Anti-Alias with complex skia.Path triggers shader compilation error and failed drawing about skia-python HOT 27 OPEN

        path = skia.Path().moveTo(self.x1, self.y1).lineTo(self.x2, self.y2)
        paint = skia.Paint(Color=parse_color(self.color))
        paint.setStyle(skia.Paint.kStroke_Style)
        paint.setStrokeWidth(self.thickness)
        canvas.drawPath(path, paint)

Shader compilation error
------------------------
   1	#version 110
   2	
   3	
   4	float _determinant2(mat2 m) {
   5	return m[0].x*m[1].y - m[0].y*m[1].x;
   6	}
   7	const float PI = 3.14159274;
   8	const float PRECISION = 4.0;
   9	const float NUM_TOTAL_EDGES = 16383.0;
  10	uniform vec4 sk_RTAdjust;
  11	uniform vec3 utessControlArgs_S0;
  12	uniform vec4 uaffineMatrix_S0;
  13	uniform vec2 utranslate_S0;
  14	attribute vec4 pts01Attr;
  15	attribute vec4 pts23Attr;
  16	attribute vec2 argsAttr;
  17	attribute float curveTypeAttr;
  18	vec2 robust_normalize_diff_f2f2f2(vec2 a, vec2 b) {
  19	    vec2 diff = a - b;
  20	    if (diff == vec2(0.0)) {
  21	        return vec2(0.0);
  22	    } else {
  23	        float invMag = 1.0 / max(abs(diff.x), abs(diff.y));
  24	        return normalize(invMag * diff);
  25	    }
  26	}
  27	vec2 unchecked_mix_f2f2f2f(vec2 a, vec2 b, float T) {
  28	    return ((b - a) * (vec2(T)) + (a));
  29	}
  30	float wangs_formula_max_fdiff_p2_ff2f2f2f2f22(vec2 p0, vec2 p1, vec2 p2, vec2 p3, mat2 matrix) {
  31	    vec2 d0 = matrix * (((vec2(-2.0)) * (p1) + (p2)) + p0);
  32	    vec2 d1 = matrix * (((vec2(-2.0)) * (p2) + (p3)) + p1);
  33	    return max(dot(d0, d0), dot(d1, d1));
  34	}
  35	float wangs_formula_conic_p2_fff2f2f2f(float _precision_, vec2 p0, vec2 p1, vec2 p2, float w) {
  36	    vec2 C = (min(min(p0, p1), p2) + max(max(p0, p1), p2)) * 0.5;
  37	    p0 -= C;
  38	    p1 -= C;
  39	    p2 -= C;
  40	    float m = sqrt(max(max(dot(p0, p0), dot(p1, p1)), dot(p2, p2)));
  41	    vec2 dp = ((vec2(-2.0 * w)) * (p1) + (p0)) + p2;
  42	    float dw = abs(((-2.0) * (w) + (2.0)));
  43	    float rp_minus_1 = max(0.0, ((m) * (_precision_) + (-1.0)));
  44	    float numer = length(dp) * _precision_ + rp_minus_1 * dw;
  45	    float denom = 4.0 * min(w, 1.0);
  46	    return numer / denom;
  47	}
  48	void main() {
  49	    float NUM_RADIAL_SEGMENTS_PER_RADIAN = utessControlArgs_S0.x;
  50	    float JOIN_TYPE = utessControlArgs_S0.y;
  51	    float STROKE_RADIUS = utessControlArgs_S0.z;
  52	    mat2 AFFINE_MATRIX = mat2(uaffineMatrix_S0.xy, uaffineMatrix_S0.zw);
  53	    vec2 TRANSLATE = utranslate_S0;
  54	    vec2 p0 = pts01Attr.xy;
  55	    vec2 p1 = pts01Attr.zw;
  56	    vec2 p2 = pts23Attr.xy;
  57	    vec2 p3 = pts23Attr.zw;
  58	    vec2 lastControlPoint = argsAttr;
  59	    float w = -1.0;
  60	    if (curveTypeAttr != 0.0) {
  61	        w = p3.x;
  62	        p3 = p2;
  63	    }
  64	    float numParametricSegments;
  65	    if (w < 0.0) {
  66	        if (p0 == p1 && p2 == p3) {
  67	            numParametricSegments = 1.0;
  68	        } else {
  69	            float _0_m = wangs_formula_max_fdiff_p2_ff2f2f2f2f22(p0, p1, p2, p3, AFFINE_MATRIX);
  70	            numParametricSegments = max(ceil(sqrt(3.0 * sqrt(_0_m))), 1.0);
  71	        }
  72	    } else {
  73	        float _1_n2 = wangs_formula_conic_p2_fff2f2f2f(PRECISION, AFFINE_MATRIX * p0, AFFINE_MATRIX * p1, AFFINE_MATRIX * p2, w);
  74	        numParametricSegments = max(ceil(sqrt(_1_n2)), 1.0);
  75	    }
  76	    vec2 tan0 = robust_normalize_diff_f2f2f2(p0 == p1 ? (p1 == p2 ? p3 : p2) : p1, p0);
  77	    vec2 tan1 = robust_normalize_diff_f2f2f2(p3, p3 == p2 ? (p2 == p1 ? p0 : p1) : p2);
  78	    if (tan0 == vec2(0.0)) {
  79	        tan0 = vec2(1.0, 0.0);
  80	        tan1 = vec2(-1.0, 0.0);
  81	    }
  82	    float edgeID = float(gl_VertexID >> 1);
  83	    if ((gl_VertexID & 1) != 0) {
  84	        edgeID = -edgeID;
  85	    }
  86	    float numEdgesInJoin = 4.0;
  87	    float turn = _determinant2(mat2(p2 - p0, p3 - p1));
  88	    float combinedEdgeID = abs(edgeID) - numEdgesInJoin;
  89	    if (combinedEdgeID < 0.0) {
  90	        tan1 = tan0;
  91	        if (lastControlPoint != p0) {
