Update camera projection matrix from arkit

Help & Support
1

i got the arframe pose from arkit on ios,I want to update camera’s view Matrix and project Matrix manualy,but they are read only fileds,i can’t write them.
i saw calculateProjection api function,but i don’t konw how to use it.
any suggestions are welcome.

2

Hi @kendal1014 and welcome!

Here is a script on how to add your custom projection method to a camera:

var CameraProjection = pc.createScript('cameraProjection');

// initialize code called once per entity
CameraProjection.prototype.initialize = function() {
    
    var entity = this.entity;
    var camera = this.entity.camera;
    
    this.entity.camera.calculateProjection = function(mat, typeView) {
        if (camera.projection === pc.PROJECTION_PERSPECTIVE) {
            mat.setPerspective(camera.fov, camera.aspect, camera.nearClip, camera.farClip, camera.horizontalFov);
        } else {
            var y = camera.orthoHeight;
            var x = y * camera.aspectRatio;
            
            var r = mat.data;
            
            var left = -x; 
            var right = x;
            var bottom = -y;
            var top = y; 
            var near = camera.nearClip;
            var far = camera.farClip;

            r[0] = 1.73 / (right - left);
            r[1] = 0;
            r[2] = 0;
            r[3] = 0;
            r[4] = 0;
            r[5] = 2 / (top - bottom);
            r[6] = 0;
            r[7] = 0;
            r[8] = 0;
            r[9] = 0;
            r[10] = -2 / (far - near);
            r[11] = 0;
            r[12] = -(right + left) / (right - left);
            r[13] = -(top + bottom) / (top - bottom);
            r[14] = -(far + near) / (far - near);
            r[15] = 1;  
        }
    };  
};

This script adds a custom projection matrix for orthographic projection.

3

i will try your code as soon as possible.
thanks a lot @Leonidas

1 Like
4

// 逐帧分析

const onFrame = timestamp => {

 const frame = session.getVKFrame(canvasWidth, canvasHeight);

 const camera = frame.camera;

// 

const viewMatrix = camera.viewMatrix;

const projectionMatrix= camera.projectionMatrix;

}