61 lines
1.9 KiB
GLSL
61 lines
1.9 KiB
GLSL
//-----------------------------------------------------------------------------
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// Outline rendering shader
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//
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// Copyright 2016 Aleksey Egorov
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//-----------------------------------------------------------------------------
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const int EMPHASIZED_AND_CONTOUR = 0;
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const int EMPHASIZED_WITHOUT_CONTOUR = 1;
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const int CONTOUR_ONLY = 2;
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const float feather = 0.5;
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attribute vec3 pos;
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attribute vec4 loc;
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attribute vec3 tan;
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attribute vec3 nol;
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attribute vec3 nor;
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uniform mat4 modelview;
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uniform mat4 projection;
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uniform float width;
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uniform float pixel;
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uniform int mode;
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varying vec3 fragLoc;
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void main() {
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// get camera direction from modelview matrix
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vec3 dir = vec3(modelview[0].z, modelview[1].z, modelview[2].z);
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// perform outline visibility test
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float ldot = dot(nol, dir);
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float rdot = dot(nor, dir);
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bool isOutline = (ldot > -1e-6) == (rdot < 1e-6) ||
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(rdot > -1e-6) == (ldot < 1e-6);
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bool isTagged = loc.w > 0.5;
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float visible = float((mode == CONTOUR_ONLY && isOutline) ||
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(mode == EMPHASIZED_AND_CONTOUR && (isOutline || isTagged)) ||
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(mode == EMPHASIZED_WITHOUT_CONTOUR && isTagged && !isOutline));
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// calculate line contour extension basis for constant width and caps
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vec3 norm = normalize(cross(tan, dir));
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norm = normalize(norm - dir * dot(dir, norm));
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vec3 perp = normalize(cross(dir, norm));
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// calculate line extension width considering antialiasing
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float ext = (width + feather * pixel) * visible;
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// extend line contour
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vec3 vertex = pos;
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vertex += ext * loc.x * normalize(perp);
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vertex += ext * loc.y * normalize(norm);
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// write fragment location for calculating caps and antialiasing
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fragLoc = vec3(loc);
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// transform resulting vertex with modelview and projection matrices
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gl_Position = projection * modelview * vec4(vertex, 1.0);
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}
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