Though to consider - the size of seam is independent from the zoom (which is performed using ScaleTransform) and always about 1 device pixel. See the attached screenshot (remember that visible magenta rectangle is formed by four neighboring magenta pixels of the test texture (image #4 above)).

Screenshot at 20-53-21.png (10,005 bytes)   

Screenshot at 20-53-21.png (10,005 bytes)   

Thanks for all this information! Could you also please attach a frame snapshot using the D3D frame debugger? (visual studio -> Debug -> Graphics -> Start Graphics Debugging)

Thanks for the debug session!

And congrats for the momentum you are talking about. You deserve it!

I still wonder what's causing this issue when using a texture brush yet it's not reproducible with a solid color brush.

This problem can also be reproduced in WPF and the source of it is that contiguous rectangles don't share the same vertices, so imprecisions can leave small holes between them letting the background be visible sometimes (you can resize the window and holes appear and disappear).

<Grid

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

UseLayoutRounding="False"

Background="Black">

<Grid.Resources>

<ImageSource x:Key="whiteImg">white.png</ImageSource>

<ImageBrush x:Key="whiteImgBrush" ImageSource="{StaticResource whiteImg}" Stretch="None" TileMode="FlipXY"/>

</Grid.Resources>

<Canvas Width="400" Height="400">

<Canvas.RenderTransform>

<TranslateTransform X="0.5" Y="0.5"/>

</Canvas.RenderTransform>

<Rectangle Canvas.Left="000" Canvas.Top="000" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="100" Canvas.Top="000" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="200" Canvas.Top="000" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="300" Canvas.Top="000" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="000" Canvas.Top="100" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="100" Canvas.Top="100" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="200" Canvas.Top="100" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="300" Canvas.Top="100" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="000" Canvas.Top="200" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="100" Canvas.Top="200" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="200" Canvas.Top="200" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="300" Canvas.Top="200" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="000" Canvas.Top="300" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="100" Canvas.Top="300" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="200" Canvas.Top="300" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

<Rectangle Canvas.Left="300" Canvas.Top="300" Width="100" Height="100" Fill="{StaticResource whiteImgBrush}"/>

</Canvas>

</Grid>

You can see the attached images produced by that xaml in Blend. The last one is using a SolidColorBrush, so you can see it is not a problem with textures.

The only way to avoid those holes is by using a single mesh (Rectangle) and tile the texture.

wpf-blackbg.png (19,009 bytes)   

wpf-blackbg.png (19,009 bytes)   

wpf-redbg.png (20,153 bytes)   

wpf-redbg.png (20,153 bytes)   

wpf-solidwhite.png (16,490 bytes)   

wpf-solidwhite.png (16,490 bytes)   

Hi Sergio,
thank you for your response and time spent to make a sample. I've totally forgotten that WPF exists when reported this! :-)

That's what I've suspected based on my previous experience by rending tiled terrain in CryoFall. After that, we've switched to a shader-based approach to draw a properly tiled terrain.

I was surprised I cannot see the seams when rendering tiles with SolidColorBrush though...In WPF there are indeed seams in either case.

I'm reworking the map to use large chunks with render textures, and will add a coordinate grid to hide the stitches! :-)
Please close this ticket.

Regards!