From e618d735e1ad74131d76bf96b408e78b0f730dfc Mon Sep 17 00:00:00 2001
From: MrLetsplay2003 <mr.letsplay2003@gmail.com>
Date: Thu, 17 Nov 2022 18:27:34 +0100
Subject: [PATCH] Improve walking on slopes

---
 .../cpp/player/defaultplayercontroller.cpp      | 17 +++++++++++++----
 src/kekengine/include/defaultplayercontroller.h |  3 ---
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/kekengine/cpp/player/defaultplayercontroller.cpp b/src/kekengine/cpp/player/defaultplayercontroller.cpp
index 1b48c13..1401f9c 100644
--- a/src/kekengine/cpp/player/defaultplayercontroller.cpp
+++ b/src/kekengine/cpp/player/defaultplayercontroller.cpp
@@ -30,14 +30,16 @@ static bool castPlayer(glm::vec3 pos, glm::vec3 delta, const btCollisionObject *
 	return true;
 }
 
-bool DefaultPlayerController::checkPlayerGrounded() {
+static bool checkPlayerGrounded(float groundDistance, float maxWalkAngle, const btCollisionObject **outGround, glm::vec3 *outNormal) {
 	glm::vec3 groundDir = glm::vec3(0,-groundDistance,0);
 
 	glm::vec3 point;
 	glm::vec3 normal;
-	bool onGround = castPlayer(kekData.player->getPosition(), groundDir, nullptr, nullptr, &point, &normal);
+	bool onGround = castPlayer(kekData.player->getPosition(), groundDir, outGround, nullptr, &point, &normal);
 	if(!onGround) return false;
 
+	if(outNormal) *outNormal = normal;
+
 	normal = glm::normalize(normal);
 
 	float angle = 180.0f - glm::angle(normal, glm::normalize(groundDir)) / M_PI * 180.0f;
@@ -77,7 +79,7 @@ glm::vec3 DefaultPlayerController::move(glm::vec3 movement) {
 
 		totalMovement += normal * 0.001f;
 
-		glm::vec3 remainingProjected = glm::normalize(glm::cross(normal, glm::cross(movement, normal))) * glm::length(movement) * (1 - frac);
+		glm::vec3 remainingProjected = glm::normalize(glm::cross(normal, glm::cross(movement, normal))) * glm::length(movement) * (1 - frac) * (angle / 90.0f);
 		movement = remainingProjected;
 		count++;
 	}
@@ -87,7 +89,9 @@ glm::vec3 DefaultPlayerController::move(glm::vec3 movement) {
 }
 
 void DefaultPlayerController::update() {
-	bool onGround = checkPlayerGrounded();
+	const btCollisionObject *ground;
+	glm::vec3 groundNormal;
+	bool onGround = checkPlayerGrounded(groundDistance, maxWalkAngle, &ground, &groundNormal);
 	kekData.player->onGround = onGround;
 
 	if(!onGround) {
@@ -120,6 +124,11 @@ void DefaultPlayerController::update() {
 
 	direction = glm::vec3(direction.x, 0, direction.z);
 
+	if(onGround) {
+		// Project movement onto ground
+		direction = glm::normalize(glm::cross(groundNormal, glm::cross(direction, groundNormal)));
+	}
+
 	glm::vec3 move = velocity;
 	if(glm::length2(direction) > 0) {
 		direction = glm::normalize(direction) * walkSpeed;
diff --git a/src/kekengine/include/defaultplayercontroller.h b/src/kekengine/include/defaultplayercontroller.h
index e31bc2e..2898946 100644
--- a/src/kekengine/include/defaultplayercontroller.h
+++ b/src/kekengine/include/defaultplayercontroller.h
@@ -7,9 +7,6 @@ namespace kek {
 
 class DefaultPlayerController: public PlayerController {
 
-protected:
-	bool checkPlayerGrounded();
-
 public:
 	glm::vec3 gravity = glm::vec3(0,-9.81,0);
 	float minSlideAngle = 5;