72 lines
2.0 KiB
Scala
72 lines
2.0 KiB
Scala
$input a_position, a_texcoord0, a_texcoord1, a_texcoord2, a_color0
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$output v_color0, v_path_length
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/*
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* Copyright 2011-2015 Branimir Karadzic. All rights reserved.
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* License: http://www.opensource.org/licenses/BSD-2-Clause
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*/
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#include "../common/common.sh"
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uniform vec4 u_line_params;
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#define thickness u_line_params.x
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#define miter u_line_params.y
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#define aspect u_line_params.z
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#define current_pos a_position
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#define prev_pos a_texcoord0
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#define next_pos a_texcoord1
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#define direction a_texcoord2.x
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#define path_length a_texcoord2.y
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void main()
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{
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vec2 aspect_vec = vec2(aspect, 1.0);
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// clip space
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vec4 current_proj = mul(u_modelViewProj, vec4(current_pos, 1.0));
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vec4 prev_proj = mul(u_modelViewProj, vec4(prev_pos, 1.0));
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vec4 next_proj = mul(u_modelViewProj, vec4(next_pos, 1.0));
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// normalized device coordinates [-1,1]x[-1,1]
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vec2 current_screen = current_proj.xy / current_proj.w;
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vec2 prev_screen = prev_proj.xy / prev_proj.w;
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vec2 next_screen = next_proj.xy / next_proj.w;
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float len = thickness;
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// uncomment the following line to get a line width
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// independent of distance to screen.
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// len *= current_proj.w;
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float orientation = direction;
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vec2 dir = vec2(0.0);
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if (current_screen == prev_screen) {
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dir = normalize(next_screen - current_screen);
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} else if (current_screen == next_screen) {
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dir = normalize (current_screen - prev_screen);
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} else {
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vec2 dirA = normalize (current_screen - prev_screen);
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if (miter == 1) {
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vec2 dirB = normalize(next_screen - current_screen);
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//now compute the miter join normal and length
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vec2 tangent = normalize(dirA + dirB);
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vec2 perp = vec2(-dirA.y, dirA.x);
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vec2 miter_vec = vec2(-tangent.y, tangent.x);
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dir = tangent;
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len = min (2.5 * thickness, thickness / dot(miter_vec, perp));
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} else {
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dir = dirA;
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}
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}
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vec2 normal = vec2(-dir.y, dir.x);
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normal *= len/2.0;
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normal.x /= aspect;
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vec4 offset = vec4(normal * orientation, 0.0, 0.0);
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gl_Position = current_proj + offset;
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v_color0 = a_color0;
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v_path_length = path_length;
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}
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