camera position fixing

game/client.c

@@ -1,4 +1,3 @@
-// game/client.c - SMOOTH TERRAIN VERSION WITH DIRECTIONAL LIGHT & SHADOWS
 #include "raylib.h"
 #include <math.h>
 #include <stdint.h>
@@ -394,6 +393,9 @@ static Vector3 v3_add(Vector3 a, Vector3 b) {
 static Vector3 v3_sub(Vector3 a, Vector3 b) {
   return v3(a.x - b.x, a.y - b.y, a.z - b.z);
 }
+static Vector3 v3_mul(Vector3 a, float s) {
+  return v3(a.x * s, a.y * s, a.z * s);
+}
 static float v3_dot(Vector3 a, Vector3 b) {
   return a.x * b.x + a.y * b.y + a.z * b.z;
 }
@@ -585,6 +587,7 @@ typedef struct MsgRoomState {
 typedef struct RemotePlayer {
   int present, alive, hp;
   Vector3 pos;
+  Vector3 prevPos;
   float yaw, pitch;
   uint8_t weapon;
   int16_t pistolMag, rifleMag, pistolAmmo, rifleAmmo, medkits;
@@ -717,6 +720,10 @@ int main(void) {
   Vector3 camPos = v3(0, 5.0f, 6);
   float yaw = 0.0f, pitch = 0.0f;
 
+  Vector3 prevBodyPos = v3(0, 5.0f, 6);
+  Vector3 currentTargetBody = v3(0, 5.0f, 6);
+  float interpTimer = 0.0f;
+
   float recoilYaw = 0.0f, recoilPitch = 0.0f, crossSpread = 0.0f;
   int scoped = 0;
   float fireCooldown = 0.0f;
@@ -793,6 +800,7 @@ int main(void) {
             continue;
 
           RemotePlayer *p = &rp[ps->id];
+          p->prevPos = p->pos;
           p->present = 1;
           p->alive = ps->alive;
           p->hp = ps->hp;
@@ -811,14 +819,9 @@ int main(void) {
         }
 
         if (myId != 255 && rp[myId].present) {
-          Vector3 body = rp[myId].pos;
-          camPos.x = body.x;
-          camPos.y = body.y + 1.0f;
-          camPos.z = body.z + 0.0001f;
-
-          // Prevent camera from clipping into terrain
-          float terrain_h = get_terrain_height(camPos.x, camPos.z);
-          camPos.y = fmaxf(camPos.y, terrain_h + 1.5f);
+          prevBodyPos = currentTargetBody;
+          currentTargetBody = rp[myId].pos;
+          interpTimer = 0.0f;
         }
       } else if (type == MSG_ITEMS && n >= (int)sizeof(MsgItems)) {
         MsgItems *m = (MsgItems *)buf;
@@ -843,6 +846,23 @@ int main(void) {
       }
     }
 
+    // Interpolate camera position
+    if (myId != 255 && rp[myId].present) {
+      float interpFactor = interpTimer / (1.0f / 20.0f);
+      if (interpFactor > 1.0f)
+        interpFactor = 1.0f;
+      Vector3 interpBody = v3_add(v3_mul(prevBodyPos, 1.0f - interpFactor),
+                                  v3_mul(currentTargetBody, interpFactor));
+      camPos.x = interpBody.x;
+      camPos.y = interpBody.y + 1.0f;
+      camPos.z = interpBody.z + 0.0001f;
+
+      // Prevent camera from clipping into terrain
+      float terrain_h = get_terrain_height(camPos.x, camPos.z);
+      camPos.y = fmaxf(camPos.y, terrain_h + 1.5f);
+    }
+    interpTimer += dt;
+
     Vector2 md = GetMouseDelta();
     const float sens = 0.0025f;
     yaw -= md.x * sens;
@@ -931,6 +951,14 @@ int main(void) {
     Vector3 forward = v3(sinf(viewYaw) * cosf(viewPitch), sinf(viewPitch),
                          cosf(viewYaw) * cosf(viewPitch));
 
+    // Offset camera position: 0.3m in front, 0.2m below
+    camPos = v3_add(camPos, v3_mul(forward, 0.3f));
+    camPos.y -= 0.2f;
+
+    // Ensure camera doesn't clip into terrain after offset
+    float terrain_h = get_terrain_height(camPos.x, camPos.z);
+    camPos.y = fmaxf(camPos.y, terrain_h + 1.5f);
+
     Camera3D cam = {0};
     cam.position = camPos;
     cam.target = v3_add(camPos, forward);
@@ -1000,7 +1028,11 @@ int main(void) {
     for (int i = 0; i < MAX_PLAYERS; i++) {
       if (!rp[i].present)
         continue;
-      Vector3 p = rp[i].pos;
+      float interpFactor = interpTimer / (1.0f / 20.0f);
+      if (interpFactor > 1.0f)
+        interpFactor = 1.0f;
+      Vector3 p = v3_add(v3_mul(rp[i].prevPos, 1.0f - interpFactor),
+                         v3_mul(rp[i].pos, interpFactor));
       Color c =
           (i == myId) ? (Color){80, 180, 255, 255} : (Color){255, 80, 80, 255};
       if (!rp[i].alive)
@@ -1020,7 +1052,12 @@ int main(void) {
     for (int i = 0; i < MAX_PLAYERS; i++) {
       if (!rp[i].present || !rp[i].username[0])
         continue;
-      Vector3 head = v3(rp[i].pos.x, rp[i].pos.y + 1.2f, rp[i].pos.z);
+      float interpFactor = interpTimer / (1.0f / 20.0f);
+      if (interpFactor > 1.0f)
+        interpFactor = 1.0f;
+      Vector3 p = v3_add(v3_mul(rp[i].prevPos, 1.0f - interpFactor),
+                         v3_mul(rp[i].pos, interpFactor));
+      Vector3 head = v3(p.x, p.y + 1.2f, p.z);
       Vector3 camForward = v3_norm(v3_sub(cam.target, cam.position));
       Vector3 toHead = v3_sub(head, cam.position);
       if (v3_dot(camForward, toHead) <= 0.0f)