Optimize drawing 10.000 2D-lines with VBO?

[chronozphere]

Ok, I'll give you some tips then.

First of all, can you show me your complete sourcecode? The last post only contains the render code, not the creation of the buffer etc..

The most confusing part of VBO's is that it uses the functions that were meant for vertex array's. I see that you are passing a pointer to the array to glVertexPointer() and glColorPointer(). This is correct for vertex array's but NOT for VBO's. The functions are used differently. You must pass the data in a glBufferDataARB() call and use 0 as the last parameter for both glVertexPointer and glColorPointer().

Just google some more and ask more specific questions. You could also check the following tutorial:

http://playcontrol.net/ewing/jibberj...er_object.html

I know that VBO's are confusing. You just HAVE to go thourgh one of the tutorials, write down the functions that are used and figure out what happens exactly.

I may write a VBO tutorial one day, for pascal. Right now, I dont have time for that.

Good luck!

[WhatJac3]

Thanks for giving me tips. I have been playing with it all day again and this is what I have at the moment (but still nothing is drawn)
(is from: http://www.ozone3d.net/tutorials/opengl_vbo_p2.php, my translation from C++ to Delphi). I checked it with your tutorial and did not see any strange things. My viewwindow is set up from (0,0) - (1024,76

var
  vc: Integer;
  ColorSize, PositionSize : Integer;
const
  BufferSize = 2;
  POSITION_OBJECT = 0;
  COLOR_OBJECT = 1;
var
  BufferName: array [0..BufferSize-1] of GLuint;
begin

  glGenBuffersARB := wglGetProcAddress('glGenBuffersARB');
  glBindBufferARB := wglGetProcAddress('glBindBufferARB');
  glBufferDataARB := wglGetProcAddress('glBufferDataARB');
  glDeleteBuffersARB := wglGetProcAddress('glDeleteBuffersARB');

  PositionSize := length(VertexBuffer) * SizeOf(TVertex2f);
  ColorSize := length(ColorBuffer) * SizeOf(TColor3f);

  vc := Length(VertexBuffer);

  // allocate a new buffer
  glGenBuffersARB(1, @BufferName[COLOR_OBJECT]);
  // bind the buffer object to use
  glBindBufferARB(GL_ARRAY_BUFFER_ARB, BufferName[COLOR_OBJECT]);
  glBufferDataARB(GL_ARRAY_BUFFER_ARB, ColorSize, @ColorBuffer[0], GL_STREAM_DRAW);
  glColorPointer(3, GL_UNSIGNED_BYTE, 0, 0);

  glGenBuffersARB(1, @BufferName[POSITION_OBJECT]);
  glBindBufferARB(GL_ARRAY_BUFFER_ARB, BufferName[POSITION_OBJECT]);
  glBufferDataARB(GL_ARRAY_BUFFER_ARB, PositionSize, @VertexBuffer[0], GL_STREAM_DRAW);
  glVertexPointer(2, GL_FLOAT, 0, 0);

  glEnableClientState(GL_VERTEX_ARRAY);
  glEnableClientState(GL_COLOR_ARRAY);

  glDrawArrays(GL_TRIANGLES, 0, vc);

  glDisableClientState(GL_VERTEX_ARRAY);
  glDisableClientState(GL_COLOR_ARRAY);

with data:

type
  TVertex2f = record
    X, Y: TPositionType;
  end;

  TColor3f = record
   R, G, B: GLubyte;
  end;

const
  VertexBuffer: array [0..5] of TVertex2f = (
    (X : 0; Y : 0;),
    (X : 200; Y : 0;),
    (X : 200; Y : 200;),
    (X : 200; Y : 200;),
    (X : 0;  Y : 200;),
    (X : 0; Y : 0;)
  );
  ColorBuffer: array [0..5] of TColor3f = (
    (R : 255; G : 0; B : 0),
    (R : 255; G : 255; B : 0),
    (R : 0; G : 255; B : 0),
    (R : 0; G : 255; B : 0),
    (R : 0; G : 0; B : 255),
    (R : 255; G : 0; B : 0)
  );

[chronozphere]

I noticed the following line:

  glBufferDataARB(GL_ARRAY_BUFFER_ARB, ColorSize, @ColorBuffer[0], GL_STREAM_DRAW);

Have a look at the last GL_STREAM_DRAW parameter. I couldn't find official documentation of this function, so I just quote the tutorial:

"stream" means the data will be changed every frame (specified once and used once).

I suggest you change it to GL_STATIC_DRAW, because I think GL_STREAM_DRAW will throw away your data after it is rendered once.

The rest of your code looks ok.

Hope this helps.

Edit: About the WYSIWYG problem, you have to enable those buttons in your profile. Forum -> Forum Actions -> General settings, and then scroll down until you see the "Message Editor Interface" optoin.