  92	            tan0 = robust_normalize_diff_f2f2f2(p0, lastControlPoint);
  93	        }
  94	        turn = _determinant2(mat2(tan0, tan1));
  95	    }
  96	    float cosTheta = clamp(dot(tan0, tan1), -1.0, 1.0);
  97	    float rotation = acos(cosTheta);
  98	    if (turn < 0.0) {
  99	        rotation = -rotation;
 100	    }
 101	    float numRadialSegments;
 102	    float strokeOutset = sign(edgeID);
 103	    if (combinedEdgeID < 0.0) {
 104	        numRadialSegments = numEdgesInJoin - 2.0;
 105	        numParametricSegments = 1.0;
 106	        p3 = (p2 = (p1 = p0));
 107	        combinedEdgeID += numRadialSegments + 1.0;
 108	        float sinEpsilon = 0.01;
 109	        bool tangentsNearlyParallel = abs(turn) * (1.0 / sqrt(dot(tan0, tan0) * dot(tan1, tan1))) < sinEpsilon;
 110	        if (!tangentsNearlyParallel || dot(tan0, tan1) < 0.0) {
 111	            if (combinedEdgeID >= 0.0) {
 112	                strokeOutset = turn < 0.0 ? min(strokeOutset, 0.0) : max(strokeOutset, 0.0);
 113	            }
 114	        }
 115	        combinedEdgeID = max(combinedEdgeID, 0.0);
 116	    } else {
 117	        float maxCombinedSegments = (NUM_TOTAL_EDGES - numEdgesInJoin) - 1.0;
 118	        numRadialSegments = max(ceil(abs(rotation) * NUM_RADIAL_SEGMENTS_PER_RADIAN), 1.0);
 119	        numRadialSegments = min(numRadialSegments, maxCombinedSegments);
 120	        numParametricSegments = min(numParametricSegments, (maxCombinedSegments - numRadialSegments) + 1.0);
 121	    }
 122	    float radsPerSegment = rotation / numRadialSegments;
 123	    float numCombinedSegments = (numParametricSegments + numRadialSegments) - 1.0;
 124	    bool isFinalEdge = combinedEdgeID >= numCombinedSegments;
 125	    if (combinedEdgeID > numCombinedSegments) {
 126	        strokeOutset = 0.0;
 127	    }
 128	    if (abs(edgeID) == 2.0) {
 129	        float _2_x = ((cosTheta) * (0.5) + (0.5));
 130	        strokeOutset *= (_2_x * JOIN_TYPE) * JOIN_TYPE >= 1.0 ? (1.0 / sqrt(_2_x)) : sqrt(_2_x);
 131	    }
 132	    vec2 tangent;
 133	    vec2 strokeCoord;
 134	    if (combinedEdgeID != 0.0 && !isFinalEdge) {
 135	        vec2 A;
 136	        vec2 B;
 137	        vec2 C = p1 - p0;
 138	        vec2 D = p3 - p0;
 139	        if (w >= 0.0) {
 140	            C *= w;
 141	            B = 0.5 * D - C;
 142	            A = (w - 1.0) * D;
 143	            p1 *= w;
 144	        } else {
 145	            vec2 E = p2 - p1;
 146	            B = E - C;
 147	            A = ((vec2(-3.0)) * (E) + (D));
 148	        }
 149	        vec2 B_ = B * (numParametricSegments * 2.0);
 150	        vec2 C_ = C * (numParametricSegments * numParametricSegments);
 151	        float lastParametricEdgeID = 0.0;
 152	        float maxParametricEdgeID = min(numParametricSegments - 1.0, combinedEdgeID);
 153	        float negAbsRadsPerSegment = -abs(radsPerSegment);
 154	        float maxRotation0 = (1.0 + combinedEdgeID) * abs(radsPerSegment);
 155	        for (int _0_exp = 4;_0_exp >= 0; --_0_exp) {
 156	            float testParametricID = lastParametricEdgeID + exp2(float(_0_exp));
 157	            if (testParametricID <= maxParametricEdgeID) {
 158	                vec2 testTan = ((vec2(testParametricID)) * (A) + (B_));
 159	                testTan = ((vec2(testParametricID)) * (testTan) + (C_));
 160	                float cosRotation = dot(normalize(testTan), tan0);
 161	                float maxRotation = ((testParametricID) * (negAbsRadsPerSegment) + (maxRotation0));
 162	                maxRotation = min(maxRotation, PI);
 163	                if (cosRotation >= cos(maxRotation)) {
 164	                    lastParametricEdgeID = testParametricID;
 165	                }
 166	            }
 167	        }
 168	        float parametricT = lastParametricEdgeID / numParametricSegments;
 169	        float lastRadialEdgeID = combinedEdgeID - lastParametricEdgeID;
 170	        float angle0 = acos(clamp(tan0.x, -1.0, 1.0));
 171	        angle0 = tan0.y >= 0.0 ? angle0 : -angle0;
 172	        float radialAngle = ((lastRadialEdgeID) * (radsPerSegment) + (angle0));
 173	        tangent = vec2(cos(radialAngle), sin(radialAngle));
