r.cost
r.cost.full.raster - Creates a raster layer of cumulative cost of moving across a raster layer whose cell values represent cost.
Raster (r.*)
ParameterRaster|input|Unit cost layer|False
ParameterRaster|start_rast|Name of starting raster points map|0|False
ParameterBoolean|-k|Use the 'Knight's move'; slower, but more accurate|False
ParameterBoolean|-n|Keep null values in output raster layer|False
OutputRaster|output|Cumulative cost