Rendering学習日記

本来ならば、コンバータをつくればよいのだろうが、
ここはcgkitを使ってobjをribに変換した。
cgkitでは、
>render.py -rレンダラ hogehoge.obj
とやると、指定のレンダラでレンダリング、geomフォルダができて
その中に、ribが生成される。これをgelatoに読み込んでみた。

このobjでは法線ベクトルがないので、カクカクしている。

#cha0.pyg

Output ("cha01.tif", "tiff", "rgb", "camera", "float gain", 1, "float gamma",

 1, "string filter", "gaussian", "float[2] filterwidth", (2, 2))

Attribute ("string projection", "perspective")

Attribute ("float fov", 20)

Attribute ("int[2] resolution", (640, 480))

#placecam 10 5 -10 0 0 0

Rotate (-19.47, 1.00, 0.00, 0.00)

Rotate (45.00, 0.00, 1.00, 0.00)

Translate (-10.00, -5.00, 10.00)



Attribute ("string geometryset", "+shadows")



World ()

Light ("light1", "pointlight", "float intensity", 350, "point from", (-10, 10, -10),"string shadowname", "shadows")

Light ("light2", "pointlight", "float intensity", 350, "point from", (10, 10, -10),"string shadowname", "shadows")



PushTransform ()

Attribute ("color C", (1, 1, 0.9))

Shader ("surface", "veinedmarble")

Scale (20,20,20)

Translate ( 0, 0, 0)

Input ("chawan.rib")

PopTransform ()



Attribute ("color C", (1, 1, 1))

Shader ("surface", "plastic")

Rotate (90.00, 1.00, 0.00, 0.00)

Input("PlaneGeom.rib")

Render()

POV−Rayと数学の関連を紹介しているサイトを参考にしました。
「数学のいずみ」http://izumi-math.jp/sanae/Pov_Ray/Pov_Ray.htm
くりかえし処理whileを使ってTranslateを変更していきました。
連続した球体が生成されます。
勉強になります。ありがとうございます。

#sphere_hansya.pyg

Output ("sphere_hansya.tif", "tiff", "rgb", "camera", "float gain", 1, "float gamma",

 1, "string filter", "gaussian", "float[2] filterwidth", (2, 2))

Attribute ("float shadingquality",1.2)

Attribute ("string projection", "perspective")

Attribute ("float fov", 30)

Attribute ("int[2] resolution", (640, 480))

#placecam 0 10 -60 0 0 0

Rotate (-9.46, 1.00, 0.00, 0.00)

Translate (0.00, -10.00, 60.00)



Attribute ("string geometryset", "+shadows")

Attribute ("string geometryset", "+reflection")



World ()

Light ( "light0", "ambientlight", "float intensity", 0.3 )

Light ("light1", "pointlight", "float intensity", 400, "point from", (0, 20, -10),"string shadowname", "shadows")

Light ("light2", "pointlight", "float intensity", 400, "point from", (5, 0, -10),"string shadowname", "shadows")



PushTransform ()

Attribute ("color C", (0.2, 0.4, 0.75))

Sphere (100, -100, 100, 360)

PopTransform ()



MyCounter = -5

while (MyCounter <= 5):

    PushTransform ()

    Attribute ("color C", (1, 1, 1))

    Shader ( "surface", "metal","string envname","reflection" )

    Translate ( 2*MyCounter+1, abs(3*MyCounter+2),4*MyCounter+3)

    Sphere (0.8, -0.8, 0.8, 360)

    PopTransform ()

    MyCounter = MyCounter + 0.5





Attribute ("color C", (1, 1, 1))

Rotate (90.00, 1.00, 0.00, 0.00)

Scale (10,10,10)

ShaderGroupBegin ()

Attribute ("color C", (1, 1, 0))

Shader ("surface", "checker", "checklayer","float stilesize",0.1,"float ttilesize",0.1,"color color2", ( 0, 0, 1 ))

Shader ("surface", "plastic", "plasticlayer")

ConnectShaders ("checklayer", "Cout", "plasticlayer", "C")

ConnectShaders ("checklayer", "fout", "plasticlayer", "Ks")

ShaderGroupEnd ()

Input("PlaneGeom.rib")

Render()

「実践CGの誘い」や、RenderMan Fastの解説サイト、RenderDotCサイトのマニュアルページに、placecam.cがある。pythonで書き換えるのもできるし、簡単にコンパイルができます。今日もありがとうございます。

/* 

 * PlaceCamera(): establish a viewpoint, viewing direction and orientation

 *  for a scene. This routine must be called before RiWorldBegin(). 

