CODEWITHSUNDEEP
javascriptthree.js
Philipp
Philipp

Reputation: 307

threejs - geometry coordinate system to screen coordinate system

the plane is 800px width:

geometry = new THREE.PlaneGeometry( 800, 20, 0, 0 );

material = new THREE.MeshBasicMaterial({ 
    color:0xFFFFFF,
    side:THREE.DoubleSide 
});

mesh = new THREE.Mesh(geometry, material);
mesh.updateMatrixWorld();
scene.add(mesh);

when I try to manipulate it, makes the coordinate system other junk

mesh.geometry.vertices[0].setY(0);
mesh.geometry.vertices[0].setX(0);
mesh.geometry.vertices[0].setZ(0);

mesh.geometry.vertices[1].setY(0);
mesh.geometry.vertices[1].setX(800);
mesh.geometry.vertices[1].setZ(0);

mesh.geometry.vertices[2].setY(20);
mesh.geometry.vertices[2].setX(0);
mesh.geometry.vertices[2].setZ(0);

mesh.geometry.vertices[3].setY(20);
mesh.geometry.vertices[3].setX(800);
mesh.geometry.vertices[3].setZ(0);

mesh.geometry.verticesNeedUpdate = true;

I can adjust the coordinate system of the geometry object to the coordinate system of the camera frame?

0px = 0

Upvotes: 0

Views: 1420

Answers (1)

Radio
Radio

Reputation: 2863

I apologize if this isn't what you're looking for. If you mean that you need to convert a vector3 position in the 3d world to its 2d pixel position on the screen, Here is a typical transformation:

    getScreenTranslation = function (obj, renderer, camera) {
        var vector = new THREE.Vector3();
        var widthHalf = 0.5 * renderer.context.canvas.width;
        var heightHalf = 0.5 * renderer.context.canvas.height;

        vector.setFromMatrixPosition(obj.matrixWorld);
        vector.project(camera);
        vector.x = vector.x * widthHalf + widthHalf;
        vector.y = -(vector.y * heightHalf) + heightHalf;
        return {
                x: vector.x,
                y: vector.y
        };
   };

Remember that you may need to compensate for the positioning of your canvas element within your webpage.

Upvotes: 2

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