MathgeomGLS

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unit uSimpleVBO;
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interface
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uses
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  Winapi.OpenGL,
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  Winapi.OpenGLext,
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  GLS.Scene,
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  GLS.Mesh,
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  GLS.VectorTypes,
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  GLS.VectorGeometry,
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  GLS.RenderContextInfo,
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  GLS.OpenGLTokens,
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  GLS.Context,
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  GLS.Material,
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  GLS.Texture;
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type
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  TGLSimpleVBO = class(TGLSceneObject)
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  protected
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    f_varr: array of TVector3f;
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    f_narr: array of TVector3f;
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    f_tarr: array of TTexPoint;
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    f_bufs: array[0..2] of Cardinal;
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    procedure _initBufs;
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  public
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    constructor CreateAsChild(a_Owner:TGLBaseSceneObject;
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      a_Array:PGLVertexDataArray; a_VertexCount:integer);
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    procedure DoRender(var a_Rci:TGLRenderContextInfo;
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        a_RenderSelf,a_RenderChildren:Boolean); override;
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    procedure loadData(a_Array:PGLVertexDataArray; a_VertexCount:integer);
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    end;
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implementation
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//
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// _initBufs
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//
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procedure TGLSimpleVBO._initBufs;
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var
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    c: integer;
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begin
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  c := Length(f_varr);
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  gl.GenBuffers(1, @f_bufs[0]);
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  gl.BindBuffer(GL_ARRAY_BUFFER, f_bufs[0]);
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  gl.BufferData(GL_ARRAY_BUFFER, 12 * c, @f_varr[0], GL_STATIC_DRAW);
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  gl.BindBuffer(GL_ARRAY_BUFFER, 0);
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  gl.GenBuffers(1, @f_bufs[1]);
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  gl.BindBuffer(GL_ARRAY_BUFFER_ARB, f_bufs[1]);
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  gl.BufferData(GL_ARRAY_BUFFER_ARB, 12 * c, @f_narr[0], GL_STATIC_DRAW);
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  gl.BindBuffer(GL_ARRAY_BUFFER_ARB, 0);
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  gl.GenBuffers(1, @f_bufs[2]);
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  gl.BindBuffer(GL_ARRAY_BUFFER, f_bufs[2]);
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  gl.BufferData(GL_ARRAY_BUFFER, 8 * c, @f_tarr[0], GL_STATIC_DRAW);
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  gl.BindBuffer(GL_ARRAY_BUFFER, 0);
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end;
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//
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// constructor
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//
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constructor TGLSimpleVBO.CreateAsChild;
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begin
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  inherited CreateAsChild(a_Owner);
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  loadData(a_Array, a_VertexCount);
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end;
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//
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// loadData
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//
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procedure TGLSimpleVBO.loadData;
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var
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    i: integer;
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begin
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  if a_VertexCount < 3 then Exit;
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  SetLength(f_varr, a_VertexCount);
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  SetLength(f_narr, a_VertexCount);
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  SetLength(f_tarr, a_VertexCount);
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  for i := 0 to a_VertexCount - 1 do begin
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    f_varr[i] := a_Array[i].coord;
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    f_narr[i] := a_Array[i].normal;
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    f_tarr[i] := a_Array[i].textCoord;
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    end;
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  _initBufs;
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end;
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//
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// DoRender
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//
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procedure TGLSimpleVBO.DoRender;
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begin
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  if High(f_varr) < 2 then Exit;
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  Material.Apply(a_Rci);
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  gl.EnableClientState(GL_VERTEX_ARRAY);
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  gl.BindBuffer(GL_ARRAY_BUFFER, f_bufs[0]);
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  gl.VertexPointer(3, GL_FLOAT, 0, nil);
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  gl.EnableClientState(GL_NORMAL_ARRAY);
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  gl.BindBuffer(GL_ARRAY_BUFFER, f_bufs[1]);
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  gl.NormalPointer(GL_FLOAT, 0, nil);
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  gl.EnableClientState(GL_TEXTURE_COORD_ARRAY);
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  gl.BindBuffer(GL_ARRAY_BUFFER, f_bufs[2]);
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  gl.TexCoordPointer(2, GL_FLOAT, 0, nil);
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  gl.DrawArrays(GL_QUADS, 0, high(f_varr) + 1);
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  gl.DisableClientState(GL_VERTEX_ARRAY);
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  gl.DisableClientState(GL_NORMAL_ARRAY);
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  gl.DisableClientState(GL_TEXTURE_COORD_ARRAY);
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  Material.UnApply(a_Rci);
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end;
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end.
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