Method CreateFromHeightData

trinity/Tr2HostBitmap.cpp:836–891

-------------------------------------------------------------------------------------- Description: Creates a height map by scaling up source data to fill the bitmap with bicubic interpolation. Imitates the result of contour layer from chartdirector used by planetary interaction. Arguments: data - source data, values from 0 to 1 width - width of the source data height - height of the source data R

//   false Otherwise
// --------------------------------------------------------------------------------------
bool Tr2HostBitmap::CreateFromHeightData( const std::vector<float>& data, int32_t width, int32_t height )
{
	float scaleX = float( width - 1 ) / float( m_width );
	float scaleY = float( height - 1 ) / float( m_height );

	int32_t yIndex[4];
	float yValues[4];

	int components = GetBytesPerPixel( m_format );
	if( !IsValid() || !( components == 4 || components == 1 ) || IsCompressed() )
	{
		return false;
	}

	for( uint32_t y = 0; y < m_height; y++ )
	{
		float sy = y * scaleY;
		int32_t dataY = int32_t( sy );
		sy = sy - dataY;

		for( int32_t yi = 0; yi < 4; yi++ )
		{
			// Clamp the y axis
			yIndex[yi] = ClampInt( dataY + yi - 1, 0, width - 1 ) * width;
		}

		for( uint32_t x = 0; x < m_width; x++ )
		{
			float sx = x * scaleX;
			int32_t dataX = int32_t( sx );
			sx = sx - dataX;

			for( int32_t i = 0; i < 4; i++ )
			{
				int32_t index = dataX + i - 1;
				// Wrap the x axis
				int32_t xIdx = index < 0 ? width - ( ( -index ) % width ) : index % width;
				yValues[i] = CubicInterpolate( data[yIndex[0] + xIdx], data[yIndex[1] + xIdx], data[yIndex[2] + xIdx], data[yIndex[3] + xIdx], sy );
			}
			uint8_t value = uint8_t( TriClamp( CubicInterpolate( yValues[0], yValues[1], yValues[2], yValues[3], sx ), 0.f, 1.f ) * 255 );

			if( components == 4 )
			{
				uint32_t d = ( value << 24 ) + ( value << 16 ) + ( value << 8 ) + value;
				char* dest = m_data.get() + y * m_width * 4 + x * 4;
				memcpy( dest, &d, 4 );
			}
			else
			{
				char* dest = m_data.get() + y * m_width + x;
				*dest = value;
			}
		}
	}
	return true;
}
#endif