3 files changed, 108 insertions, 57 deletions

diff --git a/gfx/include/gfx/util/skyquad.h b/gfx/include/gfx/util/skyquad.h
index 88c9c41..f792a13 100644
--- a/gfx/include/gfx/util/skyquad.h
+++ b/gfx/include/gfx/util/skyquad.h
@@ -1,10 +1,22 @@
 /// A skyquad is like a skybox but with a single quad.
 #pragma once
 
-typedef struct Gfx Gfx;
-typedef struct Scene Scene;
+typedef struct Gfx         Gfx;
+typedef struct Scene       Scene;
+typedef struct SceneNode   SceneNode;
 typedef struct SceneObject SceneObject;
-typedef struct Texture Texture;
+typedef struct Texture     Texture;
 
 /// Create a skyquad.
-SceneObject* gfx_make_skyquad(Gfx*, Scene*, const Texture*);
+SceneObject* gfx_make_skyquad(Gfx*, const Texture*);
+
+/// Set up a skyquad in the scene.
+///
+/// This function adds two scene nodes under the given root node:
+///   - An object node to render the skyquad in the background.
+///   - A light node to light up other objects with the skyquad.
+///
+/// Return the light node under which objects affected by the light can be
+/// rooted.
+SceneNode* gfx_setup_skyquad(
+    Gfx*, SceneNode* root, const Texture* environment_map);
diff --git a/gfx/src/util/skyquad.c b/gfx/src/util/skyquad.c
index 2461f8c..b59d7b9 100644
--- a/gfx/src/util/skyquad.c
+++ b/gfx/src/util/skyquad.c
@@ -2,8 +2,10 @@
 
 #include <gfx/gfx.h>
 #include <gfx/render_backend.h>
+#include <gfx/scene/light.h>
 #include <gfx/scene/material.h>
 #include <gfx/scene/mesh.h>
+#include <gfx/scene/node.h>
 #include <gfx/scene/object.h>
 #include <gfx/scene/scene.h>
 #include <gfx/util/geometry.h>
@@ -13,9 +15,8 @@
 
 #include <assert.h>
 
-SceneObject* gfx_make_skyquad(Gfx* gfx, Scene* scene, const Texture* texture) {
+SceneObject* gfx_make_skyquad(Gfx* gfx, const Texture* texture) {
   assert(gfx);
-  assert(scene);
   assert(texture);
 
   // TODO: pass RenderBackend directly?
@@ -84,3 +85,81 @@ cleanup:
   }
   return false;
 }
+
+/// Create an environment light node.
+static SceneNode* make_environment_light(
+    SceneNode* root, const Texture* environment_light) {
+  assert(root);
+
+  Light*     light      = 0;
+  SceneNode* light_node = 0;
+
+  light = gfx_make_light(&(LightDesc){
+      .type  = EnvironmentLightType,
+      .light = (EnvironmentLightDesc){.environment_map = environment_light}});
+  if (!light) {
+    goto cleanup;
+  }
+
+  light_node = gfx_make_light_node(light);
+  if (!light_node) {
+    goto cleanup;
+  }
+  gfx_set_node_parent(light_node, root);
+
+  return light_node;
+
+cleanup:
+  if (light) {
+    gfx_destroy_light(&light);
+  }
+  if (light_node) {
+    gfx_destroy_node(&light_node);
+  }
+  return 0;
+}
+
+SceneNode* gfx_setup_skyquad(
+    Gfx* gfx, SceneNode* root, const Texture* environment_map) {
+  assert(gfx);
+  assert(root);
+  assert(environment_map);
+
+  SceneObject* skyquad_object = 0;
+  SceneNode*   object_node    = 0;
+  SceneNode*   light_node     = 0;
+
+  // Create the skyquad object.
+  skyquad_object = gfx_make_skyquad(gfx, environment_map);
+  if (!skyquad_object) {
+    goto cleanup;
+  }
+
+  // Create an object node to render the skyquad in the background.
+  object_node = gfx_make_object_node(skyquad_object);
+  if (!object_node) {
+    goto cleanup;
+  }
+  gfx_set_node_parent(object_node, root);
+
+  // Create an environment light node under which to root objects affected by
+  // the skyquad.
+  light_node = make_environment_light(root, environment_map);
+  if (!light_node) {
+    goto cleanup;
+  }
+
+  return light_node;
+
+cleanup:
+  if (skyquad_object) {
+    gfx_destroy_object(&skyquad_object);
+  }
+  if (object_node) {
+    gfx_destroy_node(&object_node);
+  }
+  if (light_node) {
+    gfx_destroy_node(&light_node);
+  }
+  return 0;
+}
diff --git a/gltfview/src/game.c b/gltfview/src/game.c
index bd474d6..54e498b 100644
--- a/gltfview/src/game.c
+++ b/gltfview/src/game.c
@@ -55,7 +55,7 @@ static ShaderProgram* load_shader(
   return shader;
 }
 
