From c73757f740b5accc961723d2de6d741d0d68074c Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Fri, 3 Jun 2016 09:17:44 -0700
Subject: [PATCH] use many colors for collision hull rendering

---
 libraries/render-utils/src/Model.cpp | 50 ++++++++++++++++++++++++----
 1 file changed, 43 insertions(+), 7 deletions(-)

diff --git a/libraries/render-utils/src/Model.cpp b/libraries/render-utils/src/Model.cpp
index 8011b0c4c8..ded1184c24 100644
--- a/libraries/render-utils/src/Model.cpp
+++ b/libraries/render-utils/src/Model.cpp
@@ -35,7 +35,46 @@ int vec3VectorTypeId = qRegisterMetaType<QVector<glm::vec3> >();
 float Model::FAKE_DIMENSION_PLACEHOLDER = -1.0f;
 #define HTTP_INVALID_COM "http://invalid.com"
 
-model::MaterialPointer Model::_collisionHullMaterial;
+const int NUM_COLLISION_HULL_COLORS = 24;
+std::vector<model::MaterialPointer> _collisionHullMaterials;
+
+void initCollisionHullMaterials() {
+    // generates bright colors in red, green, blue, yellow, magenta, and cyan spectrums
+    // (no browns, greys, or dark shades)
+    float component[NUM_COLLISION_HULL_COLORS] = {
+        0.0f, 0.0f, 0.0f, 0.0f,
+        0.0f, 0.0f, 0.0f, 0.0f,
+        0.2f, 0.4f, 0.6f, 0.8f,
+        1.0f, 1.0f, 1.0f, 1.0f,
+        1.0f, 1.0f, 1.0f, 1.0f,
+        0.8f, 0.6f, 0.4f, 0.2f
+    };
+    _collisionHullMaterials.reserve(NUM_COLLISION_HULL_COLORS);
+
+    // each component gets the same cuve
+    // but offset by a multiple of one third the full width
+    int numComponents = 3;
+    int sectionWidth = NUM_COLLISION_HULL_COLORS / numComponents;
+    int greenPhase = sectionWidth;
+    int bluePhase = 2 * sectionWidth;
+
+    // we stride through the colors to scatter adjacent shades
+    // so they don't tend to group together for large models
+    for (int i = 0; i < sectionWidth; ++i) {
+        for (int j = 0; j < numComponents; ++j) {
+            model::MaterialPointer material;
+            material = std::make_shared<model::Material>();
+            int index = j * sectionWidth + i;
+            float red = component[index];
+            float green = component[(index + greenPhase) % NUM_COLLISION_HULL_COLORS];
+            float blue = component[(index + bluePhase) % NUM_COLLISION_HULL_COLORS];
+            material->setAlbedo(glm::vec3(red, green, blue));
+            material->setMetallic(0.02f);
+            material->setRoughness(0.5f);
+            _collisionHullMaterials.push_back(material);
+        }
+    }
+}
 
 Model::Model(RigPointer rig, QObject* parent) :
     QObject(parent),
@@ -1217,13 +1256,10 @@ void Model::segregateMeshGroups() {
         int totalParts = mesh.parts.size();
         for (int partIndex = 0; partIndex < totalParts; partIndex++) {
             if (showingCollisionHull) {
-                if (!_collisionHullMaterial) {
-                    _collisionHullMaterial = std::make_shared<model::Material>();
-                    _collisionHullMaterial->setAlbedo(glm::vec3(1.0f, 0.5f, 0.0f));
-                    _collisionHullMaterial->setMetallic(0.02f);
-                    _collisionHullMaterial->setRoughness(0.5f);
+                if (_collisionHullMaterials.empty()) {
+                    initCollisionHullMaterials();
                 }
-                _collisionRenderItemsSet << std::make_shared<MeshPartPayload>(networkMesh, partIndex, _collisionHullMaterial, transform, offset);
+                _collisionRenderItemsSet << std::make_shared<MeshPartPayload>(networkMesh, partIndex, _collisionHullMaterials[partIndex % NUM_COLLISION_HULL_COLORS], transform, offset);
             } else {
                 _modelMeshRenderItemsSet << std::make_shared<ModelMeshPartPayload>(this, i, partIndex, shapeID, transform, offset);
             }