Window scaling fails with `skia` backend and GPU/opengl acceleration enabled

Hello,

- I noticed that the sample https://github.com/aseprite/laf/blob/main/examples/shader.cpp doesn't work properly on my machine in a specific set of circumstances:
- skia backend
- GPU acceleration ON
- window scaling factor > 1

- I have compiled `skia` from https://github.com/aseprite/skia, branch `aseprite-m124`, and I have compiled `laf` with that skia backend.

---

Running the shader example out of the box, I get

which is the expected behavior.

---

If I modify https://github.com/aseprite/laf/blob/main/examples/shader.cpp#L59 to

```cpp
class ShaderWindow {
public:
ShaderWindow(const SystemRef& system)
: m_system(system)
, m_builder(SkRuntimeEffect::MakeForShader(SkString(shaderCode)).effect)
{
m_window = m_system->makeWindow(256, 256, 2); // <-- CHANGE SCALING FACTOR TO 2
m_window->setCursor(NativeCursor::Arrow);
m_window->setTitle("Shader - GPU");
m_window->setGpuAcceleration(true);
repaint();
m_window->setVisible(true);
}
```

Then I get

Which is obviously wrong. The app is still running, the surface is just black.

---

Digging in a little bit, the problem seems to be in [`os::skia::SkiaGL::createRenderTarget(...)`](https://github.com/aseprite/laf/blob/main/os/skia/skia_gl.cpp#L68-L115):

```cpp
bool SkiaGL::createRenderTarget(const gfx::Size& size,
const int scale,
sk_sp colorSpace)
{
// Create of a SkSurface (m_backbufferSurface) connected to the
// OpenGL framebuffer.

GrGLint buffer;
m_glInterfaces->fFunctions.fGetIntegerv(GR_GL_FRAMEBUFFER_BINDING, &buffer);
// PROBLEM IS APPARENTLY HERE ^^^^^^^^^^^^^^^^^^^^^^^^^

GrGLFramebufferInfo info;
info.fFBOID = (GrGLuint)buffer;
info.fFormat = GR_GL_RGBA8;
// SK_API bool GrBackendRenderTargets::GetGLFramebufferInfo(const GrBackendRenderTarget&,
// GrGLFramebufferInfo*);

GrGLint stencil = 0;
m_glInterfaces->fFunctions.fGetIntegerv(GR_GL_STENCIL_BITS, &stencil);

// GrBackendRenderTarget target(size.w, size.h, 0, stencil, info);
GrBackendRenderTarget target = GrBackendRenderTargets::MakeGL(size.w, size.h, 0, stencil, info);

// ...
}
```

The problem is that the call to `fGetIntegerv(GR_GL_FRAMEBUFFER_BINDING, &buffer)` generates `GL_INVALID_ENUM`, which can be seen by checking for errors after that call...

```cpp

// Clear any previous GL errors
while (m_glInterfaces->fFunctions.fGetError() != GR_GL_NO_ERROR) {}

GrGLint buffer;
m_glInterfaces->fFunctions.fGetIntegerv(GR_GL_FRAMEBUFFER_BINDING, &buffer);

GrGLenum error = m_glInterfaces->fFunctions.fGetError();

std::cout << "[SkiaGL::createRenderTarget] Creating render target:" << std::endl;
std::cout << " Size: " << size.w << "x" << size.h << std::endl;
std::cout << " Scale: " << scale << std::endl;
std::cout << " Current FBO binding: " << buffer << std::endl;
if (error != GR_GL_NO_ERROR) {
std::cout << " GL Error after FBO query: " << error << std::endl;
}

```

...which prints

```
[SkiaGL::createRenderTarget] Creating render target:
Size: 256x256
Scale: 2
Current FBO binding: 22005
GL Error after FBO query: 1280 // this is 0x0500, which is GL_INVALID_ENUM
```
---
My knowledge of OpenGL is rudimentary, so take this with a big grain of salt. What I think is going on here is that `GL_FRAMEBUFFER_BINDING` is not a valid parameter to `glGetIntegerv(...)`; it doesn't appear in the extensive list of params for that function in the [OpenGL 4.5 documentation](https://registry.khronos.org/OpenGL-Refpages/gl4/html/glGet.xhtml).

There are two related constants, `GL_DRAW_FRAMEBUFFER_BINDING` and `GL_READ_FRAMEBUFFER_BINDING`, and I infer from some googling that the former is equivalent/backwards compatible with `GL_FRAMEBUFFER_BINDING`. But neither of those params appear in [the `ganesh` defines within skia](https://github.com/aseprite/skia/blob/aseprite-m124/src/gpu/ganesh/gl/GrGLDefines.h) and neither of them work if I just use the literal values in that call; I get the same `GL_INVALID_ENUM` error.

The param does appear in the [OpenGL ES documentation for `glGetIntegerv(...)`](https://registry.khronos.org/OpenGL-Refpages/es2.0/xhtml/glGet.xml). But when I call `glGetVersion(...)` I get back `4.6.0 NVIDIA 560.28.03`, so I believe that means we are using core profile, not OpenGL ES, here.

---

The example works if I catch the error and hardcode the buffer to 0:

```cpp
std::cout << "[SkiaGL::createRenderTarget] Creating render target:" << std::endl;
std::cout << " Size: " << size.w << "x" << size.h << std::endl;
std::cout << " Scale: " << scale << std::endl;
std::cout << " Current FBO binding: " << buffer << std::endl;
if (error != GR_GL_NO_ERROR) {
std::cout << " GL Error after FBO query: " << error << std::endl;
std::cout << " WARNING: Using default framebuffer (0) instead" << std::endl;
buffer = 0; // Use default framebuffer
}
```

Then I can scale as much as I like:

4x:

16x:

But this seems inelegant.

