3D / voxel unit tests

tests/unit/voxel_greedy_meshing_test.py

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+#!/usr/bin/env python3
+"""Unit tests for Milestone 13: Greedy Meshing
+
+Tests that greedy meshing produces correct mesh geometry with reduced vertex count.
+"""
+
+import mcrfpy
+import sys
+
+# Test counters
+tests_passed = 0
+tests_failed = 0
+
+def test(name, condition):
+    """Simple test helper"""
+    global tests_passed, tests_failed
+    if condition:
+        tests_passed += 1
+        print(f"  PASS: {name}")
+    else:
+        tests_failed += 1
+        print(f"  FAIL: {name}")
+
+# =============================================================================
+# Test greedy meshing property
+# =============================================================================
+
+print("\n=== Testing greedy_meshing property ===")
+
+vg = mcrfpy.VoxelGrid((8, 8, 8), cell_size=1.0)
+test("Default greedy_meshing is False", vg.greedy_meshing == False)
+
+vg.greedy_meshing = True
+test("Can enable greedy_meshing", vg.greedy_meshing == True)
+
+vg.greedy_meshing = False
+test("Can disable greedy_meshing", vg.greedy_meshing == False)
+
+# =============================================================================
+# Test vertex count reduction
+# =============================================================================
+
+print("\n=== Testing vertex count reduction ===")
+
+# Create a solid 4x4x4 cube - this should benefit greatly from greedy meshing
+# Non-greedy: 6 faces per voxel for exposed faces = many quads
+# Greedy: 6 large quads (one per side)
+
+vg2 = mcrfpy.VoxelGrid((4, 4, 4), cell_size=1.0)
+stone = vg2.add_material("stone", (128, 128, 128))
+vg2.fill((stone))  # Fill entire grid
+
+# Get vertex count with standard meshing
+vg2.greedy_meshing = False
+vg2.rebuild_mesh()
+standard_vertices = vg2.vertex_count
+print(f"  Standard meshing: {standard_vertices} vertices")
+
+# Get vertex count with greedy meshing
+vg2.greedy_meshing = True
+vg2.rebuild_mesh()
+greedy_vertices = vg2.vertex_count
+print(f"  Greedy meshing: {greedy_vertices} vertices")
+
+# For a solid 4x4x4 cube, standard meshing creates:
+# Each face of the cube is 4x4 = 16 voxel faces
+# 6 cube faces * 16 faces/side * 6 vertices/face = 576 vertices
+# Greedy meshing creates:
+# 6 cube faces * 1 merged quad * 6 vertices/quad = 36 vertices
+
+test("Greedy meshing reduces vertex count", greedy_vertices < standard_vertices)
+test("Solid cube greedy: 36 vertices (6 faces * 6 verts)", greedy_vertices == 36)
+
+# =============================================================================
+# Test larger solid block
+# =============================================================================
+
+print("\n=== Testing larger solid block ===")
+
+vg3 = mcrfpy.VoxelGrid((16, 16, 16), cell_size=1.0)
+stone3 = vg3.add_material("stone", (128, 128, 128))
+vg3.fill(stone3)
+
+vg3.greedy_meshing = False
+vg3.rebuild_mesh()
+standard_verts_large = vg3.vertex_count
+print(f"  Standard: {standard_verts_large} vertices")
+
+vg3.greedy_meshing = True
+vg3.rebuild_mesh()
+greedy_verts_large = vg3.vertex_count
+print(f"  Greedy: {greedy_verts_large} vertices")
+
+# 16x16 faces = 256 quads per side -> 1 quad per side with greedy
+# Reduction factor should be significant
+reduction_factor = standard_verts_large / greedy_verts_large if greedy_verts_large > 0 else 0
+print(f"  Reduction factor: {reduction_factor:.1f}x")
+
+test("Large block greedy: still 36 vertices", greedy_verts_large == 36)
+test("Significant vertex reduction (>10x)", reduction_factor > 10)
+
+# =============================================================================
+# Test checkerboard pattern (worst case for greedy)
+# =============================================================================
+
+print("\n=== Testing checkerboard pattern (greedy stress test) ===")
+
+vg4 = mcrfpy.VoxelGrid((4, 4, 4), cell_size=1.0)
+stone4 = vg4.add_material("stone", (128, 128, 128))
+
+# Create checkerboard pattern - no adjacent same-material voxels
+for z in range(4):
+    for y in range(4):
+        for x in range(4):
+            if (x + y + z) % 2 == 0:
+                vg4.set(x, y, z, stone4)
+
+vg4.greedy_meshing = False
+vg4.rebuild_mesh()
+standard_checker = vg4.vertex_count
