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Remove pre-computation of curve points and joint products

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This commit is contained in:
Grant Sanderson 2024-08-05 14:25:15 -05:00
parent f363eaa2fd
commit 557819ad03
1 changed files with 21 additions and 26 deletions
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47
manimlib/shaders/quadratic_bezier_stroke/geom.glsl
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@ -189,37 +189,32 @@ void main() {
int count = int(round(POLYLINE_FACTOR * sqrt(area) / frame_scale));
int n_steps = min(2 + count, MAX_STEPS);
// Compute points along the curve
vec3 points[MAX_STEPS];
for (int i = 0; i < MAX_STEPS; i++){
if (i >= n_steps) break;
float t = float(i) / (n_steps - 1);
points[i] = point_on_quadratic(t, c0, c1, c2);
}
// Compute joint products
vec4 joint_products[MAX_STEPS];
joint_products[0] = v_joint_product[0];
joint_products[0].xyz *= -1;
joint_products[n_steps - 1] = v_joint_product[2];
for (int i = 1; i < MAX_STEPS; i++){
if (i >= n_steps - 1) break;
vec3 v1 = points[i] - points[i - 1];
vec3 v2 = points[i + 1] - points[i];
joint_products[i] = get_joint_product(v1, v2);
}
// Emit vertex pairs aroudn subdivided points
for (int i = 0; i < MAX_STEPS; i++){
if (i >= n_steps) break;
float t = float(i) / (n_steps - 1);
// Point and tangent
vec3 point = point_on_quadratic(t, c0, c1, c2);
vec3 tangent = tangent_on_quadratic(t, c1, c2);
// Style
float stroke_width = mix(v_stroke_width[0], v_stroke_width[2], t);
vec4 color = mix(v_color[0], v_color[2], t);
// Use middle joint product for inner points, flip cross sign for first
vec4 joint_product;
if (i == 0) joint_product = v_joint_product[0] * vec4(-1, -1, -1, 1);
else if (i < n_steps - 1) joint_product = v_joint_product[1];
else joint_product = v_joint_product[2];
// This is sent along to prevent needless joint creation
bool inside_curve = (i > 0 && i < n_steps - 1);
emit_point_with_width(
points[i],
tangent_on_quadratic(t, c1, c2),
joint_products[i],
mix(v_stroke_width[0], v_stroke_width[2], t),
mix(v_color[0], v_color[2], t),
(i > 0 && i < n_steps - 1) // Is this an inner joint
point, tangent, joint_product,
stroke_width, color,
inside_curve
);
}
EndPrimitive();