---

In case it helps:

```
$ uname -a
Linux legolas 6.8.0-41-generic #41-Ubuntu SMP PREEMPT_DYNAMIC Fri Aug 2 20:41:06 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

$ glxinfo
name of display: :0
display: :0 screen: 0
direct rendering: Yes
server glx vendor string: NVIDIA Corporation
server glx version string: 1.4
server glx extensions:
GLX_ARB_context_flush_control, GLX_ARB_create_context,
GLX_ARB_create_context_no_error, GLX_ARB_create_context_profile,
GLX_ARB_create_context_robustness, GLX_ARB_fbconfig_float,
GLX_ARB_multisample, GLX_EXT_buffer_age,
GLX_EXT_create_context_es2_profile, GLX_EXT_create_context_es_profile,
GLX_EXT_framebuffer_sRGB, GLX_EXT_import_context, GLX_EXT_libglvnd,
GLX_EXT_stereo_tree, GLX_EXT_swap_control, GLX_EXT_swap_control_tear,
GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info, GLX_EXT_visual_rating,
GLX_NV_copy_image, GLX_NV_delay_before_swap, GLX_NV_float_buffer,
GLX_NV_multigpu_context, GLX_NV_robustness_video_memory_purge,
GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, GLX_SGI_swap_control,
GLX_SGI_video_sync
client glx vendor string: NVIDIA Corporation
client glx version string: 1.4
client glx extensions:
GLX_ARB_context_flush_control, GLX_ARB_create_context,
GLX_ARB_create_context_no_error, GLX_ARB_create_context_profile,
GLX_ARB_create_context_robustness, GLX_ARB_fbconfig_float,
GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_buffer_age,
GLX_EXT_create_context_es2_profile, GLX_EXT_create_context_es_profile,
GLX_EXT_fbconfig_packed_float, GLX_EXT_framebuffer_sRGB,
GLX_EXT_import_context, GLX_EXT_stereo_tree, GLX_EXT_swap_control,
GLX_EXT_swap_control_tear, GLX_EXT_texture_from_pixmap,
GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_NV_copy_buffer,
GLX_NV_copy_image, GLX_NV_delay_before_swap, GLX_NV_float_buffer,
GLX_NV_multigpu_context, GLX_NV_multisample_coverage,
GLX_NV_robustness_video_memory_purge, GLX_NV_swap_group,
GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, GLX_SGI_swap_control,
GLX_SGI_video_sync
GLX version: 1.4
GLX extensions:
GLX_ARB_context_flush_control, GLX_ARB_create_context,
GLX_ARB_create_context_no_error, GLX_ARB_create_context_profile,
GLX_ARB_create_context_robustness, GLX_ARB_fbconfig_float,
GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_buffer_age,
GLX_EXT_create_context_es2_profile, GLX_EXT_create_context_es_profile,
GLX_EXT_framebuffer_sRGB, GLX_EXT_import_context, GLX_EXT_stereo_tree,
GLX_EXT_swap_control, GLX_EXT_swap_control_tear,
GLX_EXT_texture_from_pixmap, GLX_EXT_visual_info, GLX_EXT_visual_rating,
GLX_NV_copy_image, GLX_NV_delay_before_swap, GLX_NV_float_buffer,
GLX_NV_multigpu_context, GLX_NV_robustness_video_memory_purge,
GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, GLX_SGI_swap_control,
GLX_SGI_video_sync
Memory info (GL_NVX_gpu_memory_info):
Dedicated video memory: 12288 MB
Total available memory: 12288 MB
Currently available dedicated video memory: 9700 MB
OpenGL vendor string: NVIDIA Corporation
OpenGL renderer string: NVIDIA GeForce RTX 3080 Ti/PCIe/SSE2
OpenGL core profile version string: 4.6.0 NVIDIA 560.28.03
OpenGL core profile shading language version string: 4.60 NVIDIA
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
GL_AMD_multi_draw_indirect, GL_AMD_seamless_cubemap_per_texture,
GL_AMD_vertex_shader_layer, GL_AMD_vertex_shader_viewport_index,
GL_ARB_ES2_compatibility, GL_ARB_ES3_1_compatibility,
GL_ARB_ES3_2_compatibility, GL_ARB_ES3_compatibility,
GL_ARB_arrays_of_arrays, GL_ARB_base_instance, GL_ARB_bindless_texture,
GL_ARB_blend_func_extended, GL_ARB_buffer_storage,
GL_ARB_clear_buffer_object, GL_ARB_clear_texture, GL_ARB_clip_control,
GL_ARB_color_buffer_float, GL_ARB_compressed_texture_pixel_storage,
GL_ARB_compute_shader, GL_ARB_compute_variable_group_size,
GL_ARB_conditional_render_inverted, GL_ARB_conservative_depth,
GL_ARB_copy_buffer, GL_ARB_copy_image, GL_ARB_cull_distance,
GL_ARB_debug_output, GL_ARB_depth_buffer_float, GL_ARB_depth_clamp,
GL_ARB_depth_texture, GL_ARB_derivative_control,
GL_ARB_direct_state_access, GL_ARB_draw_buffers,
GL_ARB_draw_buffers_blend, GL_ARB_draw_elements_base_vertex,
GL_ARB_draw_indirect, GL_ARB_draw_instanced, GL_ARB_enhanced_layouts,
GL_ARB_explicit_attrib_location, GL_ARB_explicit_uniform_location,
GL_ARB_fragment_coord_conventions, GL_ARB_fragment_layer_viewport,
GL_ARB_fragment_program, GL_ARB_fragment_program_shadow,
GL_ARB_fragment_shader, GL_ARB_fragment_shader_interlock,
