feat: 摄像机初始位置可在 input.txt 配置

新增 input.txt 字段：
  camera_distance:  40.0   # 到场景中心的距离
  camera_elevation: 0      # 俯仰角
  camera_azimuth:   0      # 方位角

通过 display.txt header 传递到 draw.py，
不再硬编码在 draw.py 中。

compute.py

@@ -1461,7 +1461,10 @@ def run_simulation(save_trajectory=0):
                        "driving_force": str(DRIVING_FORCE),
                        "use_marker": str(use_marker),
                        "alpha": ",".join(str(a) for a in (alpha if isinstance(alpha, list) else [alpha])),
-                       "atom_radii": ",".join(str(r) for r in ATOM_RADII)}
+                       "atom_radii": ",".join(str(r) for r in ATOM_RADII),
+                       "camera_distance": str(config.get("camera_distance", 40.0)),
+                       "camera_elevation": str(config.get("camera_elevation", 0)),
+                       "camera_azimuth": str(config.get("camera_azimuth", 0))}
     )
     print(f"[compute] display.txt 已保存至: {disp_path} ({n_frames_actual} 帧)")
 

draw.py

@@ -114,9 +114,9 @@ info_margin  = 8
 axis_length  = 10.0
 
 initial_camera = {
-    "distance": 40.0,
+    "distance": float(h.get("camera_distance", 40.0)),
-    "elevation": 0,
+    "elevation": float(h.get("camera_elevation", 0)),
-    "azimuth": 0,
+    "azimuth": float(h.get("camera_azimuth", 0)),
     "center": (0, 0, 0),
 }
 

dynamics.py

@@ -254,7 +254,10 @@ def run_case(config_path, runtime_base, input_dir="input", output_dir="output",
                   "driving_force": str(data.get("driving_force", 0)),
                   "use_marker": str(config.get("use_marker", 0)),
                   "alpha": _fmt_alpha(data.get("alpha", 0.2)),
-                  "atom_radii": _fmt_alpha(data.get("atom_radii", []))}
+                  "atom_radii": _fmt_alpha(data.get("atom_radii", [])),
+                  "camera_distance": str(config.get("camera_distance", 40.0)),
+                  "camera_elevation": str(config.get("camera_elevation", 0)),
+                  "camera_azimuth": str(config.get("camera_azimuth", 0))}
             
             n_frames = len(indices)
             compute.save_display_txt(

examples/case06/input/input.txt

@@ -19,7 +19,7 @@ save_trajectory: 0  # 0=不保留完整轨迹文件, 1=保留 trajectory.txt（
 
 # ── 计算引擎 ──────────────────────────────────
 # 可选: python, c, cpp, fortran, java
-engine: fortran  # 默认使用 python 引擎
+engine: c  # 默认使用 python 引擎
 
 # ── 盒子 ──────────────────────────────────────
 box_a: 80.0         # 立方体半边长，粒子被限制在 [-box_a, box_a]³ 内
@@ -100,3 +100,8 @@ ball_color_b: 0.90  # B 分量
 box_color_r:  0.80
 box_color_g:  0.80
 box_color_b:  0.85
+
+# ── 摄像机初始位置 ────────────────────────────
+camera_distance:  40.0   # 摄像机到场景中心的距离
+camera_elevation: 0      # 俯仰角（度），负值=俯视
+camera_azimuth:   0      # 方位角（度）