int main( int argc, char* args[] )
{
if ( SDL_Init( SDL_INIT_VIDEO ) == -1 )
return 1;
SDL_Surface *screen = SDL_SetVideoMode( WIDTH, HEIGHT, 32, SDL_SWSURFACE );
if ( !screen )
return 1;
// Initialize the grid from the BMP file.
SDL_Surface *temp = SDL_LoadBMP( "test.bmp" );
temp = SDL_ConvertSurface( temp, screen->format, SDL_SWSURFACE );
SDL_LockSurface( temp );
for( int y=0;y<HEIGHT;y++ )
{
for ( int x=0;x<WIDTH;x++ )
{
Uint8 r,g,b;
Uint32 *src = ( (Uint32 *)( (Uint8 *)temp->pixels + y*temp->pitch ) ) + x;
SDL_GetRGB( *src, temp->format, &r, &g, &b );
// Points inside get marked with a dx/dy of zero.
// Points outside get marked with an infinitely large distance.
if ( g < 128 )
{
Put( grid1, x, y, inside );
Put( grid2, x, y, empty );
} else {
Put( grid2, x, y, inside );
Put( grid1, x, y, empty );
}
}
}
SDL_UnlockSurface( temp );
// Generate the SDF.
GenerateSDF( grid1 );
GenerateSDF( grid2 );
// Render out the results.
SDL_LockSurface( screen );
for( int y=0;y<HEIGHT;y++ )
{
for ( int x=0;x<WIDTH;x++ )
{
// Calculate the actual distance from the dx/dy
int dist1 = (int)( sqrt( (double)Get( grid1, x, y ).DistSq() ) );
int dist2 = (int)( sqrt( (double)Get( grid2, x, y ).DistSq() ) );
int dist = dist1 - dist2;
// Clamp and scale it, just for display purposes.
int c = dist*3 + 128;
if ( c < 0 ) c = 0;
if ( c > 255 ) c = 255;
Uint32 *dest = ( (Uint32 *)( (Uint8 *)screen->pixels + y*screen->pitch ) ) + x;
*dest = SDL_MapRGB( screen->format, c, c, c );
}
}
SDL_UnlockSurface( screen );
SDL_Flip( screen );
// Wait for a keypress
SDL_Event event;
while( true )
{
if ( SDL_PollEvent( &event ) )
switch( event.type )
{
case SDL_QUIT:
case SDL_KEYDOWN:
return true;
}
}
return 0;
}
bool BitmapToSDF(Pixel *SourceBitmap, BMSize SourceWidth, BMSize SourceHeight, Pixel *DestBitmap, BMSize DestWidth, BMSize DestHeight, BMSize InsertX, BMSize InsertY, BMSize InsertWidth, BMSize InsertHeight)
{
// Check parameters
if(SourceBitmap == nullptr || SourceWidth == 0 || SourceHeight == 0 || DestBitmap == nullptr || SourceBitmap == DestBitmap || DestWidth == 0 || DestHeight == 0 || (InsertX + InsertWidth) > DestWidth || (InsertY + InsertHeight) > DestHeight || InsertWidth == 0 || InsertHeight == 0)
return false;
// Sizes
const BMSize SDFWidth = SourceWidth + SDFPaddingSize;
const BMSize SDFHeight = SourceHeight + SDFPaddingSize;
// Create two 1-bit per point grids from the Source bitmap, the grids being inverses of each other
SDFPoint *Grid1 = new SDFPoint[SDFWidth*SDFHeight]();
SDFPoint *Grid2 = new SDFPoint[SDFWidth*SDFHeight]();
for(BMSize i = 0; i < SDFWidth*SDFHeight; ++i) // Fill grids with blank
{
Grid1[i] = SDFInside;
Grid2[i] = SDFOutside;
}
for(BMSize y = 0; y < SourceHeight; ++y) // Write data from source
{
for(BMSize x = 0; x < SourceWidth; ++x)
{
if(SourceBitmap[(y*SourceWidth) + x] < 128)
{
Grid1[(((SDFPaddingSize / 2) + y)*SDFWidth) + ((SDFPaddingSize / 2) + x)] = SDFInside;
Grid2[(((SDFPaddingSize / 2) + y)*SDFWidth) + ((SDFPaddingSize / 2) + x)] = SDFOutside;
}
else
{
Grid1[(((SDFPaddingSize / 2) + y)*SDFWidth) + ((SDFPaddingSize / 2) + x)] = SDFOutside;
Grid2[(((SDFPaddingSize / 2) + y)*SDFWidth) + ((SDFPaddingSize / 2) + x)] = SDFInside;
}
}
}
// Compute SDF grids
GenerateSDF(Grid1, SDFWidth, SDFHeight);
GenerateSDF(Grid2, SDFWidth, SDFHeight);
// Copy SDF to destination bitmap
if(SDFWidth == InsertWidth && SDFHeight == InsertHeight && false) // The generation size and output size are the same, so there is no need to convert
{
// Copy the final values directly to the destination bitmap
for(BMSize y = 0; y < SDFHeight; ++y)
{
for(BMSize x = 0; x < SDFWidth; ++x)
{
// Calculate the actual distance from the dx/dy
int dist1 = (int)(sqrt((double)SDFGetPoint(Grid1, x, y, SDFWidth, SDFHeight).DistSq()));
int dist2 = (int)(sqrt((double)SDFGetPoint(Grid2, x, y, SDFWidth, SDFHeight).DistSq()));
int dist = dist1 - dist2;
// Clamp
int c = dist * 3 + 128;
if(c < 0) c = 0;
if(c > 255) c = 255;
// Write to bitmap
DestBitmap[((InsertY + y)*SDFWidth) + (InsertX + x)] = c;
}
}
}
else // Need to scale the output
{
// Copy the final values to a temporary buffer first
Pixel *SDF = new Pixel[SDFWidth*SDFHeight]();
for(BMSize y = 0; y < SDFHeight; ++y)
{
for(BMSize x = 0; x < SDFWidth; ++x)
{
// Calculate the actual distance from the dx/dy
int dist1 = (int)(sqrt((double)SDFGetPoint(Grid1, x, y, SDFWidth, SDFHeight).DistSq()));
int dist2 = (int)(sqrt((double)SDFGetPoint(Grid2, x, y, SDFWidth, SDFHeight).DistSq()));
int dist = dist1 - dist2;
// Clamp
int c = dist * 3 + 128;
if(c < 0) c = 0;
if(c > 255) c = 255;
// Write to bitmap
SDF[(y*SDFWidth) + x] = c;
}
}
// Scale bitmap to final size and copy it to the destination buffer
CopyBitmap(SDF, SDFWidth, SDFHeight, DestBitmap, DestWidth, DestHeight, InsertX, InsertY, InsertWidth, InsertHeight);
delete[] SDF;
}
// Done
delete[] Grid1;
delete[] Grid2;
return true;
}