Terrain painting is blocky, especially when painting over the same area multiple times. about flaxengine HOT 7 CLOSED

For future reference, if anyone else tries to tackle this:
#1739 (comment)

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Hello, I don't know if it's related, but I think the splatmap painting quantization algorithm is iccorect (Source/Editor/Tools/Terrain/Paint/SingleLayerMode.cs -> Apply).
In the deepest of the loop, we can see that we add paintAmount to the current layer (c) and subtract this same amount to all other layers.
I think instead we should decrease each other layers by the paintAmount multiplied by their contribution (minus current layer's contribution).
Something like this:

// Paint on the active splatmap texture
var c1 = (c + 1) % 4;
var c2 = (c + 2) % 4;
var c3 = (c + 3) % 4;

var otherLayersSum = src[c1] + src[c2] + src[c3] + other[0] + other[1] + other[2] + other[3];
var decreaseAmount = paintAmount / otherLayersSum;

src[c] = Mathf.Saturate(src[c] + paintAmount);
src[c1] = Mathf.Saturate(src[c1] - decreaseAmount * src[c1]);
src[c2] = Mathf.Saturate(src[c2] - decreaseAmount * src[c2]);
src[c3] = Mathf.Saturate(src[c3] - decreaseAmount * src[c3]);
p.TempBuffer[z * p.ModifiedSize.X + x] = src;

var other = (Color)p.SourceDataOther[zz * p.HeightmapSize + xx];
//if (other.ValuesSum > 0.0f) // Skip editing the other splatmap if it's empty
{
    // Remove 'paint' from the other splatmap texture
    other[0] = Mathf.Saturate(other[0] - decreaseAmount * other[0]);
    other[1] = Mathf.Saturate(other[1] - decreaseAmount * other[1]);
    other[2] = Mathf.Saturate(other[2] - decreaseAmount * other[2]);
    other[3] = Mathf.Saturate(other[3] - decreaseAmount * other[3]);
    p.TempBufferOther[z * p.ModifiedSize.X + x] = other;
    otherModified = true;
}

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@Menotdan could you attach terrain material you use in here? (no need for textures, just material asset would be fine)

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Also, usually using more advanced blending logic than simple Lerp yields better results in realistic terrains:

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@Menotdan could you attach terrain material you use in here? (no need for textures, just material asset would be fine)

landscape.zip

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Also, usually using more advanced blending logic than simple Lerp yields better results in realistic terrains

Is Linear Blend more complicated than Lerp? Anyways that wouldn't affect the splatmap being blocky.

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Thanks @Vizepi . I used your code here 0ee5ef8. It did improve blending.

Regarding the blockiness of the paint, it's related to the implementation of this system which stores layer weights per-vertex and uses hardware interpolation of the values in-between:

To provide higher resolution or this blend use heightmap-aware blending (like suggested above) or use tessellation (also with displacement/height-based blend) or increase vertex density (eg. by scaling terrain down a little).

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