Martino Ferrari
6866457155
- loader: add available(), true only after load() has resolved every required entry point (false at the start of load()). Program::from_source and the other fallible constructors return ErrorCode::Unsupported while it is false, so a failed load() with a partially populated table can no longer fault on an unresolved entry point. - caps: GL_CONTEXT_PROFILE_MASK only exists from 3.2, so query it only on 3.2+ contexts. A 3.0/3.1 query latches GL_INVALID_ENUM in the context, which the next unrelated glGetError() (e.g. read_pixel) then reports as failure. - tests: gate the dlsym/libGL.so.1 fallback assertions on libGL being resolvable, so the GL suite also passes on a GLES-only host.
36 lines
1.6 KiB
C++
36 lines
1.6 KiB
C++
#pragma once
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#include <plot/gl/api.hpp>
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namespace plot::gl {
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/// Entry point resolver supplied by the caller, normally the *GetProcAddress
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/// of the API that owns the current context: `eglGetProcAddress`,
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/// `glXGetProcAddressARB` or `wglGetProcAddress`.
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using ProcLoader = void* (*)(const char*);
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/// Resolves every entry point of `PLOT_GL_FUNCS` (see api.hpp) into the global
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/// table declared there, so the rest of the library can call `gl*` directly.
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///
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/// Returns false when any required name cannot be found; entries that did
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/// resolve keep their pointers, so a failed load() never breaks a table that
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/// was already usable. `loader` is consulted first; when it is null, or returns
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/// null for a name, the fallback is `dlsym(RTLD_DEFAULT, name)` and then
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/// `dlopen("libGL.so.1")` + `dlsym`. The fallback makes the library usable
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/// without a caller-supplied resolver, but only a context-aware resolver is
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/// guaranteed to return pointers valid for the *current* context — pass one
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/// whenever a context is current.
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///
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/// A load() attempt invalidates the caps() cache. The table is process-global
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/// and is not synchronised, so call from the thread that owns the current
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/// context.
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bool load(ProcLoader loader = nullptr) noexcept;
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/// True once a `load()` has resolved every required entry point of the global
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/// table. This is the gate superseding per-pointer null checks: while it is
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/// false the table may be only partially populated (see load()), so no `gl*`
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/// entry point may be called. The fallible handle constructors report
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/// `ErrorCode::Unsupported` until it becomes true.
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bool available() noexcept;
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} // namespace plot::gl
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