[Fix] (DirectGLES, DirectVulkan): answer GL_SHADER_STORAGE_BUFFER_OFFSET_ALIGNMENT with the storage limit, not the uniform one

MobileGL/MG_Util/BackendLoaders/OpenGL/Loader.cpp

@@ -1064,6 +1064,16 @@ namespace MobileGL::MG_Util::BackendLoader {
         MGLOG_I("OpenGL ES capabilities:");
         glesFuncs.glGetIntegerv(GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT, &caps.UniformBufferOffsetAlignment);
         MGLOG_I("    GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT: %d", caps.UniformBufferOffsetAlignment);
+        // ES 3.1 core, so no extension gate - but a driver that somehow leaves it at zero would
+        // make every storage-range offset legal, so an unusable answer keeps the 256 default.
+        GLint shaderStorageOffsetAlignment = 0;
+        glesFuncs.glGetIntegerv(GL_SHADER_STORAGE_BUFFER_OFFSET_ALIGNMENT, &shaderStorageOffsetAlignment);
+        while (glesFuncs.glGetError() != GL_NO_ERROR) {
+        }
+        if (shaderStorageOffsetAlignment > 0) {
+            caps.ShaderStorageBufferOffsetAlignment = shaderStorageOffsetAlignment;
+        }
+        MGLOG_I("    GL_SHADER_STORAGE_BUFFER_OFFSET_ALIGNMENT: %d", caps.ShaderStorageBufferOffsetAlignment);
         GLfloat aliasedLineWidthRange[2] = {1.0f, 1.0f};
         GLfloat smoothLineWidthRange[2] = {1.0f, 1.0f};
         GLfloat smoothLineWidthGranularity = 1.0f;

MobileGL/MG_Util/BackendLoaders/OpenGL/Loader.h

@@ -1231,6 +1231,10 @@ namespace MobileGL {
             // InstanceIndex, which includes firstInstance.
             Bool IndirectDrawInstanceIdIncludesBaseInstance = 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
+            // GL_SHADER_STORAGE_BUFFER_OFFSET_ALIGNMENT.
+            Int ShaderStorageBufferOffsetAlignment = 256;
             Float AliasedLineWidthRangeMin = 1.0f;
             Float AliasedLineWidthRangeMax = 1.0f;
             Float SmoothLineWidthRangeMin = 1.0f;

MobileGL/MG_Util/BackendLoaders/Vulkan/Loader.cpp

@@ -154,6 +154,7 @@ namespace MobileGL::MG_Util::BackendLoader {
         caps.DriverVersionString = DecodeDriverVersion(p.driverVersion);
         caps.VendorId = p.vendorID;
         caps.UniformBufferOffsetAlignment = static_cast<int>(p.limits.minUniformBufferOffsetAlignment);
+        caps.ShaderStorageBufferOffsetAlignment = static_cast<int>(p.limits.minStorageBufferOffsetAlignment);
         caps.AliasedLineWidthRangeMin = p.limits.lineWidthRange[0];
         caps.AliasedLineWidthRangeMax = p.limits.lineWidthRange[1];
         caps.MaxSamplerAnisotropy = p.limits.maxSamplerAnisotropy;
@@ -272,6 +273,8 @@ namespace MobileGL::MG_Util::BackendLoader {
         caps.DriverVersionString = DecodeDriverVersion(properties.driverVersion);
         caps.VendorId = properties.vendorID;
         caps.UniformBufferOffsetAlignment = static_cast<int>(properties.limits.minUniformBufferOffsetAlignment);
+        caps.ShaderStorageBufferOffsetAlignment =
+            static_cast<int>(properties.limits.minStorageBufferOffsetAlignment);
         caps.AliasedLineWidthRangeMin = properties.limits.lineWidthRange[0];
         caps.AliasedLineWidthRangeMax = properties.limits.lineWidthRange[1];
         caps.MaxSamplerAnisotropy = properties.limits.maxSamplerAnisotropy;

MobileGL/MG_Util/BackendLoaders/Vulkan/Loader.h

@@ -18,6 +18,10 @@ namespace MobileGL {
             // VkPhysicalDeviceProperties::vendorID, for device-quirk vendor gating.
             Uint32 VendorId = 0;
             Int UniformBufferOffsetAlignment = 256;
+            // VkPhysicalDeviceLimits::minStorageBufferOffsetAlignment. A separate limit from
+            // the uniform one on Vulkan too, and the one GL_SHADER_STORAGE_BUFFER_OFFSET_ALIGNMENT
+            // has to answer with.
+            Int ShaderStorageBufferOffsetAlignment = 256;
             Float AliasedLineWidthRangeMin = 1.0f;
             Float AliasedLineWidthRangeMax = 1.0f;
             // VkPhysicalDeviceLimits::maxSamplerAnisotropy. Whether it can be used at all depends on

MobileGL/MG_Util/ShaderTranspiler/SpirvPasses/FlattenAtomicCounterBlockPass.h

@@ -44,9 +44,10 @@ namespace MobileGL {
             //
             // Why not simply rebase the offsets to zero and bind the buffer 8 bytes in: because
             // glBindBufferRange's offset must be a multiple of
-            // GL_SHADER_STORAGE_BUFFER_OFFSET_ALIGNMENT, which the target device reports as 32.
-            // A byte offset of 8 cannot be expressed as a binding at all, so the correction has
-            // to live in the shader's indexing, where it costs nothing.
+            // GL_SHADER_STORAGE_BUFFER_OFFSET_ALIGNMENT, which is 64 on Adreno 830 and no smaller
+            // than 32 on the other targets. A byte offset of 8 cannot be expressed as a binding
+            // on any of them, so the correction has to live in the shader's indexing, where it
+            // costs nothing.
             //
             // A block that is ALREADY laid out naturally - which is every shader that omits the
             // offset qualifier, and so very nearly all of them - is left byte-identical: the