1 files changed, 82 insertions, 0 deletions
diff --git a/src/quick/scenegraph/shaders_ng/shapestroke.vert b/src/quick/scenegraph/shaders_ng/shapestroke.vert
new file mode 100644
index 0000000000..e358e059eb
--- /dev/null
+++ b/src/quick/scenegraph/shaders_ng/shapestroke.vert
@@ -0,0 +1,82 @@
+#version 440
+
+layout(location = 0) in vec4 vertexCoord;
+layout(location = 1) in vec2 inA;
+layout(location = 2) in vec2 inB;
+layout(location = 3) in vec2 inC;
+layout(location = 4) in vec2 normalVector;
+
+layout(location = 0) out vec4 P;
+layout(location = 1) out vec2 A;
+layout(location = 2) out vec2 B;
+layout(location = 3) out vec2 C;
+layout(location = 4) out vec2 HG;
+layout(location = 5) out float offset;
+
+
+layout(std140, binding = 0) uniform buf {
+#if QSHADER_VIEW_COUNT >= 2
+    mat4 qt_Matrix[QSHADER_VIEW_COUNT];
+#else
+    mat4 qt_Matrix;
+#endif
+
+    float matrixScale;
+    float opacity;
+    float reserved2;
+    float reserved3;
+
+    vec4 strokeColor;
+
+    float strokeWidth;
+    float debug;
+    float reserved5;
+    float reserved6;
+} ubuf;
+
+#define SQRT2 1.41421356237
+
+float qdot(vec2 a, vec2 b)
+{
+    return a.x * b.x + a.y * b.y;
+}
+
+void main()
+{
+    P = vertexCoord + vec4(normalVector, 0.0, 0.0) * SQRT2/ubuf.matrixScale;
+
+    A = inA;
+    B = inB;
+    C = inC;
+
+    // Find the parameters H, G for the depressed cubic
+    // t^2+H*t+G=0
+    // that results from the equation
+    // Q'(s).(p-Q(s)) = 0
+    // The last parameter is the static offset between s and t:
+    // s = t - b/(3a)
+    // use it to get back the parameter t
+
+    // this is a constant for the curve
+    float a = -2. * qdot(A, A);
+    // this is a constant for the curve
+    float b = -3. * qdot(A, B);
+    //this is linear in p so it can be put into the shader with vertex data
+    float c = 2. * qdot(A, P.xy) - qdot(B, B) - 2. * qdot(A, C);
+    //this is linear in p so it can be put into the shader with vertex data
+    float d = qdot(B, P.xy) - qdot(B, C);
+    // convert to depressed cubic.
+    // both functions are linear in c and d and thus linear in p
+    float H = (3. * a * c - b * b) / (3. * a * a);
+    float G = (2. * b * b * b - 9. * a * b * c + 27. * a * a * d) / (27. * a * a * a);
+    HG = vec2(H, G);
+    offset = b/(3*a);
+
+
+
+#if QSHADER_VIEW_COUNT >= 2
+    gl_Position = ubuf.qt_Matrix[gl_ViewIndex] * P;
+#else
+    gl_Position = ubuf.qt_Matrix * P;
+#endif
+}