GLSL matrix functions

matrix.glsl

mat4 translate(vec3 d)
{
	return mat4(1, 0, 0, d.x,
	            0, 1, 0, d.y,
	            0, 0, 1, d.z,
	            0, 0, 0, 1);
}

mat4 scale(float c)
{
	return mat4(c, 0, 0, 0,
	            0, c, 0, 0,
	            0, 0, c, 0,
	            0, 0, 0, 1);
}

mat4 rotate2d(float a)
{
	return mat4(cos(a), -sin(a), 0, 0,
	            sin(a), cos(a), 0, 0,
	            0, 0, 1.0, 0,
	            0, 0, 0, 1.0);
}

mat4 ortho(float n, float f, float r, float l, float t, float b)
{
	return mat4(2.0/(r-l), 0, 0, -(r+l)/(r-l),
	            0, 2.0/(t-b), 0, -(t+b)/(t-b),
	            0, 0, -2.0/(f-n), -(f+n)/(f-n),
	            0, 0, 0, 1);
	
}

mat4 orthoX(vec2 pos, float aspect, float w)
{
	return ortho(-1.0, 1.0, w/2.0, -w/2.0, w*aspect/2.0, -w*aspect/2.0)*translate(vec3(pos,0));
}