JP4336423B2

JP4336423B2 - Image processing apparatus, image processing method, and recording medium for processing three-dimensional computer graphics

Info

Publication number: JP4336423B2
Application number: JP26271099A
Authority: JP
Inventors: 和弘光石; 洋典松本
Original assignee: Namco Ltd; Namco Bandai Games Inc
Current assignee: Namco Ltd; Bandai Namco Entertainment Inc
Priority date: 1999-09-16
Filing date: 1999-09-16
Publication date: 2009-09-30
Anticipated expiration: 2019-09-16
Also published as: JP2001084406A

Description

【０００１】
【発明の属する技術分野】
本発明は、３次元コンピュータグラフィックを処理する画像処理装置、画像処理方法、およびコンピュータに実行させる画像処理プログラムを記録したコンピュータ読取り可能な記録媒体に関する。
【０００２】
【従来の技術】
３次元コンピュータグラフィック技術において、流体中に存在する物体に働く流体力（例えば、抗力、揚力、浮力、圧力、粘着力、重力等）をシミュレーションする方法として、例えば、有限要素法によりシミュレーションする方法が用いられている。ここで、「有限要素法」とは、図１に示すように、対象の形状を有限要素（メッシュ）とよばれる小さな領域に分割し、この要素ごとに流体力と変移の方程式を立てて要素の特性の近似モデルを作成し、各要素の近似モデルから解析領域の要素全体について式を連立させて微分方程式の近似解を得る方法である。
【０００３】
【発明が解決しようとする課題】
ここで、例えば、３Ｄポリゴンのオブジェクトを表示するゲーム機において、仮想流体の抗力を考慮してオブジェクトを移動する必要があるゲーム等では、かかる抗力等の演算を高速かつリアルタイムで実行することが要求される。しかし、上記した「有限要素法」等により、流体中に存在する物体に働く力をシミュレーションすると、膨大な数の微分演算等を必要とし、ＣＰＵの処理量が非常に多くなる。従って、従来の「有限要素法」等によるシミュレーションでは、一般のパーソナルコンピュータまたはゲーム機等におけるプロセッサによって高速、かつリアルタイムにシミュレーションすることが困難であるという問題点があった。
【０００４】
また、例えば、３次元ポリゴンを用いるゲーム等においては、正確に流体中に存在する物体に働く力をシミュレートする必要性は少なく、むしろ多少の正確性は失われてもリアルタイムに演算できることが望まれている。
【０００５】
本発明の目的は、上記問題点に鑑み、従来のシミュレーション方法に比べて計算量が少なく、一般のプロセッサにおいてリアルタイムで演算することができる画像処理技術を提供することにある。
【０００６】
【課題を解決するための手段】
このような課題を達成するために、本発明に係る画像処理装置は、３次元コンピュータグラフィックを処理する画像処理装置において、３次元ポリゴンで構成され、かつ少なくとも１つの仮想流体中にその少なくとも一部分が存在する物体の像から平面像を決定する平面像決定手段と、該平面像決定手段により決定された前記平面像を用いて、前記物体が前記仮想流体から受ける力を演算する流体力演算手段とを備え、前記平面像決定手段は、前記物体に対応する１つまたは２つ以上の平面像を予め格納する第１テーブルから前記物体に対応する前記平面像を選択することにより前記平面像を決定することを特徴とする。
【００５７】
【発明の実施の形態】
図２は、本発明の実施形態に係る画像処理装置の構成の一例を示すブロック図である。
【００５８】
画像処理装置２００は、ＣＰＵ２０２、記憶装置２０４、画像処理部２０６、ディスプレイ２０８およびバス２１６から成る。
【００５９】
この画像処理装置２００は、装置全体を統括的に制御する、プログラムされたＣＰＵ２０２に、バス２１６を介して、記憶装置２０４が接続されている。また、ＣＰＵ２０２には、画像処理を司る画像処理部２０６が、バス２１６を介して接続されている。
【００６０】
ＣＰＵ２０２は、ＯＳ（Operating System）等の制御プログラム、画像処理手順を規定したプログラム、および所要データを格納するための内部メモリを有し、これらのプログラム等により、画像処理を行う。記憶装置２０４は、ハードディスク等の固定ディスク装置、フレキシブルディスク、光ディスク等のストレージ手段であり、画像処理に用いる各種のテーブル等を格納する。画像処理部２０６は、テクスチャメモリ２１０、流体処理部２１２およびフレームバッファ２１４から成る。テクスチャメモリ２１０は、３次元ポリゴンに貼り付ける模様であるテクスチャを格納するメモリである。流体処理部２１２は、後述するように、流体中の物体の流体力および回転モーメントを演算する。フレームバッファ２１４は、ディスプレイ２０８に表示される画像を格納する高速な読み出しが可能なメモリである。
【００６１】
図３は、本発明の実施形態に係る流体処理部の構成の一例を示すブロック図である。
【００６２】
流体処理部２１２は、平面像決定部３０２、流体力演算部３０４、部分像生成部３０６、回転モーメント演算部３０８から成る。
【００６３】
平面像決定部３０２は、３次元ポリゴンで構成され、かつ少なくとも１つの仮想流体中にその少なくとも一部分が存在する物体の像から平面像を決定する。流体力演算部３０４は、該平面像を用いて、物体が仮想流体から受ける流体力を演算する。部分像生成部３０６は、少なくとも１本の直線により平面像を２つ以上の部分像に分割する。回転モーメント演算部３０８は、該部分像を用いて、物体が該直線を軸として回転する場合の回転モーメントを演算する。
【００６４】
次に、図４乃至図９を参照して、平面像決定部３０２による平面像を決定方法について、説明する。
【００６５】
図４乃至図７は、流体中の物体の像から平面像を決定する一例を概念的に示す図である。
【００６６】
なお、図４乃至図７においては、流体は空気である場合を一例に説明しているが、本発明はかかる場合に限定されるものではなく、流体として、少なくとも空気である気体、少なくとも水である液体、および少なくとも光である粒子のうちいずれを用いてもよい。また、図４乃至図７においては、説明の簡略化のために、流体は１つである場合を一例に説明しているが、本発明はかかる場合に限定されるものではなく、２つ以上の流体であってもよい。また、図４乃至図７においては、物体の全部が流体中に存在している場合を一例に説明しているが、本発明はかかる場合に限定されるものではなく、例えば、水に浮かぶ船の如く、流体中にその一部分のみが存在する物体であってもよい。
【００６７】
