[Fix] (Espryt): keep the invalid-image placeholder on ANGLE instead of probing an empty unit it faults on

MobileGL/Config.h

@@ -217,8 +217,9 @@ namespace MobileGL::MG_Config {
         // MOBILEGL_ESPRYT_INVALID_IMAGE_PLACEHOLDER: DirectGLES binds an image unit GL 4.6 8.26
         // calls invalid (a level the texture does not have) to a zeroed 1x1 texture of the bind's
         // shape instead of leaving it empty. The Adreno ES driver answers a load through an EMPTY
-        // unit with alpha 1 where GL says 0; the driver POST measures that and arms this by
-        // itself, so Auto is right everywhere. The placeholder's one texel is real, so a store
+        // unit with alpha 1 where GL says 0, and ANGLE faults on any use of an empty unit; the
+        // driver POST measures the first and Auto arms this on ANGLE without probing, so Auto is
+        // right everywhere. The placeholder's one texel is real, so a store
         // through such a unit can be read back through the same unit in the same pass - which is
         // why a healthy driver keeps the empty unit. ForceOn exercises the placeholder on a
         // healthy driver; ForceOff is the negative control.

MobileGL/MG_Backend/DirectGLES/DirectGLES.cpp

@@ -2871,9 +2871,9 @@ namespace MobileGL::MG_Backend::DirectGLES {
         }
 
         // What such a unit is bound to instead, on a driver whose EMPTY unit is not enough
-        // (GLESCapabilities::EmptyImageUnitsReadNonzero): ES 3.2 8.22 leaves an invalid load's
-        // alpha undefined, and Adreno answers 1 where GL says 0. Elsewhere the unit stays empty,
-        // which is exact. A texel outside
+        // (GLESCapabilities::UseInvalidImagePlaceholder): ES 3.2 8.22 leaves an invalid load's
+        // alpha undefined, Adreno answers 1 where GL says 0, and ANGLE faults outright.
+        // Elsewhere the unit stays empty, which is exact. A texel outside
         // a level is invalid too, and that Adreno answers (0, 0, 0, 0) with the store dropped - so
         // the unit gets a 1x1 texture of the shape and format the bind names, cleared to zero each
         // time it is bound. Only texel (0, 0[, 0]) of it exists; it is private to the unit, so a
@@ -2990,7 +2990,7 @@ namespace MobileGL::MG_Backend::DirectGLES {
                 return;
             }
             if (ImageViewNamesNoTexel(view)) {
-                if (!g_GLESCapabilities.EmptyImageUnitsReadNonzero) {
+                if (!g_GLESCapabilities.UseInvalidImagePlaceholder) {
                     g_GLESFuncs.glBindImageTexture(unit, 0, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
                     return;
                 }

MobileGL/MG_Util/BackendLoaders/OpenGL/Loader.cpp

@@ -2125,24 +2125,30 @@ namespace MobileGL::MG_Util::BackendLoader {
                     ? "true (the subgroup emulation reads its scratch through atomic loads)"
                     : "false");
 
+        caps.IsAngleRenderer = caps.GLESRendererString.find("ANGLE") != String::npos;
+
         switch (MG_Config::Features.EsprytInvalidImagePlaceholder) {
             case MG_Config::QuirkOverride::ForceOn:
-                caps.EmptyImageUnitsReadNonzero = true;
+                caps.UseInvalidImagePlaceholder = true;
                 break;
             case MG_Config::QuirkOverride::ForceOff:
-                caps.EmptyImageUnitsReadNonzero = false;
+                caps.UseInvalidImagePlaceholder = false;
                 break;
             case MG_Config::QuirkOverride::Auto:
             default:
-                caps.EmptyImageUnitsReadNonzero = SelfTest::EmptyImageUnitsReadNonzero(glesFuncs);
+                // ANGLE dereferences a null texture when a dispatch or draw reaches an EMPTY image
+                // unit the program uses, so the probe cannot be run there: its subject variant is
+                // exactly that dispatch, and a crash is no verdict. ANGLE keeps the placeholder
+                // without being asked.
+                caps.UseInvalidImagePlaceholder =
+                    caps.IsAngleRenderer || SelfTest::EmptyImageUnitsReadNonzero(glesFuncs);
                 break;
         }
-        MGLOG_I("    Empty image units read nonzero: %s",
-                caps.EmptyImageUnitsReadNonzero
-                    ? "true (an invalid image unit is bound to a zeroed placeholder)"
-                    : "false");
+        MGLOG_I("    Invalid image units bound to a placeholder: %s",
+                !caps.UseInvalidImagePlaceholder ? "false (an invalid image unit stays empty)"
+                : caps.IsAngleRenderer           ? "true (ANGLE faults on a use of an empty image unit)"
+                                                 : "true (empty image units read nonzero)");
 
-        caps.IsAngleRenderer = caps.GLESRendererString.find("ANGLE") != String::npos;
         caps.IsAngleLlvmpipeRenderer =
             caps.IsAngleRenderer && caps.GLESRendererString.find("llvmpipe") != String::npos;
         caps.AvoidSamplerMipmapMinFilter =

MobileGL/MG_Util/BackendLoaders/OpenGL/Loader.h

@@ -1329,11 +1329,12 @@ namespace MobileGL {
             // Adreno). The subgroup emulation then reads its scratch through atomic loads.
             // Defaults FALSE: never assumed broken on an unmeasured driver.
             Bool SharedMemoryLoadsGoStale = false;
-            // True when a load through an EMPTY image unit returns a nonzero texel
-            // (SelfTest::EmptyImageUnitsReadNonzero - measured on Adreno: alpha 1). DirectGLES
-            // then binds an invalid unit to a zeroed placeholder instead of leaving it empty.
-            // Defaults FALSE: never assumed broken on an unmeasured driver.
-            Bool EmptyImageUnitsReadNonzero = false;
+            // True when DirectGLES binds an invalid image unit to a zeroed placeholder instead of
+            // leaving it empty: on a driver whose load through an EMPTY unit returns a nonzero
+            // texel (SelfTest::EmptyImageUnitsReadNonzero - measured on Adreno: alpha 1), and on
+            // ANGLE, which faults on a dispatch or draw that reaches an empty unit and so cannot
+            // be probed. Defaults FALSE: never assumed broken on an unmeasured driver.
+            Bool UseInvalidImagePlaceholder = false;
             Int UniformBufferOffsetAlignment = 256;
             // Its storage-buffer counterpart, queried separately because it is a separate limit:
             // Adreno 830 answers 32 for GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT and 64 for