diff --git a/manimlib/shaders/quadratic_bezier_stroke/geom.glsl b/manimlib/shaders/quadratic_bezier_stroke/geom.glsl index 5b865539..4a5d009f 100644 --- a/manimlib/shaders/quadratic_bezier_stroke/geom.glsl +++ b/manimlib/shaders/quadratic_bezier_stroke/geom.glsl @@ -50,16 +50,25 @@ const float ANGLE_THRESHOLD = 1e-3; #INSERT get_gl_Position.glsl #INSERT get_unit_normal.glsl #INSERT finalize_color.glsl +#INSERT rotate.glsl + + +float angle_between(vec2 v1, vec2 v2){ + float abs_angle = acos(clamp(dot(normalize(v1), normalize(v2)), -1.0, 1.0)); + float sgn = sign(cross2d(v1, v2)); + return sgn * abs_angle; +} void create_joint(float angle, vec2 unit_tan, float buff, vec2 static_c0, out vec2 changing_c0, vec2 static_c1, out vec2 changing_c1){ float shift; - if(abs(angle) < ANGLE_THRESHOLD || int(joint_type) == NO_JOINT){ + if(abs(angle) < ANGLE_THRESHOLD || abs(angle) > 0.99 * PI || int(joint_type) == NO_JOINT){ // No joint shift = 0; - }else if(int(joint_type) == MITER_JOINT || (int(joint_type) == AUTO_JOINT && angle > 0.9 * PI)){ + // }else if(int(joint_type) == MITER_JOINT || (int(joint_type) == AUTO_JOINT && abs(angle) > 0.95 * PI)){ + }else if(int(joint_type) == MITER_JOINT){ shift = buff * (-1.0 - cos(angle)) / sin(angle); }else{ // For a Bevel joint @@ -94,9 +103,16 @@ int get_corners( vec2 p0_perp = sgn * vec2(-v01.y, v01.x); // Pointing to the inside of the curve from p0 vec2 p2_perp = sgn * vec2(-v12.y, v12.x); // Pointing to the inside of the curve from p2 - // aaw is the added width given around the polygon for antialiasing. - // In case the normal is faced away from (0, 0, 1), the vector to the - // camera, this is scaled up. + // This is to prevent weird bevel artifacts for sharp angles + if(abs(angle_from_prev) > 0.5 * PI){ + stroke_widths[0] *= sin(angle_from_prev); + stroke_widths[1] = 0.5 * (stroke_widths[0] + stroke_widths[2]); + } + if(abs(angle_to_next) > 0.5 * PI){ + stroke_widths[2] *= sin(angle_to_next); + stroke_widths[1] = 0.5 * (stroke_widths[0] + stroke_widths[2]); + } + float buff0 = 0.5 * stroke_widths[0] + aaw; float buff2 = 0.5 * stroke_widths[2] + aaw; @@ -127,23 +143,15 @@ void main() { vec3 unit_normal = camera_rotation * vec3(0.0, 0.0, 1.0); // TODO, track true unit normal globally - // Control points are projected to the xy plane before drawing, which in turn - // gets tranlated to a uv plane. The z-coordinate information will be remembered - // by what's sent out to gl_Position, and by how it affects the lighting and stroke width - vec2 flat_controls[3]; float scaled_strokes[3]; for(int i = 0; i < 3; i++){ - float sf = perspective_scale_factor(verts[i].z, focal_distance); - flat_controls[i] = sf * verts[i].xy; - + scaled_strokes[i] = v_stroke_width[i]; if(bool(flat_stroke)){ vec3 to_cam = normalize(vec3(0.0, 0.0, focal_distance) - verts[i]); - sf *= abs(dot(unit_normal, to_cam)); + scaled_strokes[i] *= abs(dot(unit_normal, to_cam)); } - scaled_strokes[i] = v_stroke_width[i] * sf; } - // Set joint information float angle_from_prev = v_joint_angle[0]; float angle_to_next = v_joint_angle[2]; @@ -155,28 +163,44 @@ void main() { // TODO, add anti-aliasing patch to curve end angle_to_next = 0.0; } + // Recompute angles based on perspective + if(angle_from_prev > 0.0 && unit_normal != vec3(0.0, 0.0, 1.0)){ + vec3 v01 = verts[1] - verts[0]; + vec3 from_prev = rotate(v01, angle_from_prev, unit_normal); + angle_from_prev = angle_between(from_prev.xy, v01.xy); + } + if(angle_to_next > 0.0 && unit_normal != vec3(0.0, 0.0, 1.0)){ + vec3 v12 = verts[2] - verts[1]; + vec3 to_next = rotate(v12, -angle_to_next, unit_normal); + angle_to_next = angle_between(v12.xy, to_next.xy); + } + + // Control points are projected to the xy plane before drawing, which in turn + // gets tranlated to a uv plane. The z-coordinate information will be remembered + // by what's sent out to gl_Position, and by how it affects the lighting and stroke width + vec2 flat_verts[3] = vec2[3](verts[0].xy, verts[1].xy, verts[2].xy); + + // If the curve is flat, put the middle control in the midpoint + is_linear = float(abs(v_joint_angle[1]) < ANGLE_THRESHOLD); + if (bool(is_linear)){ + flat_verts[1] = 0.5 * (flat_verts[0] + flat_verts[2]); + } // We want to change the coordinates to a space where the curve // coincides with y = x^2, between some values x0 and x2. Or, in // the case of a linear curve (bezier degree 1), just put it on // the segment from (0, 0) to (1, 0) - is_linear = float(abs(v_joint_angle[1]) < ANGLE_THRESHOLD); - mat3 xy_to_uv = get_xy_to_uv(flat_controls, is_linear, is_linear); + mat3 xy_to_uv = get_xy_to_uv(flat_verts, is_linear, is_linear); float uv_scale_factor = length(xy_to_uv[0].xy); - float scaled_anti_alias_width = anti_alias_width * (frame_shape.y / pixel_shape.y); - uv_anti_alias_width = uv_scale_factor * scaled_anti_alias_width; - - // If the curve is flat, put the middle control in the midpoint - if (bool(is_linear)){ - flat_controls[1] = 0.5 * (flat_controls[0] + flat_controls[2]); - } + float scaled_aaw = anti_alias_width * (frame_shape.y / pixel_shape.y); + uv_anti_alias_width = uv_scale_factor * scaled_aaw; // Corners of a bounding region around curve vec2 corners[5]; int n_corners = get_corners( - flat_controls, scaled_strokes, - scaled_anti_alias_width, angle_from_prev, angle_to_next, + flat_verts, scaled_strokes, scaled_aaw, + angle_from_prev, angle_to_next, corners ); @@ -199,10 +223,7 @@ void main() { gloss, shadow ); - gl_Position = vec4( - get_gl_Position(vec3(corners[i], 0.0)).xy, - get_gl_Position(verts[index_map[i]]).zw - ); + gl_Position = get_gl_Position(vec3(corners[i], verts[index_map[i]].z)); EmitVertex(); } EndPrimitive();