2D tile based game, shows gaps between the tile sprites when I zoom in with the camera?

I am using the D3DXSPRITE method to draw my map tiles to the screen, i just added a zoom function which zooms in when you hold the up arrow, but noticed you can now see gaps between the tiles, here's some screen shots

normal size (32x32) per tile

zoomed in (you can see white gaps between the tiles)

zoomed out (even worst!)

Here's the code snipplet which I translate and scale the world with.

D3DXMATRIX matScale, matPos;

D3DXMatrixScaling(&matScale, zoom_, zoom_, 0.0f);
D3DXMatrixTranslation(&matPos, xpos_, ypos_, 0.0f);

device_->SetTransform(D3DTS_WORLD, &(matPos * matScale));

And this is my drawing of the map, (tiles are in a vector of a vector of tiles.. and I haven't done culling yet)

Lay开发者_JS百科erInfo *p_linfo = NULL;
  RECT rect = {0};
  D3DXVECTOR3 pos;
  pos.x = 0.0f;
  pos.y = 0.0f;
  pos.z = 0.0f;

  for (short y = 0; 
    y < BottomTile(); ++y)
  {
    for (short x = 0; 
          x < RightTile(); ++x)
    {
      for (int i = 0; i < TILE_LAYER_COUNT; ++i)
      {
        p_linfo = tile_grid_[y][x].Layer(i);

        if (p_linfo->Visible())
        {
          p_linfo->GetTextureRect(&rect);

          sprite_batch->Draw(
            p_engine_->GetTexture(p_linfo->texture_id), 
            &rect, NULL, &pos, 0xFFFFFFFF);
        }
      }
      pos.x += p_engine_->TileWidth();
    }
    pos.x = 0;
    pos.y += p_engine_->TileHeight();
  }

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Your texture indices are wrong. 0,0,32,32 is not the correct value- it should be 0,0,31,31. A zero-based index into your texture atlas of 256 pixels would yield values of 0 to 255, not 0 to 256, and a 32x32 texture should yield 0,0,31,31. In this case, the colour of the incorrect pixels depends on the colour of the next texture along the right and the bottom.

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That's the problem of magnification and minification. Your textures should have invisible border populated with part of adjacent texture. Then magnification and minification filters will use that border to calculate color of edge pixels rather than default (white) color.

I think so.

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I also had a similar problem with texture mapping. What worked for me was changing the texture address mode in the sampler state description; texture address mode is used to control what direct3d does with texture coordinates outside of the ([0.0f, 1.0f]) range: i changed the ADDRESS_U, ADDRESS_V, ADDRESS_W members to D3D11_TEXTURE_ADDRESS_CLAMP which basically clamps all out-of-range values for the texture coordinates into the [0.0f, 1.0f] range.

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After a long time searching and testing people solutions I found this rules are the most complete rules that I've ever read.

pixel-perfect-2d from Official Unity WebSite

plus with my own experience i found out that if sprite PPI is 72(for example), you should try to use more PPI for that Image(96 maybe or more).It actually make sprite more dense and make no space for white gaps to show up.

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Welcome to the world of floating-point. Those gaps exist due to imperfections using floating-point numbers.

You might be able to improve the situation by being really careful when doing your floating-point math but those seams will be there unless you make one whole mesh out of your terrain.

It's the rasterizer that given the view and projection matrix as well as the vertex positions is slightly off. You maybe able to improve on that but I don't know how successful you'll be.

Instead of drawing different quads you can index only the visible vertexes that make up your terrain and instead use texture tiling techniques to paint different stuff on there. I believe that won't get you the ugly seam because in that case, there technically isn't one.