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Fewer parameters for stroke frag shader

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This commit is contained in:
Grant Sanderson 2024-08-20 13:32:52 -05:00
parent a8784692e8
commit 82582d08bd
2 changed files with 12 additions and 14 deletions
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14
manimlib/shaders/quadratic_bezier/stroke/frag.glsl
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@ -1,18 +1,16 @@
#version 330
// Value between -1 and 1
in float dist_to_curve;
in float half_stroke_width;
in float half_anti_alias_width;
// Distance to the curve, and half the curve width, both as
// a ratio of the antialias width
in float dist_to_aaw;
in float half_width_to_aaw;
in vec4 color;
out vec4 frag_color;
void main() {
if(half_stroke_width == 0) discard;
frag_color = color;
// sdf for the region around the curve we wish to color.
float signed_dist_to_region = abs(dist_to_curve) - half_stroke_width;
frag_color.a *= smoothstep(half_anti_alias_width, -half_anti_alias_width, signed_dist_to_region);
float signed_dist_to_region = abs(dist_to_aaw) - half_width_to_aaw;
frag_color.a *= smoothstep(0.5, -0.5, signed_dist_to_region);
}

12
manimlib/shaders/quadratic_bezier/stroke/geom.glsl
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@ -17,9 +17,8 @@ in vec4 v_color[3];
in int v_vert_index[3];
out vec4 color;
out float dist_to_curve;
out float half_stroke_width;
out float half_anti_alias_width;
out float dist_to_aaw;
out float half_width_to_aaw;
// Codes for joint types
const int NO_JOINT = 0;
@ -169,19 +168,20 @@ void emit_point_with_width(
// Set styling
color = finalize_color(joint_color, point, unit_normal);
half_anti_alias_width = 0.5 * anti_alias_width * pixel_size;
half_stroke_width = 0.5 * width;
// Figure out the step from the point to the corners of the
// triangle strip around the polyline
vec3 step = step_to_corner(point, tangent, unit_normal, joint_product, inside_curve);
float aaw = max(anti_alias_width * pixel_size, 1e-8);
// Emit two corners
// The frag shader will receive a value from -1 to 1,
// reflecting where in the stroke that point is
for (int sign = -1; sign <= 1; sign += 2){
dist_to_curve = sign * (half_stroke_width + half_anti_alias_width);
float dist_to_curve = sign * 0.5 * (width + aaw);
emit_gl_Position(point + dist_to_curve * step);
half_width_to_aaw = 0.5 * width / aaw;
dist_to_aaw = dist_to_curve / aaw;
EmitVertex();
}
}