GL_ARB_framebuffer_no_attachments, GL_ARB_framebuffer_object,
GL_ARB_framebuffer_sRGB, GL_ARB_geometry_shader4,
GL_ARB_get_program_binary, GL_ARB_get_texture_sub_image, GL_ARB_gl_spirv,
GL_ARB_gpu_shader5, GL_ARB_gpu_shader_fp64, GL_ARB_gpu_shader_int64,
GL_ARB_half_float_pixel, GL_ARB_half_float_vertex, GL_ARB_imaging,
GL_ARB_indirect_parameters, GL_ARB_instanced_arrays,
GL_ARB_internalformat_query, GL_ARB_internalformat_query2,
GL_ARB_invalidate_subdata, GL_ARB_map_buffer_alignment,
GL_ARB_map_buffer_range, GL_ARB_multi_bind, GL_ARB_multi_draw_indirect,
GL_ARB_multisample, GL_ARB_multitexture, GL_ARB_occlusion_query,
GL_ARB_occlusion_query2, GL_ARB_parallel_shader_compile,
GL_ARB_pipeline_statistics_query, GL_ARB_pixel_buffer_object,
GL_ARB_point_parameters, GL_ARB_point_sprite, GL_ARB_polygon_offset_clamp,
GL_ARB_post_depth_coverage, GL_ARB_program_interface_query,
GL_ARB_provoking_vertex, GL_ARB_query_buffer_object,
GL_ARB_robust_buffer_access_behavior, GL_ARB_robustness,
GL_ARB_sample_locations, GL_ARB_sample_shading, GL_ARB_sampler_objects,
GL_ARB_seamless_cube_map, GL_ARB_seamless_cubemap_per_texture,
GL_ARB_separate_shader_objects, GL_ARB_shader_atomic_counter_ops,
GL_ARB_shader_atomic_counters, GL_ARB_shader_ballot,
GL_ARB_shader_bit_encoding, GL_ARB_shader_clock,
GL_ARB_shader_draw_parameters, GL_ARB_shader_group_vote,
GL_ARB_shader_image_load_store, GL_ARB_shader_image_size,
GL_ARB_shader_objects, GL_ARB_shader_precision,
GL_ARB_shader_storage_buffer_object, GL_ARB_shader_subroutine,
GL_ARB_shader_texture_image_samples, GL_ARB_shader_texture_lod,
GL_ARB_shader_viewport_layer_array, GL_ARB_shading_language_100,
GL_ARB_shading_language_420pack, GL_ARB_shading_language_include,
GL_ARB_shading_language_packing, GL_ARB_shadow, GL_ARB_sparse_buffer,
GL_ARB_sparse_texture, GL_ARB_sparse_texture2,
GL_ARB_sparse_texture_clamp, GL_ARB_spirv_extensions,
GL_ARB_stencil_texturing, GL_ARB_sync, GL_ARB_tessellation_shader,
GL_ARB_texture_barrier, GL_ARB_texture_border_clamp,
GL_ARB_texture_buffer_object, GL_ARB_texture_buffer_object_rgb32,
GL_ARB_texture_buffer_range, GL_ARB_texture_compression,
GL_ARB_texture_compression_bptc, GL_ARB_texture_compression_rgtc,
GL_ARB_texture_cube_map, GL_ARB_texture_cube_map_array,
GL_ARB_texture_env_add, GL_ARB_texture_env_combine,
GL_ARB_texture_env_crossbar, GL_ARB_texture_env_dot3,
GL_ARB_texture_filter_anisotropic, GL_ARB_texture_filter_minmax,
GL_ARB_texture_float, GL_ARB_texture_gather,
GL_ARB_texture_mirror_clamp_to_edge, GL_ARB_texture_mirrored_repeat,
GL_ARB_texture_multisample, GL_ARB_texture_non_power_of_two,
GL_ARB_texture_query_levels, GL_ARB_texture_query_lod,
GL_ARB_texture_rectangle, GL_ARB_texture_rg, GL_ARB_texture_rgb10_a2ui,
GL_ARB_texture_stencil8, GL_ARB_texture_storage,
GL_ARB_texture_storage_multisample, GL_ARB_texture_swizzle,
GL_ARB_texture_view, GL_ARB_timer_query, GL_ARB_transform_feedback2,
GL_ARB_transform_feedback3, GL_ARB_transform_feedback_instanced,
GL_ARB_transform_feedback_overflow_query, GL_ARB_transpose_matrix,
GL_ARB_uniform_buffer_object, GL_ARB_vertex_array_bgra,
GL_ARB_vertex_array_object, GL_ARB_vertex_attrib_64bit,
GL_ARB_vertex_attrib_binding, GL_ARB_vertex_buffer_object,
GL_ARB_vertex_program, GL_ARB_vertex_shader,
GL_ARB_vertex_type_10f_11f_11f_rev, GL_ARB_vertex_type_2_10_10_10_rev,
GL_ARB_viewport_array, GL_ARB_window_pos, GL_ATI_draw_buffers,
GL_ATI_texture_float, GL_ATI_texture_mirror_once,
GL_EXTX_framebuffer_mixed_formats, GL_EXT_Cg_shader, GL_EXT_abgr,
GL_EXT_bgra, GL_EXT_bindable_uniform, GL_EXT_blend_color,
GL_EXT_blend_equation_separate, GL_EXT_blend_func_separate,
GL_EXT_blend_minmax, GL_EXT_blend_subtract, GL_EXT_compiled_vertex_array,
GL_EXT_depth_bounds_test, GL_EXT_direct_state_access,
GL_EXT_draw_buffers2, GL_EXT_draw_instanced, GL_EXT_draw_range_elements,
GL_EXT_fog_coord, GL_EXT_framebuffer_blit, GL_EXT_framebuffer_multisample,
GL_EXT_framebuffer_multisample_blit_scaled, GL_EXT_framebuffer_object,
GL_EXT_framebuffer_sRGB, GL_EXT_geometry_shader4,
GL_EXT_gpu_program_parameters, GL_EXT_gpu_shader4,
GL_EXT_import_sync_object, GL_EXT_memory_object, GL_EXT_memory_object_fd,
GL_EXT_multi_draw_arrays, GL_EXT_multiview_texture_multisample,
GL_EXT_multiview_timer_query, GL_EXT_packed_depth_stencil,
GL_EXT_packed_float, GL_EXT_packed_pixels, GL_EXT_pixel_buffer_object,
GL_EXT_point_parameters, GL_EXT_polygon_offset_clamp,
GL_EXT_post_depth_coverage, GL_EXT_provoking_vertex,
GL_EXT_raster_multisample, GL_EXT_rescale_normal, GL_EXT_secondary_color,
