Re: [程式] 請問怎麼讓單位具有可視範圍?

[barroslee (很久沒寫Hspice 我早忘了)]

※ 引述《l314 (紅虫)》之銘言：
: 我希望我的單位(actor)，都具有可視範圍，當其它單位進入視線時，會作出反應..
: 我的每個單位都是一個Object，可以擁有自己的屬性..
: 目前只知道需要視角和可視半徑，
: 像下面這張圖一樣，單位具有可視範圍.
: http://www.cs.nccu.edu.tw/~t9148/perception.JPG
: 請先進們提示小弟一些實作的技巧..
: 謝謝..

對每個 actor 算他們的 view frustum
算是基本功


      Y
      |
      |
　　　|-------X
     /
    /
   /
  Z


enum FrustumSide
{
        RIGHT   = 0,
        LEFT,
        BOTTOM,
        TOP,
        BACK,
        FRONT
};

void CalculateFrustum()
{
        vec4 frustum[6];

        float   proj[16];       // projection matrix of an actor
        float   modl[16];       // modelview matrix of an actor
        float   clip[16];       // clipping planes of an actor

        // find projection matrix and modelview matrix
        // .....
        //
        // opengl:
        // glGetFloatv( GL_PROJECTION_MATRIX, proj );
        // glGetFloatv( GL_MODELVIEW_MATRIX, modl );


        // find clipping planes and view frustum
        clip[ 0] =   modl[ 0] * proj[ 0] +
                     modl[ 1] * proj[ 4] +
                     modl[ 2] * proj[ 8] +
                     modl[ 3] * proj[12];

        clip[ 1] =   modl[ 0] * proj[ 1] +
                     modl[ 1] * proj[ 5] +
                     modl[ 2] * proj[ 9] +
                     modl[ 3] * proj[13];

        clip[ 2] =   modl[ 0] * proj[ 2] +
                     modl[ 1] * proj[ 6] +
                     modl[ 2] * proj[10] +
                     modl[ 3] * proj[14];

        clip[ 3] =   modl[ 0] * proj[ 3] +
                     modl[ 1] * proj[ 7] +
                     modl[ 2] * proj[11] +
                     modl[ 3] * proj[15];

        clip[ 4] =   modl[ 4] * proj[ 0] +
                     modl[ 5] * proj[ 4] +
                     modl[ 6] * proj[ 8] +
                     modl[ 7] * proj[12];

        clip[ 5] =   modl[ 4] * proj[ 1] +
                     modl[ 5] * proj[ 5] +
                     modl[ 6] * proj[ 9] +
                     modl[ 7] * proj[13];

        clip[ 6] =   modl[ 4] * proj[ 2] +
                     modl[ 5] * proj[ 6] +
                     modl[ 6] * proj[10] +
                     modl[ 7] * proj[14];

        clip[ 7] =   modl[ 4] * proj[ 3] +
                     modl[ 5] * proj[ 7] +
                     modl[ 6] * proj[11] +
                     modl[ 7] * proj[15];

        clip[ 8] =   modl[ 8] * proj[ 0] +
                     modl[ 9] * proj[ 4] +
                     modl[10] * proj[ 8] +
                     modl[11] * proj[12];

        clip[ 9] =   modl[ 8] * proj[ 1] +
                     modl[ 9] * proj[ 5] +
                     modl[10] * proj[ 9] +
                     modl[11] * proj[13];

        clip[10] =   modl[ 8] * proj[ 2] +
                     modl[ 9] * proj[ 6] +
                     modl[10] * proj[10] +
                     modl[11] * proj[14];

        clip[11] =   modl[ 8] * proj[ 3] +
                     modl[ 9] * proj[ 7] +
                     modl[10] * proj[11] +
                     modl[11] * proj[15];

        clip[12] =   modl[12] * proj[ 0] +
                     modl[13] * proj[ 4] +
                     modl[14] * proj[ 8] +
                     modl[15] * proj[12];

        clip[13] =   modl[12] * proj[ 1] +
                     modl[13] * proj[ 5] +
                     modl[14] * proj[ 9] +
                     modl[15] * proj[13];

        clip[14] =   modl[12] * proj[ 2] +
                     modl[13] * proj[ 6] +
                     modl[14] * proj[10] +
                     modl[15] * proj[14];

        clip[15] =   modl[12] * proj[ 3] +
                     modl[13] * proj[ 7] +
                     modl[14] * proj[11] +
                     modl[15] * proj[15];

        frustum[RIGHT].x = clip[ 3] - clip[ 0];
        frustum[RIGHT].y = clip[ 7] - clip[ 4];
        frustum[RIGHT].z = clip[11] - clip[ 8];
        frustum[RIGHT].w = clip[15] - clip[12];


        NormalizePlane(frustum, RIGHT);

        frustum[LEFT].x = clip[ 3] + clip[ 0];
        frustum[LEFT].y = clip[ 7] + clip[ 4];
        frustum[LEFT].z = clip[11] + clip[ 8];
        frustum[LEFT].w = clip[15] + clip[12];


        NormalizePlane(m_Frustum, LEFT);


        frustum[BOTTOM].x = clip[ 3] + clip[ 1];
        frustum[BOTTOM].y = clip[ 7] + clip[ 5];
        frustum[BOTTOM].z = clip[11] + clip[ 9];
        frustum[BOTTOM].w = clip[15] + clip[13];


        NormalizePlane(frustum, BOTTOM);


        frustum[TOP].x = clip[ 3] - clip[ 1];
        frustum[TOP].y = clip[ 7] - clip[ 5];
        frustum[TOP].z = clip[11] - clip[ 9];
        frustum[TOP].w = clip[15] - clip[13];


        NormalizePlane(frustum, TOP);


        frustum[BACK].x = clip[ 3] - clip[ 2];
        frustum[BACK].y = clip[ 7] - clip[ 6];
        frustum[BACK].z = clip[11] - clip[10];
        frustum[BACK].w = clip[15] - clip[14];


        NormalizePlane(frustum, BACK);


        frustum[FRONT].x = clip[ 3] + clip[ 2];
        frustum[FRONT].y = clip[ 7] + clip[ 6];
        frustum[FRONT].z = clip[11] + clip[10];
        frustum[FRONT].w = clip[15] + clip[14];


        NormalizePlane(frustum, FRONT);
}


--

我的遊戲引擎圖
http://www.wretch.cc/album/album.php?id=barroslee&book=1

我的 blog
http://barroslee.blogspot.com/

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