From b75ad3def2a808ce1a8b450242a6a838e8c1cdcf Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sun, 3 Feb 2019 15:07:22 -0500
Subject: [PATCH] Updates the multimachine for the ScanTarget world.

---
 .../Implementation/MultiCRTMachine.cpp         | 18 +++++++++++++-----
 .../Implementation/MultiCRTMachine.hpp         |  1 +
 Outputs/OpenGL/ScanTarget.cpp                  |  5 +++++
 Outputs/OpenGL/ScanTarget.hpp                  |  1 +
 Outputs/ScanTarget.hpp                         |  4 ++++
 5 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/Analyser/Dynamic/MultiMachine/Implementation/MultiCRTMachine.cpp b/Analyser/Dynamic/MultiMachine/Implementation/MultiCRTMachine.cpp
index 73e086532..53c2ae3b1 100644
--- a/Analyser/Dynamic/MultiMachine/Implementation/MultiCRTMachine.cpp
+++ b/Analyser/Dynamic/MultiMachine/Implementation/MultiCRTMachine.cpp
@@ -48,16 +48,16 @@ void MultiCRTMachine::perform_parallel(const std::function<void(::CRTMachine::Ma
 void MultiCRTMachine::perform_serial(const std::function<void (::CRTMachine::Machine *)> &function) {
 	std::lock_guard<std::mutex> machines_lock(machines_mutex_);
 	for(const auto &machine: machines_) {
-		CRTMachine::Machine *crt_machine = machine->crt_machine();
+		CRTMachine::Machine *const crt_machine = machine->crt_machine();
 		if(crt_machine) function(crt_machine);
 	}
 }
 
 void MultiCRTMachine::set_scan_target(Outputs::Display::ScanTarget *scan_target) {
-	perform_serial([=](::CRTMachine::Machine *machine) {
-		// TODO.
-//		machine->setup_output(aspect_ratio);
-	});
+	scan_target_ = scan_target;
+
+	CRTMachine::Machine *const crt_machine = machines_.front()->crt_machine();
+	if(crt_machine) crt_machine->set_scan_target(scan_target);
 }
 
 Outputs::Speaker::Speaker *MultiCRTMachine::get_speaker() {
@@ -73,6 +73,14 @@ void MultiCRTMachine::run_for(Time::Seconds duration) {
 }
 
 void MultiCRTMachine::did_change_machine_order() {
+	if(scan_target_) scan_target_->will_change_owner();
+
+	perform_serial([=](::CRTMachine::Machine *machine) {
+		machine->set_scan_target(nullptr);
+	});
+	CRTMachine::Machine *const crt_machine = machines_.front()->crt_machine();
+	if(crt_machine) crt_machine->set_scan_target(scan_target_);
+
 	if(speaker_) {
 		speaker_->set_new_front_machine(machines_.front().get());
 	}
diff --git a/Analyser/Dynamic/MultiMachine/Implementation/MultiCRTMachine.hpp b/Analyser/Dynamic/MultiMachine/Implementation/MultiCRTMachine.hpp
index 6cd886669..bf6b3d083 100644
--- a/Analyser/Dynamic/MultiMachine/Implementation/MultiCRTMachine.hpp
+++ b/Analyser/Dynamic/MultiMachine/Implementation/MultiCRTMachine.hpp
@@ -64,6 +64,7 @@ class MultiCRTMachine: public CRTMachine::Machine {
 		std::vector<Concurrency::AsyncTaskQueue> queues_;
 		MultiSpeaker *speaker_ = nullptr;
 		Delegate *delegate_ = nullptr;
+		Outputs::Display::ScanTarget *scan_target_ = nullptr;
 
 		/*!
 			Performs a parallel for operation across all machines, performing the supplied
diff --git a/Outputs/OpenGL/ScanTarget.cpp b/Outputs/OpenGL/ScanTarget.cpp
index ff4451a12..cff0bf703 100644
--- a/Outputs/OpenGL/ScanTarget.cpp
+++ b/Outputs/OpenGL/ScanTarget.cpp
@@ -209,6 +209,11 @@ void ScanTarget::end_data(size_t actual_length) {
 		data_type_size_);
 }
 
+void ScanTarget::will_change_owner() {
+	allocation_has_failed_ = true;
+	vended_scan_ = nullptr;
+}
+
 void ScanTarget::submit() {
 	if(allocation_has_failed_) {
 		// Reset all pointers to where they were; this also means
diff --git a/Outputs/OpenGL/ScanTarget.hpp b/Outputs/OpenGL/ScanTarget.hpp
index acd36d3d4..d3b6337bc 100644
--- a/Outputs/OpenGL/ScanTarget.hpp
+++ b/Outputs/OpenGL/ScanTarget.hpp
@@ -60,6 +60,7 @@ class ScanTarget: public Outputs::Display::ScanTarget {
 		void end_data(size_t actual_length) override;
 		void submit() override;
 		void announce(Event event, bool is_visible, const Outputs::Display::ScanTarget::Scan::EndPoint &location, uint8_t colour_burst_amplitude) override;
+		void will_change_owner() override;
 
 		bool output_is_visible_ = false;
 
diff --git a/Outputs/ScanTarget.hpp b/Outputs/ScanTarget.hpp
index b7f24a9fa..83de2ef1c 100644
--- a/Outputs/ScanTarget.hpp
+++ b/Outputs/ScanTarget.hpp
@@ -264,6 +264,10 @@ struct ScanTarget {
 		/// It is required that every call to begin_data be paired with a call to end_data.
 		virtual void end_data(size_t actual_length) {}
 
+		/// Tells the scan target that its owner is about to change; this is a hint that existing
+		/// data and scan allocations should be invalidated.
+		virtual void will_change_owner() {}
+
 		/// Marks the end of an atomic set of data. Drawing is best effort, so the scan target should either:
 		///
 		///		(i)	output everything received since the previous submit; or