Libovr 1.26 Reference Guide

Returns a list of strings delimited by a single space identifying Vulkan extensions that must be enabled in order for the VR runtime to support Vulkan-based applications. The returned list reflects the current runtime version and the GPU the VR system is currently connected to. luid Specifies the luid for the relevant GPU, which is returned from ovr_Create. extensionNames is a character buffer which will receive a list of extension name strings, separated by a single space char between each extension. inoutExtensionNamesSize indicates on input the capacity of extensionNames in chars. On output it returns the number of characters written to extensionNames, including the terminating 0 char. In the case of this function returning ovrError_InsufficientArraySize, the required inoutExtensionNamesSize is returned. Returns an ovrResult indicating success or failure. In the case of failure, use ovr_GetLastErrorInfo to get more information. Returns ovrError_InsufficientArraySize in the case that inoutExtensionNameSize didn't have enough space, in which case inoutExtensionNameSize will return the required inoutExtensionNamesSize. Example code charextensionNames[4096]; uint32_textensionNamesSize=sizeof(extensionNames); ovr_GetInstanceExtensionsVk(luid,extensionsnames,&extensionNamesSize); uint32_textensionCount=0; constchar*extensionNamePtrs[256]; for(constchar*p=extensionNames;*p;++p){ if((p==extensionNames)||(p[-1]=='')){ extensionNamePtrs[extensionCount++]=p; if(p[-1]=='') p[-1]='\0'; } } VkInstanceCreateInfoinfo={...}; info.enabledExtensionCount=extensionCount; info.ppEnabledExtensionNames=extensionNamePtrs; [...]

Returns a list of strings delimited by a single space identifying Vulkan extensions that must be enabled in order for the VR runtime to support Vulkan-based applications. The returned list reflects the current runtime version and the GPU the VR system is currently connected to. luid Specifies the luid for the relevant GPU, which is returned from ovr_Create. extensionNames is a character buffer which will receive a list of extension name strings, separated by a single space char between each extension. inoutExtensionNamesSize indicates on input the capacity of extensionNames in chars. On output it returns the number of characters written to extensionNames, including the terminating 0 char. In the case of this function returning ovrError_InsufficientArraySize, the required inoutExtensionNamesSize is returned. Returns an ovrResult indicating success or failure. In the case of failure, use ovr_GetLastErrorInfo to get more information. Returns ovrError_InsufficientArraySize in the case that inoutExtensionNameSize didn't have enough space, in which case inoutExtensionNameSize will return the required inoutExtensionNamesSize.

session Specifies an ovrSession previously returned by ovr_Create. luid Specifies the luid returned from ovr_Create. instance Specifies a VkInstance to search for matching luids in. out_physicalDevice Returns the VkPhysicalDevice matching the instance and luid. Returns an ovrResult indicating success or failure. In the case of failure, use ovr_GetLastErrorInfo to get more information. This function enumerates the current physical devices and returns the one matching the luid. It must be called at least once prior to any ovr_CreateTextureSwapChainVk or ovr_CreateMirrorTextureWithOptionsVk calls, and the instance must remain valid for the lifetime of the returned objects. It is assumed the VkDevice created by the application will be for the returned physical device.

session Specifies an ovrSession previously returned by ovr_Create. queue Specifies a VkQueue to add a VkFence operation to and wait on. Returns an ovrResult indicating success or failure. In the case of failure, use ovr_GetLastErrorInfo to get more information. The queue may be changed at any time but only the value at the time ovr_SubmitFrame is called will be used. ovr_SetSynchronizationQueueVk must be called with a valid VkQueue created on the same VkDevice the texture sets were created on prior to the first call to ovr_SubmitFrame. An internally created VkFence object will be signalled by the completion of operations on queue and waited on to synchronize the VR compositor.

