From fad38c0bfbf8b4f4ce53a3305ed502963774ff88 Mon Sep 17 00:00:00 2001
From: Zach Pomerantz <zach@highfidelity.io>
Date: Thu, 14 Jan 2016 15:16:05 -0800
Subject: [PATCH] Add uniform buffer to LightStage

---
 libraries/render-utils/src/LightStage.cpp | 19 ++++++++++++++++---
 libraries/render-utils/src/LightStage.h   | 20 ++++++++++++++++----
 2 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/libraries/render-utils/src/LightStage.cpp b/libraries/render-utils/src/LightStage.cpp
index f6c2e14f2b..2217de6f28 100644
--- a/libraries/render-utils/src/LightStage.cpp
+++ b/libraries/render-utils/src/LightStage.cpp
@@ -16,6 +16,8 @@
 LightStage::Shadow::Shadow(model::LightPointer light) : _light{ light}, _frustum{ std::make_shared<ViewFrustum>() } {
     framebuffer = gpu::FramebufferPointer(gpu::Framebuffer::createShadowmap(MAP_SIZE));
     map = framebuffer->getDepthStencilBuffer();
+    Schema schema{glm::mat4(), glm::mat4(), 0, MAP_SIZE};
+    _schemaBuffer = std::make_shared<gpu::Buffer>(sizeof(Schema), (const gpu::Byte*) &schema);
 }
 
 void LightStage::Shadow::setKeylightFrustum(ViewFrustum* viewFrustum, float nearDepth, float farDepth) {
@@ -36,8 +38,8 @@ void LightStage::Shadow::setKeylightFrustum(ViewFrustum* viewFrustum, float near
     // Position the keylight frustum
     _frustum->setPosition(viewFrustum->getPosition() - (nearDepth + farDepth)*direction);
 
-    _view = _frustum->getView();
-    const Transform viewInverse{ _view.getInverseMatrix() };
+    const Transform view{ _frustum->getView()};
+    const Transform viewInverse{ view.getInverseMatrix() };
 
     viewFrustum->calculate();
     auto nearCorners = viewFrustum->getCorners(nearDepth);
@@ -67,7 +69,18 @@ void LightStage::Shadow::setKeylightFrustum(ViewFrustum* viewFrustum, float near
 
     glm::mat4 ortho = glm::ortho<float>(min.x, max.x, min.y, max.y, -max.z, -min.z);
     _frustum->setProjection(ortho);
-    _projection = ortho;
+
+    // Update the buffer
+    _schemaBuffer.edit<Schema>().projection = ortho;
+    _schemaBuffer.edit<Schema>().view = view.getMatrix();
+}
+
+const glm::mat4& LightStage::Shadow::getView() const {
+    return _frustum->getView();
+}
+
+const glm::mat4& LightStage::Shadow::getProjection() const {
+    return _frustum->getProjection();
 }
 
 const LightStage::LightPointer LightStage::addLight(model::LightPointer light) {
diff --git a/libraries/render-utils/src/LightStage.h b/libraries/render-utils/src/LightStage.h
index 3d59de6164..10c8227ff3 100644
--- a/libraries/render-utils/src/LightStage.h
+++ b/libraries/render-utils/src/LightStage.h
@@ -23,6 +23,7 @@ class LightStage {
 public:
     class Shadow {
     public:
+        using UniformBufferView = gpu::BufferView;
         const int MAP_SIZE = 2048;
 
         Shadow(model::LightPointer light);
@@ -30,16 +31,27 @@ public:
         void setKeylightFrustum(ViewFrustum* viewFrustum, float nearDepth, float farDepth);
 
         const std::shared_ptr<ViewFrustum> getFrustum() const { return _frustum; }
-        const glm::mat4& getProjection() const { return _projection; }
-        const Transform& getView() const { return _view; }
+
+        const glm::mat4& getView() const;
+        const glm::mat4& getProjection() const;
+
+        const UniformBufferView& getBuffer() const { return _schemaBuffer; }
 
         gpu::FramebufferPointer framebuffer;
         gpu::TexturePointer map;
     protected:
         model::LightPointer _light;
         std::shared_ptr<ViewFrustum> _frustum;
-        glm::mat4 _projection;
-        Transform _view;
+
+        class Schema {
+        public:
+            glm::mat4 projection;
+            glm::mat4 view;
+
+            glm::float32 bias;
+            glm::float32 scale;
+        };
+        UniformBufferView _schemaBuffer = nullptr;
     };
     using ShadowPointer = std::shared_ptr<Shadow>;