-/// Loads the skyquad texture.
+/// Load the skyquad texture.
 static Texture* load_environment_map(RenderBackend* render_backend) {
   return gfx_load_texture(
       render_backend,
@@ -75,60 +75,20 @@ static Texture* load_environment_map(RenderBackend* render_backend) {
   });
 }
 
-/// Creates an object to render the skyquad in the background.
-static SceneNode* make_skyquad_object_node(
-    Game* game, const Texture* environment_map) {
+/// Load the skyquad and return the environment light node.
+static SceneNode* load_skyquad(Game* game) {
   assert(game);
 
-  SceneObject* skyquad_object =
-      gfx_make_skyquad(game->gfx, game->scene, environment_map);
-  if (!skyquad_object) {
-    return 0;
-  }
-  SceneNode* skyquad_node = gfx_make_object_node(skyquad_object);
-  if (!skyquad_node) {
-    return 0;
-  }
-  gfx_set_node_parent(skyquad_node, gfx_get_scene_root(game->scene));
-  return skyquad_node;
-}
-
-/// Creates an environment light.
-static SceneNode* make_environment_light(
-    Game* game, const Texture* environment_light) {
-  assert(game);
-
-  Light* light = gfx_make_light(&(LightDesc){
-      .type  = EnvironmentLightType,
-      .light = (EnvironmentLightDesc){.environment_map = environment_light}});
-  if (!light) {
-    return 0;
-  }
-  SceneNode* light_node = gfx_make_light_node(light);
-  if (!light_node) {
-    return 0;
-  }
-  gfx_set_node_parent(light_node, gfx_get_scene_root(game->scene));
-  return light_node;
-}
-
-/// Loads the skyquad and returns the SceneNode with the environment light.
-static bool load_skyquad(Game* game, SceneNode** node) {
-  assert(game);
-  assert(node);
-
   Texture* environment_map = load_environment_map(game->render_backend);
   if (!environment_map) {
-    return false;
+    return 0;
   }
 
-  make_skyquad_object_node(game, environment_map);
-  *node = make_environment_light(game, environment_map);
-
-  return true;
+  return gfx_setup_skyquad(
+      game->gfx, gfx_get_scene_root(game->scene), environment_map);
 }
 
-/// Loads the 3D scene.
+/// Load the 3D scene.
 static bool load_scene(
     Game* game, const char* scene_filepath, const char* view_mode) {
   assert(game);
@@ -143,8 +103,8 @@ static bool load_scene(
   // Damaged helmet.
   spatial3_set_position(&camera->spatial, vec3_make(0, 0, 2));
 
-  SceneNode* sky_node = 0;
-  if (!load_skyquad(game, &sky_node) || !sky_node) {
+  SceneNode* sky_light_node = load_skyquad(game);
+  if (!sky_light_node) {
     return false;
   }
 
@@ -155,7 +115,7 @@ static bool load_scene(
   // }
 
   if (!gfx_load_scene(
-          game->gfx, sky_node,
+          game->gfx, sky_light_node,
           &(LoadSceneCmd){
               .origin = SceneFromFile, .filepath = scene_filepath})) {
     return false;
@@ -164,7 +124,7 @@ static bool load_scene(
   return true;
 }
 
-/// Loads a scene for debugging textures.
+/// Load a scene for debugging textures.
 static bool load_texture_debugger_scene(Game* game) {
   assert(game);