session Specifies an ovrSession previously returned by ovr_Create. device Specifies the application's VkDevice to create resources with. desc Specifies requested texture properties. See notes for more info about texture format. out_TextureSwapChain Returns the created ovrTextureSwapChain, which will be valid upon a successful return value, else it will be NULL. This texture chain must be eventually destroyed via ovr_DestroyTextureSwapChain before destroying the session with ovr_Destroy. Returns an ovrResult indicating success or failure. In the case of failure, use ovr_GetLastErrorInfo to get more information. The texture format provided in desc should be thought of as the format the distortion-compositor will use for the ShaderResourceView when reading the contents of the texture. To that end, it is highly recommended that the application requests texture swapchain formats that are in sRGB-space (e.g. OVR_FORMAT_R8G8B8A8_UNORM_SRGB) as the compositor does sRGB-correct rendering. As such, the compositor relies on the GPU's hardware sampler to do the sRGB-to-linear conversion. If the application still prefers to render to a linear format (e.g. OVR_FORMAT_R8G8B8A8_UNORM) while handling the linear-to-gamma conversion via SPIRV code, then the application must still request the corresponding sRGB format and also use the ovrTextureMisc_DX_Typeless flag in the ovrTextureSwapChainDesc's Flag field. This will allow the application to create a RenderTargetView that is the desired linear format while the compositor continues to treat it as sRGB. Failure to do so will cause the compositor to apply unexpected gamma conversions leading to gamma-curve artifacts. The ovrTextureMisc_DX_Typeless flag for depth buffer formats (e.g. OVR_FORMAT_D32_FLOAT) is ignored as they are always converted to be typeless. ovr_GetTextureSwapChainLength ovr_GetTextureSwapChainCurrentIndex ovr_GetTextureSwapChainDesc ovr_GetTextureSwapChainBufferVk ovr_DestroyTextureSwapChain

session Specifies an ovrSession previously returned by ovr_Create. chain Specifies an ovrTextureSwapChain previously returned by ovr_CreateTextureSwapChainVk index Specifies the index within the chain to retrieve. Must be between 0 and length (see ovr_GetTextureSwapChainLength), or may pass -1 to get the buffer at the CurrentIndex location (saving a call to GetTextureSwapChainCurrentIndex). out_Image Returns the VkImage retrieved. Returns an ovrResult indicating success or failure. In the case of failure, use ovr_GetLastErrorInfo to get more information.

A second call to ovr_CreateMirrorTextureWithOptionsVk for a given ovrSession before destroying the first one is not supported and will result in an error return. session Specifies an ovrSession previously returned by ovr_Create. device Specifies the VkDevice to create resources with. desc Specifies requested texture properties. See notes for more info about texture format. out_MirrorTexture Returns the created ovrMirrorTexture, which will be valid upon a successful return value, else it will be NULL. This texture must be eventually destroyed via ovr_DestroyMirrorTexture before destroying the session with ovr_Destroy. Returns an ovrResult indicating success or failure. In the case of failure, use ovr_GetLastErrorInfo to get more information. The texture format provided in desc should be thought of as the format the compositor will use for the VkImageView when writing into mirror texture. To that end, it is highly recommended that the application requests a mirror texture format that is in sRGB-space (e.g. OVR_FORMAT_R8G8B8A8_UNORM_SRGB) as the compositor does sRGB-correct rendering. If however the application wants to still read the mirror texture as a linear format (e.g. OVR_FORMAT_R8G8B8A8_UNORM) and handle the sRGB-to-linear conversion in SPIRV code, then it is recommended the application still requests an sRGB format and also use the ovrTextureMisc_DX_Typeless flag in the ovrMirrorTextureDesc's Flags field. This will allow the application to bind a ShaderResourceView that is a linear format while the compositor continues to treat is as sRGB. Failure to do so will cause the compositor to apply unexpected gamma conversions leading to gamma-curve artifacts. Example code ovrMirrorTexturemirrorTexture=nullptr; ovrMirrorTextureDescmirrorDesc={}; mirrorDesc.Format=OVR_FORMAT_R8G8B8A8_UNORM_SRGB; mirrorDesc.Width=mirrorWindowWidth; mirrorDesc.Height=mirrorWindowHeight; ovrResultresult=ovr_CreateMirrorTextureWithOptionsVk(session,vkDevice,&mirrorDesc, &mirrorTexture); [...] //Destroythetexturewhendonewithit. ovr_DestroyMirrorTexture(session,mirrorTexture); mirrorTexture=nullptr; ovr_GetMirrorTextureBufferVk ovr_DestroyMirrorTexture

session Specifies an ovrSession previously returned by ovr_Create. mirrorTexture Specifies an ovrMirrorTexture previously returned by ovr_CreateMirrorTextureWithOptionsVk out_Image Returns the VkImage pointer retrieved. Returns an ovrResult indicating success or failure. In the case of failure, use ovr_GetLastErrorInfo to get more information. Example code VkImagemirrorImage=VK_NULL_HANDLE; ovr_GetMirrorTextureBufferVk(session,mirrorTexture,&mirrorImage); ... vkCmdBlitImage(commandBuffer,mirrorImage,VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL, presentImage,VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,1,&region,VK_FILTER_LINEAR); ... vkQueuePresentKHR(queue,&presentInfo);