/*
Copyright (c) 2019 The Khronos Group Inc.
Use of this source code is governed by an MIT-style license that can be
found in the LICENSE.txt file.
*/


#ifdef GL_ES
precision mediump float;
#endif
varying vec4 color;

// Function declarations.
float function(in float par[3]);
bool is_all(const in float array[3], const in float value);
void set_all(out float array[3], const in float value);

void main (void)
{
	float par[3];
	float ret = 0.0;

	float gray = 0.0;

	// Initialize the entire array to 1.0.
	set_all(par, 1.0);

	ret = function(par);

	// The parameter should remain unchanged by the function and the function should return 1.0.
	if(is_all(par, 1.0) && (ret == 1.0))
	{
		gray = 1.0;
	}

	gl_FragColor = vec4(gray, gray, gray, 1.0);
}

// Function definition.
float function(in float par[3])
{
	// Return the value of the array.
	if(is_all(par, 1.0))
	{
		// Test parameter qualifier (default is "in").
		set_all(par, 0.0);

		return 1.0;
	}
	else
		return 0.0;
}

bool is_all(const in float array[3], const in float value)
{
	bool ret = true;

	if(array[0] != value)
		ret = false;
	if(array[1] != value)
		ret = false;
	if(array[2] != value)
		ret = false;

	return ret;
}

void set_all(out float array[3], const in float value)
{
	array[0] = value;
	array[1] = value;
	array[2] = value;
}