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#ifndef PatchParameter_INCLUDE_ONCE
#define PatchParameter_INCLUDE_ONCE

#include <vlCore/Object.hpp>

namespace vl
{
  //------------------------------------------------------------------------------
  // PatchParameter
  //------------------------------------------------------------------------------
  //! Wrapper of glPatchParameter(), specifies the parameters for patch primitives, used by vl::DrawCall::setPatchParameter().
  //! See also http://www.opengl.org/sdk/docs/man4/xhtml/glPatchParameter.xml
  class PatchParameter: public Object
  {
    VL_INSTRUMENT_CLASS(vl::PatchParameter, Object)

  public:
    //! Constructor
    PatchParameter(): mPatchVertices(0), mPatchDefaultOuterLevel(fvec4(4,4,4,4)), mPatchDefaultInnerLevel(fvec2(4,4))
    {
      VL_DEBUG_SET_OBJECT_NAME()
    }

    //! Applies the glPatchParameter values.
    void apply() const
    {
      VL_CHECK(Has_GL_ARB_tessellation_shader||Has_GL_Version_4_0);
      if (Has_GL_ARB_tessellation_shader||Has_GL_Version_4_0)
      {
        glPatchParameteri(GL_PATCH_VERTICES, mPatchVertices); VL_CHECK_OGL();
        glPatchParameterfv(GL_PATCH_DEFAULT_OUTER_LEVEL, mPatchDefaultOuterLevel.ptr()); VL_CHECK_OGL();
        glPatchParameterfv(GL_PATCH_DEFAULT_INNER_LEVEL, mPatchDefaultInnerLevel.ptr()); VL_CHECK_OGL();
      }
    }

    //! Specifies the number of vertices that will be used to make up a single patch primitive.
    //! Patch primitives are consumed by the tessellation control shader (if present) and subsequently
    //! used for tessellation. When primitives are specified using glDrawArrays or a similar function,
    //! each patch will be made from \a vertices control points, each represented by a vertex taken from
    //! the enabeld vertex arrays. \a vertices must be greater than zero, and less than or equal to the
    //! value of GL_MAX_PATCH_VERTICES.
    void setPatchVertices(int vertices) { mPatchVertices = vertices; }

    //! Returns the number of vertices that will be used to make up a single patch primitive.
    int patchVertices() const { return mPatchVertices; }

    //! The four floating-point values corresponding to the four outer tessellation levels
    //! for each subsequent patch to be used when no tessellation control shader is present.
    void setPatchDefaultOuterLevel(const fvec4& level) { mPatchDefaultOuterLevel = level; }

    //! The four floating-point values corresponding to the four outer tessellation levels
    //! for each subsequent patch to be used when no tessellation control shader is present.
    const fvec4& patchDefaultOuterLevel() const { return mPatchDefaultOuterLevel; }

    //! The two floating-point values corresponding to the tow inner tessellation levels
    //! for each subsequent patch to be used when no tessellation control shader is present.
    void setPatchDefaultInnerLevel(const fvec2& level) { mPatchDefaultInnerLevel = level; }

    //! The two floating-point values corresponding to the tow inner tessellation levels
    //! for each subsequent patch to be used when no tessellation control shader is present.
    const fvec2& patchDefaultInnerLevel() const { return mPatchDefaultInnerLevel; }

  protected:
    int mPatchVertices;
    fvec4 mPatchDefaultOuterLevel;
    fvec2 mPatchDefaultInnerLevel;
  };
}

#endif