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JoeZ

Pointer to Pointer

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Hi, I have a pointer to a memory short* video = (unsigned short*)ddsd.lpSurface; to access the memory I have to do video [x + m_pitch * y] = color ========================================== Is it possible to use a double pointer to make it work like a two dimensional array short ** video to acess the memory video[x][y] = color; Thanks!

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It's possible to do this with double pointers too.
Allocate an array of pointers to and use them as a lookup table for the video buffers' lines.
pixel **video;

void build_linebuf(pixel *surface, int pitch, int yres)
{
int y;
video = (pixel **) malloc(yres * sizeof(pixel *));

while(y = 0; y < yres; ++y) {
video[y] = surface;
surface += pitch;
}
)
However you'll have to access it as video[y][x] instead.

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unsigned short** map_2d_ushort_table(unsigned short* p, int pitch, int y_res)
{
unsigned short** tmp = new unsigned short*[y_res];

for(int y=0; y<y_res; ++y)
{
// pitch as number of pixels, not bytes
tmp[y] = p + y*pitch;
}
return tmp;
)

unsigned short** video = map_2d_ushort_table((unsigned short*)ddsd.lpSurface, m_pitch, y_res);

video[y][x] = color;


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