From f632bf388a58b036e265f3789c797beff5ab063a Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 19 Nov 2016 16:20:06 +0200
Subject: [PATCH] Eliminate the separate matrix stack in Renderer

Instead incorporate the modelview matrix into the main render state.
---
 source/renderer.cpp | 38 +++++++++++++-------------------------
 source/renderer.h   | 18 ++----------------
 2 files changed, 15 insertions(+), 41 deletions(-)

diff --git a/source/renderer.cpp b/source/renderer.cpp
index 01c17a26..3bef74b3 100644
--- a/source/renderer.cpp
+++ b/source/renderer.cpp
@@ -22,7 +22,6 @@ namespace Msp {
 namespace GL {
 
 Renderer::Renderer(const Camera *c):
-	mtx_stack(*this),
 	changed(0),
 	matrices_loaded(false),
 	shdata_applied(0),
@@ -52,24 +51,26 @@ void Renderer::begin(const Camera *c)
 
 	if(camera)
 	{
-		mtx_stack.load(camera->get_matrix());
+		state->modelview_matrix = camera->get_view_matrix();
 		standard_shdata.uniform("projection_matrix", camera->get_projection_matrix());
 	}
 	else
 	{
-		mtx_stack.load(MatrixStack::modelview().top());
+		state->modelview_matrix = MatrixStack::modelview().top();
 		standard_shdata.uniform("projection_matrix", MatrixStack::projection().top());
 	}
 }
 
 void Renderer::set_matrix(const Matrix &matrix)
 {
-	mtx_stack.load(matrix);
+	state->modelview_matrix = matrix;
+	changed |= MATRIX;
 }
 
 void Renderer::transform(const Matrix &matrix)
 {
-	mtx_stack *= matrix;
+	state->modelview_matrix *= matrix;
+	changed |= MATRIX;
 }
 
 void Renderer::set_texture(const Texture *t)
@@ -98,10 +99,10 @@ void Renderer::set_material(const Material *m)
 void Renderer::set_lighting(const Lighting *l)
 {
 	state->lighting = l;
-	state->lighting_matrix = mtx_stack.top();
+	state->lighting_matrix = state->modelview_matrix;
 	if(l)
 	{
-		l->update_shader_data(standard_shdata, mtx_stack.top());
+		l->update_shader_data(standard_shdata, state->lighting_matrix);
 		changed |= STANDARD_SHDATA;
 	}
 	changed |= LEGACY_LIGHTING;
@@ -110,9 +111,9 @@ void Renderer::set_lighting(const Lighting *l)
 void Renderer::set_clipping(const Clipping *c)
 {
 	state->clipping = c;
-	state->clipping_matrix = mtx_stack.top();
+	state->clipping_matrix = state->modelview_matrix;
 	if(c)
-		c->update_shader_data(standard_shdata, mtx_stack.top());
+		c->update_shader_data(standard_shdata, state->clipping_matrix);
 	changed |= LEGACY_CLIPPING;
 }
 
@@ -149,7 +150,6 @@ void Renderer::push_state()
 {
 	state_stack.push_back(state_stack.back());
 	state = &state_stack.back();
-	mtx_stack.push();
 }
 
 void Renderer::pop_state()
@@ -167,7 +167,6 @@ void Renderer::pop_state()
 		changed |= SHADER_DATA;
 	}
 	shdata_applied = min<unsigned>(shdata_applied, shdata_stack.size());
-	mtx_stack.pop();
 	changed |= MATRIX;
 	if(state->lighting!=old_lighting)
 	{
@@ -304,9 +303,8 @@ void Renderer::apply_state()
 		{
 			if(changed&MODERN_MATRIX)
 			{
-				const Matrix &m = mtx_stack.top();
-				standard_shdata.uniform("eye_obj_matrix", mtx_stack.top());
-				LinAl::SquareMatrix<float, 3> nm = m.block<3, 3>(0, 0);
+				standard_shdata.uniform("eye_obj_matrix", state->modelview_matrix);
+				LinAl::SquareMatrix<float, 3> nm = state->modelview_matrix.block<3, 3>(0, 0);
 				nm = transpose(invert(nm));
 				standard_shdata.uniform_matrix3("eye_obj_normal_matrix", &nm(0, 0));
 				changed = (changed&~MODERN_MATRIX)|STANDARD_SHDATA;
@@ -377,7 +375,7 @@ void Renderer::apply_state()
 
 		if(changed&LEGACY_MATRIX)
 		{
-			MatrixStack::modelview() = mtx_stack.top();
+			MatrixStack::modelview() = state->modelview_matrix;
 			changed &= ~LEGACY_MATRIX;
 		}
 	}
@@ -412,15 +410,5 @@ Renderer::State::State():
 	reverse_winding(false)
 { }
 
-
-Renderer::MtxStack::MtxStack(Renderer &r):
-	renderer(r)
-{ }
-
-void Renderer::MtxStack::update()
-{
-	renderer.changed |= MATRIX;
-}
-
 } // namespace GL
 } // namespace Msp
diff --git a/source/renderer.h b/source/renderer.h
index b114f687..157282a5 100644
--- a/source/renderer.h
+++ b/source/renderer.h
@@ -64,6 +64,7 @@ public:
 private:
 	struct State
 	{
+		Matrix modelview_matrix;
 		const Texture *texture;
 		const Texturing *texturing;
 		unsigned lowest_effect_texunit;
@@ -81,17 +82,6 @@ private:
 		State();
 	};
 
-	class MtxStack: public MatrixStack
-	{
-	private:
-		Renderer &renderer;
-
-	public:
-		MtxStack(Renderer &);
-	private:
-		virtual void update();
-	};
-
 	enum ChangeMask
 	{
 		LEGACY_MATRIX = 1,
@@ -104,7 +94,6 @@ private:
 		STANDARD_SHDATA = 64
 	};
 
-	MtxStack mtx_stack;
 	unsigned char changed;
 	bool matrices_loaded;
 	unsigned shdata_applied;
@@ -124,9 +113,6 @@ public:
 	times without an intervening end(). */
 	void begin(const Camera *);
 
-	/** Deprecated as unsafe.  Use set_matrix() or transform() instead. */
-	MatrixStack &matrix_stack() { return mtx_stack; }
-
 	/** Replaces the Renderer's modelview matrix. */
 	void set_matrix(const Matrix &);
 
@@ -134,7 +120,7 @@ public:
 	void transform(const Matrix &);
 
 	/** Returns the current modelview matrix. */
-	const Matrix &get_matrix() const { return mtx_stack.top(); }
+	const Matrix &get_matrix() const { return state->modelview_matrix; }
 
 	const Camera *get_camera() const { return camera; }
 
-- 
2.43.0