図４および図５は、流体中に存在する物体Ａの像を平面Ｂに投影した場合の陰影像を示す。ここで、平面Ｂは、流体の流れる方向（図中において矢印で示される風向）、に対し垂直な平面である場合を一例に説明しているが、あるいは、物体Ａの進行方向に垂直な平面を用いてもよい。ここで、物体Ａは、円柱形をしているため、図４および図５に示すように、物体Ａの角度により異なる陰影像が生成される。
【００６８】
ここで、陰影像の作成については、例えば、レイトレーシング法、走査線単位の方法、２段階法、シャドウポリゴン法等により作成することが周知であり（「技術編ＣＧ標準テキストブック」平成１１年３月１日財団法人画像情報教育振興協会発行第１６０頁〜第１６３頁参照）、またその他のいずれの方法により陰影像を作成してもよい。
【００６９】
図６は、物体Ａを、平面Ｂおよび風向に垂直な平面である平面Ｃに投影した場合を示す。
【００７０】
図７は、物体Ａの重心を含んだ断面像を示す。このような断面像の作成方法の一例を、図９を参照して以下に示す。
【００７１】
まず、物体Ａの重心点を演算により決定する（ステップＳ９０２）。
【００７２】
つぎに、風向に対して垂直な断面像を生成する（ステップＳ９０４）。
【００７３】
つぎに、物体Ａの重心点を含んだ断面像を決定する（ステップＳ９０６）。
【００７４】
ここで、他の実施形態として、重心点を含んだ断面像の代わりに、ステップＳ９０４で求めた各断面像の面積を演算し、面積が最大となる断面像を決定してもよい。
【００７５】
以上、平面像決定部３０２が演算により平面像を決定する場合を説明したが、図８に示すように、物体に対応する１つまたは２つ以上の平面像を予め格納する第１テーブルを備え、第１テーブルから物体に対応する平面像を選択することにより平面像を決定してもよい。記憶装置２０４に、平面像を記録した第１テーブルを予め用意しておき、平面像を第１テーブルから選択することにより、高速に平面像を決定することができる。かかる方法は、物体が単純な形状（例えば、球形等）をしている場合に、特に有効である。
【００７６】
図８は、記憶装置に格納された第１テーブルの一例を示す図である。
【００７７】
第１テーブル８０２は、物体番号８０４および平面像８０６を記録する。１つの物体に対して、複数の平面像が生ずる場合（例えば、物体の角度によって、シルエットの形状が異る場合等）もあるため、１つの物体番号に対して、複数の平面像を対応させることもできる（図８の例では、物体Ｂに対して、平面像２および３が記録されている）。以上、第１テーブルの一例を示し、予め定められたテーブルから平面像を選択する方法について説明したが、本発明はかかる実施の形態に限定されるものではなく、他のいかなる第１テーブル用いて、平面像を決定してもよい。
【００７８】
次に、再び、図４乃至図６を参照して、平面像決定部３０２において、物体が前記仮想流体から受ける流体力を演算する方法について説明する。
【００７９】
以下に、上述の方法により得た平面像の面積を用いて、物体Ａが仮想流体から受ける流体力を演算する場合を一例に説明するが、本発明はかかる場合に限定されるものではない。
【００８０】
図４および図５を用いて、風向に対し垂直な平面Ｂに投影した陰影像により、平面Ｂ上で平面的に流体シミュレーションを行って流体力を演算する場合を説明する。
【００８１】
まず、陰影像の面積Ｓを演算する。得られた面積Ｓを、流体の流速ｖ₁、物体Ａの速度ｖ₂と併せて、物体Ａが流体から受ける力である流体力Ｆの演算パラメータとして用いる。すななち、
【００８２】
【数１】
Ｆ＝ｃＳ（ｖ₁＋ｖ₂）² ・・・数式１
を演算することにより、流体力Ｆを求める。ここで、ｃは、後述する物体形状で選択する補正係数である。
【００８３】
このように、３次元ポリゴンで表される物体Ａに対する流体力を演算する場合において、有限要素法等による３次元シミュレーションと比較して、２次元の平面像を用いて演算するため、演算結果の精度には厳密さを多少欠くが、処理時間を飛躍的に減少させることができる。
【００８４】
ここで、数式１において、演算結果の精度を高めるために、演算結果を補正するための補正係数ｃを用いる。すなわち、記憶装置２０４に、物体に対応する流体力の補正係数を予め格納する第２テーブルを記録し、流体力演算部３０４における流体力の演算結果を、該補正係数ｃにより補正することにより、演算結果の精度を高めることができる。
【００８５】
図１０は、記憶装置に格納された第２テーブルの一例を示す図である。
【００８６】
第２テーブル１００２は、物体番号１００４、平面像番号１００６および流体力の補正係数ｃ１００８を記録する。補正係数ｃは、例えば、物体の形状により定める。物体の形状を、円錐形、球形、板形等の幾つかのカテゴリーに分類し、それぞれのカテゴリー毎に補正係数ｃを予め定めてもよい。１つの物体に対して、複数の形状が生ずる場合（例えば、物体の角度によって、球形になったり円錐形になったりする等、形状が異る場合）もあるため、１つの物体番号に対して、複数の補正係数を対応させることもできる（図１０の例では、物体Ｂに対して、平面像２および３が記録され、各々に補正係数ｃ２およびｃ３が記録されている）。以上、第２テーブルの一例を示し、予め定められたテーブルから補正係数を選択する方法について説明したが、本発明はかかる実施の形態に限定されるものではなく、他のいかなる第１テーブル用いて、補正係数を決定してもよい。
次に、図６を用いて、平面Ｂおよび風向に対し垂直な平面Ｃに投影した陰影像により、平面Ｃ上で平面的に流体シミュレーションを行って流体力を演算する場合を説明する。
【００８７】
まず、陰影像の面積Ｓ１を演算する。得られた面積Ｓ₁を、流体の風圧Ｆ₁、陰影像の平面Ｃに対する垂直方向の長さｌ₁と併せて、物体Ａが流体から受ける力である流体力Ｆの演算パラメータとして用いる。すななち、
【００８８】
【数２】
Ｆ＝ｃ＊Ｓ₁／ｌ₁＊Ｆ₁ ・・・数式２
を演算することにより、流体力Ｆを求める。ここで、ｃは、前述した物体形状で選択する補正係数であり、ここでは平面Ｃに投影された陰影像を用いて補正係数ｃを決定している。
【００８９】
つぎに、図７および図１１を参照して、部分像生成部３０６における部分像の生成方法、および、回転モーメント演算部３０８における回転モーメントの演算方法について説明する。
【００９０】
図１１は、部分像生成部３０６における部分像の生成方法、および、回転モーメント演算部３０８における回転モーメントの演算方法の一例を説明するフロー図である。
【００９１】
まず、図７に示すように、物体Ａの重心点を含む断面像ａを決定し、断面像ａにおいて、重心点Ｃを通る少なくとも１本の直線により２つ以上の部分像に分割する（ステップＳ１１０２）。図７においては、風向に対する第１軸および第２軸に平行になるような、直交する２つの直線を一例として説明しているが、本発明はかかる実施の形態に限定されるものではない。
【００９２】
次に、かかる２つの直線を軸として物体Ａが回転する場合の回転モーメントを後述する数式３により演算する（ステップＳ１１０４）。
【００９３】
次に、平面Ｂおよび風向に対し垂直な平面Ｄに投影した陰影像を用いて、３軸回りの回転モーメントを数式３により演算する（ステップＳ１１０６）。
【００９４】
【外１】

