[Scummvm-tracker] [ScummVM :: Bugs] #15531: GRIM: Manny completely black in first demo room on MacBook Air M1 (OpenGL renderer)

[ScummVM :: Bugs]

#15531: GRIM: Manny completely black in first demo room on MacBook Air M1 (OpenGL
renderer)
-----------------------------------+----------------------------
Reporter:  dwatteau                |       Owner:  (none)
    Type:  defect                  |      Status:  new
Priority:  high                    |   Component:  Engine: Grim
 Version:                          |  Resolution:
Keywords:  rendering issue,opengl  |        Game:  Grim Fandango
-----------------------------------+----------------------------
Comment (by dwatteau):

 FWIW, after some tests, this bug seems related to some interaction when
 the `cutoff` values (when non-`180`) given to the nearly GL_SPOT_CUTOFF
 `glLightf()` call:

 {{{
 void GfxOpenGL::setupLight(Light *light, int lightId) {
 // [...]
         } else if (light->_type == Light::Spot) {
                 lightPos[0] = light->_pos.x();
                 lightPos[1] = light->_pos.y();
                 lightPos[2] = light->_pos.z();
                 lightDir[0] = light->_dir.x();
                 lightDir[1] = light->_dir.y();
                 lightDir[2] = light->_dir.z();
                 spot_exp = 2.0f;
                 cutoff = light->_penumbraangle; // <== HERE
                 q_attenuation = 0.0f;
         }
 // [...]
 }
 }}}

 although this may seem obvious to some, reading criezy's observation
 again, eh ;)

 I'm not sure how this could be worked around, if this indeed is a bug in
 Apple's emulation of OpenGL through Metal, on (early?) Apple silicon.

 Maybe we can keep the OpenGL-with-shaders renderer the default there, when
 the release supports it.

 {{{
 diff --git a/engines/grim/grim.cpp b/engines/grim/grim.cpp
 index 8c4d9c8e749..f125c3f9f49 100644
 --- a/engines/grim/grim.cpp
 +++ b/engines/grim/grim.cpp
 @@ -280,12 +280,16 @@ GfxBase *GrimEngine::createRenderer(int screenW, int
 screenH) {
                 availableRendererTypes &= ~Graphics::kRendererTypeTinyGL;
         }

 +       // HACK: Bug #15531: Not enabling the following on Apple silicon
 desktops,
 +       // as GL_SPOT_CUTOFF glLightf() calls have issues on non-Intel
 Metal GPUs.
 +#if !(defined(MACOSX) && defined(__aarch64__))
         // For Grim Fandango, OpenGL renderer without shaders is preferred
 if available
         if (desiredRendererType == Graphics::kRendererTypeDefault &&
                 (availableRendererTypes & Graphics::kRendererTypeOpenGL)
 &&
 -           getGameType() == GType_GRIM) {
 +               getGameType() == GType_GRIM) {
                 availableRendererTypes &=
 ~Graphics::kRendererTypeOpenGLShaders;
         }
 +#endif

         // Not supported yet.
         if (getLanguage() == Common::Language::ZH_CHN || getLanguage() ==
 Common::Language::ZH_TWN
 }}}
-- 
Ticket URL: <https://bugs.scummvm.org/ticket/15531#comment:6>
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