From fea8e615f9fa68471687f3e61945879507b2d44f Mon Sep 17 00:00:00 2001
From: Swung0x48 <swung0x48@outlook.com>
Date: Thu, 2 Jul 2026 13:44:11 +0800
Subject: [PATCH] [Fix] (MG_Impl/GLImpl): fix indexed shader storage buffer
 queries [skip ci]

---
 MobileGL/MG_Impl/GLImpl/Buffer/GL_Buffer.cpp |  2 +-
 MobileGL/MG_Impl/GLImpl/Getter/GL_Getter.cpp | 30 ++++++++++++++++++--
 MobileGL/MG_Util/Types.h                     | 13 +++++++--
 3 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/MobileGL/MG_Impl/GLImpl/Buffer/GL_Buffer.cpp b/MobileGL/MG_Impl/GLImpl/Buffer/GL_Buffer.cpp
index c1dc9849..c728bcc6 100644
--- a/MobileGL/MG_Impl/GLImpl/Buffer/GL_Buffer.cpp
+++ b/MobileGL/MG_Impl/GLImpl/Buffer/GL_Buffer.cpp
@@ -1285,7 +1285,7 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         point.Bind(bufferObject);
         if (bufferObject) {
-            point.SetRange(Range1D(0, bufferObject->GetSize()));
+            point.SetRange(Range1D(0, bufferObject->GetSize()), false);
             MGLOG_D("%s: set range (0, %d)", __func__, bufferObject->GetSize());
         } else {
             point.ClearRange();
diff --git a/MobileGL/MG_Impl/GLImpl/Getter/GL_Getter.cpp b/MobileGL/MG_Impl/GLImpl/Getter/GL_Getter.cpp
index 1b36058b..c0ce3733 100644
--- a/MobileGL/MG_Impl/GLImpl/Getter/GL_Getter.cpp
+++ b/MobileGL/MG_Impl/GLImpl/Getter/GL_Getter.cpp
@@ -143,6 +143,16 @@ namespace MobileGL::MG_Impl::GLImpl {
             return queryKind == IndexedBufferQueryKind::Start || queryKind == IndexedBufferQueryKind::Size;
         }
 
+        SizeT GetIndexedBufferQueryPointCount(BufferTarget bufferTarget) {
+            const SizeT frontendCount = MG_State::pGLContext->GetBufferBindingPointCount(bufferTarget);
+            if (bufferTarget == BufferTarget::ShaderStorage && MG_Backend::pActiveBackendObject) {
+                const Int backendCount =
+                    MG_Backend::pActiveBackendObject->GetDynamicParameters().MaxShaderStorageBufferBindings;
+                return std::min(frontendCount, static_cast<SizeT>(std::max(backendCount, 0)));
+            }
+            return frontendCount;
+        }
+
         bool TryDecodeDrawBufferQuery(GLenum pname, SizeT& drawBufferIndex) {
             if (pname == GL_DRAW_BUFFER) {
                 drawBufferIndex = 0;
@@ -223,7 +233,7 @@ namespace MobileGL::MG_Impl::GLImpl {
                 return false;
             }
 
-            if (index >= MG_State::pGLContext->GetBufferBindingPointCount(bufferTarget)) {
+            if (index >= GetIndexedBufferQueryPointCount(bufferTarget)) {
                 MG_State::pGLContext->RecordError(
                     ErrorCode::InvalidValue,
                     MakeUnique<GenericErrorInfo>(
@@ -589,9 +599,17 @@ namespace MobileGL::MG_Impl::GLImpl {
                 *data = static_cast<GLint>(bufferObject->GetExternalIndex());
                 return;
             case IndexedBufferQueryKind::Start:
+                if (!bindingPoint.HasExplicitRange()) {
+                    *data = 0;
+                    return;
+                }
                 *data = static_cast<GLint>(bindingPoint.GetRange().start);
                 return;
             case IndexedBufferQueryKind::Size: {
+                if (!bindingPoint.HasExplicitRange()) {
+                    *data = 0;
+                    return;
+                }
                 const Range1D range = bindingPoint.GetRange();
                 const auto start = std::min(range.start, bufferObject->GetSize());
                 const auto end = std::min(range.end, bufferObject->GetSize());
@@ -639,9 +657,17 @@ namespace MobileGL::MG_Impl::GLImpl {
                 *data = static_cast<GLint64>(bufferObject->GetExternalIndex());
                 return;
             case IndexedBufferQueryKind::Start:
+                if (!bindingPoint.HasExplicitRange()) {
+                    *data = 0;
+                    return;
+                }
                 *data = static_cast<GLint64>(range.start);
                 return;
             case IndexedBufferQueryKind::Size: {
+                if (!bindingPoint.HasExplicitRange()) {
+                    *data = 0;
+                    return;
+                }
                 const auto start = std::min(range.start, bufferObject->GetSize());
                 const auto end = std::min(range.end, bufferObject->GetSize());
                 *data = static_cast<GLint64>(end - start);
@@ -1669,7 +1695,7 @@ namespace MobileGL::MG_Impl::GLImpl {
             *params = dynamicParameters.MaxSampleMaskWords;
             break;
         case GL_MAX_SHADER_STORAGE_BUFFER_BINDINGS:
-            *params = dynamicParameters.MaxShaderStorageBufferBindings;
+            *params = static_cast<GLint>(GetIndexedBufferQueryPointCount(BufferTarget::ShaderStorage));
             break;
         case GL_MAX_TEXTURE_BUFFER_SIZE:
             *params = dynamicParameters.MaxTextureBufferSize;
diff --git a/MobileGL/MG_Util/Types.h b/MobileGL/MG_Util/Types.h
index 54b5529d..040dfe14 100644
--- a/MobileGL/MG_Util/Types.h
+++ b/MobileGL/MG_Util/Types.h
@@ -179,12 +179,21 @@ namespace MobileGL {
 
         Range1D GetRange() const { return m_range; }
 
-        void SetRange(const Range1D& range) { m_range = range; }
+        Bool HasExplicitRange() const { return m_hasExplicitRange; }
 
-        void ClearRange() { m_range = Range1D(); }
+        void SetRange(const Range1D& range, Bool hasExplicitRange = true) {
+            m_range = range;
+            m_hasExplicitRange = hasExplicitRange;
+        }
+
+        void ClearRange() {
+            m_range = Range1D();
+            m_hasExplicitRange = false;
+        }
 
     private:
         Range1D m_range;
+        Bool m_hasExplicitRange = false;
     };
 
     struct ComponentSizes {