[Fix] (GLImpl, DirectGLES, DirectVulkan): floor every advertised sample cap and clamp the realised count in the backends

MobileGL/MG_Backend/DirectGLES/BackendObject_DirectGLES.cpp

@@ -8,6 +8,7 @@
 
 #include "BackendObject_DirectGLES.h"
 #include "MG_Backend/BackendObject.h"
+#include "MG_Backend/BackendObjects.h"
 #include <MG_Backend/DirectGLES/DirectGLES.h>
 #include <MG_Backend/DirectGLES/Managers.h>
 #include <MG_Backend/DirectGLES/Utils.h>
@@ -782,6 +783,29 @@ namespace MobileGL::MG_Backend::DirectGLES {
         PopulateFormatCapabilitiesImpl(gl, capabilities, cache);
     }
 
+    Int ClampSamplesToBackendSupport(SizeT targetIndex, TextureInternalFormat logicalFormat, GLenum imageFormat,
+                                     Int samples) {
+        if (samples <= 1) {
+            return samples;
+        }
+
+        Int maxSamples = 0;
+        const SizeT formatIndex = static_cast<SizeT>(logicalFormat);
+        if (pActiveBackendObject && targetIndex < kFormatCapabilityTargetCount &&
+            formatIndex < kFormatCapabilityFormatCount) {
+            // Descending, so the head is the largest count this device actually allocated.
+            const Vector<Int>& probedCounts =
+                pActiveBackendObject->GetFormatCapabilities().SampleCounts[targetIndex][formatIndex];
+            if (!probedCounts.empty()) {
+                maxSamples = probedCounts.front();
+            }
+        }
+        if (maxSamples <= 0) {
+            maxSamples = GetGLESFormatMaxSamples(g_GLESCapabilities, logicalFormat, imageFormat);
+        }
+        return std::min(samples, std::max(maxSamples, 1));
+    }
+
     BackendObject_DirectGLES::~BackendObject_DirectGLES() {
         DestroyEGLContext();
     }

MobileGL/MG_Backend/DirectGLES/BackendObject_DirectGLES.h

@@ -18,6 +18,16 @@ namespace MobileGL::MG_Backend::DirectGLES {
                                     const MG_External::GLESCapabilities& capabilities,
                                     FormatCapabilityCache& cache);
 
+    // Clamps a requested sample count down to what the ES driver can really deliver for this
+    // format on this format-capability target: the probed per-format list when there is one, the
+    // driver's per-class GL_MAX_*_SAMPLES otherwise. The frontend deliberately validates against
+    // the count MobileGL advertises instead (GL_Getter's GetAdvertisedMaxSamples), which on a
+    // driver reporting GL_MAX_INTEGER_SAMPLES 1 is higher than the driver accepts, so every ES
+    // allocation call has to come through here. The shadow state keeps the requested count, so
+    // GL_TEXTURE_SAMPLES and framebuffer completeness still answer what the application asked for.
+    Int ClampSamplesToBackendSupport(SizeT targetIndex, TextureInternalFormat logicalFormat, GLenum imageFormat,
+                                     Int samples);
+
     class BackendObject_DirectGLES : public BackendObject {
     public:
         ~BackendObject_DirectGLES() override;

MobileGL/MG_Backend/DirectGLES/Managers.cpp

@@ -9,6 +9,7 @@
 #include "Managers.h"
 #include "Utils.h"
 #include "DirectGLES.h"
+#include "BackendObject_DirectGLES.h"
 #include <Config.h>
 #include <MG_Util/ShaderTranspiler/ShaderCompiler.h>
 
