My code doesn't work, can somebody tell why?

[manen]

// main.c
void shaders_set_mat4(uint shader_id, char *name, mat4 val) {
  glUniform4fv(glGetUniformLocation(shader_id, name), 1, val);
}

void main() {
  mat4 trans = {
    1, 0, 0, 0,
    0, 1, 0, 0,
    0, 0, 1, 0,
    0, 0, 0, 1
  };

  shaders_set_mat4(shader_id, "trans", trans);
}

// vertex.glsl
#version 330 core
layout(location = 0) in vec3 vPos;
layout(location = 1) in vec2 textureCoord;

out vec2 texCoord;

uniform mat4 trans;

void main() {
	gl_Position = vec4((trans * vec4(vPos, 1.0)).xyz, 1.0);
	texCoord = textureCoord;
}

I'm pretty sure that's all the code that's relevant. It's all worked without the trans variables. Does anyone know what's wrong?

[shakesoda]

try glUniformMatrix4fv instead

[manen]

Oh, thanks :D
but sadly that wasn't it :(

[recp]

See https://cglm.readthedocs.io/en/latest/opengl.html

cglm matrices and vectors are aligned by default to increase speed if you didn't disable it (see https://cglm.readthedocs.io/en/latest/opt.html), aliged data may cause wrong bytes to transfer OpenGL maybe (size of matrix may not be same as packed data), I'm not sure yet. You can disable alignment or you can copy aligned data to packed temp variable then pass it to OpenGL...

---

EDIT1:

You can also check the way you build the matrix because the transform matrix itself may be wrong because of wrong order of multiplication...

EDIT2:

You also throw the w component after the vector is transformed (by setting w == 1.0 in gl_Position), I guess you are trying to disable perspective division. Maybe you just switch to ortho projection instead? Or it could be:

gl_Position = trans * vec4(vPos, 1.0);

[manen]

hm, thanks.
disabling alignment with CGLM_ALL_UNALIGNED lead to the same results sadly.
I'm starting to think, is a diagonal 1.0f transformation matrix supposed to lead to nothing changing compared to before? All the matrix and vector math is pretty new (meaning i barely don't understand it) to me.
Also, in the docs for OpenGL calls, there are some references to a count variable. What should that be? Just asking because currently I'm just passing 1 to glUniformMatrix4fv. I also tried just passing a raw array to that function, and it lead to the same nothing appearing on screen. I'm not even sure if this is the good place to ask these tho :D

[manen]

Issue solved! If anyone wondering, I failed to realize I had to call glUseProgram before calling glUniformMatrix4fv.