{

indices[current_index++] = i1 + offset;

indices[current_index++] = i2 + offset;

indices[current_index++] = i3 + offset;

Vertex *res_vertices, Index res_vertices_offset, Index *res_indices)

// Divides each side of triangle into given number of parts

// Writes data into arrays given as `res_vertices' and `res_indices',

// assuming that there are already `res_vertices_offset' vertices before `res_vertices' pointer.

{

_ASSERT(src_vertices != NULL);

_ASSERT(src_indices != NULL);

_ASSERT(res_vertices != NULL);

_ASSERT(res_indices != NULL);

// i1, i2 i3 are indices of source triangle vertices

const Index i1 = src_indices[src_index_offset];

const Index i2 = src_indices[src_index_offset + 1];

const Index i3 = src_indices[src_index_offset + 2];

const D3DXVECTOR3 step_down = (src_vertices[i1].pos - src_vertices[i2].pos)/TESSELATE_DEGREE;

const D3DXVECTOR3 step_right = (src_vertices[i3].pos - src_vertices[i1].pos)/TESSELATE_DEGREE;

res_vertices[0] = src_vertices[i2];

Index vertex = 1; // current vertex

DWORD index = 0; // current index

D3DXVECTOR3 start_pos = res_vertices[0].pos;

for( Index line = 1; line <= TESSELATE_DEGREE; ++line )

{

for( Index column = 0; column < line + 1; ++column ) // line #1 contains 2 vertices

{

res_vertices[vertex] = Vertex( start_pos

+ static_cast<FLOAT>(line)*step_down

+ static_cast<FLOAT>(column)*step_right );

if( column != 0 ) // not first coumn

{

// add outer triangle

add_triangle( vertex, vertex - 1, vertex - line - 1, res_indices, index, res_vertices_offset );

}

if( ( column != 0 ) && ( column != line ) ) // not first and not last column

{

// add inner triangle

add_triangle( vertex, vertex - line - 1, vertex - line, res_indices, index, res_vertices_offset );

}

++vertex;

}

}