Implement sky spheres.

9 files changed, 199 insertions, 24 deletions

diff --git a/libdimension/Makefile.am b/libdimension/Makefile.am
index 542e684..86caa57 100644
--- a/libdimension/Makefile.am
+++ b/libdimension/Makefile.am
@@ -47,6 +47,7 @@ nobase_include_HEADERS = dimension.h                                           \
                          dimension/progress.h                                  \
                          dimension/raytrace.h                                  \
                          dimension/scene.h                                     \
+                         dimension/sky_sphere.h                                \
                          dimension/texture.h                                   \
                          dimension/timer.h
 
@@ -90,6 +91,7 @@ libdimension_la_SOURCES = $(nobase_include_HEADERS)                            \
                           raytrace.c                                           \
                           reflective.c                                         \
                           scene.c                                              \
+                          sky_sphere.c                                         \
                           solid_pigment.c                                      \
                           sphere.c                                             \
                           texture.c                                            \
diff --git a/libdimension/color.c b/libdimension/color.c
index e91ebc1..6d2078f 100644
--- a/libdimension/color.c
+++ b/libdimension/color.c
@@ -46,6 +46,13 @@ const dmnsn_color dmnsn_white = {
   .filter = 0.0,
   .trans  = 0.0
 };
+const dmnsn_color dmnsn_clear = {
+  .R = 0.0,
+  .G = 0.0,
+  .B = 0.0,
+  .filter = 0.0,
+  .trans  = 1.0
+};
 const dmnsn_color dmnsn_red = {
   .R = 1.0,
   .G = 0.0,
diff --git a/libdimension/dimension.h b/libdimension/dimension.h
index 55b3b87..d4ce61e 100644
--- a/libdimension/dimension.h
+++ b/libdimension/dimension.h
@@ -79,6 +79,7 @@ typedef void dmnsn_free_fn(void *ptr);
 #include <dimension/lights.h>
 #include <dimension/camera.h>
 #include <dimension/cameras.h>
+#include <dimension/sky_sphere.h>
 #include <dimension/scene.h>
 #include <dimension/raytrace.h>
 
diff --git a/libdimension/dimension/color.h b/libdimension/dimension/color.h
index 26ab4bb..e214b66 100644
--- a/libdimension/dimension/color.h
+++ b/libdimension/dimension/color.h
@@ -79,6 +79,7 @@ typedef struct {
 /* Standard colors */
 extern const dmnsn_color dmnsn_black;   /**< Black.   */
 extern const dmnsn_color dmnsn_white;   /**< White.   */
+extern const dmnsn_color dmnsn_clear;   /**< Clear.   */
 extern const dmnsn_color dmnsn_red;     /**< Red.     */
 extern const dmnsn_color dmnsn_green;   /**< Green.   */
 extern const dmnsn_color dmnsn_blue;    /**< Blue.    */
diff --git a/libdimension/dimension/scene.h b/libdimension/dimension/scene.h
index 489e4e5..0889359 100644
--- a/libdimension/dimension/scene.h
+++ b/libdimension/dimension/scene.h
@@ -45,6 +45,7 @@ typedef struct dmnsn_scene {
   /* World attributes */
   dmnsn_color background;         /**< Background color. */
   dmnsn_color ambient;            /**< Global ambient color. */
+  dmnsn_sky_sphere *sky_sphere;   /**< Sky sphere. */
   dmnsn_texture *default_texture; /**< Default object texture. */
 
   /** Camera. */
@@ -85,4 +86,10 @@ dmnsn_scene *dmnsn_new_scene(void);
  */
 void dmnsn_delete_scene(dmnsn_scene *scene);
 