 174	        vec2 norm = vec2(-tangent.y, tangent.x);
 175	        float a = dot(norm, A);
 176	        float b_over_2 = dot(norm, B);
 177	        float c = dot(norm, C);
 178	        float discr_over_4 = max(b_over_2 * b_over_2 - a * c, 0.0);
 179	        float q = sqrt(discr_over_4);
 180	        if (b_over_2 > 0.0) {
 181	            q = -q;
 182	        }
 183	        q -= b_over_2;
 184	        float _5qa = (-0.5 * q) * a;
 185	        vec2 root = abs(((q) * (q) + (_5qa))) < abs(((a) * (c) + (_5qa))) ? vec2(q, a) : vec2(c, q);
 186	        float radialT = root.y != 0.0 ? root.x / root.y : 0.0;
 187	        radialT = clamp(radialT, 0.0, 1.0);
 188	        if (lastRadialEdgeID == 0.0) {
 189	            radialT = 0.0;
 190	        }
 191	        float T = max(parametricT, radialT);
 192	        vec2 ab = unchecked_mix_f2f2f2f(p0, p1, T);
 193	        vec2 bc = unchecked_mix_f2f2f2f(p1, p2, T);
 194	        vec2 cd = unchecked_mix_f2f2f2f(p2, p3, T);
 195	        vec2 abc = unchecked_mix_f2f2f2f(ab, bc, T);
 196	        vec2 bcd = unchecked_mix_f2f2f2f(bc, cd, T);
 197	        vec2 abcd = unchecked_mix_f2f2f2f(abc, bcd, T);
 198	        float u = ((w - 1.0) * (T) + (1.0));
 199	        float v = (w + 1.0) - u;
 200	        float uv = ((v - u) * (T) + (u));
 201	        if (T != radialT) {
 202	            tangent = w >= 0.0 ? robust_normalize_diff_f2f2f2(bc * u, ab * v) : robust_normalize_diff_f2f2f2(bcd, abc);
 203	        }
 204	        strokeCoord = w >= 0.0 ? abc / uv : abcd;
 205	    } else {
 206	        tangent = combinedEdgeID == 0.0 ? tan0 : tan1;
 207	        strokeCoord = combinedEdgeID == 0.0 ? p0 : p3;
 208	    }
 209	    vec2 ortho = vec2(tangent.y, -tangent.x);
 210	    strokeCoord += ortho * (STROKE_RADIUS * strokeOutset);
 211	    vec2 devCoord = AFFINE_MATRIX * strokeCoord + TRANSLATE;
 212	    gl_Position = vec4(devCoord, 0.0, 1.0);
 213	    gl_Position = vec4(gl_Position.xy * sk_RTAdjust.xz + gl_Position.ww * sk_RTAdjust.yw, 0.0, gl_Position.w);
 214	}
 215	
Errors:
ERROR: 0:82: Use of undeclared identifier 'gl_VertexID'
ERROR: 0:83: Use of undeclared identifier 'gl_VertexID'
ERROR: 0:84: Use of undeclared identifier 'edgeID'
ERROR: 0:84: Use of undeclared identifier 'edgeID'
ERROR: 0:88: Use of undeclared identifier 'edgeID'
ERROR: 0:89: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:102: Use of undeclared identifier 'edgeID'
ERROR: 0:103: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:107: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:111: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:112: Use of undeclared identifier 'strokeOutset'
ERROR: 0:112: Use of undeclared identifier 'strokeOutset'
ERROR: 0:112: Use of undeclared identifier 'strokeOutset'
ERROR: 0:115: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:115: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:124: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:125: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:126: Use of undeclared identifier 'strokeOutset'
ERROR: 0:128: Use of undeclared identifier 'edgeID'
ERROR: 0:130: Use of undeclared identifier 'strokeOutset'
ERROR: 0:134: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:134: Use of undeclared identifier 'isFinalEdge'
ERROR: 0:152: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:154: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:157: Use of undeclared identifier 'maxParametricEdgeID'
ERROR: 0:161: Use of undeclared identifier 'maxRotation0'
ERROR: 0:162: Use of undeclared identifier 'maxRotation'
ERROR: 0:162: Use of undeclared identifier 'maxRotation'
ERROR: 0:163: Use of undeclared identifier 'maxRotation'
ERROR: 0:169: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:172: Use of undeclared identifier 'lastRadialEdgeID'
ERROR: 0:173: Use of undeclared identifier 'radialAngle'
ERROR: 0:173: Use of undeclared identifier 'radialAngle'
ERROR: 0:188: Use of undeclared identifier 'lastRadialEdgeID'
ERROR: 0:206: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:207: Use of undeclared identifier 'combinedEdgeID'
ERROR: 0:210: Use of undeclared identifier 'strokeOutset'

