qa2-love2d: diamond SWAP 承認前試作（通常幅・最大幅比較）

README.md

diamond SWAP 試作

GitHub Issue「diamond SWAP の試作を確認する」用の承認前試作です。本実装ではありません。

• 端点: 端点自体をファセット付きの X 形状にする
• X の腕幅: 初版から 20% 縮小した細線版
• 接続線の中心: X 正面中心と奥行きをそろえ、透視投影後も上下位置が一致する
• 左右: 同寸・対称
• 色: CNOT と同じオレンジ系。試作は簡易 PBR 材質で、本実装では専用 diamond_SWAP シェーダと独立色設定を追加する
• 比較: 通常幅（2セル）と最大幅（6セル）

生成物は prototype_diamond_swap.py で一時モデルセットを作り、qa2-love2d の実ゲーム画面を Playwright（ヘッドレス）で撮影して比較しました。

diamond-swap-comparison.svg

prototype_diamond_swap.py

#!/usr/bin/env python3
"""PROTOTYPE — X 形 diamond SWAP の人間確認用 GLB。本実装には使わない。"""

import math
import os
import sys

sys.path.insert(0, os.path.abspath("docs/poc"))

import make_diamond_gate as gate
from make_diamond_cnot import GltfBuilder

ENDPOINT_SPAN = 1.5
LEFT_X = -ENDPOINT_SPAN / 2
RIGHT_X = ENDPOINT_SPAN / 2
ARM_LENGTH = 0.86
ARM_WIDTH = 0.16
ARM_BEVEL = 0.07
ARM_DEPTH = 0.20
BOND_RADIUS = 0.045
BOND_SIDES = 8
BOND_CENTER_Z = ARM_DEPTH * 0.78


def transform_point(point, angle, center_x, z_offset=0.0):
    x, y, z = point
    cosine = math.cos(angle)
    sine = math.sin(angle)
    return (x * cosine - y * sine + center_x, x * sine + y * cosine, z + z_offset)


def arm_outline(scale=1.0):
    half_length = ARM_LENGTH * scale / 2
    half_width = ARM_WIDTH * scale / 2
    bevel = min(ARM_BEVEL * scale, half_length * 0.45, half_width * 0.8)
    return [
        (-half_length + bevel, -half_width),
        (half_length - bevel, -half_width),
        (half_length, -half_width + bevel),
        (half_length, half_width - bevel),
        (half_length - bevel, half_width),
        (-half_length + bevel, half_width),
        (-half_length, half_width - bevel),
        (-half_length, -half_width + bevel),
    ]


def gem_arm_mesh(angle, center_x, z_offset):
    outer = arm_outline(1.0)
    inner = arm_outline(0.76)
    positions = []
    normals = []
    indices = []

    def add_triangle(a, b, c):
        start = len(positions)
        world = [
            transform_point(a, angle, center_x, z_offset),
            transform_point(b, angle, center_x, z_offset),
            transform_point(c, angle, center_x, z_offset),
        ]
        normal = gate.face_normal(*world)
        positions.extend(world)
        normals.extend([normal] * 3)
        indices.extend([start, start + 1, start + 2])

    outer_front_z = 0.02
    inner_front_z = ARM_DEPTH / 2
    crown_z = ARM_DEPTH * 0.78
    back_z = -ARM_DEPTH / 2

    # 正面中央を 8 枚の三角ファセットにする。
    for index in range(8):
        next_index = (index + 1) % 8
        add_triangle((0, 0, crown_z), (*inner[index], inner_front_z), (*inner[next_index], inner_front_z))

    # 正面外周の面取り。
    for index in range(8):
        next_index = (index + 1) % 8
        add_triangle((*outer[index], outer_front_z), (*inner[index], inner_front_z), (*inner[next_index], inner_front_z))
        add_triangle((*outer[index], outer_front_z), (*inner[next_index], inner_front_z), (*outer[next_index], outer_front_z))

