From bfc7f104c642590fd85577a6545c6bc6259ccaa4 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 26 Nov 2016 06:56:54 +0200
Subject: [PATCH] Make the camera part of changeable Renderer state

I'd like to move to a single, persistent renderer at some point and this
is a necessary step towards that.  Some effects want to use their own
camera to render into an FBO.
---
 source/renderer.cpp | 42 ++++++++++++++++++++++++------------------
 source/renderer.h   | 13 +++++++++----
 2 files changed, 33 insertions(+), 22 deletions(-)

diff --git a/source/renderer.cpp b/source/renderer.cpp
index a0dc4151..45cf241e 100644
--- a/source/renderer.cpp
+++ b/source/renderer.cpp
@@ -25,7 +25,6 @@ Renderer::Renderer(const Camera *c):
 	changed(0),
 	matrices_loaded(false),
 	shdata_applied(0),
-	camera(0),
 	state_stack(1)
 {
 	state_stack.reserve(16);
@@ -47,19 +46,17 @@ void Renderer::begin(const Camera *c)
 
 	reset_state();
 	excluded.clear();
-	camera = c;
 
-	if(camera)
-	{
-		state->modelview_matrix = camera->get_view_matrix();
-		standard_shdata.uniform("projection_matrix", camera->get_projection_matrix());
-	}
-	else
-	{
-		state->modelview_matrix = MatrixStack::modelview().top();
-		standard_shdata.uniform("projection_matrix", MatrixStack::projection().top());
-	}
-	changed |= MATRIX|STANDARD_SHDATA;
+	if(c)
+		set_camera(*c);
+}
+
+void Renderer::set_camera(const Camera &c)
+{
+	state->camera = &c;
+	standard_shdata.uniform("projection_matrix", state->camera->get_projection_matrix());
+	changed |= STANDARD_SHDATA|LEGACY_PROJECTION;
+	set_matrix(state->camera->get_view_matrix());
 }
 
 void Renderer::set_matrix(const Matrix &matrix)
@@ -161,6 +158,7 @@ void Renderer::pop_state()
 	if(state_stack.size()==1)
 		throw stack_underflow("Renderer::pop_state");
 
+	const Camera *old_camera = state->camera;
 	const Lighting *old_lighting = state->lighting;
 	const Clipping *old_clipping = state->clipping;
 	state_stack.pop_back();
@@ -172,6 +170,11 @@ void Renderer::pop_state()
 	}
 	shdata_applied = min<unsigned>(shdata_applied, shdata_stack.size());
 	changed |= MATRIX;
+	if(state->camera!=old_camera)
+	{
+		standard_shdata.uniform("projection_matrix", state->camera->get_projection_matrix());
+		changed |= STANDARD_SHDATA|LEGACY_PROJECTION;
+	}
 	if(state->lighting!=old_lighting)
 	{
 		if(state->lighting)
@@ -375,14 +378,16 @@ void Renderer::apply_state()
 		if(!matrices_loaded)
 		{
 			MatrixStack::modelview().push();
-			if(camera)
-			{
-				MatrixStack::projection().push();
-				camera->apply();
-			}
+			MatrixStack::projection().push();
 			matrices_loaded = true;
 		}
 
+		if(changed&LEGACY_PROJECTION)
+		{
+			MatrixStack::projection() = state->camera->get_projection_matrix();
+			changed &= ~LEGACY_PROJECTION;
+		}
+
 		if(changed&LEGACY_MATRIX)
 		{
 			MatrixStack::modelview() = state->modelview_matrix;
@@ -407,6 +412,7 @@ void Renderer::reset_state()
 
 
 Renderer::State::State():
+	camera(0),
 	texture(0),
 	texturing(0),
 	lowest_effect_texunit(TexUnit::get_n_units()),
diff --git a/source/renderer.h b/source/renderer.h
index 157282a5..1f4624ce 100644
--- a/source/renderer.h
+++ b/source/renderer.h
@@ -64,6 +64,7 @@ public:
 private:
 	struct State
 	{
+		const Camera *camera;
 		Matrix modelview_matrix;
 		const Texture *texture;
 		const Texturing *texturing;
@@ -91,13 +92,13 @@ private:
 		LEGACY_CLIPPING = 8,
 		SHADER_DATA = 16,
 		MATERIAL_SHDATA = 32,
-		STANDARD_SHDATA = 64
+		STANDARD_SHDATA = 64,
+		LEGACY_PROJECTION = 128
 	};
 
 	unsigned char changed;
 	bool matrices_loaded;
 	unsigned shdata_applied;
-	const Camera *camera;
 	std::vector<State> state_stack;
 	State *state;
 	ProgramData standard_shdata;
@@ -113,6 +114,12 @@ public:
 	times without an intervening end(). */
 	void begin(const Camera *);
 
+	/** Sets the camera to render from.  The modelview matrix is reset to the
+	camera's view matrix. */
+	void set_camera(const Camera &);
+
+	const Camera *get_camera() const { return state->camera; }
+
 	/** Replaces the Renderer's modelview matrix. */
 	void set_matrix(const Matrix &);
 
@@ -122,8 +129,6 @@ public:
 	/** Returns the current modelview matrix. */
 	const Matrix &get_matrix() const { return state->modelview_matrix; }
 
-	const Camera *get_camera() const { return camera; }
-
 	void set_texture(const Texture *);
 	void set_texturing(const Texturing *);
 	unsigned allocate_effect_texunit();
-- 
2.45.2