anki-3d-engine/shaders/Functions.glsl

// Copyright (C) 2009-2016, Panagiotis Christopoulos Charitos and contributors.
// All rights reserved.
// Code licensed under the BSD License.
// http://www.anki3d.org/LICENSE

#ifndef ANKI_SHADERS_FUNCTIONS_GLSL
#define ANKI_SHADERS_FUNCTIONS_GLSL

vec3 dither(in vec3 col, in float C)
{
	vec3 vDither = vec3(dot(vec2(171.0, 231.0), gl_FragCoord.xy));
	vDither.rgb = fract(vDither.rgb / vec3(103.0, 71.0, 97.0));

	col = col * (255.0 / C) + vDither.rgb;
	col = floor(col) / 255.0;
	col *= C;

	return col;
}

float dither(in float col, in float C)
{
	float vDither = dot(vec2(171.0, 231.0), gl_FragCoord.xy);
	vDither = fract(vDither / 103.0);

	col = col * (255.0 / C) + vDither;
	col = floor(col) / 255.0;
	col *= C;

	return col;
}

// Convert to linear depth
float linearizeDepth(in float depth, in float zNear, in float zFar)
{
	return (2.0 * zNear) / (zFar + zNear - depth * (zFar - zNear));
}

// This is the optimal linearizeDepth where a=(f+n)/2n and b=(n-f)/2n
float linearizeDepthOptimal(in float depth, in float a, in float b)
{
	return 1.0 / (a + depth * b);
}

#endif