From b428efe1a36d57b34075da389ed577828bd717ba Mon Sep 17 00:00:00 2001
From: Luca Conte <main@lugico.de>
Date: Mon, 24 Jun 2024 15:30:14 +0200
Subject: [PATCH] smooth camera travel

---
 src/main.c | 76 ++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 51 insertions(+), 25 deletions(-)

diff --git a/src/main.c b/src/main.c
index 069ce03..840af98 100644
--- a/src/main.c
+++ b/src/main.c
@@ -45,14 +45,36 @@ int framesSinceUpdate = 0;
 GLfloat step = 0.0f;
 const GLfloat pi = 3.14159f;
 
-vec3 cameraPosition = {0.0f, 3.0f, 5.5f};
+vec3 cameraPosition = {0.0f, 2.0f, 1.0f};
 vec3 objectPosition = {0.0f, 0.0f, 0.0f};
+
+vec3 cameraTravelPosition = {0.0f, 3.0f, 5.5f};
+bool cameraTraveling = true;
+
 GLfloat radius = 1.0f;
 mat4 viewingTransformation;
 
 // Define a global scene graph root node
 SceneNode* rootNode;
 
+void handleCameraTravel() {
+    if (cameraTraveling) {
+        vec3 delta;
+
+        vec3Subtract(&delta, &cameraTravelPosition, &cameraPosition);
+
+        if (vec3Length(&delta) < 0.0001) cameraTraveling = false;
+
+        vec3Multiply(&delta, &delta, 0.1);
+        vec3Add(&cameraPosition, &cameraPosition, &delta);
+    }
+}
+
+void travelCamera(vec3 newPosition) {
+    cameraTravelPosition = newPosition;
+    cameraTraveling = true;
+}
+
 /**
  * Input handler for camera movement.
  *  */ 
@@ -60,40 +82,42 @@ void handleInputs(double deltaTime) {
     assert(window != NULL);
 
     if (glfwGetKey(window, GLFW_KEY_1) == GLFW_PRESS) {
-        cameraPosition = (vec3){0.0f, 1.7f, 2.4f};
+        travelCamera((vec3){0.0f, 1.7f, 2.4f});
     }
     if (glfwGetKey(window, GLFW_KEY_2) == GLFW_PRESS) {
-        cameraPosition = (vec3){3.3f, 3.4f, -11.0f};
+        travelCamera((vec3){3.3f, 3.4f, -11.0f});
     }
     if (glfwGetKey(window, GLFW_KEY_3) == GLFW_PRESS) {
-        cameraPosition = (vec3){-3.0f, 2.9f, -7.5f};
+        travelCamera((vec3){-3.0f, 2.9f, -7.5f});
     }
     if (glfwGetKey(window, GLFW_KEY_4) == GLFW_PRESS) {
-        cameraPosition = (vec3){-0.6f, 2.1f, -4.5f};
+        travelCamera((vec3){-0.6f, 2.1f, -4.5f});
     }
     if (glfwGetKey(window, GLFW_KEY_5) == GLFW_PRESS) {
-        cameraPosition = (vec3){-10.6f, 22.1f, -4.5f};
+        travelCamera((vec3){-10.6f, 22.1f, -4.5f});
     }
     if (glfwGetKey(window, GLFW_KEY_6) == GLFW_PRESS) {
-        cameraPosition = (vec3){3.574698f, 0.966039f, 3.852249f};
+        travelCamera((vec3){3.574698f, 0.966039f, 3.852249f});
     }
-    if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS) {
-        cameraPosition.z += deltaTime * 10;
-    }
-    if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS) {
-        cameraPosition.z -= deltaTime * 10;
-    }
-    if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS) {
-        cameraPosition.x += deltaTime * 10;
-    }
-    if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS) {
-        cameraPosition.x -= deltaTime * 10;
-    }
-    if (glfwGetKey(window, GLFW_KEY_F) == GLFW_PRESS) {
-        cameraPosition.y += deltaTime * 10;
-    }
-    if (glfwGetKey(window, GLFW_KEY_R) == GLFW_PRESS) {
-        cameraPosition.y -= deltaTime * 10;
+    if (!cameraTraveling) {
+        if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS) {
+            cameraPosition.z += deltaTime * 10;
+        }
+        if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS) {
+            cameraPosition.z -= deltaTime * 10;
+        }
+        if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS) {
+            cameraPosition.x += deltaTime * 10;
+        }
+        if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS) {
+            cameraPosition.x -= deltaTime * 10;
+        }
+        if (glfwGetKey(window, GLFW_KEY_F) == GLFW_PRESS) {
+            cameraPosition.y += deltaTime * 10;
+        }
+        if (glfwGetKey(window, GLFW_KEY_R) == GLFW_PRESS) {
+            cameraPosition.y -= deltaTime * 10;
+        }
     }
 
     if (glfwGetKey(window, GLFW_KEY_L) == GLFW_PRESS) {
@@ -251,7 +275,7 @@ void init(void) {
 
 void updateStats() {
     printf("\rFPS: %.1f", framesSinceUpdate / timeSinceUpdate);
-    printf(" - Camera Position: [%f, %f, %f]", cameraPosition.x, cameraPosition.y, cameraPosition.z);
+    printf(" - Camera Position: [%f, %f, %f] - Traveling: %s   ", cameraPosition.x, cameraPosition.y, cameraPosition.z, cameraTraveling ? "true" : "false");
     fflush(stdout);
 }
 
@@ -260,6 +284,8 @@ void updateStats() {
  */
 void draw(void) {
 
+    handleCameraTravel();
+
     // FPS Counter
     framesSinceUpdate++;
     double deltaTime = glfwGetTime();