GLES20 How to get global position of vertex after translating and rotating it

Question

I have a vertex (Which i will not be showing/rendering in the scene)

float vertex[] = {
            1.0f, 1.0f, 1.0f,
};

And i have a mesh, which i have translated and rotated using:

Matrix.translateM(World.mModelMatrix, tmOffset, globalPositionX, globalPositionY, globalPositionZ);


Matrix.rotateM(World.mModelMatrix, rmOffset, globalRotationZ, 0, 0, 1);
Matrix.rotateM(World.mModelMatrix, rmOffset, globalRotationY, 0, 1, 0);
Matrix.rotateM(World.mModelMatrix, rmOffset, globalRotationX, 1, 0, 0);

How can apply those translations and rotations to the vertex, and get its global position (x,y,z) after?

BDL · Accepted Answer · 2016-07-16T22:59:45.210

0

Use the Matrix.multiplyMV method:

float vertex[] = { 1.0f, 1.0f, 1.0f, 1.0f };
float result[] = { 0.0f, 0.0f, 0.0f, 0.0f };

Matrix.multiplyMV(result, 0, matrix, 0, vertex, 0);

Note, that you will have to add a homogeneous coordinate to your vector to make it work.

edited Jul 16 '16 at 22:59

answered Jul 14 '16 at 09:52

BDL

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is there a way to add multiple vertices, instead of looping one by one? – Rami Dabain Jul 16 '16 at 22:47
Not that I would know, but I'm not very experienced with android. – BDL Jul 16 '16 at 23:01

GLES20 How to get global position of vertex after translating and rotating it

1 Answers1