GL_EXT_semaphore, GL_EXT_semaphore_fd, GL_EXT_separate_shader_objects,
GL_EXT_separate_specular_color, GL_EXT_shader_image_load_formatted,
GL_EXT_shader_image_load_store, GL_EXT_shader_integer_mix,
GL_EXT_shadow_funcs, GL_EXT_sparse_texture2, GL_EXT_stencil_two_side,
GL_EXT_stencil_wrap, GL_EXT_texture3D, GL_EXT_texture_array,
GL_EXT_texture_buffer_object, GL_EXT_texture_compression_dxt1,
GL_EXT_texture_compression_latc, GL_EXT_texture_compression_rgtc,
GL_EXT_texture_compression_s3tc, GL_EXT_texture_cube_map,
GL_EXT_texture_edge_clamp, GL_EXT_texture_env_add,
GL_EXT_texture_env_combine, GL_EXT_texture_env_dot3,
GL_EXT_texture_filter_anisotropic, GL_EXT_texture_filter_minmax,
GL_EXT_texture_integer, GL_EXT_texture_lod, GL_EXT_texture_lod_bias,
GL_EXT_texture_mirror_clamp, GL_EXT_texture_object, GL_EXT_texture_sRGB,
GL_EXT_texture_sRGB_R8, GL_EXT_texture_sRGB_decode,
GL_EXT_texture_shadow_lod, GL_EXT_texture_shared_exponent,
GL_EXT_texture_storage, GL_EXT_texture_swizzle, GL_EXT_timer_query,
GL_EXT_transform_feedback2, GL_EXT_vertex_array, GL_EXT_vertex_array_bgra,
GL_EXT_vertex_attrib_64bit, GL_EXT_window_rectangles,
GL_EXT_x11_sync_object, GL_IBM_rasterpos_clip,
GL_IBM_texture_mirrored_repeat, GL_KHR_blend_equation_advanced,
GL_KHR_blend_equation_advanced_coherent, GL_KHR_context_flush_control,
GL_KHR_debug, GL_KHR_no_error, GL_KHR_parallel_shader_compile,
GL_KHR_robust_buffer_access_behavior, GL_KHR_robustness,
GL_KHR_shader_subgroup, GL_KTX_buffer_region,
GL_NVX_blend_equation_advanced_multi_draw_buffers,
GL_NVX_conditional_render, GL_NVX_gpu_memory_info, GL_NVX_nvenc_interop,
GL_NVX_progress_fence, GL_NV_ES1_1_compatibility,
GL_NV_ES3_1_compatibility, GL_NV_alpha_to_coverage_dither_control,
GL_NV_bindless_multi_draw_indirect,
GL_NV_bindless_multi_draw_indirect_count, GL_NV_bindless_texture,
GL_NV_blend_equation_advanced, GL_NV_blend_equation_advanced_coherent,
GL_NV_blend_minmax_factor, GL_NV_blend_square, GL_NV_clip_space_w_scaling,
GL_NV_command_list, GL_NV_compute_program5,
GL_NV_compute_shader_derivatives, GL_NV_conditional_render,
GL_NV_conservative_raster, GL_NV_conservative_raster_dilate,
GL_NV_conservative_raster_pre_snap,
GL_NV_conservative_raster_pre_snap_triangles,
GL_NV_conservative_raster_underestimation, GL_NV_copy_depth_to_color,
GL_NV_copy_image, GL_NV_depth_buffer_float, GL_NV_depth_clamp,
GL_NV_draw_texture, GL_NV_draw_vulkan_image, GL_NV_explicit_multisample,
GL_NV_feature_query, GL_NV_fence, GL_NV_fill_rectangle,
GL_NV_float_buffer, GL_NV_fog_distance, GL_NV_fragment_coverage_to_color,
GL_NV_fragment_program, GL_NV_fragment_program2,
GL_NV_fragment_program_option, GL_NV_fragment_shader_barycentric,
GL_NV_fragment_shader_interlock, GL_NV_framebuffer_mixed_samples,
GL_NV_framebuffer_multisample_coverage, GL_NV_geometry_shader4,
GL_NV_geometry_shader_passthrough, GL_NV_gpu_multicast,
GL_NV_gpu_program4, GL_NV_gpu_program4_1, GL_NV_gpu_program5,
GL_NV_gpu_program5_mem_extended, GL_NV_gpu_program_fp64,
GL_NV_gpu_program_multiview, GL_NV_gpu_shader5, GL_NV_half_float,
GL_NV_internalformat_sample_query, GL_NV_light_max_exponent,
GL_NV_memory_attachment, GL_NV_memory_object_sparse, GL_NV_mesh_shader,
GL_NV_multisample_coverage, GL_NV_multisample_filter_hint,
GL_NV_occlusion_query, GL_NV_packed_depth_stencil,
GL_NV_parameter_buffer_object, GL_NV_parameter_buffer_object2,
GL_NV_path_rendering, GL_NV_path_rendering_shared_edge,
GL_NV_pixel_data_range, GL_NV_point_sprite, GL_NV_primitive_restart,
GL_NV_primitive_shading_rate, GL_NV_query_resource,
GL_NV_query_resource_tag, GL_NV_register_combiners,
GL_NV_register_combiners2, GL_NV_representative_fragment_test,
GL_NV_robustness_video_memory_purge, GL_NV_sample_locations,
GL_NV_sample_mask_override_coverage, GL_NV_scissor_exclusive,
GL_NV_shader_atomic_counters, GL_NV_shader_atomic_float,
GL_NV_shader_atomic_float64, GL_NV_shader_atomic_fp16_vector,
GL_NV_shader_atomic_int64, GL_NV_shader_buffer_load,
GL_NV_shader_storage_buffer_object, GL_NV_shader_subgroup_partitioned,
GL_NV_shader_texture_footprint, GL_NV_shader_thread_group,
GL_NV_shader_thread_shuffle, GL_NV_shading_rate_image,
GL_NV_stereo_view_rendering, GL_NV_texgen_reflection,
GL_NV_texture_barrier, GL_NV_texture_compression_vtc,
GL_NV_texture_dirty_tile_map, GL_NV_texture_env_combine4,
GL_NV_texture_multisample, GL_NV_texture_rectangle,
GL_NV_texture_rectangle_compressed, GL_NV_texture_shader,
GL_NV_texture_shader2, GL_NV_texture_shader3, GL_NV_timeline_semaphore,