【００９５】
まず、陰影像をＳ₁とＳ₂の部分像に分割し、それぞれの高さをｌ₁およびｌ₂とする。すると、Ｓ₁およびＳ₂にかかる力は、それぞれ、Ｆ₁＝ｃＳ₁ｖ²、Ｆ₂＝ｃＳ₂ｖ²となる。ここで、ｖは相対速度、ｃは物体形状で選択する補正係数である。
【００９６】
【外２】

【００９７】
【数３】

【００９８】
により演算する。ここで、ｃは物体形状で選択する補正係数であり、Ｂは陰影の形状で選択する補正係数である。
【００９９】
このように、３次元ポリゴンで表される物体Ａに対する回転モーメントを演算する場合に、本発明では２次元の平面像を用いて演算するため、従来の３次元シミュレーションによる演算と比較して、演算結果の精度には厳密さを多少欠くが、処理時間を飛躍的に減少させることができる。
【０１００】
ここで、数式３において、演算結果の精度を高めるために、演算結果を補正するための補正係数ｃおよびＢを用いる。すなわち、記憶装置２０４に、物体に対応する回転モーメントの補正係数を予め格納する第３テーブルを記録し、回転モーメント演算部３０８における回転モーメントの演算結果を、該補正係数ｃおよびＢにより補正することにより、演算結果の精度を高めることができる。
【０１０１】
（他の実施の形態）
他の実施の形態においては、上述したような方法により平面像を決定する際に、物体から流体処理用に構成ポリゴン数を少なくした「簡易オブジェクト」を作成し、かかる「簡易オブジェクト」を用いて平面像を決定してもよい。流体処理をする際には、流体中の物体の形状は必ずしも正確である必要はない。そこで、例えば、数十から数百個のポリゴンから構成される第1物体については、その物体の主要形状を規定する数個のポリゴンからなる「簡易オブジェクト」を用いて、平面像を決定することにより、流体処理の演算量をさらに軽減することができる。該「簡易オブジェクト」の作成方法については、物体に対する少なくとも１つの「簡易オブジェクト」を予めテーブルに格納しておいて必要時に選択する方法、表面積または体積が大きいポリゴンから順にポリゴンを選択していき、予め定めたポリゴン数からなるオブジェクトを作成する方法等がある。
【０１０２】
また、他の実施の形態においては、上述した補正係数を、物体の材質により定めても良い。例えば、物体の表面が金属の如く鏡面で構成されている場合と、木材の如く粗面で構成されている場合とでは、流体からの受ける流体力には差異があるため、物体の材質に応じて補正係数を定めることにより、より正確な流体シミュレーションが可能になる。
【０１０３】
一方、本発明の他の実施の形態において、本発明はコンピュータ・システムにおいて使用するためのコンピュータプログラム製品として実施することができる。本発明の各手段を定義するプログラムは、多くのフォーム（形式）でコンピュータに導入することができるのは当業者には自明である。これらのフォームの例としては、（ａ）コンピュータで使用可能な非書き込み記憶媒体（例えば、コンピュータの入出力装置によって読み取ることのできるＲＯＭ、ＣＤ−ＲＯＭディスク、ＤＶＤ−ＲＯＭディスク等）中に永久的に保持されている情報のフォーム、（ｂ）コンピュータで使用可能な書き込み可能な記憶媒体（例えば、フロッピー・ディスク及びハード・ディスク駆動装置等）中に、前もって保持されている情報のフォーム、（ｃ）例えばデジタルデータストリームまたは搬送波に乗せられたコンピュータデータ信号等のごとく、モデムを通る電話回線やネットワークのような伝送媒体を介してコンピュータに伝達される情報のフォーム、などがあり、本発明はこれらのフォームに限定されるものではない。従って、本発明の画像処理方法を管理する、コンピュータで読み取り可能な命令を記録した媒体は、本発明の他の実施の形態を与える。
【０１０４】
【発明の効果】
以上説明したように、本発明によれば、従来の３次元シミュレーションによる流体処理に比べて計算量が少なく、一般のプロセッサにおいてリアルタイムで流体処理を行うことができる画像処理技術を提供することができる。
【０１０５】
また、特に、流体中の抗力を考慮してオブジェクトを移動させなければならないゲーム等のリアルタイムシミュレーションにおいて、例えば、正面と側面で大きく形態の違う物体に対して、空気抵抗を即座に演算しゲームに反映することができる。
【０１０６】
さらに、例えば、羽を閉じていたものが広げるというように形態を変化されるようなオブジェクトの空気抵抗を即座に求めることができ、かつ流体中の物体の移動量の変化を容易に求めることができる。
【図面の簡単な説明】
【図１】３次元グラフィックス技術における有限要素法の概念を示す図である。
【図２】本発明の実施形態に係る画像処理装置の構成の一例を示すブロック図である。
【図３】本発明の実施形態に係る流体処理部の構成の一例を示すブロック図である。
【図４】流体中に存在する物体Ａの像を平面Ｂに投影した場合の陰影像を示す図である。
【図５】流体中に存在する物体Ａの像を平面Ｂに投影した場合の陰影像を示す図である。
【図６】物体Ａを、平面Ｂおよび風向に垂直な平面である平面Ｃに投影した場合を示す図である。
【図７】物体Ａの重心を含んだ断面像を示す図である。
【図８】記憶装置に格納された第１テーブルの一例を示す図である。
【図９】断面像の作成方法の一例を示すフロー図である。
【図１０】記憶装置に格納された第２テーブルの一例を示す図である。
【図１１】部分像生成部における部分像の生成方法、および、回転モーメント演算部における回転モーメントの演算方法の一例を説明するフロー図である。
【符号の説明】
２００画像処理装置
２０２ＣＰＵ
２０４記憶装置
２０６画像処理部
２０８ディスプレイ
２１０テクスチャメモリ
２１２流体処理部
２１４フレームバッファ
２１６バス
３０２平面像決定部
３０４流体力演算部
３０６部分像生成部
３０８回転モーメント演算部
８０２第１テーブル
８０４物体番号
８０６平面像
１００２第２テーブル
１００４物体番号
１００６平面像番号
１００８流体力の補正係数ｃ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus that processes three-dimensional computer graphics, an image processing method, and a computer-readable recording medium that records an image processing program to be executed by a computer.
[0002]
[Prior art]
In the three-dimensional computer graphic technology, as a method of simulating fluid force (for example, drag, lift, buoyancy, pressure, adhesive force, gravity, etc.) acting on an object existing in a fluid, for example, there is a method of simulating by a finite element method. It is used. Here, the “finite element method” means that, as shown in FIG. 1, the target shape is divided into small areas called finite elements (mesh), and the equations of fluid force and transition are set for each element. This is a method of creating an approximate model of the above characteristic and obtaining an approximate solution of the differential equation by simultaneously formulating the formulas for all the elements in the analysis region from the approximate model of each element.
[0003]
[Problems to be solved by the invention]
Here, for example, in a game machine that displays an object of 3D polygon, in a game that needs to move the object in consideration of the drag of the virtual fluid, it is required to perform the calculation of the drag in high speed and in real time. Is done. However, if the force acting on the object existing in the fluid is simulated by the above-described “finite element method” or the like, a huge number of differential calculations are required, and the processing amount of the CPU becomes very large. Therefore, in the conventional simulation by the “finite element method” or the like, there is a problem that it is difficult to perform simulation at high speed and in real time by a processor in a general personal computer or a game machine.
[0004]
In addition, for example, in a game using a three-dimensional polygon, there is little need to accurately simulate the force acting on an object existing in a fluid, and it is hoped that computation can be performed in real time even if some accuracy is lost. It is rare.
[0005]
In view of the above-described problems, an object of the present invention is to provide an image processing technique that has a smaller amount of calculation than a conventional simulation method and can be performed in real time in a general processor.
[0006]
[Means for Solving the Problems]
In order to achieve such an object, an image processing apparatus according to the present invention is an image processing apparatus for processing a three-dimensional computer graphic, which is composed of a three-dimensional polygon, and at least a part of which is at least one virtual fluid. A plane image determining unit that determines a plane image from an image of an existing object; and a fluid force calculating unit that calculates a force that the object receives from the virtual fluid using the plane image determined by the plane image determining unit. The plane image determining means determines the plane image by selecting the plane image corresponding to the object from a first table that stores in advance one or more plane images corresponding to the object. It is characterized by doing.
[0057]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 is a block diagram showing an example of the configuration of the image processing apparatus according to the embodiment of the present invention.
[0058]
The image processing apparatus 200 includes a CPU 202, a storage device 204, an image processing unit 206, a display 208 and a bus 216.
