vulkan mip maps

mipmaps.cpp

	void Renderer::generate_mipmaps(vk::CommandBuffer commands, DeviceImage image) {

		size_t levels = image.info.mipLevels();
		assert(levels > 0);

		vk::Extent3D extent = image.info.extent();
		vk::Offset3D upper (extent.width(), extent.height(), extent.depth());

		auto prepare_write = vk::ImageMemoryBarrier()
				.dstAccessMask(vk::AccessFlagBits::eTransferWrite)
				.newLayout(vk::ImageLayout::eTransferDstOptimal)
				.subresourceRange(subresource_range().baseMipLevel(1).levelCount(levels - 1))
				.image(image.image);

		image_barrier(commands, vk::PipelineStageFlagBits::eTopOfPipe, vk::PipelineStageFlagBits::eTransfer, {prepare_write});

		for(size_t i = 0; i < levels - 1; ++i) {

			vk::Offset3D next (half_mip(upper.x()), half_mip(upper.y()), half_mip(upper.z()));

//			log(next.x(), next.y(), next.z());

			auto region = vk::ImageBlit()
				.srcSubresource(subresource_layers(i))
				.dstSubresource(subresource_layers(i + 1))
				.srcOffsets( { vk::Offset3D(0, 0, 0), upper })
				.dstOffsets( { vk::Offset3D(0, 0, 0), next });


			commands.blitImage(image.image, vk::ImageLayout::eGeneral,
					image.image, vk::ImageLayout::eGeneral, {region}, vk::Filter::eLinear);


			auto blit_finished = vk::ImageMemoryBarrier()
					.srcAccessMask(vk::AccessFlagBits::eTransferWrite)
					.dstAccessMask(vk::AccessFlagBits::eTransferRead | vk::AccessFlagBits::eShaderRead)
					.oldLayout(vk::ImageLayout::eTransferDstOptimal)
					.newLayout(vk::ImageLayout::eGeneral)
					.subresourceRange(subresource_range().baseMipLevel(i + 1))
					.image(image.image);

			image_barrier(commands, vk::PipelineStageFlagBits::eTransfer,
				vk::PipelineStageFlagBits::eTransfer | vk::PipelineStageFlagBits::eFragmentShader, {blit_finished});

			upper = next;
		}
	}