Removed redundant barrier.

The transition of the swapchain image(s) can happen implicitly in the renderpass. This approach has been stated to be more efficient than using an explicit barrier.
See "Vulkan Programming Guide", Chapter 7: "Graphics Pipelines", section "Renderpasses".

examples/vulkan_example/main.cpp

@@ -130,7 +130,7 @@ static void resize_vulkan(GLFWwindow* /*window*/, int w, int h)
         attachment.stencilLoadOp = VK_ATTACHMENT_LOAD_OP_DONT_CARE;
         attachment.stencilStoreOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;
         attachment.initialLayout = VK_IMAGE_LAYOUT_UNDEFINED;
-        attachment.finalLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
+        attachment.finalLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;
         VkAttachmentReference color_attachment = {};
         color_attachment.attachment = 0;
         color_attachment.layout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
@@ -554,19 +554,6 @@ static void frame_end()
 {
     VkResult err;
     vkCmdEndRenderPass(g_CommandBuffer[g_FrameIndex]);
-    {
-        VkImageMemoryBarrier barrier = {};
-        barrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
-        barrier.srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
-        barrier.dstAccessMask = VK_ACCESS_MEMORY_READ_BIT;
-        barrier.oldLayout = VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL;
-        barrier.newLayout = VK_IMAGE_LAYOUT_PRESENT_SRC_KHR;
-        barrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
-        barrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
-        barrier.image = g_BackBuffer[g_BackBufferIndex];
-        barrier.subresourceRange = g_ImageRange;
-        vkCmdPipelineBarrier(g_CommandBuffer[g_FrameIndex], VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT, VK_PIPELINE_STAGE_BOTTOM_OF_PIPE_BIT, 0, 0, NULL, 0, NULL, 1, &barrier);
-    }
     {
         VkPipelineStageFlags wait_stage = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
         VkSubmitInfo info = {};