From 853978004335d158dae6c1867e1d71ead9b36911 Mon Sep 17 00:00:00 2001
From: Warwick <warwick.l.e.new@gmail.com>
Date: Thu, 3 Feb 2022 16:16:32 +0000
Subject: [PATCH] Using a different set of maths to manipulate the camera

---
 src/PlayerCamera.cpp | 49 ++++++++++----------------------------------
 src/PlayerCamera.h   |  8 +++-----
 2 files changed, 14 insertions(+), 43 deletions(-)

diff --git a/src/PlayerCamera.cpp b/src/PlayerCamera.cpp
index 494568d..cde03a9 100644
--- a/src/PlayerCamera.cpp
+++ b/src/PlayerCamera.cpp
@@ -8,50 +8,23 @@ PlayerCamera::PlayerCamera() {
 PlayerCamera::~PlayerCamera() {}
 
 void PlayerCamera::tick() {
-  pos.vectorPos = glm::vec4(0.0f, 0.0f, 5.0f, 1.0f);
-  // Get the mouse movement
-  int mouseX, mouseY;
-  SDL_GetRelativeMouseState(&mouseX, &mouseY);
+  // get camera right
+  glm::vec3 up = glm::vec3(0.0f, 1.0f, 0.0f);
+  glm::vec3 cameraRight = glm::normalize(glm::cross(up, cameraForward));
 
-  // Calculate rotation
-  pos.yaw -= mouseX * mouseSensitivity;
-  pos.pitch -= mouseX * mouseSensitivity;
+  // get position to look at
+  glm::vec3 cameraTarget = cameraPosition + cameraForward;
 
-  // Stop camera from looking too far up/down
-  const float maxPitch = glm::radians(89.0f);
-  if (pos.pitch > maxPitch)
-    pos.pitch = maxPitch;
-  if (pos.pitch < -maxPitch)
-    pos.pitch = -maxPitch;
+  // MVP stuff
+  glm::mat4 model = glm::mat4(1.0f);
 
-  glm::vec4 playerForward(0.0f, 0.0f, -1.0f, 0.0f);
-  glm::mat4 playerRotation;
-  // Rotate yaw
-  playerRotation =
-      glm::rotate(playerRotation, pos.yaw, glm::vec3(0.0f, 1.0f, 0.0f));
-  // Rotate pitch
-  playerRotation =
-      glm::rotate(playerRotation, pos.pitch, glm::vec3(1.0f, 0.0f, 0.0f));
-  playerForward = playerRotation * playerForward;
+  glm::mat4 view;
+  view = glm::lookAt(cameraPosition, cameraTarget, up);
 
-  // until we add keyboard stuff set the position to a static value
-
-  // create MVP
-  glm::mat4 view = glm::lookAt(
-      glm::vec3(pos.vectorPos),
-      glm::vec3(pos.vectorPos +
-                playerForward /* glm::vec4(0.0f, 0.0f, -1.0f, 0.0f) */),
-      glm::vec3(0.0f, 1.0f, 0.0f));
-
-  // Projection matrix : 45° Field of View, 4:3 ratio, display range : 0.1
-  // unit <-> 100 units
-  float width = 800;
-  float height = 600;
   glm::mat4 projection = glm::perspective(
-      glm::radians(45.0f), (float)width / (float)height, 0.1f, 100.0f);
-  glm::mat4 transform = glm::mat4(1.0f);
+      glm::radians(45.0f), (float)800 / (float)600, 0.1f, 100.0f);
 
-  MVP = projection * view * transform;
+  MVP = projection * view * model;
 }
 
 glm::mat4 PlayerCamera::getMVP() { return MVP; }
diff --git a/src/PlayerCamera.h b/src/PlayerCamera.h
index b100a10..5c9b9f9 100644
--- a/src/PlayerCamera.h
+++ b/src/PlayerCamera.h
@@ -16,11 +16,9 @@ private:
   const float mouseSensitivity = 0.005f;
 
   // Player position
-  struct position {
-    glm::vec4 vectorPos;
-    float pitch;
-    float yaw;
-  } pos;
+  glm::vec3 cameraPosition = glm::vec3(0.0f, 0.0f, 3.0f);
+  glm::vec3 cameraForward = glm::vec3(0.0f, 0.0f, -1.0f);
+  glm::vec3 cameraUp = glm::vec3(0.0f, 0.0f, -1.0f);
 
   // Mouse position
   int mouseX, mouseY;