59 lines
2.0 KiB
C#
59 lines
2.0 KiB
C#
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using Godot;
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using System;
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using Rokojori.Extensions;
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namespace Rokojori
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{
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/** How a HeightMapGeneratorLayer combines with what is already in the map.
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All three are <marked>native</marked> BlitMaterial blend modes, so a layer
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costs one content blit into a scratch buffer plus one hardware-blended blit
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onto the map - no ping-pong buffer and no accumulation read anywhere.
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The int values are passed to HeightMapShape.gdshader as shape_blend_mode,
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which decides whether the falloff goes into RGB (Add/Subtract, premultiplied
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so the hardware just sums it) or into alpha (Replace, so Mix crossfades to
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the layer's height across the falloff). Do not renumber without updating the
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shader.
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*/
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public enum HeightMapBlendMode
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{
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/** Adds the layer's height on top of what is underneath. The default, and
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the one that makes a stack of layers read as constructive.
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*/
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Add = 0,
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/** Subtracts it - craters, trenches, cut-outs. */
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Subtract = 1,
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/** Overwrites with the layer's height, fading back to what is underneath
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across the falloff. The layer's height value is an <marked>absolute</marked>
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world height here, not a delta - plateaus and flattened build sites.
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*/
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Replace = 2
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}
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public static class HeightMapBlendModeX
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{
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public static BlitMaterial.BlendModeEnum ToBlitBlendMode( this HeightMapBlendMode mode )
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{
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switch ( mode )
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{
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case HeightMapBlendMode.Add: return BlitMaterial.BlendModeEnum.Add;
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case HeightMapBlendMode.Subtract: return BlitMaterial.BlendModeEnum.Sub;
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case HeightMapBlendMode.Replace: return BlitMaterial.BlendModeEnum.Mix;
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}
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return BlitMaterial.BlendModeEnum.Add;
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}
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/** True when the layer's height value means "this world height", false when
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it means "this much height on top of what is there".
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*/
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public static bool IsAbsolute( this HeightMapBlendMode mode )
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{
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return mode == HeightMapBlendMode.Replace;
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}
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}
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}
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