Fixed all issues found by vulkan debug report. Reasons for the major design changes are commented.

Examples: Vulkan: Disable IMGUI_VULKAN_DEBUG_REPORT by default. Update .bat files for newer VulkanSDK.

Vulkan backend: optionally enabling vulkan validation layers and debug report callback ...

Additional layer, extension and the callback itself are used/created when IMGUI_VULKAN_DEBUG_REPORT is defined. The callback reports seven (potential!) errors which will be fixed with another pull request.

Merge branch 'ParticlePeter-g_FrameIndex_not_used_fix'

Merge branch 'g_FrameIndex_not_used_fix' of https://github.com/ParticlePeter/imgui into ParticlePeter-g_FrameIndex_not_used_fix

Examples: Vulkan: windows batch file for 64-bits.

Comments

Merge branch 'martty-vk_small_fix'

Merge branch 'vk_small_fix' of https://github.com/martty/imgui into martty-vk_small_fix

Examples: SDL2: Tweaked batch files for Win32.

Merge pull request #1080 from SaschaWillems/master ...

Examples: Vulkan: Small changes to be in line with specs and fix validation layer errors/warnings

Examples: SDL2: Added build .bat files for win32.

Ignoring unreasonnable Clang -wformat-pedantic warning (#1090) ...

See e.g.
http://clang-developers.42468.n3.nabble.com/The-p-conversion-and-cast-to-void-td4044226.html

Renamed ImDrawList::PathFill() to ImDrawList::PathFillConvex() for clarity. (breaking API)

Merge branch 'ecraven-addimagequad'

ImDrawList::AddImage* renamed uv_ parameters to be more consistent. Fix AddImageQuad to use IM_COL32_A_MASK (#1009)

Merge branch 'addimagequad' of https://github.com/ecraven/imgui into ecraven-addimagequad

Merge branch 'greggman-fix-opengl3-example'

Examples: SDL2+GL3: Fix blend func state save/restore (#1120)

Fix blend func state save/restore ...

AFAIK there's no such enum as `GL_BLEND_SRC` or `GL_BLEND_DST` in OpenGL3 and OpenGL4.

Maybe they're left over from previous versions? They don't even seem to exist in OpenGL 2.1. In fact checking they were deprecated in OpenGL 1.5 (they exist in 1.3)

End() avoid calling Columns() if no columns set is open, not sure what it wasn't the case. ...

Pros: Faster. Avoid early crashes StackId underflow that are meant to be more gracefully caught by CheckStacksSize() (with more explicit assert). Cons: Excercise less code.

Clarified asserts in CheckStacksSize() when there is a stack mismatch

Update README.md

Update README.md

Update README.md

Added UnrealEngine_ImGui link

Add ImDrawList::AddImageQuad ...

Adds a function
  AddImageQuad(user_texture_id, a, b, c, d, uva, uvb, uvc, uvd, col)
that shows a texture on a full quad. This allows showing arbitrary
rotations of a texture.

imconfig: Added comment about redefining ImDrawIdx

Comments to redirect people to OpenGL3 examples (#1116)

Examples: GLFW+GL3, SDL+GL3: Fixed modifying bound Texture0 (#1087, #1088, #1116)