[0059]
In this image processing apparatus 200, a storage device 204 is connected to a programmed CPU 202 that controls the entire apparatus through a bus 216. In addition, an image processing unit 206 that performs image processing is connected to the CPU 202 via a bus 216.
[0060]
The CPU 202 has a control program such as an OS (Operating System), a program defining an image processing procedure, and an internal memory for storing required data, and performs image processing using these programs. The storage device 204 is a storage unit such as a fixed disk device such as a hard disk, a flexible disk, or an optical disk, and stores various tables used for image processing. The image processing unit 206 includes a texture memory 210, a fluid processing unit 212, and a frame buffer 214. The texture memory 210 is a memory that stores a texture that is a pattern to be pasted on a three-dimensional polygon. As will be described later, the fluid processing unit 212 calculates a fluid force and a rotational moment of an object in the fluid. The frame buffer 214 is a memory that stores an image displayed on the display 208 and that can be read at high speed.
[0061]
FIG. 3 is a block diagram showing an example of the configuration of the fluid processing unit according to the embodiment of the present invention.
[0062]
The fluid processing unit 212 includes a planar image determination unit 302, a fluid force calculation unit 304, a partial image generation unit 306, and a rotational moment calculation unit 308.
[0063]
The planar image determination unit 302 determines a planar image from an image of an object that is composed of a three-dimensional polygon and at least a part of which is present in at least one virtual fluid. The fluid force calculation unit 304 calculates the fluid force that the object receives from the virtual fluid using the planar image. The partial image generation unit 306 divides the planar image into two or more partial images by at least one straight line. The rotational moment calculation unit 308 calculates the rotational moment when the object rotates about the straight line using the partial image.
[0064]
Next, a method for determining a plane image by the plane image determination unit 302 will be described with reference to FIGS.
[0065]
4 to 7 are diagrams conceptually illustrating an example of determining a planar image from an image of an object in a fluid.
[0066]
4 to 7, the case where the fluid is air is described as an example. However, the present invention is not limited to this case, and the fluid is at least a gas that is air and at least water. Any one of a certain liquid and particles that are at least light may be used. 4 to 7, for the sake of simplicity of explanation, the case where there is one fluid is described as an example. However, the present invention is not limited to such a case, and two or more fluids may be used. It may be a fluid. 4 to 7 exemplify the case where the entire object is present in the fluid, the present invention is not limited to such a case. For example, a ship floating in water As described above, an object in which only a part thereof exists in the fluid may be used.
[0067]
4 and 5 show shadow images when an image of the object A existing in the fluid is projected onto the plane B. FIG. Here, the case where the plane B is a plane perpendicular to the direction in which the fluid flows (wind direction indicated by an arrow in the drawing) is described as an example, or alternatively, the plane B is a plane perpendicular to the traveling direction of the object A May be used. Here, since the object A has a cylindrical shape, different shadow images are generated depending on the angle of the object A as shown in FIGS. 4 and 5.
[0068]
Here, it is well known that shadow images are created by, for example, a ray tracing method, a scanning line method, a two-step method, a shadow polygon method, etc. ("Technical Edition CG Standard Text Book" 1999). March 1 (see pages 160 to 163, issued by the Association for Promotion of Image Information Education), and any other method may be used to create a shadow image.
[0069]
FIG. 6 shows a case where the object A is projected onto the plane B and the plane C that is a plane perpendicular to the wind direction.
[0070]
FIG. 7 shows a cross-sectional image including the center of gravity of the object A. An example of a method for creating such a cross-sectional image is described below with reference to FIG.
[0071]
First, the center of gravity of the object A is determined by calculation (step S902).
[0072]
Next, a cross-sectional image perpendicular to the wind direction is generated (step S904).
[0073]
Next, a cross-sectional image including the barycentric point of the object A is determined (step S906).
[0074]
Here, as another embodiment, instead of the cross-sectional image including the barycentric point, the cross-sectional image having the maximum area may be determined by calculating the area of each cross-sectional image obtained in step S904.
[0075]
As described above, the case where the plane image determination unit 302 determines the plane image by calculation has been described. As shown in FIG. 8, a first table that stores in advance one or more plane images corresponding to an object is provided. The plane image may be determined by selecting the plane image corresponding to the object from the first table. By preparing a first table in which a planar image is recorded in the storage device 204 and selecting the planar image from the first table, the planar image can be determined at high speed. Such a method is particularly effective when the object has a simple shape (for example, a spherical shape).
[0076]
FIG. 8 is a diagram illustrating an example of the first table stored in the storage device.
[0077]
The first table 802 records an object number 804 and a planar image 806. Since there are cases where a plurality of plane images are generated for one object (for example, the shape of the silhouette differs depending on the angle of the object), a plurality of plane images are associated with one object number. (In the example of FIG. 8, the