   while (glfw.get_key(window, glfw.KEY_ESCAPE) != glfw.PRESS
            and not glfw.window_should_close(window)):
            glfw.wait_events()

Shader compilation error
------------------------
   1    #version 110
   2
   3    uniform vec4 sk_RTAdjust;
   4    uniform vec2 uatlas_adjust_S0;
   5    attribute vec4 fillBounds;
   6    attribute vec4 color;
   7    attribute vec4 locations;
   8    varying vec2 vatlasCoord_S0;
   9    varying vec4 vcolor_S0;
  10    void main() {
  11        vec2 unitCoord = vec2(float(gl_VertexID & 1), float(gl_VertexID >> 1));
  12        vec2 devCoord = mix(fillBounds.xy, fillBounds.zw, unitCoord);
  13        vec2 atlasTopLeft = vec2(abs(locations.x) - 1.0, locations.y);
  14        vec2 devTopLeft = locations.zw;
  15        bool transposed = locations.x < 0.0;
  16        vec2 atlasCoord = devCoord - devTopLeft;
  17        if (transposed) {
  18            atlasCoord = atlasCoord.yx;
  19        }
  20        atlasCoord += atlasTopLeft;
  21        vatlasCoord_S0 = atlasCoord * uatlas_adjust_S0;
  22        vcolor_S0 = color;
  23        gl_Position = vec4(devCoord, 0.0, 1.0);
  24        gl_Position = vec4(gl_Position.xy * sk_RTAdjust.xz + gl_Position.ww * sk_RTAdjust.yw, 0.0, gl_Position.w);
  25    }
  26
Errors:
ERROR: 0:11: Use of undeclared identifier 'gl_VertexID'
ERROR: 0:11: Use of undeclared identifier 'gl_VertexID'
ERROR: 0:12: Use of undeclared identifier 'unitCoord'
ERROR: 0:16: Use of undeclared identifier 'devCoord'
ERROR: 0:18: Use of undeclared identifier 'atlasCoord'
ERROR: 0:18: Use of undeclared identifier 'atlasCoord'
ERROR: 0:20: Use of undeclared identifier 'atlasCoord'
ERROR: 0:21: Use of undeclared identifier 'atlasCoord'
ERROR: 0:23: Use of undeclared identifier 'devCoord'

context = skia.GrDirectContext.MakeGL()
assert context is not None                                # assert here

(fb_width, fb_height) = glfw.get_framebuffer_size(window) # segfault against 3.9, 3.11

assert surface is not None
# strerr "GLFWError: (65545) b'NSGL: Failed to find a suitable pixel format'"