GL_NV_transform_feedback, GL_NV_transform_feedback2,
GL_NV_uniform_buffer_std430_layout, GL_NV_uniform_buffer_unified_memory,
GL_NV_vdpau_interop, GL_NV_vdpau_interop2, GL_NV_vertex_array_range,
GL_NV_vertex_array_range2, GL_NV_vertex_attrib_integer_64bit,
GL_NV_vertex_buffer_unified_memory, GL_NV_vertex_program,
GL_NV_vertex_program1_1, GL_NV_vertex_program2,
GL_NV_vertex_program2_option, GL_NV_vertex_program3,
GL_NV_viewport_array2, GL_NV_viewport_swizzle, GL_OVR_multiview,
GL_OVR_multiview2, GL_S3_s3tc, GL_SGIS_generate_mipmap,
GL_SGIS_texture_lod, GL_SGIX_depth_texture, GL_SGIX_shadow,
GL_SUN_slice_accum

OpenGL version string: 4.6.0 NVIDIA 560.28.03
OpenGL shading language version string: 4.60 NVIDIA
OpenGL context flags: (none)
OpenGL profile mask: (none)
OpenGL extensions:
GL_AMD_multi_draw_indirect, GL_AMD_seamless_cubemap_per_texture,
GL_AMD_vertex_shader_layer, GL_AMD_vertex_shader_viewport_index,
GL_ARB_ES2_compatibility, GL_ARB_ES3_1_compatibility,
GL_ARB_ES3_2_compatibility, GL_ARB_ES3_compatibility,
GL_ARB_arrays_of_arrays, GL_ARB_base_instance, GL_ARB_bindless_texture,
GL_ARB_blend_func_extended, GL_ARB_buffer_storage,
GL_ARB_clear_buffer_object, GL_ARB_clear_texture, GL_ARB_clip_control,
GL_ARB_color_buffer_float, GL_ARB_compatibility,
GL_ARB_compressed_texture_pixel_storage, GL_ARB_compute_shader,
GL_ARB_compute_variable_group_size, GL_ARB_conditional_render_inverted,
GL_ARB_conservative_depth, GL_ARB_copy_buffer, GL_ARB_copy_image,
GL_ARB_cull_distance, GL_ARB_debug_output, GL_ARB_depth_buffer_float,
GL_ARB_depth_clamp, GL_ARB_depth_texture, GL_ARB_derivative_control,
GL_ARB_direct_state_access, GL_ARB_draw_buffers,
GL_ARB_draw_buffers_blend, GL_ARB_draw_elements_base_vertex,
GL_ARB_draw_indirect, GL_ARB_draw_instanced, GL_ARB_enhanced_layouts,
GL_ARB_explicit_attrib_location, GL_ARB_explicit_uniform_location,
GL_ARB_fragment_coord_conventions, GL_ARB_fragment_layer_viewport,
GL_ARB_fragment_program, GL_ARB_fragment_program_shadow,
GL_ARB_fragment_shader, GL_ARB_fragment_shader_interlock,
GL_ARB_framebuffer_no_attachments, GL_ARB_framebuffer_object,
GL_ARB_framebuffer_sRGB, GL_ARB_geometry_shader4,
GL_ARB_get_program_binary, GL_ARB_get_texture_sub_image, GL_ARB_gl_spirv,
GL_ARB_gpu_shader5, GL_ARB_gpu_shader_fp64, GL_ARB_gpu_shader_int64,
GL_ARB_half_float_pixel, GL_ARB_half_float_vertex, GL_ARB_imaging,
GL_ARB_indirect_parameters, GL_ARB_instanced_arrays,
GL_ARB_internalformat_query, GL_ARB_internalformat_query2,
GL_ARB_invalidate_subdata, GL_ARB_map_buffer_alignment,
GL_ARB_map_buffer_range, GL_ARB_multi_bind, GL_ARB_multi_draw_indirect,
GL_ARB_multisample, GL_ARB_multitexture, GL_ARB_occlusion_query,
GL_ARB_occlusion_query2, GL_ARB_parallel_shader_compile,
GL_ARB_pipeline_statistics_query, GL_ARB_pixel_buffer_object,
GL_ARB_point_parameters, GL_ARB_point_sprite, GL_ARB_polygon_offset_clamp,
GL_ARB_post_depth_coverage, GL_ARB_program_interface_query,
GL_ARB_provoking_vertex, GL_ARB_query_buffer_object,
GL_ARB_robust_buffer_access_behavior, GL_ARB_robustness,
GL_ARB_sample_locations, GL_ARB_sample_shading, GL_ARB_sampler_objects,
GL_ARB_seamless_cube_map, GL_ARB_seamless_cubemap_per_texture,
GL_ARB_separate_shader_objects, GL_ARB_shader_atomic_counter_ops,
GL_ARB_shader_atomic_counters, GL_ARB_shader_ballot,
GL_ARB_shader_bit_encoding, GL_ARB_shader_clock,
GL_ARB_shader_draw_parameters, GL_ARB_shader_group_vote,
GL_ARB_shader_image_load_store, GL_ARB_shader_image_size,
GL_ARB_shader_objects, GL_ARB_shader_precision,
GL_ARB_shader_storage_buffer_object, GL_ARB_shader_subroutine,
GL_ARB_shader_texture_image_samples, GL_ARB_shader_texture_lod,
GL_ARB_shader_viewport_layer_array, GL_ARB_shading_language_100,
GL_ARB_shading_language_420pack, GL_ARB_shading_language_include,
GL_ARB_shading_language_packing, GL_ARB_shadow, GL_ARB_sparse_buffer,
GL_ARB_sparse_texture, GL_ARB_sparse_texture2,
GL_ARB_sparse_texture_clamp, GL_ARB_spirv_extensions,
GL_ARB_stencil_texturing, GL_ARB_sync, GL_ARB_tessellation_shader,
GL_ARB_texture_barrier, GL_ARB_texture_border_clamp,
GL_ARB_texture_buffer_object, GL_ARB_texture_buffer_object_rgb32,
GL_ARB_texture_buffer_range, GL_ARB_texture_compression,
GL_ARB_texture_compression_bptc, GL_ARB_texture_compression_rgtc,
GL_ARB_texture_cube_map, GL_ARB_texture_cube_map_array,
GL_ARB_texture_env_add, GL_ARB_texture_env_combine,
GL_ARB_texture_env_crossbar, GL_ARB_texture_env_dot3,
GL_ARB_texture_filter_anisotropic, GL_ARB_texture_filter_minmax,
GL_ARB_texture_float, GL_ARB_texture_gather,
