OpenGL FF sample does not show geometry

[vircon32]

Hello, I have built and run the current sources in /video/opengl/libretro_test_gl_fixedfunction in 3 different machines (Windows 7, Windows 10 and MacOS 10.14). In all 3 cases the core shows a flat color window, but the rectangle that should be drawn does not appear.

I have tried several variations for vertex coordinates and matrices, but no geometry is ever drawn. The background color does show, which suggests that the screen clear and the copy to framebuffer are indeed working. I also verified that the core is running in a compatibility context, and no GL_INVALID_OPERATION happens with glBegin(), etc. Any clue what could be happening here?

[vircon32]

A quick update: for some reason, drawing GL_POINTS seems to be the only way that geometry is drawn. If I replace the sample code's GL_TRIANGLES with this:

glBegin(GL_POINTS);
glColor4f(1.0f, 0.0f, 0.0f, 1.0f);
glVertex2f(0.5f, 0.5f);
glEnd();

Then a point is indeed drawn. However the stated color and coordinates seem to be ignored for some reason. The point is always drawn at the center and is always black. This is quite weird!