This fixes an issue introduced in
340f531c71 where embedded OpenGL windows
would incorrectly have the WS_EX_LAYERED style bit set, which in turn
prevented them from displaying correctly.
Before the window-transparency refactoring, OpenGL windows would not
have the layered bit set because only peers with windowIsSemiTransparent
were created with the layered bit, and the layered bit was only updated
if the peer alpha was changed.
The new behaviour is to always set WS_EX_LAYERED if the peer's component
is non-opaque with no titlebar, or if the component has an alpha < 1.0f.
The OpenGLContext's placeholder component has no titlebar, so it must be
opaque in order to avoid setting the layered style bit.
Previously, code such as the following (where MyGLComponent is rendering
using an OpenGLContext) could result in GL errors, as the destruction of
the inner context unbound the array buffer and element array buffer
after use, instead of setting them to the previous values set up by the
outer context.
Additionally, a VAO was only set up in the OpenGLContext, so rendering
into a GL-backed LowLevel graphics context could fail if no VAO was
bound.
void MyGLComponent::paint (juce::Graphics& g)
{
juce::Image image { juce::Image::PixelFormat::ARGB, width, height, false, juce::OpenGLImageType() };
{
juce::Graphics innerContext { image };
// draw into innerContext
}
g.drawImage (image, juce::Rectangle<float> { width, height });
}
The OpenGL renderer uses ColourGradient::createLookupTable to generate
gradient textures. However, the tweening method used was different to
the tweening used by CoreGraphics gradients, and by the software
renderer.
Gradient tweening is now computed using non-premultiplied colours, to
ensure consistency between gradients rendered using OpenGL, and with
other renderers.
The significant change here is that the XSaveContext call in the OpenGL
NativeContext now has a matching XDeleteContext call. This breaks the
connection between the X window and the ComponentPeer, so that we avoid
dereferencing a dangling ComponentPeer pointer if the window receives
events after the peer is destroyed.
