unit renderers_3D;

{$MODE OBJFPC}
{$M+}

interface
uses framebuffers, colors, images;

{ TODO: what to use? floating-point math? fixed-point math? integer arithmetic? }
{ TODO does that stuff still support clipping? No, so don't draw directly upon a I2DGraphics that goes on screen. }
type
  ITexture = interface
  end;

  ISimpleTexture = interface(ITexture)
    property Color : IColor;
  end;

  IImageTexture = interface(ITexture)
    property Image : IImage;
  end;

  IMipmappedPixmapTexture = interface(IImageTexture)
    function GetClosestMatch(aWidth, aHeight : Cardinal) : IImageTexture;
  end;


  TVertex = array[0..2] of Integer; { X, Y, Z }
  TTriangleVertices = array[0..2] of TVertex;
  //PVertex = ^TVertex;

  TTexturePoint = array[0..1] of Integer; // point on texture (between the pixels of the texture).

  I3DRenderer = interface
    { vertices are counter-clockwise. }
    procedure DrawTriangle(const aVertices : TTriangleVertices); overload;
    procedure DrawTriangle(const aVertex0, aVertex1, aVertex2 : TVertex); overload;
    procedure DrawTriangle(const aVertex0 : TVertex; const aTexturePoint0 : TTexturePoint;
                           const aVertex1 : TVertex; const aTexturePoint1 : TTexturePoint;
                           const aVertex2 : TVertex; const aTexturePoint2 : TTexturePoint); overload;

    { note that triangles are triangular, so the entire (rectangular) texture is NOT going to be used for one triangle, just the biggest triangle-shaped part of it. }
    property Texture : ITexture;
  end;

  { TODO cache stuff about Triangle in a triangle class (with low footprint) for the viewpoint? }


implementation

end.