    # 側面と背面。
    for index in range(8):
        next_index = (index + 1) % 8
        add_triangle((*outer[index], back_z), (*outer[index], outer_front_z), (*outer[next_index], outer_front_z))
        add_triangle((*outer[index], back_z), (*outer[next_index], outer_front_z), (*outer[next_index], back_z))
        add_triangle((0, 0, back_z), (*outer[next_index], back_z), (*outer[index], back_z))

    return positions, normals, indices


def merge_meshes(meshes):
    positions = []
    normals = []
    indices = []
    for mesh_positions, mesh_normals, mesh_indices in meshes:
        offset = len(positions)
        positions.extend(mesh_positions)
        normals.extend(mesh_normals)
        indices.extend(index + offset for index in mesh_indices)
    return positions, normals, indices


def endpoint_mesh(center_x):
    return merge_meshes(
        [
            gem_arm_mesh(math.radians(45), center_x, -0.025),
            gem_arm_mesh(math.radians(-45), center_x, 0.025),
        ]
    )


def faceted_bond_mesh(min_x, max_x, radius, sides, center_z):
    positions = []
    normals = []
    indices = []
    for index in range(sides):
        angle_a = math.tau * index / sides
        angle_b = math.tau * (index + 1) / sides
        ya, za = math.cos(angle_a) * radius, center_z + math.sin(angle_a) * radius
        yb, zb = math.cos(angle_b) * radius, center_z + math.sin(angle_b) * radius
        start = len(positions)
        vertices = [(min_x, ya, za), (max_x, ya, za), (max_x, yb, zb), (min_x, yb, zb)]
        normal = gate.face_normal(vertices[0], vertices[1], vertices[2])
        positions.extend(vertices)
        normals.extend([normal] * 4)
        indices.extend([start, start + 1, start + 2, start, start + 2, start + 3])
    return positions, normals, indices


def build(output_path):
    builder = GltfBuilder()
    left = endpoint_mesh(LEFT_X)
    right = endpoint_mesh(RIGHT_X)
    bond = faceted_bond_mesh(LEFT_X, RIGHT_X, BOND_RADIUS, BOND_SIDES, BOND_CENTER_Z)
    meshes = [
        {"name": "SWAP_x0_diamond_mesh", "primitives": [builder.primitive(*left, 0)]},
        {"name": "SWAP_x1_diamond_mesh", "primitives": [builder.primitive(*right, 0)]},
        {"name": "SWAP_bond_bar_mesh", "primitives": [builder.primitive(*bond, 0)]},
    ]
    gltf = {
        "asset": {"version": "2.0", "generator": "PROTOTYPE prototype_diamond_swap.py"},
        "scene": 0,
        "scenes": [{"nodes": [0, 1, 2]}],
        "nodes": [
            {"mesh": 0, "name": "SWAP_x0_diamond"},
            {"mesh": 1, "name": "SWAP_x1_diamond"},
            {"mesh": 2, "name": "SWAP_bond_bar"},
        ],
        "meshes": meshes,
        "materials": [
            {
                "name": "prototype_diamond_SWAP",
                "alphaMode": "OPAQUE",
                "emissiveFactor": [1.0, 0.62, 0.18],
                "pbrMetallicRoughness": {
                    "baseColorFactor": [1.0, 0.62, 0.18, 1.0],
                    "metallicFactor": 0.7,
                    "roughnessFactor": 0.28,
                },
            }
        ],
        "bufferViews": builder.buffer_views,
        "accessors": builder.accessors,
        "buffers": [{"byteLength": len(builder.bin_chunk)}],
    }
    gate.save_glb(output_path, 2, gltf, bytes(builder.bin_chunk))


if __name__ == "__main__":
    if len(sys.argv) != 2:
        raise SystemExit("usage: prototype_diamond_swap.py OUTPUT.glb")
    os.makedirs(os.path.dirname(sys.argv[1]), exist_ok=True)
    build(sys.argv[1])
    print(sys.argv[1])