GL_ARB_texture_mirror_clamp_to_edge, GL_ARB_texture_mirrored_repeat,
GL_ARB_texture_multisample, GL_ARB_texture_non_power_of_two,
GL_ARB_texture_query_levels, GL_ARB_texture_query_lod,
GL_ARB_texture_rectangle, GL_ARB_texture_rg, GL_ARB_texture_rgb10_a2ui,
GL_ARB_texture_stencil8, GL_ARB_texture_storage,
GL_ARB_texture_storage_multisample, GL_ARB_texture_swizzle,
GL_ARB_texture_view, GL_ARB_timer_query, GL_ARB_transform_feedback2,
GL_ARB_transform_feedback3, GL_ARB_transform_feedback_instanced,
GL_ARB_transform_feedback_overflow_query, GL_ARB_transpose_matrix,
GL_ARB_uniform_buffer_object, GL_ARB_vertex_array_bgra,
GL_ARB_vertex_array_object, GL_ARB_vertex_attrib_64bit,
GL_ARB_vertex_attrib_binding, GL_ARB_vertex_buffer_object,
GL_ARB_vertex_program, GL_ARB_vertex_shader,
GL_ARB_vertex_type_10f_11f_11f_rev, GL_ARB_vertex_type_2_10_10_10_rev,
GL_ARB_viewport_array, GL_ARB_window_pos, GL_ATI_draw_buffers,
GL_ATI_texture_float, GL_ATI_texture_mirror_once,
GL_EXTX_framebuffer_mixed_formats, GL_EXT_Cg_shader, GL_EXT_abgr,
GL_EXT_bgra, GL_EXT_bindable_uniform, GL_EXT_blend_color,
GL_EXT_blend_equation_separate, GL_EXT_blend_func_separate,
GL_EXT_blend_minmax, GL_EXT_blend_subtract, GL_EXT_compiled_vertex_array,
GL_EXT_depth_bounds_test, GL_EXT_direct_state_access,
GL_EXT_draw_buffers2, GL_EXT_draw_instanced, GL_EXT_draw_range_elements,
GL_EXT_fog_coord, GL_EXT_framebuffer_blit, GL_EXT_framebuffer_multisample,
GL_EXT_framebuffer_multisample_blit_scaled, GL_EXT_framebuffer_object,
GL_EXT_framebuffer_sRGB, GL_EXT_geometry_shader4,
GL_EXT_gpu_program_parameters, GL_EXT_gpu_shader4,
GL_EXT_import_sync_object, GL_EXT_memory_object, GL_EXT_memory_object_fd,
GL_EXT_multi_draw_arrays, GL_EXT_multiview_texture_multisample,
GL_EXT_multiview_timer_query, GL_EXT_packed_depth_stencil,
GL_EXT_packed_float, GL_EXT_packed_pixels, GL_EXT_pixel_buffer_object,
GL_EXT_point_parameters, GL_EXT_polygon_offset_clamp,
GL_EXT_post_depth_coverage, GL_EXT_provoking_vertex,
GL_EXT_raster_multisample, GL_EXT_rescale_normal, GL_EXT_secondary_color,
GL_EXT_semaphore, GL_EXT_semaphore_fd, GL_EXT_separate_shader_objects,
GL_EXT_separate_specular_color, GL_EXT_shader_image_load_formatted,
GL_EXT_shader_image_load_store, GL_EXT_shader_integer_mix,
GL_EXT_shadow_funcs, GL_EXT_sparse_texture2, GL_EXT_stencil_two_side,
GL_EXT_stencil_wrap, GL_EXT_texture3D, GL_EXT_texture_array,
GL_EXT_texture_buffer_object, GL_EXT_texture_compression_dxt1,
GL_EXT_texture_compression_latc, GL_EXT_texture_compression_rgtc,
GL_EXT_texture_compression_s3tc, GL_EXT_texture_cube_map,
GL_EXT_texture_edge_clamp, GL_EXT_texture_env_add,
GL_EXT_texture_env_combine, GL_EXT_texture_env_dot3,
GL_EXT_texture_filter_anisotropic, GL_EXT_texture_filter_minmax,
GL_EXT_texture_integer, GL_EXT_texture_lod, GL_EXT_texture_lod_bias,
GL_EXT_texture_mirror_clamp, GL_EXT_texture_object, GL_EXT_texture_sRGB,
GL_EXT_texture_sRGB_R8, GL_EXT_texture_sRGB_decode,
GL_EXT_texture_shadow_lod, GL_EXT_texture_shared_exponent,
GL_EXT_texture_storage, GL_EXT_texture_swizzle, GL_EXT_timer_query,
GL_EXT_transform_feedback2, GL_EXT_vertex_array, GL_EXT_vertex_array_bgra,
GL_EXT_vertex_attrib_64bit, GL_EXT_window_rectangles,
GL_EXT_x11_sync_object, GL_IBM_rasterpos_clip,
GL_IBM_texture_mirrored_repeat, GL_KHR_blend_equation_advanced,
GL_KHR_blend_equation_advanced_coherent, GL_KHR_context_flush_control,
GL_KHR_debug, GL_KHR_no_error, GL_KHR_parallel_shader_compile,
GL_KHR_robust_buffer_access_behavior, GL_KHR_robustness,
GL_KHR_shader_subgroup, GL_KTX_buffer_region,
GL_NVX_blend_equation_advanced_multi_draw_buffers,
GL_NVX_conditional_render, GL_NVX_gpu_memory_info, GL_NVX_nvenc_interop,
GL_NVX_progress_fence, GL_NV_ES1_1_compatibility,
GL_NV_ES3_1_compatibility, GL_NV_alpha_to_coverage_dither_control,
GL_NV_bindless_multi_draw_indirect,
GL_NV_bindless_multi_draw_indirect_count, GL_NV_bindless_texture,
GL_NV_blend_equation_advanced, GL_NV_blend_equation_advanced_coherent,
GL_NV_blend_minmax_factor, GL_NV_blend_square, GL_NV_clip_space_w_scaling,
GL_NV_command_list, GL_NV_compute_program5,
GL_NV_compute_shader_derivatives, GL_NV_conditional_render,
GL_NV_conservative_raster, GL_NV_conservative_raster_dilate,
GL_NV_conservative_raster_pre_snap,
GL_NV_conservative_raster_pre_snap_triangles,
GL_NV_conservative_raster_underestimation, GL_NV_copy_depth_to_color,
GL_NV_copy_image, GL_NV_depth_buffer_float, GL_NV_depth_clamp,
GL_NV_draw_texture, GL_NV_draw_vulkan_image, GL_NV_explicit_multisample,