@@ -2648,16 +2649,24 @@ namespace MobileGL::MG_Backend::DirectGLES {
                     if (TextureImpl::IsMultisampleTextureTarget(targetInternal)) {
                         DebugImpl::ErrorLopper::Clear();
                         BufferImpl::BindPixelUnpackBufferId(0); // no-op once the resting 0 state is pinned
+                        // The frontend validates against the count MobileGL advertises, which can
+                        // exceed what the driver takes for this format (Adreno: GL_MAX_SAMPLES 4,
+                        // GL_MAX_INTEGER_SAMPLES 1). Clamp the ES call - and only the ES call:
+                        // stateTextureObject keeps the requested count so GL_TEXTURE_SAMPLES and
+                        // framebuffer completeness still report what the application asked for.
+                        const auto backendSamples = static_cast<GLsizei>(ClampSamplesToBackendSupport(
+                            GetFormatCapabilityTargetIndex(targetInternal), textureMipmapObject->GetFormat(),
+                            glFormat, static_cast<Int>(stateTextureObject->GetSamples())));
                         switch (targetInternal) {
                         case TextureTarget::Texture2DMultisample:
                             g_GLESFuncs.glTexStorage2DMultisample(
-                                target, static_cast<GLsizei>(stateTextureObject->GetSamples()), glInternalFormat,
+                                target, backendSamples, glInternalFormat,
                                 static_cast<GLsizei>(baseSize.x()), static_cast<GLsizei>(baseSize.y()),
                                 stateTextureObject->HasFixedSampleLocations() ? GL_TRUE : GL_FALSE);
                             break;
                         case TextureTarget::Texture2DMultisampleArray:
                             g_GLESFuncs.glTexStorage3DMultisample(
-                                target, static_cast<GLsizei>(stateTextureObject->GetSamples()), glInternalFormat,
+                                target, backendSamples, glInternalFormat,
                                 static_cast<GLsizei>(baseSize.x()), static_cast<GLsizei>(baseSize.y()),
                                 static_cast<GLsizei>(baseSize.z()),
                                 stateTextureObject->HasFixedSampleLocations() ? GL_TRUE : GL_FALSE);
@@ -5621,9 +5630,14 @@ namespace MobileGL::MG_Backend::DirectGLES {
             TextureImpl::GenerateRenderbufferFormatInfo(internalFormat, &glInternalFormat, &glFormat, &glType);
 
             if (samples > 0) {
-                g_GLESFuncs.glRenderbufferStorageMultisample(
-                    GL_RENDERBUFFER, static_cast<GLsizei>(samples), glInternalFormat, static_cast<GLsizei>(width),
-                    static_cast<GLsizei>(height));
+                // Same clamp as the multisample texture path: the frontend accepts the count it
+                // advertised, the driver only takes the count it supports for this format, and
+                // the state object keeps reporting the requested one.
+                const auto backendSamples = static_cast<GLsizei>(ClampSamplesToBackendSupport(
+                    GetRenderbufferFormatCapabilityTargetIndex(), internalFormat, glFormat, samples));
+                g_GLESFuncs.glRenderbufferStorageMultisample(GL_RENDERBUFFER, backendSamples, glInternalFormat,
+                                                             static_cast<GLsizei>(width),
+                                                             static_cast<GLsizei>(height));
             } else {
                 g_GLESFuncs.glRenderbufferStorage(GL_RENDERBUFFER, glInternalFormat, static_cast<GLsizei>(width),
                                                   static_cast<GLsizei>(height));

MobileGL/MG_Backend/DirectVulkan/Renderer/VkTextureManager.cpp

@@ -1848,6 +1848,19 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                         }
                     }
                 }
+                if (rounded == 0 && (supported & VK_SAMPLE_COUNT_1_BIT) != 0) {
+                    // Nothing at two samples or above. Reachable because the frontend validates
+                    // multisample allocations against the count MobileGL ADVERTISES (GL requires
+                    // GL_MAX_SAMPLES >= 4) rather than against the device's per-format support, so
+                    // a format this device cannot multisample at all now gets here instead of
+                    // being refused up front. Keeping the unsupported count would hand
+                    // vkCreateImage an invalid VkImageCreateInfo; one sample is at least a legal
+                    // image, and the samples-08726 hazard above is the lesser of the two.
+                    MGLOG_W_ONCE("Multisample texture format %d supports no count above one on this device; "
+                                 "backing it with a single sample",
+                                 static_cast<Int>(format));
+                    rounded = static_cast<Uint32>(VK_SAMPLE_COUNT_1_BIT);
+                }
                 if (rounded != 0) {
                     resolvedSampleCount = static_cast<VkSampleCountFlagBits>(rounded);
                 }