Created attachment 137196 [details]
The Canvas issue

SUMMARY
Issues with canvas rendering on nightly builds ever since version 5.0.0-prealpha (git d526093) <-last working normaly version.

STEPS TO REPRODUCE
1. Open Krita
2. New document
3. 

OBSERVED RESULT
Canvas rendering as if with alpha masking.

EXPECTED RESULT
Normal rendering

SOFTWARE/OS VERSIONS
Windows: 10


ADDITIONAL INFORMATION

Krita

 Version: 5.0.0-prealpha (git 1b3b197)
 Languages: en_US, en
 Hidpi: true

Qt

  Version (compiled): 5.12.9
  Version (loaded): 5.12.9

OS Information

  Build ABI: x86_64-little_endian-llp64
  Build CPU: x86_64
  CPU: x86_64
  Kernel Type: winnt
  Kernel Version: 10.0.19042
  Pretty Productname: Windows 10 (10.0)
  Product Type: windows
  Product Version: 10

OpenGL Info
 
  Vendor:  "ATI Technologies Inc." 
  Renderer:  "Radeon RX 570 Series" 
  Version:  "3.0.14736 Compatibility Profile Context 20.10.1 27.20.12033.1007" 
  Shading language:  "4.60" 
  Requested format:  QSurfaceFormat(version 3.0, options QFlags<QSurfaceFormat::FormatOption>(DeprecatedFunctions), depthBufferSize 24, redBufferSize 8, greenBufferSize 8, blueBufferSize 8, alphaBufferSize 8, stencilBufferSize 8, samples -1, swapBehavior QSurfaceFormat::DoubleBuffer, swapInterval 0, colorSpace QSurfaceFormat::DefaultColorSpace, profile  QSurfaceFormat::CompatibilityProfile) 
  Current format:    QSurfaceFormat(version 3.0, options QFlags<QSurfaceFormat::FormatOption>(DeprecatedFunctions), depthBufferSize 24, redBufferSize 8, greenBufferSize 8, blueBufferSize 8, alphaBufferSize 8, stencilBufferSize 8, samples 0, swapBehavior QSurfaceFormat::DoubleBuffer, swapInterval 1, colorSpace QSurfaceFormat::sRGBColorSpace, profile  QSurfaceFormat::NoProfile) 
     Version: 3.0
     Supports deprecated functions true 
     is OpenGL ES: false 

QPA OpenGL Detection Info 
  supportsDesktopGL: true 
  supportsAngleD3D11: true 
  isQtPreferAngle: true 

Hardware Information

  GPU Acceleration: desktop
  Memory: 24532 Mb
  Number of Cores: 8
  Swap Location: C:/Users/Nikola/AppData/Local/Temp

Current Settings

  Current Swap Location: C:/Users/Nikola/AppData/Local/Temp
  Current Swap Location writable: true
  Undo Enabled: true
  Undo Stack Limit: 30
  Use OpenGL: true
  Use OpenGL Texture Buffer: true
  Use AMD Vectorization Workaround: false
  Canvas State: OPENGL_SUCCESS
  Autosave Interval: 300
  Use Backup Files: true
  Number of Backups Kept: 3
  Backup File Suffix: ~
  Backup Location: Same Folder as the File
  Backup Location writable: false
  Use Win8 Pointer Input: false
  Use RightMiddleTabletButton Workaround: false
  Levels of Detail Enabled: false
  Use Zip64: false


Display Information
Number of screens: 2
	Screen: 0
		Name: \\.\DISPLAY1
		Depth: 32
		Scale: 1
		Resolution in pixels: 1920x1080
		Manufacturer: 
		Model: 
		Refresh Rate: 59
	Screen: 1
		Name: \\.\DISPLAY2
		Depth: 32
		Scale: 1
		Resolution in pixels: 1024x1280
		Manufacturer: 
		Model: 
		Refresh Rate: 60