Add camera movement

as3/README.md

@@ -34,10 +34,12 @@ run the executable with the following command:
 
 # Instructions on how to use the program
 
-Use W and S to accelerate the penguin forward and backward. Use A and D to
-change heading direction. The penguin will only accelerate in the direction
-facing and will retain its velocity even when not accelerating or changing
-direction.
+Hold W and S to accelerate the penguin forward and backward. Use A and D to
+change heading direction. This allows you to steer the penguin around the
+environment.
+
+Use the arrow keys to change the camera's rotation (pitch and yaw) with respect
+to the penguin, allowing you to look around while the penguin moves.
 
 # Readme Question
 
@@ -50,3 +52,7 @@ otherwise the velocity would be in terms of units per frame rather than units
 per second. By multiplying the velocity by `dt`, it converts the velocity to
 units per second, allowing for consistent movement regardless of the frame
 rate.
+
+# Extra Credit
+
+The camera moves with the penguin and can be rotated around the penguin using the arrow keys.

as3/as3.cpp

@@ -7,6 +7,7 @@
 #include "raylib.h"
 #include <raylib-cpp.hpp>
 #include <cmath>
+#include <algorithm>
 #include <iostream>
 
 #define SKYBOX_IMPLEMENTATION
@@ -46,15 +47,30 @@ int main() {
 
     raylib::Model penguin("models/penguin.glb");
 
+    // behind and above the penguin (in penguin-local space)
+    const float CAM_DIST = 512.0f;
+    const float CAM_HEIGHT = 256.0f;
+    const float CAM_ANGULAR_VELOCITY = 2.0f;
+    const float CAM_PITCH_MIN = -0.5f;
+    const float CAM_PITCH_MAX = 1.5f;
+
+    float camYaw = 3.14f; // offset by 90 deg so it faces in the proper direction
+    float camPitch = 0;
+
     raylib::Camera3D camera(
-        { 0, 120, 500 },
-        { 0, 0, -1 },
+        { 0, CAM_DIST * std::sin(camPitch), CAM_DIST * std::cos(camPitch) },
+        { 0, 0, 0 },
         { 0, 1, 0 },
         45.0f);
 
     raylib::Model ground = raylib::Mesh::Plane(10000, 10000, 50, 50, 25);
+
+    raylib::Texture snowTexture("textures/snow.jpg");
+    ground.GetMaterials()[0].maps[MATERIAL_MAP_DIFFUSE].texture = snowTexture;
+
     cs381::SkyBox skybox("textures/skybox.png");
 
+    // penguin physics
     raylib::Vector3 position = { 0, 0, 0 };
     raylib::Vector3 velocity = { 0, 0, 0 };
     float heading = 0.0f;
@@ -76,6 +92,7 @@ int main() {
 
         position += velocity * dt * 0.5f;
 
+        // movement for penguin
         if (IsKeyDown(KEY_W)) {
             speed += ACCELERATION * dt;
         }
@@ -105,6 +122,35 @@ int main() {
         // ds = 1/2 * (v0 + v1) * dt
         position += velocity * dt * 0.5f;
 
+        // movement for camera
+        if (IsKeyDown(KEY_LEFT)) {
+            camYaw += CAM_ANGULAR_VELOCITY * dt;
+        }
+        if (IsKeyDown(KEY_RIGHT)) {
+            camYaw -= CAM_ANGULAR_VELOCITY * dt;
+        }
+        if (IsKeyDown(KEY_UP)) {
+            camPitch += CAM_ANGULAR_VELOCITY * dt;
+        }
+        if (IsKeyDown(KEY_DOWN)) {
+            camPitch -= CAM_ANGULAR_VELOCITY * dt;
+        }
+
+        // clamp the angle between
+        camPitch = std::clamp(camPitch, CAM_PITCH_MIN, CAM_PITCH_MAX);
+
+        // x = cos(pitch) * sin(yaw)
+        // y = sin(pitch)
+        // z = cos(pitch) * cos(yaw)
+        float yaw = camYaw + heading; // follow penguin
+        raylib::Vector3 camOffset = {
+            CAM_DIST * std::cos(camPitch) * std::sin(yaw),
+            CAM_DIST * std::sin(camPitch) + CAM_HEIGHT,
+            CAM_DIST * std::cos(camPitch) * std::cos(yaw)
+        };
+        camera.SetPosition(position + camOffset);
+        camera.SetTarget(position);
+
         camera.BeginMode();
         skybox.Draw();