GL_NV_feature_query, GL_NV_fence, GL_NV_fill_rectangle,
GL_NV_float_buffer, GL_NV_fog_distance, GL_NV_fragment_coverage_to_color,
GL_NV_fragment_program, GL_NV_fragment_program2,
GL_NV_fragment_program_option, GL_NV_fragment_shader_barycentric,
GL_NV_fragment_shader_interlock, GL_NV_framebuffer_mixed_samples,
GL_NV_framebuffer_multisample_coverage, GL_NV_geometry_shader4,
GL_NV_geometry_shader_passthrough, GL_NV_gpu_multicast,
GL_NV_gpu_program4, GL_NV_gpu_program4_1, GL_NV_gpu_program5,
GL_NV_gpu_program5_mem_extended, GL_NV_gpu_program_fp64,
GL_NV_gpu_program_multiview, GL_NV_gpu_shader5, GL_NV_half_float,
GL_NV_internalformat_sample_query, GL_NV_light_max_exponent,
GL_NV_memory_attachment, GL_NV_memory_object_sparse, GL_NV_mesh_shader,
GL_NV_multisample_coverage, GL_NV_multisample_filter_hint,
GL_NV_occlusion_query, GL_NV_packed_depth_stencil,
GL_NV_parameter_buffer_object, GL_NV_parameter_buffer_object2,
GL_NV_path_rendering, GL_NV_path_rendering_shared_edge,
GL_NV_pixel_data_range, GL_NV_point_sprite, GL_NV_primitive_restart,
GL_NV_primitive_shading_rate, GL_NV_query_resource,
GL_NV_query_resource_tag, GL_NV_register_combiners,
GL_NV_register_combiners2, GL_NV_representative_fragment_test,
GL_NV_robustness_video_memory_purge, GL_NV_sample_locations,
GL_NV_sample_mask_override_coverage, GL_NV_scissor_exclusive,
GL_NV_shader_atomic_counters, GL_NV_shader_atomic_float,
GL_NV_shader_atomic_float64, GL_NV_shader_atomic_fp16_vector,
GL_NV_shader_atomic_int64, GL_NV_shader_buffer_load,
GL_NV_shader_storage_buffer_object, GL_NV_shader_subgroup_partitioned,
GL_NV_shader_texture_footprint, GL_NV_shader_thread_group,
GL_NV_shader_thread_shuffle, GL_NV_shading_rate_image,
GL_NV_stereo_view_rendering, GL_NV_texgen_reflection,
GL_NV_texture_barrier, GL_NV_texture_compression_vtc,
GL_NV_texture_dirty_tile_map, GL_NV_texture_env_combine4,
GL_NV_texture_multisample, GL_NV_texture_rectangle,
GL_NV_texture_rectangle_compressed, GL_NV_texture_shader,
GL_NV_texture_shader2, GL_NV_texture_shader3, GL_NV_timeline_semaphore,
GL_NV_transform_feedback, GL_NV_transform_feedback2,
GL_NV_uniform_buffer_std430_layout, GL_NV_uniform_buffer_unified_memory,
GL_NV_vdpau_interop, GL_NV_vdpau_interop2, GL_NV_vertex_array_range,
GL_NV_vertex_array_range2, GL_NV_vertex_attrib_integer_64bit,
GL_NV_vertex_buffer_unified_memory, GL_NV_vertex_program,
GL_NV_vertex_program1_1, GL_NV_vertex_program2,
GL_NV_vertex_program2_option, GL_NV_vertex_program3,
GL_NV_viewport_array2, GL_NV_viewport_swizzle, GL_OVR_multiview,
GL_OVR_multiview2, GL_S3_s3tc, GL_SGIS_generate_mipmap,
GL_SGIS_texture_lod, GL_SGIX_depth_texture, GL_SGIX_shadow,
GL_SUN_slice_accum

OpenGL ES profile version string: OpenGL ES 3.2 NVIDIA 560.28.03
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20
OpenGL ES profile extensions:
GL_ANDROID_extension_pack_es31a, GL_EXT_EGL_image_external_wrap_modes,
GL_EXT_base_instance, GL_EXT_blend_func_extended, GL_EXT_blend_minmax,
GL_EXT_buffer_storage, GL_EXT_clear_texture, GL_EXT_clip_control,
GL_EXT_clip_cull_distance, GL_EXT_color_buffer_float,
GL_EXT_color_buffer_half_float, GL_EXT_compressed_ETC1_RGB8_sub_texture,
GL_EXT_conservative_depth, GL_EXT_copy_image, GL_EXT_debug_label,
GL_EXT_depth_clamp, GL_EXT_discard_framebuffer,
GL_EXT_disjoint_timer_query, GL_EXT_draw_buffers_indexed,
GL_EXT_draw_elements_base_vertex, GL_EXT_draw_transform_feedback,
GL_EXT_float_blend, GL_EXT_frag_depth, GL_EXT_geometry_point_size,
GL_EXT_geometry_shader, GL_EXT_gpu_shader5, GL_EXT_map_buffer_range,
GL_EXT_memory_object, GL_EXT_memory_object_fd, GL_EXT_multi_draw_indirect,
GL_EXT_multisample_compatibility, GL_EXT_multisampled_render_to_texture,
GL_EXT_multisampled_render_to_texture2,
GL_EXT_multiview_texture_multisample, GL_EXT_multiview_timer_query,
GL_EXT_occlusion_query_boolean, GL_EXT_polygon_offset_clamp,
GL_EXT_post_depth_coverage, GL_EXT_primitive_bounding_box,
GL_EXT_raster_multisample, GL_EXT_read_format_bgra, GL_EXT_render_snorm,
GL_EXT_robustness, GL_EXT_sRGB, GL_EXT_sRGB_write_control,
GL_EXT_semaphore, GL_EXT_semaphore_fd, GL_EXT_separate_shader_objects,
GL_EXT_shader_group_vote, GL_EXT_shader_implicit_conversions,
GL_EXT_shader_integer_mix, GL_EXT_shader_io_blocks,
GL_EXT_shader_non_constant_global_initializers, GL_EXT_shader_texture_lod,
GL_EXT_shadow_samplers, GL_EXT_sparse_texture, GL_EXT_sparse_texture2,
GL_EXT_tessellation_point_size, GL_EXT_tessellation_shader,
GL_EXT_texture_border_clamp, GL_EXT_texture_buffer,
