Method ApplyPipeline

engine/PoseidonGL33/EngineGL33_State.cpp:155–344

Atomic pipeline bind reading from `RenderPassDescriptor`. Declares the full backend state every draw needs and forwards to the state- helper functions (`ApplyDepthMode`, `ApplyBlendMode`, etc.) which keep their own per-state caches (`_vertexShaderSel`, `_pixelShaderSel`, `_formatSet`, `_texGenMode`) to short-circuit redundant work. Single source of truth: each helper's own cache. ApplyPipeline

// mirrored / shadow / double-sided draws bind the right winding
// without a force-bind defensive symptom-fix.
void EngineGL33::ApplyPipeline(const Poseidon::render::RenderPassDescriptor& d)
{
    if (!_glContext)
        return;

    // Pass-state dedup (perf effort 06): identical descriptor under the same
    // pass context means identical GL state — skip the re-apply. The A2C
    // inputs (3D pass + coverage toggle) are part of the key because the
    // alpha-test branch below derives from them, not just from d.
    const bool ctxIn3d = IsIn3DPass();
    const bool ctxA2c = GetAlphaToCoverage();
    const PipelineVertexInput vertexInput = _pipelineVertexInput;
    const bool meshVertexInput = vertexInput == PipelineVertexInput::Mesh ||
                                 (vertexInput == PipelineVertexInput::ActivePass && IsIn3DPass());
    if (_lastApplied.valid && ctxIn3d == _lastApplied.in3d && ctxA2c == _lastApplied.a2c &&
        vertexInput == _lastApplied.vertexInput && d == _lastApplied.d)
        return;

    // Validate the descriptor against the invariants listed in
    // `ValidateRenderPassDescriptor.hpp`.  Violations come from a
    // producer / translation bug (not from runtime data), so logging
    // once per draw is fine — the warning identifies which invariant
    // broke and the rest of the pipeline still binds.  In release
    // builds the check is effectively free (return-on-success in a
    // header-inlined linear scan).
    if (const char* invariant = Poseidon::render::ValidateRenderPassDescriptor(d))
    {
        LOG_DEBUG(Graphics, "GL33: descriptor invariant violated: {} (pass={}, blend={}, depth={}, fog={})", invariant,
                  static_cast<int>(d.pass), static_cast<int>(d.blend), static_cast<int>(d.depth),
                  static_cast<int>(d.fog));
    }

    // -- Sampler --------------------------------------------------------
    _pointSampling = (d.sampler.filter == Poseidon::render::SamplerFilter::Point);
    _lastClampU = d.sampler.clampU;
    _lastClampV = d.sampler.clampV;
    ApplySamplerState();

    // -- Depth + stencil ------------------------------------------------
    // Poseidon::render::DepthMode / BlendMode positions match the engine enums;
    // static_cast through the underlying type keeps the conversion
    // trivial.  A switch would be more defensive against future
    // reordering, but the static_asserts further down would catch that.
    ApplyDepthMode(static_cast<DepthMode>(static_cast<int>(d.depth)));

    // -- Blend ----------------------------------------------------------
    ApplyBlendMode(static_cast<BlendMode>(static_cast<int>(d.blend)));

    // -- Fog ------------------------------------------------------------
    SetShaderFogEnabled(d.fog == Poseidon::render::FogMode::Enabled);

    // -- Alpha test ----------------------------------------------------
    const bool alphaTest =
        (d.alpha == Poseidon::render::AlphaMode::Test || d.alpha == Poseidon::render::AlphaMode::TestAndBlend);
    // Alpha-to-coverage only on OPAQUE cutout draws in the 3D pass.  The
    // blend gate is load-bearing: AlphaMode::Test also rides on blended
    // descriptors (IsAlphaFog glass / IsLight flares / shadow quads use a
    // ref=1 discard as a reject-fully-transparent optimization), and the A2C