From 14845bf3f2b658d7cdb5895e9355d3171b6028a9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fernando=20Garc=C3=ADa=20Li=C3=B1=C3=A1n?=
 <fernandogarcialinan@gmail.com>
Date: Tue, 24 Dec 2019 03:34:37 +0100
Subject: [PATCH] Compositor: Provide previous frame transformation matrices
 and the sunlight direction as uniforms

---
 simgear/scene/model/SGLight.cxx     |  6 +++++-
 simgear/scene/viewer/Compositor.cxx | 30 ++++++++++++++++++++++++++++-
 simgear/scene/viewer/Compositor.hxx |  5 +++++
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/simgear/scene/model/SGLight.cxx b/simgear/scene/model/SGLight.cxx
index 269829e1..d7af021b 100644
--- a/simgear/scene/model/SGLight.cxx
+++ b/simgear/scene/model/SGLight.cxx
@@ -118,7 +118,11 @@ SGLight::appendLight(const SGPropertyNode *configNode,
             light->getRange());
     }
     osg::ShapeDrawable *debug_drawable = new osg::ShapeDrawable(debug_shape);
-    debug_drawable->setColor(osg::Vec4(1.0, 0.0, 0.0, 1.0));
+    debug_drawable->setColor(
+        osg::Vec4(configNode->getFloatValue("debug-color/r", 1.0f),
+                  configNode->getFloatValue("debug-color/g", 0.0f),
+                  configNode->getFloatValue("debug-color/b", 0.0f),
+                  configNode->getFloatValue("debug-color/a", 1.0f)));
     osg::Geode *debug_geode = new osg::Geode;
     debug_geode->addDrawable(debug_drawable);
 
diff --git a/simgear/scene/viewer/Compositor.cxx b/simgear/scene/viewer/Compositor.cxx
index 964e387d..e91b1d44 100644
--- a/simgear/scene/viewer/Compositor.cxx
+++ b/simgear/scene/viewer/Compositor.cxx
@@ -28,10 +28,20 @@
 #include <simgear/scene/material/EffectCullVisitor.hxx>
 #include <simgear/scene/util/SGReaderWriterOptions.hxx>
 #include <simgear/scene/util/RenderConstants.hxx>
+#include <simgear/scene/util/SGUpdateVisitor.hxx>
 #include <simgear/structure/exception.hxx>
 
 #include "CompositorUtil.hxx"
 
+
+class LightDirectionCallback : public osg::Uniform::Callback {
+public:
+    virtual void operator()(osg::Uniform *uniform, osg::NodeVisitor *nv) {
+        SGUpdateVisitor *uv = dynamic_cast<SGUpdateVisitor *>(nv);
+        uniform->set(toOsg(uv->getLightDirection()));
+    }
+};
+
 namespace simgear {
 namespace compositor {
 
@@ -113,10 +123,16 @@ Compositor::Compositor(osg::View *view,
     new osg::Uniform("fg_ViewMatrixInverse", osg::Matrixf()),
     new osg::Uniform("fg_ProjectionMatrix", osg::Matrixf()),
     new osg::Uniform("fg_ProjectionMatrixInverse", osg::Matrixf()),
+    new osg::Uniform("fg_PrevViewMatrix", osg::Matrixf()),
+    new osg::Uniform("fg_PrevViewMatrixInverse", osg::Matrixf()),
+    new osg::Uniform("fg_PrevProjectionMatrix", osg::Matrixf()),
+    new osg::Uniform("fg_PrevProjectionMatrixInverse", osg::Matrixf()),
     new osg::Uniform("fg_CameraPositionCart", osg::Vec3f()),
-    new osg::Uniform("fg_CameraPositionGeod", osg::Vec3f())
+    new osg::Uniform("fg_CameraPositionGeod", osg::Vec3f()),
+    new osg::Uniform("fg_LightDirection", osg::Vec3f())
     }
 {
+    _uniforms[LIGHT_DIRECTION]->setUpdateCallback(new LightDirectionCallback);
 }
 
 Compositor::~Compositor()
@@ -149,6 +165,18 @@ Compositor::update(const osg::Matrix &view_matrix,
     SGGeod camera_pos_geod = SGGeod::fromCart(
         SGVec3d(camera_pos.x(), camera_pos.y(), camera_pos.z()));
 
+    osg::Matrixf prev_view_matrix, prev_view_matrix_inv;
+    _uniforms[VIEW_MATRIX]->get(prev_view_matrix);
+    _uniforms[VIEW_MATRIX_INV]->get(prev_view_matrix_inv);
+    osg::Matrixf prev_proj_matrix, prev_proj_matrix_inv;
+    _uniforms[PROJECTION_MATRIX]->get(prev_proj_matrix);
+    _uniforms[PROJECTION_MATRIX_INV]->get(prev_proj_matrix_inv);
+
+    _uniforms[PREV_VIEW_MATRIX]->set(prev_view_matrix);
+    _uniforms[PREV_VIEW_MATRIX_INV]->set(prev_view_matrix_inv);
+    _uniforms[PREV_PROJECTION_MATRIX]->set(prev_proj_matrix);
+    _uniforms[PREV_PROJECTION_MATRIX_INV]->set(prev_proj_matrix_inv);
+
     for (int i = 0; i < TOTAL_BUILTIN_UNIFORMS; ++i) {
         osg::ref_ptr<osg::Uniform> u = _uniforms[i];
         switch (i) {
diff --git a/simgear/scene/viewer/Compositor.hxx b/simgear/scene/viewer/Compositor.hxx
index f2d0cc75..23855347 100644
--- a/simgear/scene/viewer/Compositor.hxx
+++ b/simgear/scene/viewer/Compositor.hxx
@@ -51,8 +51,13 @@ public:
         VIEW_MATRIX_INV,
         PROJECTION_MATRIX,
         PROJECTION_MATRIX_INV,
+        PREV_VIEW_MATRIX,
+        PREV_VIEW_MATRIX_INV,
+        PREV_PROJECTION_MATRIX,
+        PREV_PROJECTION_MATRIX_INV,
         CAMERA_POSITION_CART,
         CAMERA_POSITION_GEOD,
+        LIGHT_DIRECTION,
         TOTAL_BUILTIN_UNIFORMS
     };