109 lines
3.5 KiB
GDScript
109 lines
3.5 KiB
GDScript
@tool
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# XYZ files are text files containing a list of 3D points.
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# They can be found in GIS software as an export format for heightmaps.
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# In order to turn it into a heightmap we may calculate bounds first
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# to find the origin and then set points in an image.
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class HT_XYZBounds:
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# Note: it is important for these to be double-precision floats,
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# GIS data can have large coordinates
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var min_x := 0.0
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var min_y := 0.0
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var max_x := 0.0
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var max_y := 0.0
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var line_count := 0
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var image_width := 0
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var image_height := 0
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# TODO `split_float` returns 32-bit floats, despite internally parsing doubles...
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# Despite that, I still use it here because it doesn't seem to cause issues and is faster.
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# If it becomes an issue, we'll have to switch to `split` and casting to `float`.
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static func load_bounds(f: FileAccess) -> HT_XYZBounds:
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# It is faster to get line and split floats than using CSV functions
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var line := f.get_line()
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var floats := line.split_floats(" ")
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# We only care about X and Y, it makes less operations to do in the loop.
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# Z is the height and will remain as-is at the end.
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var min_pos_x := floats[0]
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var min_pos_y := floats[1]
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var max_pos_x := min_pos_x
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var max_pos_y := min_pos_y
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# Start at 1 because we just read the first line
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var line_count := 1
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# We know the file is a series of float triplets
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while not f.eof_reached():
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line = f.get_line()
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# The last line can be empty
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if len(line) < 2:
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break
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floats = line.split_floats(" ")
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var pos_x := floats[0]
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var pos_y := floats[1]
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min_pos_x = minf(min_pos_x, pos_x)
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min_pos_y = minf(min_pos_y, pos_y)
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max_pos_x = maxf(max_pos_x, pos_x)
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max_pos_y = maxf(max_pos_y, pos_y)
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line_count += 1
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var bounds := HT_XYZBounds.new()
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bounds.min_x = min_pos_x
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bounds.min_y = min_pos_y
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bounds.max_x = max_pos_x
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bounds.max_y = max_pos_y
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bounds.line_count = line_count
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bounds.image_width = int(max_pos_x - min_pos_x) + 1
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bounds.image_height = int(max_pos_y - min_pos_y) + 1
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return bounds
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# Loads points into an image with existing dimensions and format.
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# `f` must be positionned at the beginning of the series of points.
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# If `bounds` is `null`, it will be computed.
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static func load_heightmap(f: FileAccess, dst_image: Image, bounds: HT_XYZBounds):
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# We are not going to read the entire file directly in memory, because it can be really big.
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# Instead we'll parse it directly and the only thing we retain in memory is the heightmap.
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# This can be really slow on big files. If we can assume the file is square and points
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# separated by 1 unit each in a grid pattern, it could be a bit faster, but
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# parsing points from text really is the main bottleneck (40 seconds to load a 2000x2000 file!).
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# Bounds can be precalculated
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if bounds == null:
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var file_begin := f.get_position()
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bounds = load_bounds(f)
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f.seek(file_begin)
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# Put min coordinates on the GDScript stack so they are faster to access
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var min_pos_x := bounds.min_x
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var min_pos_y := bounds.min_y
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var line_count := bounds.line_count
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for i in line_count:
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var line := f.get_line()
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var floats := line.split_floats(" ")
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var x := int(floats[0] - min_pos_x)
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var y := int(floats[1] - min_pos_y)
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# Make sure the coordinate is inside the image,
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# due to float imprecision or potentially non-grid-aligned points.
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# Could use `Rect2` to check faster but it uses floats.
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# `Rect2i` would be better but is only available in Godot 4.
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if x >= 0 and y >= 0 and x < dst_image.get_width() and y < dst_image.get_height():
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dst_image.set_pixel(x, y, Color(floats[2], 0, 0))
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