change alpha with trackpad while holding a panel

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

@@ -1,17 +1,39 @@
 #include "app.h"
 #include "panel.h"
 #include "util.h"
+#include <X11/extensions/Xrandr.h>
 #include <cassert>
 
 App::App()
 {
-	_tracking_origin = vr::ETrackingUniverseOrigin::TrackingUniverseStanding;
+	_tracking_origin = vr::TrackingUniverseStanding;
 
 	InitOVR();
 	InitX11();
 	InitGLFW();
+	printf("\n");
 
-	_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);
+
+	float pixels_per_meter = 1920;
+	float x_min = -(monitor_info[0].x + monitor_info[0].width / 2.0f);
+
+	for (int i = 0; i < monitor_count; i++)
+	{
+		XRRMonitorInfo mon = monitor_info[i];
+		printf("screen %d: pos(%d, %d) %dx%d\n", i, mon.x, mon.y, mon.width, mon.height);
+
+		float pos_x = (x_min + mon.x) / pixels_per_meter;
+		float pos_y = 1.2f;
+		vr::HmdMatrix34_t start_pose = {{{1, 0, 0, pos_x}, {0, 1, 0, pos_y}, {0, 0, 1, 0}}};
+		_panels.push_back(Panel(this, start_pose, i, mon.x, mon.y, mon.width, mon.height));
+	}
 }
 
 App::~App()
@@ -36,8 +58,9 @@ void App::InitX11()
 void App::InitOVR()
 {
 	vr::EVRInitError init_err;
-	vr_sys = vr::VR_Init(&init_err, vr::EVRApplicationType::VRApplication_Background);
-	if (init_err == vr::EVRInitError::VRInitError_Init_NoServerForBackgroundApp)
+	// would normally be using VRApplication_Overlay, but Background allows it to quit if steamvr is not running, instead of opening steamvr.
+	vr_sys = vr::VR_Init(&init_err, vr::VRApplication_Background);
+	if (init_err == vr::VRInitError_Init_NoServerForBackgroundApp)
 	{
 		printf("SteamVR is not running\n");
 		exit(1);
@@ -55,7 +78,7 @@ void App::InitGLFW()
 {
 	assert(glfwInit() == true);
 	glfwWindowHint(GLFW_VISIBLE, false);
-	// TODO this is creating a 1x1 window, should it be bigger?
+	// creating a 1x1 window, since it is hidden anyway
 	_gl_window = glfwCreateWindow(1, 1, "Overlay", nullptr, nullptr);
 	assert(_gl_window != nullptr);
 	glfwMakeContextCurrent(_gl_window);
@@ -64,12 +87,31 @@ 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();
 	}
 }
 
+std::vector<TrackerID> App::GetControllers()
+{
+	static const auto max_len = 64;
+	TrackerID controllers[max_len];
+	int controller_count = vr_sys->GetSortedTrackedDeviceIndicesOfClass(vr::TrackedDeviceClass_Controller, controllers, max_len);
+	return std::vector<TrackerID>(controllers, controllers + controller_count);
+}
+
 glm::mat4 App::GetTrackerPose(TrackerID tracker)
 {
 	vr::VRControllerState_t state;
@@ -83,21 +125,24 @@ glm::mat4 App::GetTrackerPose(TrackerID tracker)
 	return ConvertMat(tracked_pose.mDeviceToAbsoluteTracking);
 }
 
-bool App::IsGrabActive(vr::TrackedDeviceIndex_t controller)
+vr::VRControllerState_t App::GetControllerState(TrackerID controller)
 {
 	vr::VRControllerState_t state;
 	auto get_state_err = vr_sys->GetControllerState(controller, &state, sizeof(vr::VRControllerState_t));
 	if (get_state_err == false)
-	{
-		printf("Error getting controller state: %d\n", get_state_err);
-		return false;
-	}
-	// printf("got state\n");
+		printf("failed to get state of controller %d\n", controller);
+	return state;
+}
 
-	auto trigger_mask = vr::ButtonMaskFromId(vr::EVRButtonId::k_EButton_SteamVR_Trigger);
-	auto b_mask = vr::ButtonMaskFromId(vr::EVRButtonId::k_EButton_IndexController_B);
-	auto mask = trigger_mask | b_mask;
-	return (state.ulButtonPressed & mask) == mask;
+bool App::IsGrabActive(TrackerID controller)
+{
+	vr::VRControllerState_t state;
+	auto get_state_err = vr_sys->GetControllerState(controller, &state, sizeof(vr::VRControllerState_t));
+	if (get_state_err == false)
+		return false;
+
+	auto trigger_mask = vr::ButtonMaskFromId(vr::k_EButton_SteamVR_Trigger);
+	return state.ulButtonPressed & trigger_mask;
 }
 
