From d41ec7dfaa635bbaea9e902d5f5c60bd4a887891 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Thu, 30 Oct 2014 10:21:18 +0200
Subject: [PATCH] State management improvements in Renderer

Only update modelview matrix in standard_shdata if it actually changed.

Don't re-apply all shader data unless the program changed.

React to lighting changes caused by pop_state.
---
 source/renderer.cpp | 54 ++++++++++++++++++++++++++++++---------------
 source/renderer.h   |  5 ++++-
 2 files changed, 40 insertions(+), 19 deletions(-)

diff --git a/source/renderer.cpp b/source/renderer.cpp
index 54d12051..2f253e2a 100644
--- a/source/renderer.cpp
+++ b/source/renderer.cpp
@@ -24,6 +24,7 @@ Renderer::Renderer(const Camera *c):
 	mtx_stack(*this),
 	changed(MATRIX),
 	matrices_loaded(false),
+	shdata_applied(0),
 	camera(c),
 	state_stack(1),
 	element_buffer(0)
@@ -85,10 +86,6 @@ void Renderer::set_shader_program(const Program *p, const ProgramData *d)
 	state->shprog = p;
 	if(p && d)
 		add_shader_data(*d);
-
-	/* Even if we have no new shdata, the existing ones need to be re-applied
-	to the new program */
-	shdata_changed = true;
 }
 
 void Renderer::add_shader_data(const ProgramData &d)
@@ -130,12 +127,23 @@ void Renderer::pop_state()
 	if(state_stack.size()==1)
 		throw stack_underflow("Renderer::pop_state");
 
+	const Lighting *old_lighting = state->lighting;
 	state_stack.pop_back();
 	state = &state_stack.back();
 	if(shdata_stack.size()>state->shdata_count)
+	{
 		shdata_stack.erase(shdata_stack.begin()+state->shdata_count, shdata_stack.end());
+		changed |= SHADER_DATA;
+	}
+	shdata_applied = min<unsigned>(shdata_applied, shdata_stack.size());
 	mtx_stack.pop();
-	changed |= MATRIX|SHADER_DATA;
+	changed |= MATRIX;
+	if(state->lighting!=old_lighting)
+	{
+		if(state->lighting)
+			state->lighting->update_shader_data(standard_shdata, state->lighting_matrix);
+		changed |= LIGHTING;
+	}
 }
 
 void Renderer::escape()
@@ -233,7 +241,7 @@ void Renderer::apply_state()
 			{
 				MatrixStack::modelview() = state->lighting_matrix;
 				state->lighting->bind();
-				changed = (changed&~LIGHTING)|MATRIX;
+				changed = (changed&~LIGHTING)|LEGACY_MATRIX;
 			}
 			else
 				Lighting::unbind();
@@ -242,28 +250,38 @@ void Renderer::apply_state()
 
 	if(state->shprog)
 	{
+		bool shprog_changed = (state->shprog!=Program::current());
 		state->shprog->bind();
 
 		if(!legacy_bindings)
 		{
-			const Matrix &m = mtx_stack.top();
-			standard_shdata.uniform("eye_obj_matrix", mtx_stack.top());
-			LinAl::SquareMatrix<float, 3> nm;
-			for(unsigned i=0; i<3; ++i)
-				for(unsigned j=0; j<3; ++j)
-					nm(i, j) = m(i, j);
-			nm = transpose(invert(nm));
-			standard_shdata.uniform_matrix3("eye_obj_normal_matrix", &nm(0, 0));
+			if(changed&MODERN_MATRIX)
+			{
+				const Matrix &m = mtx_stack.top();
+				standard_shdata.uniform("eye_obj_matrix", mtx_stack.top());
+				LinAl::SquareMatrix<float, 3> nm;
+				for(unsigned i=0; i<3; ++i)
+					for(unsigned j=0; j<3; ++j)
+						nm(i, j) = m(i, j);
+				nm = transpose(invert(nm));
+				standard_shdata.uniform_matrix3("eye_obj_normal_matrix", &nm(0, 0));
+				changed &= ~MODERN_MATRIX;
+			}
+
 			if(state->material)
 				state->material->get_shader_data().apply();
 			standard_shdata.apply();
 		}
 
-		if(changed&SHADER_DATA)
+		if((changed&SHADER_DATA) || shprog_changed)
 		{
-			for(vector<const ProgramData *>::const_iterator i=shdata_stack.begin(); i!=shdata_stack.end(); ++i)
+			vector<const ProgramData *>::const_iterator i = shdata_stack.begin();
+			if(!shprog_changed)
+				i += shdata_applied;
+			for(; i!=shdata_stack.end(); ++i)
 				(*i)->apply();
 			changed &= ~SHADER_DATA;
+			shdata_applied = shdata_stack.size();
 		}
 	}
 	else
@@ -305,10 +323,10 @@ void Renderer::apply_state()
 			matrices_loaded = true;
 		}
 
-		if(changed&MATRIX)
+		if(changed&LEGACY_MATRIX)
 		{
 			MatrixStack::modelview() = mtx_stack.top();
-			changed &= ~MATRIX;
+			changed &= ~LEGACY_MATRIX;
 		}
 	}
 }
diff --git a/source/renderer.h b/source/renderer.h
index a3ddaa3b..dd946412 100644
--- a/source/renderer.h
+++ b/source/renderer.h
@@ -91,7 +91,9 @@ private:
 
 	enum ChangeMask
 	{
-		MATRIX = 1,
+		LEGACY_MATRIX = 1,
+		MODERN_MATRIX = 2,
+		MATRIX = LEGACY_MATRIX|MODERN_MATRIX,
 		LIGHTING = 4,
 		SHADER_DATA = 8
 	};
@@ -99,6 +101,7 @@ private:
 	MtxStack mtx_stack;
 	unsigned char changed;
 	bool matrices_loaded;
+	unsigned shdata_applied;
 	const Camera *camera;
 	std::vector<State> state_stack;
 	State *state;
-- 
2.43.0