Vulkan: drawElements with GL_LINE_LOOP and an offset

src/libANGLE/renderer/vulkan/VertexArrayVk.cpp

@@ -415,9 +415,11 @@ gl::Error VertexArrayVk::drawElements(const gl::Context *context,
         }
         else
         {
+            // When using an element array buffer, 'indices' is an offset to the first element.
+            intptr_t offset                = reinterpret_cast<intptr_t>(drawCallParams.indices());
             BufferVk *elementArrayBufferVk = vk::GetImpl(elementArrayBuffer);
             ANGLE_TRY(mLineLoopHelper.getIndexBufferForElementArrayBuffer(
-                renderer, elementArrayBufferVk, indexType, drawCallParams.indexCount(),
+                renderer, elementArrayBufferVk, indexType, drawCallParams.indexCount(), offset,
                 &mCurrentElementArrayBufferHandle, &mCurrentElementArrayBufferOffset));
         }
     }

src/libANGLE/renderer/vulkan/vk_helpers.cpp

@@ -370,23 +370,26 @@ gl::Error LineLoopHelper::getIndexBufferForElementArrayBuffer(RendererVk *render
                                                               BufferVk *elementArrayBufferVk,
                                                               VkIndexType indexType,
                                                               int indexCount,
+                                                              intptr_t elementArrayOffset,
                                                               VkBuffer *bufferHandleOut,
                                                               VkDeviceSize *bufferOffsetOut)
 {
     ASSERT(indexType == VK_INDEX_TYPE_UINT16 || indexType == VK_INDEX_TYPE_UINT32);
 
     uint32_t *indices = nullptr;
-    uint32_t offset   = 0;
+    uint32_t destinationOffset = 0;
 
     auto unitSize = (indexType == VK_INDEX_TYPE_UINT16 ? sizeof(uint16_t) : sizeof(uint32_t));
     size_t allocateBytes = unitSize * (indexCount + 1);
     ANGLE_TRY(mDynamicIndexBuffer.allocate(renderer, allocateBytes,
                                            reinterpret_cast<uint8_t **>(&indices), bufferHandleOut,
-                                           &offset, nullptr));
-    *bufferOffsetOut = static_cast<VkDeviceSize>(offset);
+                                           &destinationOffset, nullptr));
+    *bufferOffsetOut = static_cast<VkDeviceSize>(destinationOffset);
 
-    VkBufferCopy copy1 = {0, offset, static_cast<VkDeviceSize>(indexCount) * unitSize};
-    VkBufferCopy copy2 = {0, offset + static_cast<VkDeviceSize>(indexCount) * unitSize, unitSize};
+    VkDeviceSize sourceOffset = static_cast<VkDeviceSize>(elementArrayOffset);
+    uint64_t unitCount        = static_cast<VkDeviceSize>(indexCount);
+    VkBufferCopy copy1        = {sourceOffset, destinationOffset, unitCount * unitSize};
+    VkBufferCopy copy2        = {sourceOffset, destinationOffset + unitCount * unitSize, unitSize};
     std::array<VkBufferCopy, 2> copies = {{copy1, copy2}};
 
     vk::CommandBuffer *commandBuffer;

src/libANGLE/renderer/vulkan/vk_helpers.h

@@ -131,6 +131,7 @@ class LineLoopHelper final : public vk::CommandGraphResource
                                                   BufferVk *elementArrayBufferVk,
                                                   VkIndexType indexType,
                                                   int indexCount,
+                                                  intptr_t elementArrayOffset,
                                                   VkBuffer *bufferHandleOut,
                                                   VkDeviceSize *bufferOffsetOut);
     gl::Error getIndexBufferForClientElementArray(RendererVk *renderer,

src/tests/gl_tests/LineLoopTest.cpp

@@ -169,11 +169,6 @@ TEST_P(LineLoopTest, LineLoopUByteIndexBuffer)
 
 TEST_P(LineLoopTest, LineLoopUShortIndexBuffer)
 {
-    // TODO(lucferron): Looks like we have a bug supporting ushort as index buffers
-    // on line loops drawing.
-    // http://anglebug.com/2473
-    ANGLE_SKIP_TEST_IF(IsVulkan());
-
     // Disable D3D11 SDK Layers warnings checks, see ANGLE issue 667 for details
     ignoreD3D11SDKLayersWarnings();