drawable_trackball_uniforms.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
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 * Copyright(C) 2021-2026                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the              *
 * Mozilla Public License Version 2.0                                        *
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#ifndef VCL_BGFX_DRAWABLE_UNIFORMS_DRAWABLE_TRACKBALL_UNIFORMS_H
#define VCL_BGFX_DRAWABLE_UNIFORMS_DRAWABLE_TRACKBALL_UNIFORMS_H
 
#include <vclib/bgfx/uniform.h>
#include <vclib/space/core/color.h>
 
namespace vcl {
 
class DrawableTrackballUniforms
{
    static constexpr float DRAGGING_ALPHA     = 0.9f;
    static constexpr float NOT_DRAGGING_ALPHA = 0.5f;
 
    // the only component is alpha
    inline static std::array<float, 4> sTrackBallSettings =
        {NOT_DRAGGING_ALPHA, 0, 0, 0};
 
    inline static Uniform sTrackballSettingsUniform;
 
public:
    DrawableTrackballUniforms() = delete;
 
    static void setDragging(bool dragging)
    {
        sTrackBallSettings[0] = dragging ? DRAGGING_ALPHA : NOT_DRAGGING_ALPHA;
    }
 
    static void bind()
    {
        // lazy initialization
        // to avoid creating uniforms before bgfx is initialized
        if (!sTrackballSettingsUniform.isValid())
            sTrackballSettingsUniform =
                Uniform("u_trackballSettingsPack", bgfx::UniformType::Vec4);
        sTrackballSettingsUniform.bind(sTrackBallSettings.data());
    }
};
 
} // namespace vcl
 
#endif // VCL_BGFX_DRAWABLE_UNIFORMS_DRAWABLE_TRACKBALL_UNIFORMS_H