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fgdata/Shaders/HDR/smaa_edge_detection.frag

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3.7 KiB
GLSL

/**
* Adaptation of SMAA (Enhanced Subpixel Morphological Antialiasing)
* for FlightGear.
* See http://www.iryoku.com/smaa/ for details.
* Licensed under the MIT license, see below.
*/
/**
* Copyright (C) 2013 Jorge Jimenez (jorge@iryoku.com)
* Copyright (C) 2013 Jose I. Echevarria (joseignacioechevarria@gmail.com)
* Copyright (C) 2013 Belen Masia (bmasia@unizar.es)
* Copyright (C) 2013 Fernando Navarro (fernandn@microsoft.com)
* Copyright (C) 2013 Diego Gutierrez (diegog@unizar.es)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is furnished to
* do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software. As clarification, there
* is no requirement that the copyright notice and permission be included in
* binary distributions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#version 330 core
layout(location = 0) out vec4 fragColor;
in vec2 texcoord;
in vec4 v_offset[3];
uniform sampler2D color_tex;
//-----------------------------------------------------------------------------
#define SMAA_THRESHOLD 0.1
#define SMAA_LOCAL_CONTRAST_ADAPTATION_FACTOR 2.0
//-----------------------------------------------------------------------------
// Edge Detection Pixel Shaders (First Pass)
/**
* Luma Edge Detection
*
* IMPORTANT NOTICE: luma edge detection requires gamma-corrected colors, and
* thus 'colorTex' should be a non-sRGB texture.
*/
void main()
{
vec2 threshold = vec2(SMAA_THRESHOLD);
// Calculate lumas:
vec3 weights = vec3(0.2126, 0.7152, 0.0722);
float L = dot(texture(color_tex, texcoord).rgb, weights);
float Lleft = dot(texture(color_tex, v_offset[0].xy).rgb, weights);
float Ltop = dot(texture(color_tex, v_offset[0].zw).rgb, weights);
// We do the usual threshold:
vec4 delta;
delta.xy = abs(L - vec2(Lleft, Ltop));
vec2 edges = step(threshold, delta.xy);
// Then discard if there is no edge:
if (dot(edges, vec2(1.0, 1.0)) == 0.0)
discard;
// Calculate right and bottom deltas:
float Lright = dot(texture(color_tex, v_offset[1].xy).rgb, weights);
float Lbottom = dot(texture(color_tex, v_offset[1].zw).rgb, weights);
delta.zw = abs(L - vec2(Lright, Lbottom));
// Calculate the maximum delta in the direct neighborhood:
vec2 maxDelta = max(delta.xy, delta.zw);
// Calculate left-left and top-top deltas:
float Lleftleft = dot(texture(color_tex, v_offset[2].xy).rgb, weights);
float Ltoptop = dot(texture(color_tex, v_offset[2].zw).rgb, weights);
delta.zw = abs(vec2(Lleft, Ltop) - vec2(Lleftleft, Ltoptop));
// Calculate the final maximum delta:
maxDelta = max(maxDelta.xy, delta.zw);
float finalDelta = max(maxDelta.x, maxDelta.y);
// Local contrast adaptation:
edges.xy *= step(finalDelta, SMAA_LOCAL_CONTRAST_ADAPTATION_FACTOR * delta.xy);
fragColor = vec4(edges, 0.0, 1.0);
}