 *  position: a point giving the camera position

 *  aim: a point giving the location at which the camera is aimed

 *  roll: an optional rotation of the camera about its direction axis 

 *  coneangle: an optional spotlight shader cone angle

 */  

   

#include   

#include 

#include 



#define PI 3.1415926535897932  

   

void usage(void)

{

    printf("usage: placecam pos_x pos_y pos_z aim_x aim_y aim_z\n");

    printf(" [coneangle] [roll_angle]\n");

    printf(" Calculate RenderMan transforms needed for camera transform\n");

    printf(" from light position to aim point with the given roll angle.\n");

    exit(1);

}  

   

typedef double RtPoint[3];  



void RiRotate(double angle, double x, double y, double z)

{

    if (fabs(angle) > 0.001) {

      printf("Rotate %0.2f %0.2f %0.2f %0.2f\n", angle, x, y, z);

      }

}



void RiTranslate(double dx, double dy, double dz)

{

    printf("Translate %0.2f %0.2f %0.2f\n", dx, dy, dz);

}   



/* 

 * AimZ(): rotate the world so the direction vector points in 

 *  positive z by rotating about the y axis, then x. The cosine 

 *  of each rotation is given by components of the normalized 

 *  direction vector.  Before the y rotation the direction vector 

 *  might be in negative z, but not afterward.

 */

void AimZ(RtPoint direction)

{

    double xzlen, yzlen, yrot, xrot;   

   

    if (direction[0]==0 && direction[1]==0 && direction[2]==0)

      return;



    /*

     * The initial rotation about the y axis is given by the projection of

     * the direction vector onto the x,z plane: the x and z components

     * of the direction. 

     */

    xzlen = sqrt(direction[0]*direction[0]+direction[2]*direction[2]);

    if (xzlen == 0)

      yrot = (direction[1] < 0) ? 180 : 0;

    else

      yrot = 180*acos(direction[2]/xzlen)/PI;   

   

    /*

     * The second rotation, about the x axis, is given by the projection on

     * the y,z plane of the y-rotated direction vector: the original y

     * component, and the rotated x,z vector from above. 

     */

    yzlen = sqrt(direction[1]*direction[1]+xzlen*xzlen);

    xrot = 180*acos(xzlen/yzlen)/PI;     /* yzlen should never be 0 */   

   

    if (direction[1] > 0)

      RiRotate(xrot, 1.0, 0.0, 0.0);

    else

      RiRotate(-xrot, 1.0, 0.0, 0.0);



    /* The last rotation declared gets performed first */

    if (direction[0] > 0)

      RiRotate(-yrot, 0.0, 1.0, 0.0);

    else

      RiRotate(yrot, 0.0, 1.0, 0.0);

}

   

void PlaceCamera(RtPoint position, RtPoint direction, float roll)

{

    RiRotate(-roll, 0.0, 0.0, 1.0);

    AimZ(direction);

    RiTranslate(-position[0], -position[1], -position[2]);

}   



int main(int argc, char *argv[])

{

    RtPoint pos, aim, dir;

    double roll;

    double coneangle, fov;  

   

    if (argc < 7) usage();  

   

    pos[0] = atof(argv[1]);

    pos[1] = atof(argv[2]);

    pos[2] = atof(argv[3]);

    aim[0] = atof(argv[4]);

    aim[1] = atof(argv[5]);

    aim[2] = atof(argv[6]);  

   

    if (argc > 7) coneangle = atof(argv[7]);

      else coneangle = 0.0;   

   

    if (argc > 8) roll = atof(argv[8]);

      else roll = 0.0;   

   

    printf("position: %0.2f, %0.2f, %0.2f\n", pos[0], pos[1], pos[2]);

    printf("aim:   %0.2f, %0.2f, %0.2f\n", aim[0], aim[1], aim[2]);

    printf("coneangle: %0.4f\n", coneangle);

    printf("roll:   %0.2f\n\n", roll);   

   

    if (coneangle != 0.0) {

      fov = coneangle * 360.0 / PI;

      printf("Projection \"perspective\" \"fov\" [%0.2f]\n", fov); 

      }   

   

    dir[0] = aim[0] - pos[0];

    dir[1] = aim[1] - pos[1];

    dir[2] = aim[2] - pos[2];   

   

    PlaceCamera(pos, dir, roll);

    return 0;

}