static void tetrahedron(GLdouble p0[3], GLdouble radius, GLenum shadeType)
{
int i;
for (i = 0; i < 4; i++)
drawtriangle(i, 2, 1, p0, radius, shadeType, 0);
}
void myDisplay(void)
{
// 清除。GL_COLOR_BUFFER_BIT表示清除颜色
/*
在RGB模式下，使用glClearColor来指定“空”的颜色，它需要四个参数，其参数的意义跟glColor4f相似。
在索引颜色模式下，使用glClearIndex来指定“空”的颜色所在的索引，它需要一个参数，其意义跟glIndexi相似。
*/
glClearColor(0.5f, 0.5f, 0.5f, 0.5f);
glClear(GL_COLOR_BUFFER_BIT);
drawrect();
drawpoint();
drawline();
drawpolygon();
draw5star();
drawsin();
drawtriangle();
//保证前面的OpenGL命令立即执行（而不是让它们在缓冲区中等待）。其作用跟fflush(stdout)类似。
glFlush();
}
static void
tetrahedron(GLenum shadeType)
{
int i;
for (i = 3; i >= 0; i--)
drawtriangle(i, tdata, tndex, shadeType);
}
static void
icosahedron(GLenum shadeType)
{
int i;
for (i = 19; i >= 0; i--) {
drawtriangle(i, idata, index, shadeType);
}
}
static void
octahedron(GLenum shadeType)
{
int i;
for (i = 7; i >= 0; i--) {
drawtriangle(i, odata, ondex, shadeType);
}
}
void icosadraw(float xyzr[4])
{
/* This routine draws a Gouraud shade icosahedron. */
int i;
xoff = xyzr[0]; yoff = xyzr[1]; zoff = xyzr[2];
radius = xyzr[3];
/* Draw the icosahedron. */
for (i = 0; i < 20; i++)
{
drawtriangle(&vdata[tindices[i][0]][0],
&vdata[tindices[i][1]][0],
&vdata[tindices[i][2]][0]);
}
}
void subdivide(float *v1, float *v2, float *v3, int depth)
{
float v12[3], v23[3], v31[3], d;
int i;
void drawtrinagle(float *v1, float *v2, float *v3);
/* Draw this triangle when depth is zero. */
if (depth == 0)
{
drawtriangle(v1,v2,v3);
return;
}
/* Normalize the midpoints of each triangle side. */
for (i = 0; i < 3; i++)
{
v12[i] = v1[i] + (v2[i]-v1[i])/2.;
v23[i] = v2[i] + (v3[i]-v2[i])/2.;
v31[i] = v3[i] + (v1[i]-v3[i])/2.;
}
d = sqrt(v12[0]*v12[0] + v12[1]*v12[1] + v12[2]*v12[2]);
if (d > 0.0)
{ v12[0] /= d; v12[1] /= d; v12[2] /= d; }
d = sqrt(v23[0]*v23[0] + v23[1]*v23[1] + v23[2]*v23[2]);
if (d > 0.0)
{ v23[0] /= d; v23[1] /= d; v23[2] /= d; }
d = sqrt(v31[0]*v31[0] + v31[1]*v31[1] + v31[2]*v31[2]);
if (d > 0.0)
{ v31[0] /= d; v31[1] /= d; v31[2] /= d; }
/* Recursively subdivide the new triangles. */
subdivide(v1,v12,v31,depth-1);
subdivide(v2,v23,v12,depth-1);
subdivide(v3,v31,v23,depth-1);
subdivide(v12,v23,v31,depth-1);
}