+/**
+ * Initialize a scene.
+ * @param[in,out] scene  The scene to initalize.
+ */
+void dmnsn_scene_init(dmnsn_scene *scene);
+
 #endif /* DIMENSION_SCENE_H */
diff --git a/libdimension/dimension/sky_sphere.h b/libdimension/dimension/sky_sphere.h
new file mode 100644
index 0000000..5edacb0
--- /dev/null
+++ b/libdimension/dimension/sky_sphere.h
@@ -0,0 +1,63 @@
+/*************************************************************************
+ * Copyright (C) 2010 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+/**
+ * @file
+ * Sky spheres.
+ */
+
+#ifndef DIMENSION_SKY_SPHERE_H
+#define DIMENSION_SKY_SPHERE_H
+
+/** A sky sphere. */
+typedef struct dmnsn_sky_sphere {
+  /** An array of pigments in inside-to-outside order. */
+  dmnsn_array *pigments;
+  dmnsn_matrix trans;
+} dmnsn_sky_sphere;
+
+/**
+ * Create a sky sphere.
+ * @return A new blank sky sphere.
+ */
+dmnsn_sky_sphere *dmnsn_new_sky_sphere();
+
+/**
+ * Delete a sky sphere.
+ * @param[in,out] sky_sphere  The sky sphere to delete.
+ */
+void dmnsn_delete_sky_sphere(dmnsn_sky_sphere *sky_sphere);
+
+/**
+ * Initialize a sky sphere.
+ * @param[in,out] sky_sphere  The sky sphere to initialize.
+ */
+void dmnsn_sky_sphere_init(dmnsn_sky_sphere *sky_sphere);
+
+/**
+ * Evaluate the color of the sky sphere.
+ * @param[in] sky_sphere  The sky sphere to evaluate.
+ * @param[in] d           The direction to look.
+ * @return The color of the sky in the direction of \p d.
+ */
+dmnsn_color dmnsn_sky_sphere_color(const dmnsn_sky_sphere *sky_sphere,
+                                   dmnsn_vector d);
+
+#endif /* DIMENSION_SKY_SPHERE_H */
diff --git a/libdimension/raytrace.c b/libdimension/raytrace.c
index e6596e4..3534331 100644
--- a/libdimension/raytrace.c
+++ b/libdimension/raytrace.c
@@ -77,13 +77,11 @@ dmnsn_raytrace_scene_thread(void *ptr)
 {
   dmnsn_raytrace_payload *payload = ptr;
 
+  /* Pre-calculate bounding box transformations, etc. */
+  dmnsn_scene_init(payload->scene);
+
   /* Time the bounding tree construction */
   payload->scene->bounding_timer = dmnsn_new_timer();
-    /* Pre-calculate bounding box transformations, etc. */
-    DMNSN_ARRAY_FOREACH (dmnsn_object **, object, payload->scene->objects) {
-      dmnsn_object_init(*object);
-    }
-
     payload->prtree = dmnsn_new_prtree(payload->scene->objects);
   dmnsn_complete_timer(payload->scene->bounding_timer);
 
@@ -210,21 +208,16 @@ dmnsn_raytrace_scene_impl(dmnsn_progress *progress, dmnsn_scene *scene,
   /* Iterate through each pixel */
   for (size_t y = index; y < scene->canvas->height; y += threads) {
     for (size_t x = 0; x < scene->canvas->width; ++x) {
-      /* Set the pixel to the background color */
-      dmnsn_color color = scene->background;
-
-      if (scene->quality) {
-        /* Get the ray corresponding to the (x,y)'th pixel */
-        dmnsn_line ray = dmnsn_camera_ray(
-          scene->camera,
-          ((double)x)/(scene->canvas->width - 1),
-          ((double)y)/(scene->canvas->height - 1)
-        );
+      /* Get the ray corresponding to the (x,y)'th pixel */
+      dmnsn_line ray = dmnsn_camera_ray(
+        scene->camera,
+        ((double)x)/(scene->canvas->width - 1),
+        ((double)y)/(scene->canvas->height - 1)
+      );
 
-        /* Shoot a ray */
-        state.reclevel = scene->reclimit;
-        color = dmnsn_raytrace_shoot(&state, ray);
-      }
+      /* Shoot a ray */
+      state.reclevel = scene->reclimit;
+      dmnsn_color color = dmnsn_raytrace_shoot(&state, ray);
 
       dmnsn_set_pixel(scene->canvas, x, y, color);
     }
@@ -272,6 +265,22 @@ dmnsn_raytrace_scene_impl(dmnsn_progress *progress, dmnsn_scene *scene,
    ? (state)->intersection->interior->ior       \
    : 1.0)
 
+/** Calculate the background color. */
+static dmnsn_color
+dmnsn_raytrace_background(dmnsn_raytrace_state *state, dmnsn_line ray)
+{
+  dmnsn_color color = state->scene->background;
+  if (state->scene->sky_sphere
+      && (state->scene->quality & DMNSN_RENDER_PIGMENT))
+  {
+    dmnsn_color sky = dmnsn_sky_sphere_color(state->scene->sky_sphere,
+                                             dmnsn_vector_normalize(ray.n));
+    color = dmnsn_color_add(dmnsn_color_filter(color, sky), sky);
+  }
+
+  return color;
+}
+
 /** Calculate the base pigment at the intersection. */
 static void
 dmnsn_raytrace_pigment(dmnsn_raytrace_state *state)
@@ -465,12 +474,11 @@ dmnsn_raytrace_shoot(dmnsn_raytrace_state *state, dmnsn_line ray)
     return dmnsn_black;
   --state->reclevel;
 