[WhatJac3]

Well I finally solved it. The GL_STREAM_DRAW was not the solution. My problem was that I was using multiple libraries. The default 'OpenGL' from Delphi combined with the dglOpenGL (and sometimes even GL library and copied GL functions from NeHe). The combination of this all made it impossible to use VBO's. So I removed all other code except for the dglOpenGL. Thanks for the help guys.

[chronozphere]

Good to know you solved it.

I'd suggest that you only use dglOpengl. It's the best set of headers out there IMHO.

[phibermon]

Here's some VBO code from my P3D Model lib :

procedure TP3DModel.UploadVBOS;
var
   VerticiesSize : uint32;
   NormalsSize : uint32;
   UVsSize : uint32;
   VertexBonesSize : uint32;
   VertexRelToJointSize : uint32;
   CurrentOffset : uint32;
   TotalSize : uint32;
begin
     if FLoaded and not FVBOUploaded then
     begin
         //Generate VBOs
         glGenBuffers(1, @VBO);

         VerticiesSize := length(mesh.Vertex) * sizeof(tvertex);
         NormalsSize := length(mesh.Normal) * sizeof(tvertex);
         UVsSize := length(mesh.UV) * sizeof(TVector2f);
         VertexBonesSize := length(mesh.VertexBones) * sizeof(tvector);
         VertexRelToJointSize := length(mesh.VertexRelToJoint) * sizeof(tvector);

         VBOVerticesOffset := 0;
         VBONormalsOffset := VerticiesSize;
         VBOUVsOffset := VBONormalsOffset + NormalsSize;
         VBOVertexBonesOffset := VBOUVsOffset + UVsSize;
         VBOVertexRelToJointOffset := VBOVertexBonesOffset + VertexBonesSize;

         TotalSize := VerticiesSize + NormalsSize + UVsSize + VertexBonesSize + VertexRelToJointSize;

         //bind and upload data
         glBindBuffer(GL_ARRAY_BUFFER, VBO);

         glBufferData(GL_ARRAY_BUFFER, TotalSize  , nil , GL_STATIC_DRAW); //allocate memory for buffer

         //load in seperate buffers at correct offsets
         glBufferSubData(GL_ARRAY_BUFFER, VBOVerticesOffset, VerticiesSize  , @mesh.Vertex[0]);
         glBufferSubData(GL_ARRAY_BUFFER, VBONormalsOffset, NormalsSize , @mesh.normal[0]);
         glBufferSubData(GL_ARRAY_BUFFER, VBOUVsOffset, UVsSize , @mesh.UV[0]);
         glBufferSubData(GL_ARRAY_BUFFER, VBOVertexBonesOffset, VertexBonesSize , @mesh.VertexBones[0]);
         glBufferSubData(GL_ARRAY_BUFFER, VBOVertexRelToJointOffset, VertexRelToJointSize , @mesh.VertexRelToJoint[0]);
         glBindBuffer(GL_ARRAY_BUFFER, 0);

         //create index vbo
         glGenBuffers(1, @VBOIndicies);
         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, VBOIndicies);
         glBufferData(GL_ELEMENT_ARRAY_BUFFER, length(Mesh.Indicies)*sizeof(GLuint), @mesh.Indicies[0], GL_STATIC_DRAW);

         glbindbuffer(GL_ARRAY_BUFFER,0);
         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
     end;
end;

procedure TP3DModel.DeleteVBOS;
begin
     if FVBOUploaded then
     begin
          glDeleteBuffers(1, @VBO);
          glDeleteBuffers(1, @VBOIndicies);
          FVBOUploaded := false;
          VBO := 0;
          VBOIndicies := 0;
     end;
end;

and here's how it renders :

procedure TP3DModel.RenderDynamic;
var
   i1, i2, k, m:  integer;
   currentMaterial: integer;
   currentShaderId: integer;
   temptime: single;


   attribname : string;
   v : TVector;
begin
     //enable shader
     FArmatureShader.Enable;

     if FDynamicRenderMode = DRMVBO then
     begin
         //Bind VBO Before setting pointers
         glBindBuffer(GL_ARRAY_BUFFER, VBO);

         //enable Attrib Arrays VBO
         glEnableVertexAttribArray(FModelManagerLink^.AttribNormals);
         glEnableVertexAttribArray(FModelManagerLink^.AttribVertices);
         glEnableVertexAttribArray(FModelManagerLink^.AttribVertexRelToJoint);
         glEnableVertexAttribArray(FModelManagerLink^.AttribUVs);
         glEnableVertexAttribArray(FModelManagerLink^.AttribVertexBones);

