From 2341b3575c874b1960814264fa759ad584bf3134 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 28 Jul 2019 02:05:55 +0300
Subject: [PATCH] Add an object LoD bias parameter to Renderer

This could be used by environment map and similar effects to render the
scene at lower detail.
---
 source/objectinstance.cpp | 5 +++++
 source/objectinstance.h   | 2 +-
 source/renderer.cpp       | 8 +++++++-
 source/renderer.h         | 4 ++++
 4 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/source/objectinstance.cpp b/source/objectinstance.cpp
index 450c8106..ef4afffe 100644
--- a/source/objectinstance.cpp
+++ b/source/objectinstance.cpp
@@ -27,6 +27,11 @@ void ObjectInstance::setup_render(Renderer &renderer, const Tag &) const
 	renderer.transform(matrix);
 }
 
+unsigned ObjectInstance::get_level_of_detail(const Renderer &renderer) const
+{
+	return renderer.get_object_lod_bias();
+}
+
 
 ObjectInstance::Loader::Loader(ObjectInstance &o):
 	DataFile::ObjectLoader<ObjectInstance>(o)
diff --git a/source/objectinstance.h b/source/objectinstance.h
index 6577dd2a..1ad221c7 100644
--- a/source/objectinstance.h
+++ b/source/objectinstance.h
@@ -51,7 +51,7 @@ public:
 	anything. */
 	virtual void finish_render(Renderer &, const Tag &) const { }
 
-	virtual unsigned get_level_of_detail(const Renderer &) const { return 0; }
+	virtual unsigned get_level_of_detail(const Renderer &) const;
 };
 
 } // namespace GL
diff --git a/source/renderer.cpp b/source/renderer.cpp
index cc00ac8e..90ac4551 100644
--- a/source/renderer.cpp
+++ b/source/renderer.cpp
@@ -162,6 +162,11 @@ void Renderer::set_reverse_winding(bool r)
 	state->reverse_winding = r;
 }
 
+void Renderer::set_object_lod_bias(unsigned b)
+{
+	state->object_lod_bias = b;
+}
+
 void Renderer::push_state()
 {
 	state_stack.push_back(state_stack.back());
@@ -449,7 +454,8 @@ Renderer::State::State():
 	mesh(0),
 	vertex_setup(0),
 	winding_test(0),
-	reverse_winding(false)
+	reverse_winding(false),
+	object_lod_bias(0)
 { }
 
 } // namespace GL
diff --git a/source/renderer.h b/source/renderer.h
index dbb2d490..973e1b00 100644
--- a/source/renderer.h
+++ b/source/renderer.h
@@ -81,6 +81,7 @@ private:
 		const VertexSetup *vertex_setup;
 		const WindingTest *winding_test;
 		bool reverse_winding;
+		unsigned object_lod_bias;
 
 		State();
 	};
@@ -155,6 +156,9 @@ public:
 	void set_winding_test(const WindingTest *);
 	void set_reverse_winding(bool);
 
+	void set_object_lod_bias(unsigned);
+	unsigned get_object_lod_bias() const { return state->object_lod_bias; }
+
 	/** Saves the current state so it can be restored later. */
 	void push_state();
 
-- 
2.45.2