First of all, we have to work out the details for that first placement. We have a few things to consider.
1. What size should we start with? We randomly choose a size based on the [size]_rate settings. These rates are treated as _weights_, meaning that we add all the weights together to get a _total weight_, and the probability of selecting each size is that size’s weight divided by the total weight. For example:
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In this case, the _total weight _is 10 + 25 + 50 + 60 = 145. Therefore, there’s a 10 ÷ 145 ≅ 7% chance of choosing a huge texture, a 25 ÷ 145 ≅ 17% chance of a large texture, etc.
2. Where should it go in the world? The first placement can only successfully be placed in the biome specified by place_on_biome. We randomly select any location in the world that satisfies this constraint.
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3. How tall should it be? We randomly select a height scaling factor in the range specified by size_relative_height. In our example from fig. 1 where we chose a large texture, we would choose a scaling factor between 0.2 and 0.6. See relative height for more details.
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4. Which texture should it use? Textures are randomly selected from each size category. In this particular case, there is only one large texture to choose from, so we know we’ll be using tex_stamp_hoodoo_large_01.
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Once we’ve chosen these parameters for the first placement, we move onto the sub-scatter.