GL_EXT_texture_compression_bptc, GL_EXT_texture_compression_dxt1,
GL_EXT_texture_compression_rgtc, GL_EXT_texture_compression_s3tc,
GL_EXT_texture_cube_map_array, GL_EXT_texture_filter_anisotropic,
GL_EXT_texture_filter_minmax, GL_EXT_texture_format_BGRA8888,
GL_EXT_texture_mirror_clamp_to_edge, GL_EXT_texture_norm16,
GL_EXT_texture_query_lod, GL_EXT_texture_rg, GL_EXT_texture_sRGB_R8,
GL_EXT_texture_sRGB_decode, GL_EXT_texture_shadow_lod,
GL_EXT_texture_storage, GL_EXT_texture_view, GL_EXT_unpack_subimage,
GL_EXT_window_rectangles, GL_KHR_blend_equation_advanced,
GL_KHR_blend_equation_advanced_coherent, GL_KHR_context_flush_control,
GL_KHR_debug, GL_KHR_no_error, GL_KHR_parallel_shader_compile,
GL_KHR_robust_buffer_access_behavior, GL_KHR_robustness,
GL_KHR_shader_subgroup, GL_KHR_texture_compression_astc_hdr,
GL_KHR_texture_compression_astc_ldr,
GL_KHR_texture_compression_astc_sliced_3d,
GL_NVX_blend_equation_advanced_multi_draw_buffers, GL_NV_bgr,
GL_NV_bindless_texture, GL_NV_blend_equation_advanced,
GL_NV_blend_equation_advanced_coherent, GL_NV_blend_minmax_factor,
GL_NV_clip_space_w_scaling, GL_NV_compute_shader_derivatives,
GL_NV_conditional_render, GL_NV_conservative_raster,
GL_NV_conservative_raster_pre_snap_triangles, GL_NV_copy_buffer,
GL_NV_copy_image, GL_NV_draw_buffers, GL_NV_draw_instanced,
GL_NV_draw_texture, GL_NV_draw_vulkan_image,
GL_NV_explicit_attrib_location, GL_NV_fbo_color_attachments,
GL_NV_fill_rectangle, GL_NV_fragment_coverage_to_color,
GL_NV_fragment_shader_barycentric, GL_NV_fragment_shader_interlock,
GL_NV_framebuffer_blit, GL_NV_framebuffer_mixed_samples,
GL_NV_framebuffer_multisample, GL_NV_generate_mipmap_sRGB,
GL_NV_geometry_shader_passthrough, GL_NV_gpu_shader5, GL_NV_image_formats,
GL_NV_instanced_arrays, GL_NV_internalformat_sample_query,
GL_NV_memory_attachment, GL_NV_memory_object_sparse, GL_NV_mesh_shader,
GL_NV_non_square_matrices, GL_NV_occlusion_query_samples,
GL_NV_pack_subimage, GL_NV_packed_float, GL_NV_packed_float_linear,
GL_NV_path_rendering, GL_NV_path_rendering_shared_edge,
GL_NV_pixel_buffer_object, GL_NV_polygon_mode,
GL_NV_primitive_shading_rate, GL_NV_read_buffer, GL_NV_read_depth,
GL_NV_read_depth_stencil, GL_NV_read_stencil,
GL_NV_representative_fragment_test, GL_NV_sRGB_formats,
GL_NV_sample_locations, GL_NV_sample_mask_override_coverage,
GL_NV_scissor_exclusive, GL_NV_shader_atomic_fp16_vector,
GL_NV_shader_noperspective_interpolation,
GL_NV_shader_subgroup_partitioned, GL_NV_shader_texture_footprint,
GL_NV_shading_rate_image, GL_NV_shadow_samplers_array,
GL_NV_shadow_samplers_cube, GL_NV_stereo_view_rendering,
GL_NV_texture_array, GL_NV_texture_barrier, GL_NV_texture_border_clamp,
GL_NV_texture_compression_latc, GL_NV_texture_compression_s3tc,
GL_NV_texture_compression_s3tc_update, GL_NV_texture_dirty_tile_map,
GL_NV_timeline_semaphore, GL_NV_timer_query, GL_NV_viewport_array,
GL_NV_viewport_array2, GL_NV_viewport_swizzle,
GL_OES_compressed_ETC1_RGB8_texture, GL_OES_copy_image, GL_OES_depth24,
GL_OES_depth32, GL_OES_depth_texture, GL_OES_depth_texture_cube_map,
GL_OES_draw_buffers_indexed, GL_OES_draw_elements_base_vertex,
GL_OES_element_index_uint, GL_OES_fbo_render_mipmap,
GL_OES_geometry_point_size, GL_OES_geometry_shader,
GL_OES_get_program_binary, GL_OES_gpu_shader5, GL_OES_mapbuffer,
GL_OES_packed_depth_stencil, GL_OES_primitive_bounding_box,
GL_OES_rgb8_rgba8, GL_OES_sample_shading, GL_OES_sample_variables,
GL_OES_shader_image_atomic, GL_OES_shader_io_blocks,
GL_OES_shader_multisample_interpolation, GL_OES_standard_derivatives,
GL_OES_tessellation_point_size, GL_OES_tessellation_shader,
GL_OES_texture_border_clamp, GL_OES_texture_buffer,
GL_OES_texture_cube_map_array, GL_OES_texture_float,
GL_OES_texture_float_linear, GL_OES_texture_half_float,
GL_OES_texture_half_float_linear, GL_OES_texture_npot,
GL_OES_texture_stencil8, GL_OES_texture_storage_multisample_2d_array,
GL_OES_texture_view, GL_OES_vertex_array_object, GL_OES_vertex_half_float,
GL_OES_viewport_array, GL_OVR_multiview, GL_OVR_multiview2,
GL_OVR_multiview_multisampled_render_to_texture

< snipped>
```

Reproduce the issue with examples/shader.cpp using the skia backend, GPU acceleration, and a scale factor above 1. Then inspect os/skia/skia_gl.cpp, especially SkiaGL::createRenderTarget(...), and trace the framebuffer query and render-target setup. Done means the shader example renders correctly at scaled window factors without introducing OpenGL errors.

Written by the indexing model from the issue text.