diff --git a/MobileGL/MG_Impl/GLImpl/Drawing/GL_Drawing.cpp b/MobileGL/MG_Impl/GLImpl/Drawing/GL_Drawing.cpp
index 572b8f6d..2f91ea24 100644
--- a/MobileGL/MG_Impl/GLImpl/Drawing/GL_Drawing.cpp
+++ b/MobileGL/MG_Impl/GLImpl/Drawing/GL_Drawing.cpp
@@ -162,6 +162,43 @@ namespace MobileGL::MG_Impl::GLImpl {
             return false;
         }
 
+        // A geometry stage only accepts the primitive types that decompose into its declared
+        // input primitive (GL 4.6 core 11.3.1); anything else is INVALID_OPERATION. GL_PATCHES
+        // is the tessellation pipeline's input and reaches the geometry stage already
+        // converted, so it is not constrained here.
+        const auto& currentProgram = MG_State::pGLContext->GetCurrentProgram();
+        const GLenum gsInput = currentProgram ? currentProgram->GetGeometryInputType() : GL_NONE;
+        if (gsInput != GL_NONE && mode != GL_PATCHES) {
+            Bool compatible = false;
+            switch (gsInput) {
+            case GL_POINTS:
+                compatible = mode == GL_POINTS;
+                break;
+            case GL_LINES:
+                compatible = mode == GL_LINES || mode == GL_LINE_STRIP || mode == GL_LINE_LOOP;
+                break;
+            case GL_LINES_ADJACENCY:
+                compatible = mode == GL_LINES_ADJACENCY || mode == GL_LINE_STRIP_ADJACENCY;
+                break;
+            case GL_TRIANGLES:
+                compatible = mode == GL_TRIANGLES || mode == GL_TRIANGLE_STRIP || mode == GL_TRIANGLE_FAN;
+                break;
+            case GL_TRIANGLES_ADJACENCY:
+                compatible = mode == GL_TRIANGLES_ADJACENCY || mode == GL_TRIANGLE_STRIP_ADJACENCY;
+                break;
+            default:
+                break;
+            }
+            if (!compatible) {
+                MG_State::pGLContext->RecordError(
+                    ErrorCode::InvalidOperation,
+                    MakeUnique<GenericErrorInfo>(
+                        "MG_Impl/GLImpl", functionName,
+                        "Primitive mode is incompatible with the geometry shader's input primitive type."));
+                return false;
+            }
+        }
+
         // While transform feedback is active the draw's primitive type must match
         // the feedback primitive mode (GL 3.3 core 13.2.2). With a geometry shader
         // the constraint moves to the shader's output primitive type instead, so
diff --git a/MobileGL/MG_State/GLState/ProgramState/ProgramObject.cpp b/MobileGL/MG_State/GLState/ProgramState/ProgramObject.cpp
index 222c8f41..11db3fa0 100644
--- a/MobileGL/MG_State/GLState/ProgramState/ProgramObject.cpp
+++ b/MobileGL/MG_State/GLState/ProgramState/ProgramObject.cpp
@@ -174,6 +174,7 @@ namespace MobileGL::MG_State::GLState {
         m_xfbStrides.clear();
         m_xfbBufferMode = GL_INTERLEAVED_ATTRIBS;
         m_xfbVaryingNameMaxLength = 0;
+        m_gsInputPrimitive = GL_NONE;
         m_linkStatus = false;
     }
 
@@ -542,6 +543,20 @@ namespace MobileGL::MG_State::GLState {
             return;
         }
 
+        // GL_GEOMETRY_INPUT_TYPE. A draw's primitive type has to be compatible with it
+        // (GL 4.6 core 11.3.1), so it is resolved for every link, not only a capturing one.
+        m_gsInputPrimitive = GL_NONE;
+        if (const glslang::TIntermediate* gs = m_program->getIntermediate(EShLangGeometry)) {
+            switch (gs->getInputPrimitive()) {
+            case glslang::ElgPoints: m_gsInputPrimitive = GL_POINTS; break;
+            case glslang::ElgLines: m_gsInputPrimitive = GL_LINES; break;
+            case glslang::ElgLinesAdjacency: m_gsInputPrimitive = GL_LINES_ADJACENCY; break;
+            case glslang::ElgTriangles: m_gsInputPrimitive = GL_TRIANGLES; break;
+            case glslang::ElgTrianglesAdjacency: m_gsInputPrimitive = GL_TRIANGLES_ADJACENCY; break;
+            default: break;
+            }
+        }
+
         MGLOG_D("ProgramObject %u: Starting reflection", m_externalIndex);
         DoReflection();
         MGLOG_D("ProgramObject %u: Reflection done (linkStatus=%d)", m_externalIndex, (int)m_linkStatus);
diff --git a/MobileGL/MG_State/GLState/ProgramState/ProgramObject.h b/MobileGL/MG_State/GLState/ProgramState/ProgramObject.h
index e9518edc..e8dadf3c 100644
--- a/MobileGL/MG_State/GLState/ProgramState/ProgramObject.h
+++ b/MobileGL/MG_State/GLState/ProgramState/ProgramObject.h
@@ -497,6 +497,10 @@ namespace MobileGL::MG_State::GLState {
         Bool HasGsTriangleStripCaptureFixup() const { return m_gsStripCaptureFixup; }
         // Triangles per strip, in emission order, for ONE geometry invocation.
         const Vector<Uint32>& GetGsStripTriangles() const { return m_gsStripTriangles; }
+        // GL_GEOMETRY_INPUT_TYPE of the linked geometry stage (GL_POINTS, GL_LINES,
+        // GL_LINES_ADJACENCY, GL_TRIANGLES or GL_TRIANGLES_ADJACENCY), or GL_NONE when the
+        // program has no geometry stage. Draws must present a compatible primitive type.
+        GLenum GetGeometryInputType() const { return m_gsInputPrimitive; }
 
         Uint GetExternalIndex() const { return m_externalIndex; }
         // Globally-unique, never-reused id for this program object's lifetime. Unlike the GL
@@ -604,6 +608,7 @@ namespace MobileGL::MG_State::GLState {
         Vector<Uint32> m_xfbStrides;
         Vector<Uint32> m_gsStripTriangles;
         Bool m_gsStripCaptureFixup = false;
+        GLenum m_gsInputPrimitive = GL_NONE;
         GLenum m_xfbBufferMode = GL_INTERLEAVED_ATTRIBS;
         Int m_xfbVaryingNameMaxLength = 0;
     };