Method Init3DState

engine/PoseidonGL33/EngineGL33_State.cpp:457–556

}

void EngineGL33::Init3DState()
{
    if (!_glContext)
        return;

    _bias = 0;
    _clipANearEnabled = false;
    _clipAFarEnabled = false;
    _texLoc = TexLocalVidMem;
    // Capability bits (_can*, _dxtFormats, _hasStencilBuffer, _canDetailTex,
    // _canZBias) are static constexpr in EngineGL33.hpp — nothing to set here.

    // Guard band: OpenGL has no hardware guard band (unlike D3D9/D3D11).
    // Use a modest guard band — vertices outside NDC [-1,1] are clipped by OpenGL's
    // fixed-function pipeline, but small overflows are safe with depth clamping.
    float maxBand = 1024 * 4;
    _minGuardX = static_cast<int>(-maxBand);
    _maxGuardX = static_cast<int>(_w + maxBand);
    _minGuardY = static_cast<int>(-maxBand);
    _maxGuardY = static_cast<int>(_h + maxBand);

    _nightEye = 0;
    _pixelSize = 32;
    _depthBpp = 32;

    int viewportW, viewportH;
    RenderTargetSize(viewportW, viewportH);

    // Set viewport
    glViewport(0, 0, viewportW, viewportH);

    // Use D3D-compatible clip space: Z ∈ [0, 1] instead of OpenGL's default [-1, 1].
    // This matches the projection matrix convention used by D3D11 and avoids
    // halving the depth buffer precision.
    if (GLAD_GL_ARB_clip_control)
    {
        glClipControl(GL_LOWER_LEFT, GL_ZERO_TO_ONE);
        LOG_DEBUG(Graphics, "GL33: glClipControl(GL_LOWER_LEFT, GL_ZERO_TO_ONE) enabled");
    }
    else
    {
        LOG_WARN(Graphics, "GL33: GL_ARB_clip_control not available — depth precision will be reduced");
    }

    // Apply default state
    InvalidatePipelineCache();
    ApplyDepthMode(DepthMode::Normal);
    ApplyBlendMode(BlendMode::AlphaBlend);

    // Default rasterizer: backface cull
    // D3D convention: CW = front face. With glClipControl(GL_LOWER_LEFT),
    // no viewport Y-flip occurs, so mesh winding is preserved from NDC to window.
    Poseidon::render::cull::Back();
    Poseidon::render::cull::FrontFaceCW();

    _pointSampling = false;
    _lastClampU = false;
    _lastClampV = false;