimension/dimension/sphere.h
index 2547965..d7a8f54 100644
--- a/libdimension/dimension/sphere.h
+++ b/libdimension/dimension/sphere.h
@@ -18,13 +18,13 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
-#ifndef DIMENSION_SPHERE_H
-#define DIMENSION_SPHERE_H
-
 /*
  * A sphere object, of radius 1, centered at the origin.
  */
 
+#ifndef DIMENSION_SPHERE_H
+#define DIMENSION_SPHERE_H
+
 dmnsn_object *dmnsn_new_sphere();
 void dmnsn_delete_sphere(dmnsn_object *sphere);