 CursorPos App::GetCursorPosition()

src/app.h

@@ -1,3 +1,4 @@
+#define GL_GLEXT_PROTOTYPES
 #include "util.h"
 #include <GLFW/glfw3.h>
 #include <X11/Xutil.h>
@@ -17,13 +18,16 @@ class App
 	~App();
 	void Update();
 
+	std::vector<TrackerID> GetControllers();
 	glm::mat4 GetTrackerPose(TrackerID tracker);
-	bool IsGrabActive(vr::TrackedDeviceIndex_t controller);
+	vr::VRControllerState_t GetControllerState(TrackerID controller);
+	bool IsGrabActive(TrackerID controller);
 	CursorPos GetCursorPosition();
 
 	Display *_xdisplay;
 	Window _root_window;
 	GLFWwindow *_gl_window;
+	GLuint _gl_frame;
 
 	int _root_width;
 	int _root_height;

src/panel.cpp

@@ -2,11 +2,11 @@
 #include "app.h"
 #include "util.h"
 
-#include <GLFW/glfw3.h>
 #include <X11/Xutil.h>
+#include <glm/common.hpp>
 #include <glm/glm.hpp>
 
-Panel::Panel(App *app, int index, int x, int y, int width, int height)
+Panel::Panel(App *app, vr::HmdMatrix34_t start_pose, int index, int x, int y, int width, int height)
 	: _app(app),
 	  _index(index),
 	  _x(x),
@@ -16,12 +16,18 @@ Panel::Panel(App *app, int index, int x, int y, int width, int height)
 {
 	_name = "screen_view_" + std::to_string(index);
 	_alpha = 1.0f;
+	_meters = 1.0f;
 	_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::EColorSpace::ColorSpace_Auto;
-	_texture.eType = vr::ETextureType::TextureType_OpenGL;
+	_texture.eColorSpace = vr::ColorSpace_Auto;
+	_texture.eType = vr::TextureType_OpenGL;
 	_texture.handle = (void *)(uintptr_t)_gl_texture;
 
 	// create overlay
@@ -29,7 +35,6 @@ 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);
 		uint8_t col[4] = {20, 50, 50, 255};
 		_app->vr_overlay->SetOverlayRaw(_id, &col, 1, 1, 4);
 		printf("Created overlay instance %d\n", _index);
@@ -37,8 +42,7 @@ 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);
+		_app->vr_overlay->SetOverlayTransformAbsolute(_id, _app->_tracking_origin, &start_pose);
 	}
 }
 
@@ -49,44 +53,56 @@ void Panel::Update()
 
 	if (!_is_held)
 	{
-		vr::TrackedDeviceIndex_t controllers[8];
-		auto controller_count = _app->vr_sys->GetSortedTrackedDeviceIndicesOfClass(vr::ETrackedDeviceClass::TrackedDeviceClass_Controller, controllers, 8);
-
-		for (unsigned int i = 0; i < controller_count; i++)
+		for (auto controller : _app->GetControllers())
+		{
+			if (_app->IsGrabActive(controller))
 			{
-			auto controller = controllers[i];
-
 				vr::HmdMatrix34_t overlay_pose;
 				vr::ETrackingUniverseOrigin tracking_universe;
 				_app->vr_overlay->GetOverlayTransformAbsolute(_id, &tracking_universe, &overlay_pose);
 
-			auto controller_pose = _app->GetTrackerPose(controller);
-			auto controller_pos = glm::vec3(controller_pose[3]);
-			auto overlay_pos = glm::vec3(ConvertMat(overlay_pose)[3]);
+				auto controller_pos = GetPos(_app->GetTrackerPose(controller));
 
-			bool close_enough = glm::length(overlay_pos - controller_pos) < 1.0f;
-			// close_enough = true;
+				auto local_pos = glm::inverse(ConvertMat(overlay_pose)) * glm::vec4(controller_pos - GetPos(overlay_pose), 0);
 