+print(f"  Standard: {standard_checker} vertices")
+
+vg4.greedy_meshing = True
+vg4.rebuild_mesh()
+greedy_checker = vg4.vertex_count
+print(f"  Greedy: {greedy_checker} vertices")
+
+# In checkerboard, greedy meshing can't merge much, so counts should be similar
+test("Checkerboard: greedy meshing works (produces vertices)", greedy_checker > 0)
+# Greedy might still reduce a bit due to row merging
+test("Checkerboard: greedy <= standard", greedy_checker <= standard_checker)
+
+# =============================================================================
+# Test different materials (no cross-material merging)
+# =============================================================================
+
+print("\n=== Testing multi-material (no cross-material merging) ===")
+
+vg5 = mcrfpy.VoxelGrid((4, 4, 4), cell_size=1.0)
+red = vg5.add_material("red", (255, 0, 0))
+blue = vg5.add_material("blue", (0, 0, 255))
+
+# Half red, half blue
+vg5.fill_box((0, 0, 0), (1, 3, 3), red)
+vg5.fill_box((2, 0, 0), (3, 3, 3), blue)
+
+vg5.greedy_meshing = True
+vg5.rebuild_mesh()
+multi_material_verts = vg5.vertex_count
+print(f"  Multi-material greedy: {multi_material_verts} vertices")
+
+# Should have 6 quads per material half = 12 quads = 72 vertices
+# But there's a shared face between them that gets culled
+# Actually: each 2x4x4 block has 5 exposed faces (not the shared internal face)
+# So 5 + 5 = 10 quads = 60 vertices, but may be more due to the contact face
+test("Multi-material produces vertices", multi_material_verts > 0)
+
+# =============================================================================
+# Test hollow box (interior faces)
+# =============================================================================
+
+print("\n=== Testing hollow box ===")
+
+vg6 = mcrfpy.VoxelGrid((8, 8, 8), cell_size=1.0)
+stone6 = vg6.add_material("stone", (128, 128, 128))
+vg6.fill_box_hollow((0, 0, 0), (7, 7, 7), stone6, thickness=1)
+
+vg6.greedy_meshing = False
+vg6.rebuild_mesh()
+standard_hollow = vg6.vertex_count
+print(f"  Standard: {standard_hollow} vertices")
+
+vg6.greedy_meshing = True
+vg6.rebuild_mesh()
+greedy_hollow = vg6.vertex_count
+print(f"  Greedy: {greedy_hollow} vertices")
+
+# Hollow box has 6 outer faces and 6 inner faces
+# Greedy should merge each face into one quad
+# Expected: 12 quads * 6 verts = 72 vertices
+test("Hollow box: greedy reduces vertices", greedy_hollow < standard_hollow)
+
+# =============================================================================
+# Test floor slab (single layer)
+# =============================================================================
+
+print("\n=== Testing floor slab (single layer) ===")
+
+vg7 = mcrfpy.VoxelGrid((10, 1, 10), cell_size=1.0)
+floor_mat = vg7.add_material("floor", (100, 80, 60))
+vg7.fill(floor_mat)
+
+vg7.greedy_meshing = False
+vg7.rebuild_mesh()
+standard_floor = vg7.vertex_count
+print(f"  Standard: {standard_floor} vertices")
+
+vg7.greedy_meshing = True
+vg7.rebuild_mesh()
+greedy_floor = vg7.vertex_count
+print(f"  Greedy: {greedy_floor} vertices")
+
+# Floor slab: 10x10 top face + 10x10 bottom face + 4 edge faces (10x1 each)
+# Greedy: 6 quads = 36 vertices
+test("Floor slab: greedy = 36 vertices", greedy_floor == 36)
+
+# =============================================================================
+# Test that mesh is marked dirty when property changes
+# =============================================================================
+
+print("\n=== Testing dirty flag behavior ===")
+
+vg8 = mcrfpy.VoxelGrid((4, 4, 4), cell_size=1.0)
+stone8 = vg8.add_material("stone", (128, 128, 128))
+vg8.fill(stone8)
+
+# Build mesh first
+vg8.greedy_meshing = False
+vg8.rebuild_mesh()
+first_count = vg8.vertex_count
+
+# Change greedy_meshing - mesh should be marked dirty
+vg8.greedy_meshing = True
+# Rebuild
+vg8.rebuild_mesh()
+second_count = vg8.vertex_count
+
+test("Changing greedy_meshing affects vertex count", first_count != second_count)
+
+# =============================================================================
+# Summary
+# =============================================================================
+
+print(f"\n=== Results: {tests_passed} passed, {tests_failed} failed ===")
+
+if tests_failed > 0:
+    sys.exit(1)
+else:
+    print("All tests passed!")
+    sys.exit(0)