[Bug] IconLayer: Texture corruption caused by premature generateMipmapsWebGL() calls in v9.2

[Sixeight]

Description

In v9.2, due to luma.gl Texture API changes, generateMipmapsWebGL() must be called manually (previously automatic via mipmaps: true property).

icon-manager.ts was updated to call generateMipmapsWebGL(), but it's called at inappropriate timings - specifically before texture data is fully written, leading to texture corruption:

Flavors

• Script tag
• React
• Python/Jupyter notebook
• MapboxOverlay
• GoogleMapsOverlay
• CARTO
• ArcGIS

Expected Behavior

Mipmap generation is performed only when a texture exists.

Steps to Reproduce

1. Create an IconLayer with auto-packing enabled (default)
2. Use many icons with dynamic updates
3. Use different icon types/colors (forces texture atlas resize)
4. Icons disappear (especially on low-performance GPU environments)

Minimal Reproduction Script

Run this script in browser console after loading your deck.gl app:

// Delay mipmap generation to force the bug
(function() {
  const canvas = document.querySelector('canvas');
  const gl = canvas.getContext('webgl2') || canvas.getContext('webgl');

  const originalGenerateMipmap = gl.generateMipmap.bind(gl);

  gl.generateMipmap = function(target) {
    const delay = 50 + Math.random() * 100; // 50-150ms delay
    setTimeout(() => {
      originalGenerateMipmap(target);
    }, delay);
  };

  console.log('Mipmap delay enabled - icons should disappear soon');
})();

Environment

• Framework version: v9.2.2
• Browser: Chrome
• OS: macOS

Logs

No response