Instruction for IVR interface

Transcription

1 This document is aimed at helping users to use IVR interface developing applications that will be able to run and display on integrated computer. Instruction for IVR interface IDEALENS

2 CONTENTS 1. File List IVR Interface integrated approach Data type defined in the interface Instruction FOR Interface ) Initialization function ) Resume/pause function ) Acquire device information function... 3 Use parameter eyetexturefov to create projection matrix... 3 Use parameter IPD to adjust model_veiw matrix ) Head pose function ) Texture setting function ) Render function Render sequence Page 1

3 1. FILE LIST ivr.h libivr.so including all kinds of data types and function interface declarations Through this so automatic link system library to call actually needed function 2. IVR INTERFACE INTEGRATED APPROACH Through include ivr.h to call interface function in code, just integrate libivr.so in app when use. Specific calling procedure can refer to the following render sequence. 3. DATA TYPE DEFINED IN THE INTERFACE Type Instruction IVRQuatf Quaternionic vector, its component is x, y, z, w IVRVector3f Ternary vector, its component is x, y, z, IVRInstance Show VR relevant contextual handles IVRHmdType Show device type IVREyeType IVREye_Left = 0, IVREye_Right = 1 float eyetexturefov[2]: FOV of left and right eyes IVRHmdInfo float ipd In meters IVRHmdType type: Device type Return types of function, IVRStatus.OK is for success, other types show something unusual. IVR_STATUS_OK, //return if success IVRStatus IVR_STATUS_ERROR, IVR_STATUS_INIT_FAIL, IVR_STATUS_UNKOWN Page 2

4 4. INSTRUCTION FOR INTERFACE 1) INITIALIZATION FUNCTION IVRInstance ivrinit(jobject activity, JavaVM * VRJavaVM) Return the instance object handle, which contains context associated with VR in the thread and at the same time also initializes some global variables needed in the VR, will be used in the subsequent function calling. Return NULL shows failure to initialize. Please ensure EGL context has been initialized Before calling ivrinit. Call this function before initialization of EGL, which can lead to error exiting. IVRStatus ivrdeinit(ivrinstance instance) Used for destroy handle, if there is no calling, which will cause a memory leak. 2) RESUME/PAUSE FUNCTION IVRStatus ivrresume( IVRInstance instance ) IVRStatus ivrpause( IVRInstance instance ) These two functions need to be called in the onresume/onpause of activity for controlling the VR to enter and exit. Get parameter of instance from return value of IVR_Init. Please make sure that call ivrresume/ivrpause and initialization function IVRINIT with the same thread. 3) ACQUIRE DEVICE INFORMATION FUNCTION IVRStatus ivrgetdeviceinfo(ivrinstance instance, IVRHmdInfo& info ) Acquire VR device information, provide including information such as the projection matrix, information represents with IVRHmdInfo structure Introduce the application of two parameters that eyetexturefov and ipd briefly. Use parameter eyetexturefov to create projection matrix Page 3

5 EyeTextureFov is the fovy in this picture, you can create the projection matrix by using this parameter. This formula gives a reference, please according to actual circumstances to use the appropriate projection matrix formula: Of which, Use parameter IPD to adjust MODEL_VEIW matrix Parameter ipd is interpupillary distance. Each frame of program operating on the VR all-in-one device needs to draw a picture for each eye. The typical steps of three-dimensional rendering as follows: 1. Create a master camera: Application controls the only master camera. All the logical animations are only for the master camera, so that what our treatment for the camera interacting with other objects will become simple and unified, in additional, the master camera will not be involved in the real rendering. The master camera also has a benefit for switching between dual stereo view and traditional single view. 2. Use two camera to render: except the master camera, VR application needs additional two cameras to handle rendering really. The two camera need to be consistent with the master camera's position and facing, just a little bit different, that is they want to turn left and right sides respectively a little to simulate our interpupillary distance. Page 4

6 3. Render to two viewport: VR application has created rendering camera for left and right eyes respectively, their viewport width is half of the width of the screen and height is the screen height. Interpupillary distance parameter ipd needs to be used in the second step, reference the method of application as following: Const float eyeoffset = ( eye? -0.5f : 0.5f ) * ipd ; Translate_matrix = { 1.0f, 0.0f, 0.0f, eyeoffset, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f}; Multiply(Translate_matrix, current_view_matrix); Page 5 4) HEAD POSE FUNCTION IVRStatus ivrgethmdpose(ivrinstance instance, IVRQuatf &orientation, IVRVector3f &position, float &fov) Acquire Rotation, Position and FOV information of current head from sensor through this API. Parameter orientation is quaternary vectors used to store Rotation information. Parameter position is ternary vectors used to store displacement information and there is no use in the absence of realizing gesture tracking temporarily. Calculate the view matrix through orientation Parameter fov can be used to calculate the projection matrix IVRStatus ivrgethmdposebyeye(ivrinstance instance, IVREyeType eye, IVRQuatf &orientation, float &fov) According to the view matrix after correct for left and right, suggesting that use this function when calculating the view matrix to get the orientation of left and right eyes and fov and by it to calculate view matrix and projection matrix. Just call one function of ivrgethmdpose and ivrgethmdposebyeye to acquire head pose information. IVRStatus ivrresetpose( IVRInstance instance ) Used for reset head pose mainly for cooperating with reset function of VR all-in-one device, cannot use normally.

7 5) TEXTURE SETTING FUNCTION IVRStatus ivrsettexture(ivrinstance instance, IVREyeType eye, int textureid) Used for set up function of left and right eyes texture, parameter eye is one of IVREyeType. 6) RENDER FUNCTION IVRStatus ivrsettexture(ivrinstance instance,ivreyetype eye, int textureid) Call device to render interface and draw the translated texture to the screen. Make sure that ivrinit ivrsettexture, ivrgethmdpose/ivrgethmdposebyeye have been called before rendering. 5. RENDER SEQUENCE Page 6

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