# From Section 8.13.2 (Interpolation Functions) of the GLSL 4.60 spec:
#
#   "For all of the interpolation functions, interpolant must be an l-value
#    from an in declaration; this can include a variable, a block or
#    structure member, an array element, or some combination of these."
#

[require]
GLSL >= 1.50
GL_ARB_gpu_shader5

[vertex shader]
in vec4 piglit_vertex;

struct S {
   vec2 b; /* second variable to test that varying packing doesn't break anything */
   vec3 a;
};

out S vs2ps;

void main()
{
   gl_Position = piglit_vertex;

   vs2ps.a = piglit_vertex.xyz;
   vs2ps.b = vec2(0.0, 1.0);
}

[fragment shader]
#extension GL_ARB_gpu_shader5 : enable

struct S {
   vec2 b;
   vec3 a;
};

in S vs2ps;

out vec4 color;

void main()
{
   /* All pixels are fully covered, so these should be the same. */
   vec3 delta = vs2ps.a - interpolateAtCentroid(vs2ps.a);

   if (delta != vec3(0.0)) {
      color = vec4(1.0, delta.x + 0.5, delta.y + 0.5, delta.z + 0.5);
   } else {
      color = vec4(vs2ps.b.x, vs2ps.b.y, 0.0, 1.0);
   }
}

[test]
clear color 0.0 0.0 0.0 0.0
clear

draw rect -1 -1 2 2
probe all rgba 0.0 1.0 0.0 1.0