From: Mikko Rasa <tdb@tdb.fi>
Date: Tue, 9 Nov 2021 10:37:15 +0000 (+0200)
Subject: Create a Device class to hold the graphics context
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=f0414f06fc2463e9765c9492dce60e0468dceb3c;p=libs%2Fgl.git

Create a Device class to hold the graphics context

This is necessary to make the selected backend transparent to
applications, and also because Vulkan needs access to the VkDevice.
---

diff --git a/demos/desertpillars/source/desertpillars.cpp b/demos/desertpillars/source/desertpillars.cpp
index 53f0a86c..532a9499 100644
--- a/demos/desertpillars/source/desertpillars.cpp
+++ b/demos/desertpillars/source/desertpillars.cpp
@@ -23,10 +23,10 @@ DesertPillars::Options::Options()
 
 DesertPillars::DesertPillars(int, char **):
 	window(display, opts.wnd_opts),
-	gl_ctx(window, opts.gl_opts),
+	gl_device(window, opts.gl_opts),
 	keyboard(window),
 	resources(&res_mgr),
-	view(window, gl_ctx),
+	view(window),
 	camera(resources.get<GL::Camera>("Camera.camera")),
 	lighting(resources.get<GL::Lighting>("Desert.lightn")),
 	sphere(resources.get<GL::Object>("Sphere.object")),
diff --git a/demos/desertpillars/source/desertpillars.h b/demos/desertpillars/source/desertpillars.h
index 4e478099..352b8c2c 100644
--- a/demos/desertpillars/source/desertpillars.h
+++ b/demos/desertpillars/source/desertpillars.h
@@ -5,6 +5,7 @@
 #include <msp/core/application.h>
 #include <msp/datafile/directorysource.h>
 #include <msp/gl/camera.h>
+#include <msp/gl/device.h>
 #include <msp/gl/environmentmap.h>
 #include <msp/gl/objectinstance.h>
 #include <msp/gl/orderedscene.h>
@@ -16,7 +17,6 @@
 #include <msp/gl/technique.h>
 #include <msp/gl/windowview.h>
 #include <msp/graphics/display.h>
-#include <msp/graphics/glcontext.h>
 #include <msp/graphics/window.h>
 #include <msp/input/keyboard.h>
 #include <msp/time/timestamp.h>
@@ -69,7 +69,7 @@ private:
 	Msp::Graphics::Display display;
 	Options opts;
 	Msp::Graphics::Window window;
-	Msp::Graphics::GLContext gl_ctx;
+	Msp::GL::Device gl_device;
 	Msp::Input::Keyboard keyboard;
 	Msp::GL::ResourceManager res_mgr;
 	Resources resources;
diff --git a/source/backends/opengl/device_backend.cpp b/source/backends/opengl/device_backend.cpp
new file mode 100644
index 00000000..5429c0c1
--- /dev/null
+++ b/source/backends/opengl/device_backend.cpp
@@ -0,0 +1,11 @@
+#include "device_backend.h"
+
+namespace Msp {
+namespace GL {
+
+OpenGLDevice::OpenGLDevice(Graphics::Window &wnd, const Graphics::GLOptions &opts):
+	context(wnd, opts)
+{ }
+
+} // namespace GL
+} // namespace Msp
diff --git a/source/backends/opengl/device_backend.h b/source/backends/opengl/device_backend.h
new file mode 100644
index 00000000..e64352d3
--- /dev/null
+++ b/source/backends/opengl/device_backend.h
@@ -0,0 +1,26 @@
+#ifndef MSP_GL_DEVICE_BACKEND_H_
+#define MSP_GL_DEVICE_BACKEND_H_
+
+#include <msp/core/noncopyable.h>
+#include <msp/graphics/glcontext.h>
+
+namespace Msp {
+namespace GL {
+
+class OpenGLDevice: public NonCopyable
+{
+protected:
+	Graphics::GLContext context;
+
+	OpenGLDevice(Graphics::Window &, const Graphics::GLOptions &);
+
+	Graphics::GLContext &get_context() { return context; }
+};
+
+using DeviceBackend = OpenGLDevice;
+using DeviceOptions = Graphics::GLOptions;
+
+} // namespace GL
+} // namespace Msp
+
+#endif
diff --git a/source/core/device.cpp b/source/core/device.cpp
new file mode 100644
index 00000000..9a24a1f2
--- /dev/null
+++ b/source/core/device.cpp
@@ -0,0 +1,29 @@
+#include "device.h"
+#include "error.h"
+
+namespace Msp {
+namespace GL {
+
+Device *Device::current = 0;
+
+Device::Device(Graphics::Window &w, const DeviceOptions &o):
+	DeviceBackend(w, o)
+{
+	current = this;
+}
+
+Device::~Device()
+{
+	if(this==current)
+		current = 0;
+}
+
+Device &Device::get_current()
+{
+	if(!current)
+		throw invalid_operation("no current device");
+	return *current;
+}
+
+} // namespace GL
+} // namespace Msp
diff --git a/source/core/device.h b/source/core/device.h
new file mode 100644
index 00000000..6a6a7608
--- /dev/null
+++ b/source/core/device.h
@@ -0,0 +1,32 @@
+#ifndef MSP_GL_DEVICE_H_
+#define MSP_GL_DEVICE_H_
+
+#include <msp/graphics/window.h>
+#include "device_backend.h"
+
+namespace Msp {
+namespace GL {
+
+/**
+Represents a graphics device.  An instance must be created to use the library.
+*/
+class Device: public DeviceBackend
+{
+	friend DeviceBackend;
+
+private:
+	static Device *current;
+
+public:
+	Device(Graphics::Window &, const DeviceOptions & = DeviceOptions());
+	~Device();
+
+	using DeviceBackend::get_context;
+
+	static Device &get_current();
+};
+
+} // namespace GL
+} // namespace Msp
+
+#endif
diff --git a/source/render/windowview.cpp b/source/render/windowview.cpp
index b32a0b67..e139436b 100644
--- a/source/render/windowview.cpp
+++ b/source/render/windowview.cpp
@@ -6,10 +6,10 @@ using namespace std;
 namespace Msp {
 namespace GL {
 
