From 6604c27f232f61a842cc78ccf775a81cf858e200 Mon Sep 17 00:00:00 2001
From: SamGondelman <samuel_gondelman@brown.edu>
Date: Thu, 4 Aug 2016 10:55:37 -0700
Subject: [PATCH] polyvox fade WIP

---
 .../src/RenderableEntityItem.cpp              |  2 +-
 .../src/RenderablePolyLineEntityItem.h        |  2 +-
 .../src/RenderablePolyVoxEntityItem.cpp       |  6 +++++
 .../src/RenderablePolyVoxEntityItem.h         |  2 ++
 libraries/entities-renderer/src/polyvox.slf   | 23 +++++++++++++++++--
 5 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/libraries/entities-renderer/src/RenderableEntityItem.cpp b/libraries/entities-renderer/src/RenderableEntityItem.cpp
index bd34506250..359b050803 100644
--- a/libraries/entities-renderer/src/RenderableEntityItem.cpp
+++ b/libraries/entities-renderer/src/RenderableEntityItem.cpp
@@ -1,4 +1,4 @@
- //
+//
 //  RenderableEntityItem.cpp
 //  interface/src
 //
diff --git a/libraries/entities-renderer/src/RenderablePolyLineEntityItem.h b/libraries/entities-renderer/src/RenderablePolyLineEntityItem.h
index 6d3dab4647..c06f4a721a 100644
--- a/libraries/entities-renderer/src/RenderablePolyLineEntityItem.h
+++ b/libraries/entities-renderer/src/RenderablePolyLineEntityItem.h
@@ -33,7 +33,7 @@ public:
     virtual void update(const quint64& now) override;
     virtual bool needsToCallUpdate() const override { return true; }
 
-    bool isTransparent() override { return Interpolate::calculateFadeRatio(_fadeStartTime) < 1.0f; }
+    bool isTransparent() override { return true; }
 
     SIMPLE_RENDERABLE();
 
diff --git a/libraries/entities-renderer/src/RenderablePolyVoxEntityItem.cpp b/libraries/entities-renderer/src/RenderablePolyVoxEntityItem.cpp
index eb6db2874f..769670b99c 100644
--- a/libraries/entities-renderer/src/RenderablePolyVoxEntityItem.cpp
+++ b/libraries/entities-renderer/src/RenderablePolyVoxEntityItem.cpp
@@ -596,6 +596,9 @@ void RenderablePolyVoxEntityItem::render(RenderArgs* args) {
         auto state = std::make_shared<gpu::State>();
         state->setCullMode(gpu::State::CULL_BACK);
         state->setDepthTest(true, true, gpu::LESS_EQUAL);
+        state->setBlendFunction(true,
+            gpu::State::SRC_ALPHA, gpu::State::BLEND_OP_ADD, gpu::State::INV_SRC_ALPHA,
+            gpu::State::FACTOR_ALPHA, gpu::State::BLEND_OP_ADD, gpu::State::ONE);
 
         _pipeline = gpu::Pipeline::create(program, state);
     }
@@ -642,6 +645,9 @@ void RenderablePolyVoxEntityItem::render(RenderArgs* args) {
     int voxelVolumeSizeLocation = _pipeline->getProgram()->getUniforms().findLocation("voxelVolumeSize");
     batch._glUniform3f(voxelVolumeSizeLocation, voxelVolumeSize.x, voxelVolumeSize.y, voxelVolumeSize.z);
 
+    int alphaLocation = _pipeline->getProgram()->getUniforms().findLocation("alpha");
+    batch._glUniform1f(alphaLocation, 0.5f);
+
     batch.drawIndexed(gpu::TRIANGLES, (gpu::uint32)mesh->getNumIndices(), 0);
 }
 
diff --git a/libraries/entities-renderer/src/RenderablePolyVoxEntityItem.h b/libraries/entities-renderer/src/RenderablePolyVoxEntityItem.h
index c46a26deb5..cec6ddf7c5 100644
--- a/libraries/entities-renderer/src/RenderablePolyVoxEntityItem.h
+++ b/libraries/entities-renderer/src/RenderablePolyVoxEntityItem.h
@@ -131,6 +131,8 @@ public:
 
     void setVolDataDirty() { withWriteLock([&] { _volDataDirty = true; }); }
 
+    bool isTransparent() override { return true; }
+
 private:
     // The PolyVoxEntityItem class has _voxelData which contains dimensions and compressed voxel data.  The dimensions
     // may not match _voxelVolumeSize.
diff --git a/libraries/entities-renderer/src/polyvox.slf b/libraries/entities-renderer/src/polyvox.slf
index b7682913a7..a3c8315b62 100644
--- a/libraries/entities-renderer/src/polyvox.slf
+++ b/libraries/entities-renderer/src/polyvox.slf
@@ -1,7 +1,7 @@
 <@include gpu/Config.slh@>
 <$VERSION_HEADER$>
 //  Generated on <$_SCRIBE_DATE$>
-//  model.frag
+//  polyvox.frag
 //  fragment shader
 //
 //  Created by Seth Alves on 2015-8-3
@@ -23,6 +23,7 @@ uniform sampler2D xMap;
 uniform sampler2D yMap;
 uniform sampler2D zMap;
 uniform vec3 voxelVolumeSize;
+uniform float alpha;
 
 void main(void) {
     vec3 worldNormal = cross(dFdy(_worldPosition.xyz), dFdx(_worldPosition.xyz));
@@ -41,5 +42,23 @@ void main(void) {
     vec3 yzDiffuseScaled = yzDiffuse.rgb * abs(worldNormal.x);
     vec4 diffuse = vec4(xyDiffuseScaled + xzDiffuseScaled + yzDiffuseScaled, 1.0);
 
-    packDeferredFragment(_normal, 1.0, vec3(diffuse), DEFAULT_ROUGHNESS, DEFAULT_METALLIC, DEFAULT_EMISSIVE, DEFAULT_OCCLUSION, DEFAULT_SCATTERING);
+    const float ALPHA_THRESHOLD = 0.999;
+    if (alpha < ALPHA_THRESHOLD) {
+        packDeferredFragmentTranslucent(
+            _normal,
+            alpha,
+            vec3(diffuse),
+            DEFAULT_FRESNEL,
+            DEFAULT_ROUGHNESS);
+    } else {
+        packDeferredFragment(
+            _normal,
+            1.0,
+            vec3(diffuse),
+            DEFAULT_ROUGHNESS,
+            DEFAULT_METALLIC,
+            DEFAULT_EMISSIVE,
+            DEFAULT_OCCLUSION,
+            DEFAULT_SCATTERING);
+    }
 }