planar images

2 and 3 are recorded for the object B). As described above, an example of the first table is shown and the method for selecting a planar image from a predetermined table has been described. However, the present invention is not limited to such an embodiment, and any other first table is used. A plane image may be determined.
[0078]
Next, referring to FIGS. 4 to 6 again, a method of calculating the fluid force that the object receives from the virtual fluid in the planar image determination unit 302 will be described.
[0079]
Hereinafter, a case where the fluid force that the object A receives from the virtual fluid is calculated using the area of the planar image obtained by the above-described method will be described as an example. However, the present invention is not limited to this case.
[0080]
A case where the fluid force is calculated by performing a fluid simulation on the plane B by using a shadow image projected on the plane B perpendicular to the wind direction will be described with reference to FIGS. 4 and 5.
[0081]
First, the area S of the shadow image is calculated. The obtained area S is used as a calculation parameter for the fluid force F, which is the force that the object A receives from the fluid, together with the fluid flow velocity v ₁ and the velocity v ₂ of the object A. That is,
[0082]
[Expression 1]
F = cS (v ₁ + v ₂ ) ² Equation 1
Is calculated to obtain the fluid force F. Here, c is a correction coefficient selected by an object shape to be described later.
[0083]
In this way, when calculating the fluid force for the object A represented by the three-dimensional polygon, since the calculation is performed using a two-dimensional plane image as compared with the three-dimensional simulation by the finite element method or the like, Although accuracy is somewhat less precise, processing time can be dramatically reduced.
[0084]
Here, in Equation 1, a correction coefficient c for correcting the calculation result is used to increase the accuracy of the calculation result. That is, a second table that stores in advance a fluid force correction coefficient corresponding to an object is stored in the storage device 204, and the fluid force calculation result in the fluid force calculation unit 304 is corrected by the correction coefficient c. The accuracy of calculation results can be increased.
[0085]
FIG. 10 is a diagram illustrating an example of the second table stored in the storage device.
[0086]
The second table 1002 records an object number 1004, a planar image number 1006, and a fluid force correction coefficient c1008. The correction coefficient c is determined by, for example, the shape of the object. The shape of the object may be classified into several categories such as a conical shape, a spherical shape, and a plate shape, and the correction coefficient c may be determined in advance for each category. There are cases where multiple shapes occur for one object (for example, the shape may be spherical or conical depending on the angle of the object). A plurality of correction coefficients can also be made to correspond (in the example of FIG. 10, the

