From d521315475587075d7cd9b146ccfbd0d499aefb4 Mon Sep 17 00:00:00 2001
From: SamGondelman <samuel_gondelman@brown.edu>
Date: Wed, 3 Aug 2016 17:03:52 -0700
Subject: [PATCH] fade polylines (needs testing)

---
 .../entities-renderer/src/RenderablePolyLineEntityItem.cpp | 2 ++
 .../entities-renderer/src/RenderablePolyLineEntityItem.h   | 7 ++++---
 libraries/entities-renderer/src/paintStroke.slf            | 2 +-
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/libraries/entities-renderer/src/RenderablePolyLineEntityItem.cpp b/libraries/entities-renderer/src/RenderablePolyLineEntityItem.cpp
index 600b876d39..54a6edadd4 100644
--- a/libraries/entities-renderer/src/RenderablePolyLineEntityItem.cpp
+++ b/libraries/entities-renderer/src/RenderablePolyLineEntityItem.cpp
@@ -204,5 +204,7 @@ void RenderablePolyLineEntityItem::render(RenderArgs* args) {
     batch.setInputFormat(_format);
     batch.setInputBuffer(0, _verticesBuffer, 0, _format->getChannels().at(0)._stride);
 
+    batch._glColor4f(1.0f, 1.0f, 1.0f, Interpolate::calculateFadeRatio(_fadeStartTime));
+
     batch.draw(gpu::TRIANGLE_STRIP, _numVertices, 0);
 };
diff --git a/libraries/entities-renderer/src/RenderablePolyLineEntityItem.h b/libraries/entities-renderer/src/RenderablePolyLineEntityItem.h
index 46716e5bab..6d3dab4647 100644
--- a/libraries/entities-renderer/src/RenderablePolyLineEntityItem.h
+++ b/libraries/entities-renderer/src/RenderablePolyLineEntityItem.h
@@ -18,6 +18,7 @@
 #include <PolyLineEntityItem.h>
 #include "RenderableEntityItem.h"
 #include <TextureCache.h>
+#include <Interpolate.h>
 
 #include <QReadWriteLock>
 
@@ -30,9 +31,9 @@ public:
 
     virtual void render(RenderArgs* args) override;
     virtual void update(const quint64& now) override;
-    virtual bool needsToCallUpdate() const override { return true; };
+    virtual bool needsToCallUpdate() const override { return true; }
 
-    bool isTransparent() override { return true; }
+    bool isTransparent() override { return Interpolate::calculateFadeRatio(_fadeStartTime) < 1.0f; }
 
     SIMPLE_RENDERABLE();
 
@@ -49,7 +50,7 @@ protected:
     gpu::BufferView _uniformBuffer;
     unsigned int _numVertices;
     QVector<glm::vec3> _vertices;
-
+    quint64 _fadeStartTime { usecTimestampNow() };
 };
 
 
diff --git a/libraries/entities-renderer/src/paintStroke.slf b/libraries/entities-renderer/src/paintStroke.slf
index 9b7193bbfc..bfbe6d7e5a 100644
--- a/libraries/entities-renderer/src/paintStroke.slf
+++ b/libraries/entities-renderer/src/paintStroke.slf
@@ -39,7 +39,7 @@ void main(void) {
     vec3 color = varColor.rgb;
     packDeferredFragmentTranslucent(
         interpolatedNormal * frontCondition,
-        texel.a,
+        texel.a * varColor.a,
         polyline.color * texel.rgb,
         vec3(0.01, 0.01, 0.01),
         10.0);