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[fix] [sdf] Sdf text alpha double multiplication #2

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Merged
chiefcll merged 1 commit into from
May 8, 2026
Merged

[fix] [sdf] Sdf text alpha double multiplication #2

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10 changes: 4 additions & 6 deletions src/core/renderers/webgl/WebGlRenderer.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -600,18 +600,16 @@ export class WebGlRenderer extends CoreRenderer {

// Pre-compute the merged color (with alpha) packed as ABGR for
// UNSIGNED_BYTE normalized attribute.
// NOTE: Do NOT premultiply RGB by alpha here — the SDF fragment shader
// already multiplies v_color.rgb by the computed opacity (which includes
// v_color.a).
const mergedColor = mergeColorAlpha(color, worldAlpha);
const r = mergedColor >>> 24;
const g = (mergedColor >>> 16) & 0xff;
const b = (mergedColor >>> 8) & 0xff;
const a = mergedColor & 0xff;
// Premultiply alpha into RGB for correct blending
const na = a / 255;
const pr = (r * na) | 0;
const pg = (g * na) | 0;
const pb = (b * na) | 0;
// Pack as ABGR uint32 (little-endian read as vec4(r,g,b,a) normalized)
const packedColor = ((a << 24) | (pb << 16) | (pg << 8) | pr) >>> 0;
const packedColor = ((a << 24) | (b << 16) | (g << 8) | r) >>> 0;

// Transform matrix components (column-major 3x3)
// Pre-multiply fontScale here to save 4 multiplications per glyph in the hot loop
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