planar images

2 and 3 are recorded for the object B, and the correction coefficients c2 and c3 are recorded respectively). As described above, an example of the second table is shown and the method of selecting the correction coefficient from the predetermined table has been described. However, the present invention is not limited to such an embodiment, and any other first table is used. The correction coefficient may be determined.
Next, a case where the fluid force is calculated by performing a fluid simulation on the plane C in a plane using the shadow image projected on the plane B and the plane C perpendicular to the wind direction will be described with reference to FIG.
[0087]
First, the area S1 of the shadow image is calculated. The obtained area S ₁ is used as a calculation parameter for the fluid force F, which is the force that the object A receives from the fluid, together with the wind pressure F _{1 of} the fluid and the length l _{1 in the} direction perpendicular to the plane C of the shadow image. That is,
[0088]
[Expression 2]
F = c * S ₁ / l ₁ * F ₁ ... Formula 2
Is calculated to obtain the fluid force F. Here, c is a correction coefficient to be selected based on the object shape described above. Here, the correction coefficient c is determined using a shadow image projected on the plane C.
[0089]
Next, with reference to FIGS. 7 and 11, a partial image generation method in the partial image generation unit 306 and a rotation moment calculation method in the rotation moment calculation unit 308 will be described.
[0090]
FIG. 11 is a flowchart for explaining an example of a partial image generation method in the partial image generation unit 306 and a rotation moment calculation method in the rotation moment calculation unit 308.
[0091]
First, as shown in FIG. 7, a cross-sectional image a including the center of gravity of the object A is determined, and the cross-sectional image a is divided into two or more partial images by at least one straight line passing through the center of gravity C (step S1102). In FIG. 7, two orthogonal straight lines that are parallel to the first axis and the second axis with respect to the wind direction are described as an example, but the present invention is not limited to such an embodiment.
[0092]
Next, the rotational moment when the object A rotates with the two straight lines as axes is calculated by Equation 3 described later (step S1104).
[0093]
Next, using the shadow image projected on the plane B and the plane D perpendicular to the wind direction, the rotational moment about the three axes is calculated by Equation 3 (step S1106).
[0094]
[Outside 1]

[0095]
First, the shadow image is divided into partial images of S ₁ and S ₂ , and the respective heights are defined as l ₁ and l ₂ . Then, the forces applied to S ₁ and S ₂ are F ₁ = cS ₁ v ² and F ₂ = cS ₂ v ² , respectively. Here, v is a relative speed, and c is a correction coefficient selected by the object shape.
[0096]
[Outside 2]

[0097]
[Equation 3]

[0098]
Calculate by Here, c is a correction coefficient selected by the object shape, and B is a correction coefficient selected by the shadow shape.
[0099]
In this way, when calculating the rotational moment with respect to the object A represented by a three-dimensional polygon, the calculation is performed using a two-dimensional plane image in the present invention. Although the accuracy of the results is somewhat strict, the processing time can be drastically reduced.
[0100]
Here, in Equation 3, correction coefficients c and B for correcting the calculation result are used to increase the accuracy of the calculation result. That is, a third table that stores in advance a rotational moment correction coefficient corresponding to an object is recorded in the storage device 204, and the rotational moment calculation result in the rotational moment calculation unit 308 is corrected by the correction coefficients c and B. As a result, the accuracy of the calculation result can be increased.
[0101]
(Other embodiments)
In another embodiment, when a plane image is determined by the method as described above, a “simple object” in which the number of constituent polygons is reduced for fluid processing is created from the object, and the “simple object” is used. A planar image may be determined. When performing fluid treatment, the shape of an object in the fluid does not necessarily have to be accurate. Therefore, for example, for a first object composed of several tens to several hundreds of polygons, a plane image is determined using a “simple object” composed of several polygons that define the main shape of the object. As a result, the calculation amount of the fluid processing can be further reduced. As for the method of creating the “simple object”, at least one “simple object” for an object is stored in a table in advance, and is selected when necessary. Polygons are selected in order from polygons having a large surface area or volume, There is a method for creating an object having a predetermined number of polygons.
[0102]
In other embodiments, the correction coefficient described above may be determined by the material of the object. For example, there is a difference in the fluid force from the fluid when the surface of the object is made of a mirror like metal and when it is made of a rough surface like wood, so depending on the material of the object By determining the correction coefficient, more accurate fluid simulation becomes possible.
[0103]
On the other hand, in other embodiments of the present invention, the present invention can be implemented as a computer program product for use in a computer system. It is obvious to those skilled in the art that the program defining each means of the present invention can be introduced into a computer in many forms. Examples of these forms are: (a) permanently in a computer-usable non-write storage medium (eg, ROM, CD-ROM disc, DVD-ROM disc, etc. that can be read by computer I / O devices). (B) a form of information previously held in a computer writable storage medium (eg, floppy disk and hard disk drive, etc.), (c) ) For example, a digital data stream or a computer data signal carried on a carrier wave, a form of information transmitted to a computer via a transmission line such as a telephone line or a network passing through a modem, etc. It is not limited to the form. Therefore, a medium storing computer-readable instructions for managing the image processing method of the present invention provides another embodiment of the present invention.
[0104]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an image processing technique that requires less computation than conventional fluid processing by three-dimensional simulation and can perform fluid processing in real time in a general processor. .
[0105]
In particular, in real-time simulations such as games where the object must be moved in consideration of drag in the fluid, for example, the air resistance can be immediately calculated for an object with a greatly different shape on the front and side surfaces. Can be reflected.
[0106]
Furthermore, for example, it is possible to immediately obtain the air resistance of an object whose shape is changed such that the one whose wings are closed widens, and to easily obtain the change in the amount of movement of the object in the fluid. it can.
[Brief description of the drawings]
FIG. 1 is a diagram showing a concept of a finite element method in a three-dimensional graphics technique.
FIG. 2 is a block diagram illustrating an example of a configuration of an image processing apparatus according to an embodiment of the present invention.
FIG. 3 is a block diagram illustrating an example of a configuration of a fluid processing unit according to the embodiment of the present invention.
FIG. 4 is a diagram showing a shadow image when an image of an object A existing in a fluid is projected onto a plane B;
FIG. 5 is a diagram showing a shadow image when an image of an object A existing in a fluid is projected on a plane B;
FIG. 6 is a diagram illustrating a case where an object A is projected onto a plane B and a plane C that is a plane perpendicular to the wind direction.
7 is a diagram showing a cross-sectional image including the center of gravity of an object A. FIG.
FIG. 8 is a diagram illustrating an example of a first table stored in a storage device.
FIG. 9 is a flowchart showing an example of a method for creating a cross-sectional image.
FIG. 10 is a diagram illustrating an example of a second table stored in a storage device.
FIG. 11 is a flowchart for explaining an example of a partial image generation method in a partial image generation unit and a rotation moment calculation method in a rotation moment calculation unit.
[Explanation of symbols]
200 Image processing apparatus 202 CPU
204 Storage Device 206 Image Processing Unit 208 Display 210 Texture Memory 212 Fluid Processing Unit 214 Frame Buffer 216 Bus 302 Plane Image Determination Unit 304 Fluid Force Calculation Unit 306 Partial Image Generation Unit 308 Rotation Moment Calculation Unit 802 First Table 804 Object Number 806 Plane Image 1002 Second table 1004 Object number 1006 Plane image number 1008 Fluid force correction coefficient c

