72 lines
3 KiB
Clojure
72 lines
3 KiB
Clojure
;; Functions to apply a heightmap to a world.
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;;
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;; Heightmaps are considered only as greyscale images, so colour is redundent (will be
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;; ignored). Darker shades are higher.
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(ns mw-engine.heightmap
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(:import [java.awt.image BufferedImage])
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(:use mw-engine.utils
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mw-engine.world
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;; interestingly the imagez load-image is failing for me, while the
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;; collage version is problem free.
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[mikera.image.core :only [filter-image get-pixels]]
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[mikera.image.filters]
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[fivetonine.collage.util]
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))
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(defn- abs
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"Surprisingly, Clojure doesn't seem to have an abs function, or else I've
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missed it. So here's one of my own. Maps natural numbers onto themselves,
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and negative integers onto natural numbers. Also maps negative real numbers
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onto positive real numbers.
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* `n` a number, on the set of real numbers."
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[n]
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(cond (< n 0) (- 0 n) true n))
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(defn transform-altitude
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"Set the altitude of this cell from the corresponding pixel of this heightmap.
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If the heightmap you supply is smaller than the world, this will break.
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* `cell` a cell, as discussed in world.clj, q.v. Alternatively, a map;
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* `heightmap` an (ideally) greyscale image, whose x and y dimensions should
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exceed those of the world of which the `cell` forms part."
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[cell heightmap]
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(merge cell
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{:altitude
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(+ (get-int cell :altitude)
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(- 256
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(abs
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(mod
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(.getRGB heightmap
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(get-int cell :x)
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(get-int cell :y)) 256))))}))
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(defn- apply-heightmap-row
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"Set the altitude of each cell in this sequence from the corresponding pixel
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of this heightmap.
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If the heightmap you supply is smaller than the world, this will break.
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* `row` a row in a world, as discussed in world.clj, q.v. Alternatively, a
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sequence of maps;
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* `heightmap` an (ideally) greyscale image, whose x and y dimensions should
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exceed those of the world of which the `cell` forms part."
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[row heightmap]
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(apply vector (map #(transform-altitude % heightmap) row)))
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(defn apply-heightmap
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"Apply the image file loaded from this path to this world, and return a world whose
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altitudes are modified (added to) by the altitudes in the heightmap. It is assumed that
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the heightmap is at least as large in x and y dimensions as the world.
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* `world` a world, as defined in `world.clj`, q.v.; if world is not supplied,
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a world the size of the heightmap will be created.
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* `imagepath` a file path or URL which indicates an image file."
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([world imagepath]
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;; bizarrely, the collage load-util is working for me, but the imagez version isn't.
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(let [heightmap (filter-image (grayscale)(load-image imagepath))]
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(apply vector (map #(apply-heightmap-row % heightmap) world))))
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([imagepath]
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(let [heightmap (filter-image (grayscale)(load-image imagepath))
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world (make-world (.getWidth heightmap) (.getHeight heightmap))]
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(apply vector (map #(apply-heightmap-row % heightmap) world))))) |