1 files changed, 18 insertions, 3 deletions

diff --git a/src/quick/scenegraph/coreapi/qsgbatchrenderer.cpp b/src/quick/scenegraph/coreapi/qsgbatchrenderer.cpp
index 77bac7c8a5..ea1a1a9b93 100644
--- a/src/quick/scenegraph/coreapi/qsgbatchrenderer.cpp
+++ b/src/quick/scenegraph/coreapi/qsgbatchrenderer.cpp
@@ -2215,6 +2215,15 @@ void Renderer::uploadBatch(Batch *b)
          */
     int bufferSize =  b->vertexCount * g->sizeOfVertex();
     int ibufferSize = 0;
+    // At this point, we need to check if the vertices byte size is 4 byte aligned or not.
+    // If an unaligned value is used in a shared buffer with indices, it causes problems with
+    // glDrawElements. We need to do a 4 byte alignment so that it can work with both
+    // QSGGeometry::UnsignedShortType and QSGGeometry::UnsignedIntType
+    int paddingBytes = 0;
+    if (!m_context->separateIndexBuffer()) {
+        paddingBytes = aligned(bufferSize, 4) - bufferSize;
+        bufferSize += paddingBytes;
+    }
     if (b->merged) {
         ibufferSize = b->indexCount * mergedIndexElemSize();
         if (m_useDepthBuffer)
@@ -2239,7 +2248,7 @@ void Renderer::uploadBatch(Batch *b)
         char *zData = vertexData + b->vertexCount * g->sizeOfVertex();
         char *indexData = separateIndexBuffer
                 ? b->ibo.data
-                : zData + (int(m_useDepthBuffer) * b->vertexCount * sizeof(float));
+                : zData + (int(m_useDepthBuffer) * b->vertexCount * sizeof(float)) + paddingBytes;
 
         quint16 iOffset16 = 0;
         quint32 iOffset32 = 0;
@@ -2287,7 +2296,7 @@ void Renderer::uploadBatch(Batch *b)
     } else {
         char *vboData = b->vbo.data;
         char *iboData = separateIndexBuffer ? b->ibo.data
-                                            : vboData + b->vertexCount * g->sizeOfVertex();
+                                            : vboData + b->vertexCount * g->sizeOfVertex() + paddingBytes;
         Element *e = b->first;
         while (e) {
             QSGGeometry *g = e->node->geometry();
@@ -3176,8 +3185,14 @@ void Renderer::renderUnmergedBatch(const Batch *batch) // legacy (GL-only)
 
     int vOffset = 0;
     char *iOffset = indexBase;
+    // If a shared buffer is used, 4 byte alignment was done to avoid issues
+    // while using glDrawElements with both QSGGeometry::UnsignedShortType and
+    // QSGGeometry::UnsignedIntType. Here, we need to take this into account
+    // while calculating iOffset value to end up with the correct offset for drawing.
+    int vertexDataByteSize = batch->vertexCount * gn->geometry()->sizeOfVertex();
+    vertexDataByteSize = aligned(vertexDataByteSize, 4);
     if (!separateIndexBuffer)
-        iOffset += batch->vertexCount * gn->geometry()->sizeOfVertex();
+        iOffset += vertexDataByteSize;
 
     QMatrix4x4 rootMatrix = batch->root ? qsg_matrixForRoot(batch->root) : QMatrix4x4();