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Replace the 3D sphere brush with a square stamp in the surface tangent plane whose shape and opacity come from a grayscale/alpha mask. Masks are assignable via an inspector list with a live-switchable active index; an empty list falls back to a procedurally generated circle mask that reproduces the previous round brush. - Mask drives opacity (luma * alpha * brushOpacity) via source-over blend instead of a hard threshold cut; gray 0.5 = 50%. - GPU and CPU paths stay identical; non-readable textures are supported on the CPU via GPU blit-readback. - Dilate pass treats any alpha > 0 as painted so soft edges survive seam padding. - Brush alignment enum (Camera/World) plus manual rotation; tangent frame handedness fixed so stamps read upright and unmirrored in both modes.
74 lines
2.6 KiB
Plaintext
74 lines
2.6 KiB
Plaintext
// GPU edge padding / texture dilation against visible UV seams.
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//
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// Between the UV islands there is an unpainted border (gutter). During bilinear
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// sampling at an island edge, the GPU mixes the painted edge with the unpainted
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// base color -> bright seam lines. This pass "bleeds" the painted color up to
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// _Pad texels beyond the island edges.
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//
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// The dilation source is exclusively painted texels (alpha > 0). The padding
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// texels produced get alpha = 0 -> next frame they are NO LONGER a source, so the
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// padding does not grow unbounded (it stays at _Pad texels). The threshold is > 0
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// (not >= 0.5) so soft, partially transparent brush edges count as painted too.
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Shader "Hidden/MeshPaintDilate"
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{
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Properties
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{
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_MainTex ("Texture", 2D) = "white" {}
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}
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SubShader
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{
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Tags { "RenderType" = "Opaque" }
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Pass
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{
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ZTest Always
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ZWrite Off
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Cull Off
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Blend Off
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CGPROGRAM
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#pragma vertex vert_img
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#pragma fragment frag
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#include "UnityCG.cginc"
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sampler2D _MainTex;
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float4 _MainTex_TexelSize; // (1/w, 1/h, w, h)
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int _Pad;
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#define MAXPAD 16
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fixed4 frag (v2f_img i) : SV_Target
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{
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fixed4 c = tex2D(_MainTex, i.uv);
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if (c.a > 0.0) return c; // already painted (even partially) -> leave unchanged
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float2 ts = _MainTex_TexelSize.xy;
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float best = 1e20;
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fixed3 bestCol = c.rgb;
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bool found = false;
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// Search the neighborhood (up to _Pad texels) for the nearest painted texel.
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[loop] for (int y = -MAXPAD; y <= MAXPAD; y++)
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{
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if (abs(y) > _Pad) continue;
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[loop] for (int x = -MAXPAD; x <= MAXPAD; x++)
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{
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if (abs(x) > _Pad) continue;
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fixed4 s = tex2D(_MainTex, i.uv + float2(x, y) * ts);
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if (s.a > 0.0)
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{
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float dd = (float)(x * x + y * y);
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if (dd < best) { best = dd; bestCol = s.rgb; found = true; }
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}
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}
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}
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// Gutter: color of the nearest painted texel, but alpha = 0 (not a source).
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if (found) return fixed4(bestCol, 0.0);
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return c; // out of range -> base color unchanged
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}
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ENDCG
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}
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}
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Fallback Off
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}
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