本文整理汇总了C++中optional::emplace方法的典型用法代码示例。如果您正苦于以下问题：C++ optional::emplace方法的具体用法？C++ optional::emplace怎么用？C++ optional::emplace使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类optional的用法示例。
在下文中一共展示了optional::emplace方法的3个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1:
static const abi_serializer& get_abi_serializer() {
static optional<abi_serializer> _abi_serializer;
if (!_abi_serializer) {
_abi_serializer.emplace(eosio_contract_abi(abi_def()));
}
return *_abi_serializer;
}示例2: create_pipeline
// Creates the graphics pipeline object
void create_pipeline() {
// Vulkan shader stage descriptors
auto shader_stage_descriptors = get_layout().shader_stage_descriptors();
// Blend operation descriptor for each attachment
lib::vector<vk::vk_blend_op_descriptor> attachment_blend_ops;
for (auto &a : fb_layout) {
const framebuffer_attachment_layout &attachment = a.second;
// Blend operation is only applicable for color attachments
const bool is_depth_attachment = format_is_depth(attachment.image_format);
if (is_depth_attachment)
continue;
vk::vk_blend_op_descriptor desc = attachment.blend;
attachment_blend_ops.push_back(std::move(desc));
}
// Set viewport and scissor as dynamic states
lib::vector<VkDynamicState> dynamic_states = {
static_cast<VkDynamicState>(pipeline_dynamic_state::viewport),
static_cast<VkDynamicState>(pipeline_dynamic_state::scissor),
};
// Create the graphics pipeline object
graphics_pipeline.emplace(ctx.get().device(),
shader_stage_descriptors,
get_layout(),
device_renderpass.get(),
0,
VkViewport{},
VkRect2D{},
vertex_input_descriptor.vertex_input_binding_descriptors,
vertex_input_descriptor.vertex_input_attribute_descriptors,
static_cast<VkPrimitiveTopology>(pipeline_settings.topology),
pipeline_settings.rasterizer_op,
pipeline_settings.depth_op,
attachment_blend_ops,
pipeline_settings.blend_constants,
dynamic_states,
pipeline_name.data(),
&ctx.get().device().pipeline_cache().current_thread_cache());
}示例3: create_renderpass
// Creates the Vulkan renderpass object
void create_renderpass() {
auto renderpass = fb_layout.create_compatible_renderpass(ctx.get());
device_renderpass.emplace(std::move(renderpass));
}