Clément Foucault
e90638b911
This was caused by points well behind the near clip making the computation of the width wrong. The fix is to clip the line to the near clip plane.
87 lines
1.9 KiB
GLSL
87 lines
1.9 KiB
GLSL
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layout(lines) in;
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layout(triangle_strip, max_vertices = 4) out;
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uniform vec4 color;
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uniform vec2 viewportSize;
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uniform float lineWidth;
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#if !defined(UNIFORM)
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in vec4 finalColor_g[];
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#endif
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#ifdef CLIP
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in float clip_g[];
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out float clip;
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#endif
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out vec4 finalColor;
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noperspective out float smoothline;
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#define SMOOTH_WIDTH 1.0
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/* Clips point to near clip plane before perspective divide. */
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vec4 clip_line_point_homogeneous_space(vec4 p, vec4 q)
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{
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if (p.z < -p.w) {
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/* Just solves p + (q - p) * A; for A when p.z / p.w = -1.0. */
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float denom = q.z - p.z + q.w - p.w;
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if (denom == 0.0) {
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/* No solution. */
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return p;
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}
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float A = (-p.z - p.w) / denom;
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p = p + (q - p) * A;
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}
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return p;
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}
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void do_vertex(const int i, vec4 pos, vec2 ofs)
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{
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#if defined(UNIFORM)
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finalColor = color;
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#elif defined(FLAT)
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/* WATCH: Assuming last provoking vertex. */
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finalColor = finalColor_g[1];
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#elif defined(SMOOTH)
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finalColor = finalColor_g[i];
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#endif
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#ifdef CLIP
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clip = clip_g[i];
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#endif
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smoothline = (lineWidth + SMOOTH_WIDTH) * 0.5;
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gl_Position = pos;
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gl_Position.xy += ofs * pos.w;
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EmitVertex();
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smoothline = -(lineWidth + SMOOTH_WIDTH) * 0.5;
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gl_Position = pos;
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gl_Position.xy -= ofs * pos.w;
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EmitVertex();
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}
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void main(void)
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{
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vec4 p0 = clip_line_point_homogeneous_space(gl_in[0].gl_Position, gl_in[1].gl_Position);
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vec4 p1 = clip_line_point_homogeneous_space(gl_in[1].gl_Position, gl_in[0].gl_Position);
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vec2 e = normalize(((p1.xy / p1.w) - (p0.xy / p0.w)) * viewportSize.xy);
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#if 0 /* Hard turn when line direction changes quadrant. */
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e = abs(e);
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vec2 ofs = (e.x > e.y) ? vec2(0.0, 1.0 / e.x) : vec2(1.0 / e.y, 0.0);
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#else /* Use perpendicular direction. */
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vec2 ofs = vec2(-e.y, e.x);
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#endif
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ofs /= viewportSize.xy;
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ofs *= lineWidth + SMOOTH_WIDTH;
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do_vertex(0, p0, ofs);
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do_vertex(1, p1, ofs);
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EndPrimitive();
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}
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