自绘实心球，如何进行纹理映射

chjyangli

各位大侠
我用以下算法自绘球体，该如何进行纹理映射。
#define M_PI 3.1415926
static void circleTable(double **sint,double **cost,const int n)
{
int i;

/* Table size, the sign of n flips the circle direction */

const int size = abs(n);

/* Determine the angle between samples */

const double angle = 2*M_PI/(double)n;

/* Allocate memory for n samples, plus duplicate of first entry at the end */

*sint = (double *) calloc(sizeof(double), size+1);
*cost = (double *) calloc(sizeof(double), size+1);

/* Bail out if memory allocation fails, fgError never returns */

if (!(*sint) || !(*cost))
{
free(*sint);
free(*cost);
//fgError("Failed to allocate memory in circleTable");
}

/* Compute cos and sin around the circle */

for (i=0; i<size; i++)
{
(*sint) = sin(angle*i);
(*cost) = cos(angle*i);
}

/* Last sample is duplicate of the first */

(*sint)[size] = (*sint)[0];
(*cost)[size] = (*cost)[0];
}


/*
* Compute lookup table of cos and sin values forming a cirle
*
* Notes:
* It is the responsibility of the caller to free these tables
* The size of the table is (n+1) to form a connected loop
* The last entry is exactly the same as the first
* The sign of n can be flipped to get the reverse loop
*/
/*
* Draws a solid sphere
*/
void renderSolidSphere(GLdouble radius, GLint slices, GLint stacks)
{
         int i,j;

         /* Adjust z and radius as stacks are drawn. */

         double z0,z1;
         double r0,r1;

         /* Pre-computed circle */

         double *sint1,*cost1;
         double *sint2,*cost2;
         circleTable(&sint1,&cost1,-slices);
         circleTable(&sint2,&cost2,stacks*2);

         /* The top stack is covered with a triangle fan */

         z0 = 1.0;
         z1 = cost2[1];
         r0 = 0.0;
         r1 = sint2[1];

         glBegin(GL_TRIANGLE_FAN);
                 glNormal3d(0,0,1);
                 glVertex3d(0,0,radius);

                 for (j=slices; j>=0; j--)
                 {
                         glNormal3d(cost1[j]*r1, sint1[j]*r1, z1 );
                         glVertex3d(cost1[j]*r1*radius, sint1[j]*r1*radius, z1*radius);
                 }
         glEnd();

         /* Cover each stack with a quad strip, except the top and bottom stacks */
         for( i=1; i<stacks-1; i++ )
         {
                 z0 = z1; z1 = cost2[i+1];
                 r0 = r1; r1 = sint2[i+1];

                 glBegin(GL_QUAD_STRIP);
                         for(j=0; j<=slices; j++)
                         {
                                 glNormal3d(cost1[j]*r1, sint1[j]*r1, z1 );
                                 glVertex3d(cost1[j]*r1*radius, sint1[j]*r1*radius, z1*radius);
                                 glNormal3d(cost1[j]*r0, sint1[j]*r0, z0 );
                                 glVertex3d(cost1[j]*r0*radius, sint1[j]*r0*radius, z0*radius);
                         }
                 glEnd();
         }

         /* The bottom stack is covered with a triangle fan */
         z0 = z1;
         r0 = r1;
         glBegin(GL_TRIANGLE_FAN);
                 glNormal3d(0,0,-1);
                 glVertex3d(0,0,-radius);

                 for (j=0; j<=slices; j++)
                 {
                         glNormal3d(cost1[j]*r0, sint1[j]*r0, z0 );
                         glVertex3d(cost1[j]*r0*radius, sint1[j]*r0*radius, z0*radius);
                 }
         glEnd();

         /* Release sin and cos tables */

         free(sint1);
         free(cost1);
         free(sint2);
         free(cost2);
}
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tandunming

论坛太恶心了 传个附件这么麻烦 建议你看看计算机图形学课的书看看 要是找不到Email：tan_dunming@foxmail.com

chjyangli

给你发信了tan_dunming@foxmail.com

chjyangli

再次感谢tan_dunming@foxmail.com
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