Claims

In an image processing apparatus for processing three-dimensional computer graphics,
Plane image determination means for determining a plane image from an image of an object that is composed of a three-dimensional polygon and at least a part of which is present in at least one virtual fluid;
Fluid force calculation means for calculating the force that the object receives from the virtual fluid using the plane image determined by the plane image determination means,
The planar image determining means determines the planar image by selecting the planar image corresponding to the object from a first table that stores in advance one or more planar images corresponding to the object. A featured image processing apparatus.

In an image processing apparatus for processing three-dimensional computer graphics,
Plane image determination means for determining a plane image from an image of an object that is composed of a three-dimensional polygon and at least a part of which is present in at least one virtual fluid;
Fluid force calculation means for calculating the force that the object receives from the virtual fluid using the plane image determined by the plane image determination means,
The planar image determining means includes
A shadow image generating means for generating a shadow image when the image of the object is projected onto a plane;
An image processing apparatus, wherein the shadow image generated by the shadow image generation means is determined as the planar image.

In an image processing apparatus for processing three-dimensional computer graphics,
Plane image determination means for determining a plane image from an image of an object that is composed of a three-dimensional polygon and at least a part of which is present in at least one virtual fluid;
Fluid force calculation means for calculating the force that the object receives from the virtual fluid using the plane image determined by the plane image determination means,
The planar image determining means includes
Centroid point determining means for determining the centroid point of the object;
Cross-sectional image generating means for generating a cross-sectional image of at least one of the objects,
An image processing apparatus, wherein the cross-sectional image including the barycentric point of the object is determined as the planar image.

In an image processing apparatus for processing three-dimensional computer graphics,
Plane image determination means for determining a plane image from an image of an object that is composed of a three-dimensional polygon and at least a part of which is present in at least one virtual fluid;
Fluid force calculation means for calculating the force that the object receives from the virtual fluid using the plane image determined by the plane image determination means,
The planar image determining means includes
Cross-sectional image generating means for generating a cross-sectional image of at least one of the objects;
An area determining means for determining an area of the cross-sectional image generated by the cross-sectional image generating means,
An image processing apparatus, wherein the cross-sectional image having the maximum area is determined as the planar image.

Before SL fluid force calculating means uses the area of the plane image, wherein the object is described in any one of claims 1 to 4, characterized in that for calculating the fluid force received from the virtual fluid Image processing device.

Before SL virtual fluid gas is at least air, liquid is at least water, and / or, any one of claims 1, characterized in that at least one of the particles is at least light according to claim 5 1 The image processing apparatus described in one .

In an image processing apparatus for processing three-dimensional computer graphics,
Plane image determination means for determining a plane image from an image of an object that is composed of a three-dimensional polygon and at least a part of which is present in at least one virtual fluid;
Fluid force calculation means for calculating the force that the object receives from the virtual fluid using the plane image determined by the plane image determination means,
Correction means for correcting the calculation result by the fluid force calculation means with the correction coefficient corresponding to the object selected from the second table that stores in advance the correction coefficient of the fluid force corresponding to the object. An image processing apparatus.

The image processing apparatus according to claim 7.
The image processing apparatus according to claim 1, wherein the correction coefficient is determined by a shape and / or material of the object.

In the image processing apparatus, an image processing method for processing a three-dimensional computer graphic implemented by control by a control unit included in the image processing apparatus,
A plane image determining step of determining a plane image from an image of an object composed of a three-dimensional polygon and having at least a portion thereof in at least one virtual fluid;
Using the plane image determined by the plane image determination step, a fluid force calculation step of calculating a force that the object receives from the virtual fluid, and
The planar image determining step determines the planar image by selecting the planar image corresponding to the object from a first table that stores in advance one or more planar images corresponding to the object. A featured image processing method.

In the image processing apparatus, an image processing method for processing a three-dimensional computer graphic implemented by control by a control unit included in the image processing apparatus,
A plane image determining step of determining a plane image from an image of an object composed of a three-dimensional polygon and having at least a portion thereof in at least one virtual fluid;
Using the plane image determined by the plane image determination step, a fluid force calculation step of calculating a force that the object receives from the virtual fluid, and
The planar image determining step includes:
A shadow image generating step for generating a shadow image when the image of the object is projected onto a plane;
An image processing method, wherein the shadow image generated by the shadow image generation step is determined as the planar image.

