From ce60561dfdb3d3cb583bcc38cbcb93b9cd1b13a6 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Tue, 26 Jan 2021 21:13:41 +0000
Subject: Basic mouse navigation

---
 application/main.cpp | 42 ++++++++++++++++++++++++++++++++++++++++++
 gfx/gl/camera.cpp    |  6 ++++++
 gfx/gl/camera.h      |  1 +
 3 files changed, 49 insertions(+)

diff --git a/application/main.cpp b/application/main.cpp
index fe81b88..912fa4f 100644
--- a/application/main.cpp
+++ b/application/main.cpp
@@ -82,6 +82,7 @@ public:
 		auto t_start = std::chrono::high_resolution_clock::now();
 		const auto framelen = std::chrono::milliseconds {1000} / 120;
 
+		bool mrb {false}, ctrl {false};
 		while (isRunning) {
 			while (SDL_PollEvent(&e)) {
 				switch (e.type) {
@@ -108,9 +109,50 @@ public:
 							case SDLK_KP_9:
 								camera.RotateY(-0.04);
 								break;
+							case SDLK_LCTRL:
+							case SDLK_RCTRL:
+								ctrl = true;
+								break;
 						}
 						shader.setView(camera.GetViewProjection());
 						break;
+					case SDL_KEYUP:
+						switch (e.key.keysym.sym) {
+							case SDLK_LCTRL:
+							case SDLK_RCTRL:
+								ctrl = false;
+								break;
+						}
+						break;
+					case SDL_MOUSEBUTTONDOWN:
+						switch (e.button.button) {
+							case SDL_BUTTON_RIGHT:
+								SDL_SetRelativeMouseMode(SDL_TRUE);
+								mrb = true;
+								break;
+						}
+						break;
+					case SDL_MOUSEBUTTONUP:
+						switch (e.button.button) {
+							case SDL_BUTTON_RIGHT:
+								SDL_SetRelativeMouseMode(SDL_FALSE);
+								mrb = false;
+								break;
+						}
+						break;
+					case SDL_MOUSEMOTION:
+						if (mrb) {
+							if (ctrl) {
+								camera.RotateY(-0.01F * e.motion.xrel);
+								camera.Pitch(-0.01F * e.motion.yrel);
+							}
+							else {
+								camera.MoveRight(e.motion.xrel);
+								camera.SlideForward(e.motion.yrel);
+							}
+							shader.setView(camera.GetViewProjection());
+						}
+						break;
 				}
 			}
 
diff --git a/gfx/gl/camera.cpp b/gfx/gl/camera.cpp
index b4a76d0..2f48ca5 100644
--- a/gfx/gl/camera.cpp
+++ b/gfx/gl/camera.cpp
@@ -19,6 +19,12 @@ Camera::MoveForward(float amt)
 	pos += forward * amt;
 }
 
+void
+Camera::SlideForward(float amt)
+{
+	pos += forward * amt * glm::vec3 {1, 0, 1};
+}
+
 void
 Camera::MoveRight(float amt)
 {
diff --git a/gfx/gl/camera.h b/gfx/gl/camera.h
index fa4296d..90d88a3 100644
--- a/gfx/gl/camera.h
+++ b/gfx/gl/camera.h
@@ -10,6 +10,7 @@ public:
 	[[nodiscard]] glm::mat4 GetViewProjection() const;
 
 	void MoveForward(float amt);
+	void SlideForward(float amt);
 	void MoveRight(float amt);
 	void Pitch(float angle);
 	void RotateY(float angle);
-- 
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