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qad/qglview/shaders/selection_halo.frag

20 lines
818 B
GLSL

#version 150
uniform vec2 dt;
uniform vec4 selected, color;
uniform sampler2D t0;
uniform float fill;
void main(void) {
vec2 tc = qgl_FragTexture.xy;
vec4 ds0 = abs(textureLodOffset(t0, tc, 0., ivec2(-1, 0)) - selected);
vec4 ds1 = abs(textureLodOffset(t0, tc, 0., ivec2( 1, 0)) - selected);
vec4 ds2 = abs(textureLodOffset(t0, tc, 0., ivec2(0, -1)) - selected);
vec4 ds3 = abs(textureLodOffset(t0, tc, 0., ivec2(0, 1)) - selected);
float d0 = dot(ds0, vec4(1., 1., 1., 1.)), d1 = dot(ds1, vec4(1., 1., 1., 1.)), d2 = dot(ds2, vec4(1., 1., 1., 1.)), d3 = dot(ds3, vec4(1., 1., 1., 1.));
float vs = step(1e-6, d0 + d1 + d2 + d3);
float vm = step(1e-3, (d0 * 255.) * (d1 * 255.) * (d2 * 255.) * (d3 * 255.));
float v = mix(vs - vm, vs - vm - vm + 1, fill);
qgl_FragData[0] = vec4(color.rgb, v * color.a);
}