Fix terrain curriculum traversal and hfield roughness

scripts/gen_dreamwaq_terrain.py

@@ -22,7 +22,12 @@ BORDER_M = 5.0
 PROPORTIONS = [0.1, 0.1, 0.35, 0.35, 0.1]
 CUM = [sum(PROPORTIONS[:i + 1]) for i in range(len(PROPORTIONS))]
 PLATFORM_M = 3.0
-_SLOPE_SCALE = 0.4   # 上游原值（已验证 z_scale 上限远超 0.54）
+_SLOPE_SCALE = 0.25  # MotrixSim-friendly slope range
+ROUGH_GRID_M = 0.20  # Correlate roughness over 20 cm, not each 5 cm pixel.
+ROUGH_BASE_M = 0.01
+ROUGH_GAIN_M = 0.03
+OBSTACLE_BASE_M = 0.03
+OBSTACLE_GAIN_M = 0.10
 
 CELL_PX = int(CELL_M / HS)       # 160
 BORDER_PX = int(BORDER_M / HS)   # 100
@@ -61,11 +66,16 @@ def draw_slope(canvas, x0, y0, difficulty, noise=False):
     hi = max(edge_h, 0)
     hf = np.clip(hf, lo, hi).astype(np.uint16)
     if noise:
-        na = int(0.05 / VS)
-        n = np.random.randint(-na, na + 1, (CELL_PX, CELL_PX), dtype=np.int16)
-        # 噪声也只在平台外
+        # Independent 5 cm samples created 10 cm jumps between adjacent
+        # pixels. Interpolate a 20 cm grid for physically coherent roughness.
+        coarse_px = max(2, int(round(ROUGH_GRID_M / HS)))
+        amp = ROUGH_BASE_M + ROUGH_GAIN_M * difficulty
+        coarse = np.random.uniform(
+            -amp, amp, (coarse_px, coarse_px)).astype(np.float32)
+        n = cv2.resize(coarse, (CELL_PX, CELL_PX), interpolation=cv2.INTER_LINEAR)
         n[cx - p2:cx + p2, cy - p2:cy + p2] = 0
-        hf = np.clip(hf.astype(np.int32) + n, 0, 65535).astype(np.uint16)
+        hf = np.clip(hf.astype(np.float32) * VS + n, 0, None)
+        hf = np.rint(hf / VS).astype(np.uint16)
     canvas[y0:y0 + CELL_PX, x0:x0 + CELL_PX] += hf
 
 
@@ -105,7 +115,7 @@ def draw_obstacles(canvas, x0, y0, difficulty):
     """离散障碍物（随机矩形块）。"""
     if difficulty <= 0:
         return
-    max_h = int((0.05 + 0.2 * difficulty) / VS)
+    max_h = int((OBSTACLE_BASE_M + OBSTACLE_GAIN_M * difficulty) / VS)
     if max_h <= 0:
         return
     p2 = PLATFORM_PX // 2