java - Don't understand Vertex Shader Translation -

i need translate vertices x , y value. have tried code below uniform of translation want doesn't work.

translationx , translationy assigned uniforms code similar to:

int my_value_loc = glgetuniformlocation(shader, "translationx"); gluniform1f(my_value_loc, 10.0f); 

here shader:

#version 330 uniform float translationx; uniform float translationy; void main(){ gl_position=vec4(vvertex.x+translationx, vvertex.y+translationy, 0.0, } 

i'd prefer sending translation matrix.

shader code:

uniform mat4 trans; attribute vec3 vertex; void main() { gl_position = trans * vec4(vertex, 1.0); }