This is the O3D source tree's initial commit to the Chromium tree. It

is not built or referenced at all by the chrome build yet, and doesn't 
yet build in it's new home.  We'll change that shortly.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@17035 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 123 insertions, 0 deletions

diff --git a/o3d/samples/io/dynamic_lights.js b/o3d/samples/io/dynamic_lights.js
new file mode 100644
index 0000000..9a5b1f9
--- /dev/null
+++ b/o3d/samples/io/dynamic_lights.js
@@ -0,0 +1,123 @@
+/*
+ * Copyright 2009, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+/**
+ * @fileoverview  Manage all the dynamic lights in a level.
+ */
+
+
+var s_light_array = new Array();
+var s_number_of_lights_in_scene = 0;
+
+var s_number_of_lights_in_program = 0;
+var s_light_parameter_array = new Array();
+
+// Call this before any UpdateLightsInProgram.
+function InitializeLightParameters(context, number_of_lights) {
+  s_number_of_lights_in_program = number_of_lights;
+  for (var l = 0; l < number_of_lights; ++l) {
+    s_light_parameter_array[l] = {};
+    s_light_parameter_array[l].location = context.createParam(
+        'light' + l + '_location', 'ParamFloat3');
+    s_light_parameter_array[l].location.value = [0, 0, 0];
+
+    // For the light, the final color parameter is the attentuation.
+    s_light_parameter_array[l].color = context.createParam(
+        'light' + l + '_color', 'ParamFloat4');
+    s_light_parameter_array[l].color.value = [0, 0, 0, 1];
+  }
+}
+
+// Returns the index of the new light for future manipulation.
+// World location and color should be arrays.
+// These will be assigned to Param objects.
+function AddLight(world_location, color) {
+  var light_index = s_number_of_lights_in_scene++;
+  s_light_array[light_index] = {};
+  s_light_array[light_index].location = world_location;
+  s_light_array[light_index].color = color;
+  return light_index;
+}
+
+// Sets the shader parameters to render using the closest lights
+// to the 'focus' (whatever's passed in).
+// |focus_location| must provide .x, .y, and .z for determining the
+//                  distance to each light.
+function UpdateLightsInProgram(focus_location) {
+  // TODO: Modulate the lights' color / add behaviors for the lights.
+  var lights_to_render = new Array();
+  for (var i = 0; i < s_number_of_lights_in_program; ++i) {
+    lights_to_render[i] = {};
+    lights_to_render[i].distance = 10000000000000.0; // Arbitrary large number.
+    lights_to_render[i].index = -1;
+  }
+  var number_of_lights = s_number_of_lights_in_scene;
+  for (var l = 0; l < number_of_lights; ++l) {
+    var x_diff = s_light_array[l].location.x - focus_location.x;
+    var y_diff = s_light_array[l].location.y - focus_location.y;
+    // TODO: This should be focus_location.z, but the avatar's location that is
+    // passed in is offset from the world coordinates.  For our relatively flat
+    // levels, this works more predictably.
+    var z_diff = s_light_array[l].location.z - 0;
+    var distance_to_focus = x_diff * x_diff + y_diff * y_diff + z_diff * z_diff;
+    // This may change if we assign to an entry early in the list.
+    var index_to_assign = l;
+    for (var i = 0; i < s_number_of_lights_in_program; ++i) {
+      if (distance_to_focus < lights_to_render[i].distance) {
+        // Swap the index into this entry.  We will percolate the
+        // light up.
+        var replaced_index = lights_to_render[i].index;
+        lights_to_render[i].index = index_to_assign;
+        index_to_assign = replaced_index;
+
+        var replaced_distance = lights_to_render[i].distance;
+        lights_to_render[i].distance = distance_to_focus;
+        distance_to_focus = replaced_distance;
+      }
+      if (index_to_assign < 0) {
+        break;
+      }
+    }
+  }
+
+  // Finally, assign to the actual shader parameters.
+  for (var i = 0; i < s_number_of_lights_in_program; ++i) {
+    var light_index = lights_to_render[i].index;
+    if (light_index >= 0) {
+      s_light_parameter_array[i].location.value =
+          s_light_array[light_index].location;
+      s_light_parameter_array[i].color.value =
+          s_light_array[light_index].color;
+    }
+  }
+}
+