         //set attrib pointers VBO
         glVertexAttribPointer(FModelManagerLink^.AttribVertices,3,GL_FLOAT,false,0,nil);
         glVertexAttribPointer(FModelManagerLink^.AttribNormals,3,GL_FLOAT,false,0,pglvoid(VBONormalsOffset));
         glVertexAttribPointer(FModelManagerLink^.AttribUVs,2,GL_FLOAT,false,0,pglvoid(VBOUVsOffset));
         glVertexAttribPointer(FModelManagerLink^.AttribVertexBones,4,GL_FLOAT,false,0,pglvoid(VBOVertexBonesOffset));
         glVertexAttribPointer(FModelManagerLink^.AttribVertexRelToJoint,4,GL_FLOAT,false,0,pglvoid(VBOVertexRelToJointOffset));

         //bind index buffer for rendering
         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, VBOIndicies);
    end;

    if FDynamicRenderMode = DRMAttribArray then
    begin
     //enable the attrib arrays used in shader
           glEnableVertexAttribArray(FModelManagerLink^.AttribNormals);
           glEnableVertexAttribArray(FModelManagerLink^.AttribVertices);
           glEnableVertexAttribArray(FModelManagerLink^.AttribVertexRelToJoint);
           glEnableVertexAttribArray(FModelManagerLink^.AttribUVs);
           glEnableVertexAttribArray(FModelManagerLink^.AttribVertexBones);

           //point the arrays at the data in system memory
           glVertexAttribPointer(FModelManagerLink^.AttribVertices,3,GL_FLOAT,false,0,@Mesh.Vertex[0][0]);
           glVertexAttribPointer(FModelManagerLink^.AttribNormals,3,GL_FLOAT,false,0,@Mesh.Normal[0][0]);
           glVertexAttribPointer(FModelManagerLink^.AttribUVs,2,GL_FLOAT,false,0,@Mesh.UV[0][0]);
           glVertexAttribPointer(FModelManagerLink^.AttribVertexBones,4,GL_FLOAT,false,0,@Mesh.VertexBones[0][0]);
           glVertexAttribPointer(FModelManagerLink^.AttribVertexRelToJoint,4,GL_FLOAT,false,0,@Mesh.VertexRelToJoint[0][0]);

    end;

    //i3 := round((SDL_GetTicks/10)) mod 100;


    inc(i7);
    if i7 >= length(Self.Armature.Actions[0].AnimFrames) then i7 := 0;

    //bind uniforms for mesh (can only bind after shader is bound)

    if (FModelManagerLink^.SkinningMode = SMQuat) or (FModelManagerLink^.SkinningMode = SMDualQuat) then
    begin
         glUniform4fv(FModelManagerLink^.UPos,31,@armature.Actions[0].AnimFrames[i7].BonePos[0]);
         glUniform4fv(FModelManagerLink^.URot,31,@armature.Actions[0].AnimFrames[i7].BoneRot[0]);
    end else
    if (FModelManagerLink^.SkinningMode = SMMatrix) then
    begin
         gluniformmatrix4fv(FModelManagerLink^.UMat,31,false,@armature.Actions[0].AnimFrames[i7].BoneMatrix[0][0][0]);
    end;

    glActiveTexture( GL_TEXTURE0 );
    glBindTexture( GL_TEXTURE_2D, TextureID );


    if DynamicRenderMode = DRMVBO then
    glDrawElements( GL_TRIANGLES,Mesh.IndexCount, GL_UNSIGNED_INT, nil) else
    if DynamicRenderMode = DRMAttribArray then
    glDrawElements( GL_TRIANGLES,Mesh.IndexCount, GL_UNSIGNED_INT, @Mesh.Indicies[0]);

    FArmatureShader.disable;

    if FDynamicRenderMode = DRMVBO then
    begin
         gldisableVertexAttribArray(FModelManagerLink^.AttribNormals);
         gldisableVertexAttribArray(FModelManagerLink^.AttribVertices);
         gldisableVertexAttribArray(FModelManagerLink^.AttribVertexRelToJoint);
         gldisableVertexAttribArray(FModelManagerLink^.AttribUVs);
         gldisableVertexAttribArray(FModelManagerLink^.AttribVertexBones);

         glbindbuffer(GL_ARRAY_BUFFER,0);
         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
    end;


    if FDynamicRenderMode = DRMAttribArray then
    begin
         gldisableVertexAttribArray(FModelManagerLink^.AttribNormals);
         gldisableVertexAttribArray(FModelManagerLink^.AttribVertices);
         gldisableVertexAttribArray(FModelManagerLink^.AttribVertexRelToJoint);
         gldisableVertexAttribArray(FModelManagerLink^.AttribUVs);
         gldisableVertexAttribArray(FModelManagerLink^.AttribVertexBones);
    end;

end;

sorry if it's a bit confusing, it's designed for bone-animation on the GPU (called hardware skinning) but it does show how to populate a VBO, how to render from it and a reasonably good way of falling back on cards without VBO.

I'll try and help best I can if you get stuck, let me know.