In the image processing apparatus, an image processing method for processing a three-dimensional computer graphic implemented by control by a control unit included in the image processing apparatus,
A plane image determining step of determining a plane image from an image of an object composed of a three-dimensional polygon and having at least a portion thereof in at least one virtual fluid;
Using the plane image determined by the plane image determination step, a fluid force calculation step of calculating a force that the object receives from the virtual fluid, and
The planar image determining step includes:
A barycentric point determining step for determining a barycentric point of the object;
A cross-sectional image generating step for generating a cross-sectional image of at least one of the objects,
An image processing method, wherein the cross-sectional image including the barycentric point of the object is determined as the planar image.

In the image processing apparatus, an image processing method for processing a three-dimensional computer graphic implemented by control by a control unit included in the image processing apparatus,
A plane image determining step of determining a plane image from an image of an object composed of a three-dimensional polygon and having at least a portion thereof in at least one virtual fluid;
Using the plane image determined by the plane image determination step, a fluid force calculation step of calculating a force that the object receives from the virtual fluid, and
The planar image determining step includes:
A cross-sectional image generating step for generating a cross-sectional image of at least one of the objects;
An area determining step for determining an area of the cross-sectional image generated by the cross-sectional image generating step,
An image processing method, wherein the cross-sectional image having the maximum area is determined as the planar image.

Before SL fluid force calculating step, using the area of the plane image, wherein the object according to any one of claims 12 to claim 9, wherein computing the fluid force received from the virtual fluid Image processing method.

Before SL virtual fluid gas is at least air, liquid is at least water, and / or any of claims 13 claim 9, characterized in that at least one of the particles is at least light 1 The image processing method as described in one .

In the image processing apparatus, an image processing method for processing a three-dimensional computer graphic implemented by control by a control unit included in the image processing apparatus,
A plane image determining step of determining a plane image from an image of an object composed of a three-dimensional polygon and having at least a portion thereof in at least one virtual fluid;
Using the plane image determined by the plane image determination step, a fluid force calculation step of calculating a force that the object receives from the virtual fluid, and
A correction step of correcting the calculation result of the fluid force calculation step by the correction coefficient by selecting the correction coefficient corresponding to the object from a second table that stores in advance a correction coefficient of the fluid force corresponding to the object. An image processing method comprising:

The image processing method according to claim 15, wherein
The image processing method, wherein the correction coefficient is determined by a shape and / or material of the object.

In a computer, a computer-readable recording medium recording a program for executing an image processing method for processing three-dimensional computer graphics under the control of a control unit provided in the computer, wherein the image processing method includes:
A plane image determining step of determining a plane image from an image of an object composed of a three-dimensional polygon and having at least a portion thereof in at least one virtual fluid;
Using the plane image determined by the plane image determination step, a fluid force calculation step of calculating a force that the object receives from the virtual fluid, and
The planar image determining step determines the planar image by selecting the planar image corresponding to the object from a first table that stores in advance one or more planar images corresponding to the object. A computer-readable recording medium.

In a computer, a computer-readable recording medium recording a program for executing an image processing method for processing three-dimensional computer graphics under the control of a control unit provided in the computer, wherein the image processing method includes:
A plane image determining step of determining a plane image from an image of an object composed of a three-dimensional polygon and having at least a portion thereof in at least one virtual fluid;
Using the plane image determined by the plane image determination step, a fluid force calculation step of calculating a force that the object receives from the virtual fluid, and
The planar image determining step includes:
A shadow image generating step for generating a shadow image when the image of the object is projected onto a plane;
A computer-readable recording medium, wherein the shadow image generated by the shadow image generation step is determined as the planar image.

In a computer, a computer-readable recording medium recording a program for executing an image processing method for processing three-dimensional computer graphics under the control of a control unit provided in the computer, wherein the image processing method includes:
A plane image determining step of determining a plane image from an image of an object composed of a three-dimensional polygon and having at least a portion thereof in at least one virtual fluid;
Using the plane image determined by the plane image determination step, a fluid force calculation step of calculating a force that the object receives from the virtual fluid, and
The planar image determining step includes:
A barycentric point determining step for determining a barycentric point of the object;
A cross-sectional image generating step for generating a cross-sectional image of at least one of the objects,
A computer-readable recording medium, wherein the cross-sectional image including the barycentric point of the object is determined as the planar image.

In a computer, a computer-readable recording medium recording a program for executing an image processing method for processing three-dimensional computer graphics under the control of a control unit provided in the computer, wherein the image processing method includes:
A plane image determining step of determining a plane image from an image of an object composed of a three-dimensional polygon and having at least a portion thereof in at least one virtual fluid;
Using the plane image determined by the plane image determination step, a fluid force calculation step of calculating a force that the object receives from the virtual fluid, and
The planar image determining step includes:
A cross-sectional image generating step for generating a cross-sectional image of at least one of the objects;
An area determining step for determining an area of the cross-sectional image generated by the cross-sectional image generating step,
The computer-readable recording medium, wherein the cross-sectional image having the maximum area is determined as the planar image.

Before SL fluid force calculating step, using the area of the plane image, wherein the object according to any one of claims 20 to claim 17, wherein computing the fluid force received from the virtual fluid Computer-readable recording medium.

Before SL virtual fluid gas is at least air, liquid is at least water, and / or any one of claims 21 claim 17, characterized in that at least one of the particles is at least light A computer-readable recording medium described in 1 .

In a computer, a computer-readable recording medium recording a program for executing an image processing method for processing three-dimensional computer graphics under the control of a control unit provided in the computer, wherein the image processing method includes:
A plane image determining step of determining a plane image from an image of an object composed of a three-dimensional polygon and having at least a portion thereof in at least one virtual fluid;
Using the plane image determined by the plane image determination step, a fluid force calculation step of calculating a force that the object receives from the virtual fluid, and
A correction step of correcting the calculation result of the fluid force calculation step by the correction coefficient by selecting the correction coefficient corresponding to the object from a second table that stores in advance a correction coefficient of the fluid force corresponding to the object. A computer-readable recording medium comprising:

The recording medium according to claim 23,
The computer-readable recording medium, wherein the correction coefficient is determined by the shape and / or material of the object.