iris
3cb18ac5c2
The emulator was blamed for two days for what is iris's own defect on any GL adapter. `GpuTextures::new` created the atlas `texture_2d_array` with one layer; wgpu-hal picks the GL target from the descriptor alone (`gles::Texture::get_info_from_desc`, `(false, 1) => TEXTURE_2D`), so the shader's `sampler2DArray` was handed a `GL_TEXTURE_2D`, the unit was incomplete, every `textureSample` returned (0,0,0,1), and `draw_glyph`'s `color.a *= texel.a` painted the whole glyph quad. `MIN_ARRAY_LAYERS = 2`, with the account at `create_array_texture` and a `debug_assert!` there. Vulkan -- the phone's build and the desktop's default backend -- was never affected. `force-gles` now switches the desktop backend too, so the GLES path is reproducible on a machine with a real GPU in seconds rather than only through an APK: that is how this was found, with two shader probes showing the sample was exactly (0,0,0,1).