-WindowView::WindowView(Graphics::Window &w, Graphics::GLContext &c):
+WindowView::WindowView(Graphics::Window &w):
 	View(Framebuffer::system()),
 	window(w),
-	context(c)
+	device(Device::get_current())
 {
 	window.signal_resize.connect(sigc::mem_fun(this, &WindowView::window_resized));
 	window_resized(window.get_width(), window.get_height());
@@ -18,7 +18,7 @@ WindowView::WindowView(Graphics::Window &w, Graphics::GLContext &c):
 void WindowView::render(Renderer &renderer)
 {
 	View::render(renderer);
-	context.swap_buffers();
+	device.get_context().swap_buffers();
 }
 
 void WindowView::window_resized(unsigned w, unsigned h)
diff --git a/source/render/windowview.h b/source/render/windowview.h
index 9646a65d..028e9805 100644
--- a/source/render/windowview.h
+++ b/source/render/windowview.h
@@ -2,8 +2,8 @@
 #define MSP_GL_WINDOWVIEW_H_
 
 #include <sigc++/trackable.h>
-#include <msp/graphics/glcontext.h>
 #include <msp/graphics/window.h>
+#include "device.h"
 #include "view.h"
 
 namespace Msp {
@@ -21,13 +21,12 @@ class WindowView: public View, public sigc::trackable
 {
 private:
 	Graphics::Window &window;
-	Graphics::GLContext &context;
+	Device &device;
 
 public:
-	WindowView(Graphics::Window &, Graphics::GLContext &);
+	WindowView(Graphics::Window &);
 
 	Graphics::Window &get_window() { return window; }
-	Graphics::GLContext &get_context() { return context; }
 	virtual unsigned get_width() const { return window.get_width(); }
 	virtual unsigned get_height() const { return window.get_height(); }
 
diff --git a/tools/viewer.cpp b/tools/viewer.cpp
index fde5b8d4..b6452a3c 100644
--- a/tools/viewer.cpp
+++ b/tools/viewer.cpp
@@ -5,12 +5,14 @@
 #include <msp/datafile/packsource.h>
 #include <msp/fs/stat.h>
 #include <msp/fs/utils.h>
-#include <msp/graphics/simplewindow.h>
+#include <msp/graphics/display.h>
+#include <msp/graphics/window.h>
 #include <msp/gl/animatedobject.h>
 #include <msp/gl/animation.h>
 #include <msp/gl/animationplayer.h>
 #include <msp/gl/blend.h>
 #include <msp/gl/camera.h>
+#include <msp/gl/device.h>
 #include <msp/gl/directionallight.h>
 #include <msp/gl/framebuffer.h>
 #include <msp/gl/lighting.h>
@@ -63,7 +65,7 @@ private:
 	Options opts;
 	Graphics::Display display;
 	Graphics::Window window;
-	Graphics::GLContext gl_ctx;
+	GL::Device gl_device;
 	Input::Mouse mouse;
 	Resources resources;
 	GL::WindowView view;
@@ -132,9 +134,9 @@ Viewer::Options::Options(int argc, char **argv)
 Viewer::Viewer(int argc, char **argv):
 	opts(argc, argv),
 	window(display, opts.wnd_opts),
-	gl_ctx(window, opts.gl_opts),
+	gl_device(window, opts.gl_opts),
 	mouse(window),
-	view(window, gl_ctx),
+	view(window),
 	sequence(0),
 	renderable(0),
 	anim_object(0),