-			if (close_enough && _app->IsGrabActive(controller))
+				float grab_area_thickness = 0.3f;
+				bool close_enough = glm::abs(local_pos.z) < grab_area_thickness;
+				close_enough &= glm::abs(local_pos.x) < _meters / 2.0f;
+				close_enough &= glm::abs(local_pos.y) < _meters / 2.0f;
+
+				if (close_enough)
 				{
 					ControllerGrab(controller);
 				}
 			}
 		}
+	}
 	else
 	{
 		if (!_app->IsGrabActive(_active_hand))
 		{
 			ControllerRelease();
 		}
+		auto state = _app->GetControllerState(_active_hand);
+		auto touchpad = state.rAxis[0];
+		if (touchpad.x != 0.0f)
+		{
+			// TODO take into account the current framerate
+			_alpha += touchpad.x * 0.05;
+			_alpha = glm::clamp(_alpha, 0.1f, 1.0f);
+			_app->vr_overlay->SetOverlayAlpha(_id, _alpha);
+		}
 	}
 }
 
 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);
@@ -94,13 +110,20 @@ void Panel::Render()
 
 void Panel::UpdateCursor()
 {
-	auto global = _app->GetCursorPosition();
+	auto global_pos = _app->GetCursorPosition();
+	if (global_pos.x < _x || global_pos.x >= _x + _width || global_pos.y < _y || global_pos.y >= _y + _height)
+	{
+		_app->vr_overlay->ClearOverlayCursorPositionOverride(_id);
+		return;
+	}
+	int local_x = global_pos.x - _x;
+	int local_y = global_pos.y - _y;
+
 	// TODO: make this work when aspect ratio is >1 (root window is taller than it is wide)
-	// TODO take into account that the panel is smaller than the root window
 	float ratio = (float)_height / (float)_width;
 	float top_edge = 0.5f - ratio / 2.0f;
-	float x = global.x / (float)_width;
-	float y = 1.0f - (global.y / (float)_width + top_edge);
+	float x = local_x / (float)_width;
+	float y = 1.0f - (local_y / (float)_width + top_edge);
 	auto pos = vr::HmdVector2_t{x, y};
 	_app->vr_overlay->SetOverlayCursorPositionOverride(_id, &pos);
 }
@@ -111,6 +134,8 @@ void Panel::ControllerGrab(TrackerID controller)
 	_is_held = true;
 	_active_hand = controller;
 
+	_app->vr_overlay->SetOverlayColor(_id, 0.6f, 1.0f, 1.0f);
+
 	vr::HmdMatrix34_t abs_pose;
 	vr::ETrackingUniverseOrigin tracking_universe;
 
@@ -129,6 +154,8 @@ void Panel::ControllerRelease()
 	printf("Released panel %d\n", _index);
 	_is_held = false;
 
+	_app->vr_overlay->SetOverlayColor(_id, 1.0f, 1.0f, 1.0f);
+
 	vr::HmdMatrix34_t relative_pose;
 	_app->vr_overlay->GetOverlayTransformTrackedDeviceRelative(_id, &_active_hand, &relative_pose);
 	auto relative_mat = ConvertMat(relative_pose);

src/panel.h

@@ -1,14 +1,16 @@
+#define GL_GLEXT_PROTOTYPES
 #include "util.h"
 #include <GLFW/glfw3.h>
 #include <string>
 
 const vr::HmdMatrix34_t DEFAULT_POSE = {{{1, 0, 0, 0}, {0, 1, 0, 1}, {0, 0, 1, 0}}};
+
 class App;
 
 class Panel
 {
   public:
-	Panel(App *app, int index, int xmin, int xmax, int ymin, int ymax);
+	Panel(App *app, vr::HmdMatrix34_t start_pose, int index, int xmin, int xmax, int ymin, int ymax);
 
 	void Update();
 
@@ -26,8 +28,9 @@ class Panel
 	TrackerID _active_hand;
 	bool _is_held;
 
-	unsigned int _x, _y;
-	unsigned int _width, _height;
+	int _x, _y;
+	int _width, _height;
+	float _meters;
 	float _alpha;
 
 	vr::Texture_t _texture;

src/util.h

@@ -46,3 +46,8 @@ inline glm::vec3 GetPos(glm::mat4x4 mat)
 {
 	return glm::vec3(mat[3][0], mat[3][1], mat[3][2]);
 }
+
+inline glm::vec3 GetPos(vr::HmdMatrix34_t mat)
+{
+	return glm::vec3(mat.m[0][3], mat.m[1][3], mat.m[2][3]);
+}