-  dmnsn_intersection intersection;
-  bool intersected
-    = dmnsn_prtree_intersection(state->prtree, ray, &intersection);
+  /* Calculate the background color */
+  dmnsn_color color = dmnsn_raytrace_background(state, ray);
 
-  dmnsn_color color = state->scene->background;
-  if (intersected) {
+  dmnsn_intersection intersection;
+  if (dmnsn_prtree_intersection(state->prtree, ray, &intersection)) {
     state->intersection = &intersection;
     state->r = dmnsn_line_point(state->intersection->ray,
                                 state->intersection->t);
diff --git a/libdimension/scene.c b/libdimension/scene.c
index 9eca7b7..c43a93a 100644
--- a/libdimension/scene.c
+++ b/libdimension/scene.c
@@ -34,6 +34,7 @@ dmnsn_new_scene()
 
   scene->background      = dmnsn_black;
   scene->ambient         = dmnsn_white;
+  scene->sky_sphere      = NULL;
   scene->default_texture = dmnsn_new_texture();
   scene->camera          = NULL;
   scene->canvas          = NULL;
@@ -68,6 +69,19 @@ dmnsn_delete_scene(dmnsn_scene *scene)
     dmnsn_delete_canvas(scene->canvas);
     dmnsn_delete_camera(scene->camera);
     dmnsn_delete_texture(scene->default_texture);
+    dmnsn_delete_sky_sphere(scene->sky_sphere);
     dmnsn_free(scene);
   }
 }
+
+void
+dmnsn_scene_init(dmnsn_scene *scene)
+{
+  if (scene->sky_sphere) {
+    dmnsn_sky_sphere_init(scene->sky_sphere);
+  }
+
+  DMNSN_ARRAY_FOREACH (dmnsn_object **, object, scene->objects) {
+    dmnsn_object_init(*object);
+  }
+}
diff --git a/libdimension/sky_sphere.c b/libdimension/sky_sphere.c
new file mode 100644
index 0000000..bb38c16
--- /dev/null
+++ b/libdimension/sky_sphere.c
@@ -0,0 +1,72 @@
+/*************************************************************************
+ * Copyright (C) 2009-2010 Tavian Barnes <tavianator@gmail.com>          *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+/**
+ * @file
+ * Sky spheres.
+ */
+
+#include "dimension.h"
+
+dmnsn_sky_sphere *
+dmnsn_new_sky_sphere()
+{
+  dmnsn_sky_sphere *sky_sphere = dmnsn_malloc(sizeof(dmnsn_sky_sphere));
+  sky_sphere->pigments = dmnsn_new_array(sizeof(dmnsn_pigment *));
+  sky_sphere->trans = dmnsn_identity_matrix();
+  return sky_sphere;
+}
+
+void
+dmnsn_delete_sky_sphere(dmnsn_sky_sphere *sky_sphere)
+{
+  if (sky_sphere) {
+    DMNSN_ARRAY_FOREACH (dmnsn_pigment **, pigment, sky_sphere->pigments) {
+      dmnsn_delete_pigment(*pigment);
+    }
+    dmnsn_free(sky_sphere);
+  }
+}
+
+void
+dmnsn_sky_sphere_init(dmnsn_sky_sphere *sky_sphere)
+{
+  DMNSN_ARRAY_FOREACH (dmnsn_pigment **, pigment, sky_sphere->pigments) {
+    (*pigment)->trans = dmnsn_matrix_mul(sky_sphere->trans, (*pigment)->trans);
+    dmnsn_pigment_init(*pigment);
+  }
+}
+
+dmnsn_color
+dmnsn_sky_sphere_color(const dmnsn_sky_sphere *sky_sphere, dmnsn_vector d)
+{
+  dmnsn_color color = dmnsn_black;
+  color.trans = 1.0;
+
+  DMNSN_ARRAY_FOREACH (const dmnsn_pigment **, pigment, sky_sphere->pigments) {
+    dmnsn_pigment_fn *pigment_fn = (*pigment)->pigment_fn;
+    if (pigment_fn) {
+      dmnsn_color sky = (*pigment_fn)(*pigment, d);
+      color = dmnsn_color_add(dmnsn_color_filter(color, sky), sky);
+    }
+  }
+
+  return color;
+}