在Vulkan中,可以使用以下方法来避免每帧更改纹理布局:
// 创建图像时指定初始布局
VkImageCreateInfo imageCreateInfo = {};
imageCreateInfo.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO;
imageCreateInfo.imageType = VK_IMAGE_TYPE_2D;
imageCreateInfo.format = VK_FORMAT_R8G8B8A8_UNORM;
imageCreateInfo.extent.width = width;
imageCreateInfo.extent.height = height;
imageCreateInfo.extent.depth = 1;
imageCreateInfo.mipLevels = 1;
imageCreateInfo.arrayLayers = 1;
imageCreateInfo.samples = VK_SAMPLE_COUNT_1_BIT;
imageCreateInfo.tiling = VK_IMAGE_TILING_OPTIMAL;
imageCreateInfo.usage = VK_IMAGE_USAGE_SAMPLED_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;
imageCreateInfo.initialLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
VkImage image;
vkCreateImage(device, &imageCreateInfo, nullptr, &image);
// 在每个帧的开始和结束时转换布局
// 帧开始时,将布局转换为VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL
VkImageMemoryBarrier layoutBarrier = {};
layoutBarrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
layoutBarrier.oldLayout = VK_IMAGE_LAYOUT_UNDEFINED;
layoutBarrier.newLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
layoutBarrier.srcAccessMask = 0;
layoutBarrier.dstAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
layoutBarrier.image = image;
layoutBarrier.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
layoutBarrier.subresourceRange.baseMipLevel = 0;
layoutBarrier.subresourceRange.levelCount = 1;
layoutBarrier.subresourceRange.baseArrayLayer = 0;
layoutBarrier.subresourceRange.layerCount = 1;
vkCmdPipelineBarrier(commandBuffer, VK_PIPELINE_STAGE_TOP_OF_PIPE_BIT, VK_PIPELINE_STAGE_TRANSFER_BIT,
0, 0, nullptr, 0, nullptr, 1, &layoutBarrier);
// 帧结束时,将布局转换为VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL
layoutBarrier.oldLayout = VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL;
layoutBarrier.newLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
layoutBarrier.srcAccessMask = VK_ACCESS_TRANSFER_WRITE_BIT;
layoutBarrier.dstAccessMask = VK_ACCESS_SHADER_READ_BIT;
vkCmdPipelineBarrier(commandBuffer, VK_PIPELINE_STAGE_TRANSFER_BIT, VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT,
0, 0, nullptr, 0, nullptr, 1, &layoutBarrier);
通过正确设置初始布局和使用布局转换,可以避免在Vulkan中每帧更改纹理布局,从而提高性能。