separate overlays by screen

Makefile

@@ -1,7 +1,7 @@
 
 
 build:
-	CPATH=. g++ -Wall -lX11 -lglfw -lGL openvr/libopenvr_api.so src/*.cpp -o overlay
+	CPATH=. g++ -Wall -lX11 -lXrandr -lglfw -lGL openvr/libopenvr_api.so src/*.cpp -o overlay
 
 run: build
 	./overlay

src/app.cpp

@@ -1,6 +1,7 @@
 #include "app.h"
 #include "panel.h"
 #include "util.h"
+#include <X11/extensions/Xrandr.h>
 #include <cassert>
 
 App::App()
@@ -11,7 +12,21 @@ App::App()
 	InitX11();
 	InitGLFW();
 
-	_panels.push_back(Panel(this, 0, 0, 0, _root_width, _root_height));
+	glGenTextures(1, &_gl_frame);
+	glBindTexture(GL_TEXTURE_2D, _gl_frame);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+
+	int monitor_count;
+	XRRMonitorInfo *monitor_info = XRRGetMonitors(_xdisplay, _root_window, 1, &monitor_count);
+	printf("found %d monitors:\n", monitor_count);
+
+	for (int i = 0; i < monitor_count; i++)
+	{
+		XRRMonitorInfo mon = monitor_info[i];
+		printf("screen %d: pos(%d, %d) wh(%d, %d)\n", i, mon.x, mon.y, mon.width, mon.height);
+
+		_panels.push_back(Panel(this, i, mon.x, mon.y, mon.width, mon.height));
+	}
 }
 
 App::~App()
@@ -65,6 +80,17 @@ void App::InitGLFW()
 
 void App::Update()
 {
+	auto frame = XGetImage(
+		_xdisplay,
+		_root_window,
+		0, 0,
+		_root_width, _root_height,
+		AllPlanes,
+		ZPixmap);
+	glBindTexture(GL_TEXTURE_2D, _gl_frame);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, _root_width, _root_height, 0, GL_BGRA, GL_UNSIGNED_BYTE, frame->data);
+	XDestroyImage(frame);
+
 	for (auto &panel : _panels)
 	{
 		panel.Update();

src/app.h

@@ -1,3 +1,4 @@
+#define GL_GLEXT_PROTOTYPES
 #include "util.h"
 #include <GLFW/glfw3.h>
 #include <X11/Xutil.h>
@@ -25,6 +26,7 @@ class App
 	Display *_xdisplay;
 	Window _root_window;
 	GLFWwindow *_gl_window;
+	GLuint _gl_frame;
 
 	int _root_width;
 	int _root_height;

src/panel.cpp

@@ -2,7 +2,6 @@
 #include "app.h"
 #include "util.h"
 
-#include <GLFW/glfw3.h>
 #include <X11/Xutil.h>
 #include <glm/glm.hpp>
 
@@ -19,6 +18,11 @@ Panel::Panel(App *app, int index, int x, int y, int width, int height)
 	_active_hand = -1;
 	glGenTextures(1, &_gl_texture);
 	glBindTexture(GL_TEXTURE_2D, _gl_texture);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexImage2D(
+		GL_TEXTURE_2D, 0, GL_RGB,
+		_width, _height, 0,
+		GL_BGRA, GL_UNSIGNED_BYTE, 0);
 
 	_texture.eColorSpace = vr::ColorSpace_Auto;
 	_texture.eType = vr::TextureType_OpenGL;
@@ -29,7 +33,7 @@ Panel::Panel(App *app, int index, int x, int y, int width, int height)
 		auto overlay_create_err = _app->vr_overlay->CreateOverlay(_name.c_str(), _name.c_str(), &_id);
 		assert(overlay_create_err == 0);
 		_app->vr_overlay->ShowOverlay(_id);
-		_app->vr_overlay->SetOverlayWidthInMeters(_id, 2.5f);
+		// _app->vr_overlay->SetOverlayWidthInMeters(_id, 2.5f);
 		uint8_t col[4] = {20, 50, 50, 255};
 		_app->vr_overlay->SetOverlayRaw(_id, &col, 1, 1, 4);
 		printf("Created overlay instance %d\n", _index);
@@ -37,7 +41,9 @@ Panel::Panel(App *app, int index, int x, int y, int width, int height)
 		// (flipping uv on y axis because opengl and xorg are opposite)
 		vr::VRTextureBounds_t bounds{0, 1, 1, 0};
 		_app->vr_overlay->SetOverlayTextureBounds(_id, &bounds);
-		_app->vr_overlay->SetOverlayTransformAbsolute(_id, _app->_tracking_origin, &DEFAULT_POSE);
+		vr::HmdMatrix34_t start_pose = DEFAULT_POSE;
+		start_pose.m[0][3] += index * 1.5f;
+		_app->vr_overlay->SetOverlayTransformAbsolute(_id, _app->_tracking_origin, &start_pose);
 	}
 }
 
@@ -76,9 +82,12 @@ void Panel::Update()
 
 void Panel::Render()
 {
-	auto frame = XGetImage(_app->_xdisplay, _app->_root_window, _x, _y, _width, _height, AllPlanes, ZPixmap);
-	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, _width, _height, 0, GL_BGRA, GL_UNSIGNED_BYTE, frame->data);
-	XDestroyImage(frame);
+	glCopyImageSubData(
+		_app->_gl_frame, GL_TEXTURE_2D, 0,
+		_x, _y, 0,
+		_gl_texture, GL_TEXTURE_2D, 0,
+		0, 0, 0,
+		_width, _height, 1);
 
 	auto set_texture_err = _app->vr_overlay->SetOverlayTexture(_id, &_texture);
 	assert(set_texture_err == 0);

src/panel.h

@@ -1,3 +1,4 @@
+#define GL_GLEXT_PROTOTYPES
 #include "util.h"
 #include <GLFW/glfw3.h>
 #include <string>