Setting clip_area is broken.

[DDR0]

To reproduce: Check out Frogatto's minimal-clip-area-bug branch. Run ./anura --level=test.cfg.

The coin on screen should turn invisible, but instead of just darkens as a result of the set(brightness, 128) call right before the set(clip_area, ...) call.

Notes:

• The call does "apply" clip_area if you enter the editor. This is confirmed in the positive and negative case.
• The bug has existed for more than three months or so, now.
• In some cases, something happens which causes this bug to not reproduce on more complicated objects.

[DDR0]

And now, coming at it from the other end, we have Frogatto's maximal-clip-area-bug branch. It seems that tweaking the liquid shader's end_zorder is enough to fix or break clip_area.

[DDR0]

identity_op works too.

[DDR0]

In level.cpp, commenting out shaders.emplace_back(e.shader); in frameBufferEnterZorder() stops the "fix" from working.

[DDR0]

I think shaders are setting something elsewhere, as as far as I can tell the critical path for them is shader->setUniformValue(shader->getPVUniform(), glm::value_ptr(pvmat)); in DeviceOGL.cpp's DisplayDeviceOpenGL::render.

[DDR0]

I have applied a general hack around this for Frogatto. Search for the _add_shader_fix_for_clip_area_to_fix_anura_issue_340 in the FFL there.