polygon node: early crude implementation

app/shaders/polygon.frag

@@ -0,0 +1,44 @@
+#version 150
+
+uniform vec2[256] points_in;
+uniform int points_in_count;
+uniform vec4 color_in;
+
+uniform vec2 ove_resolution;
+
+in vec2 ove_texcoord;
+
+out vec4 fragColor;
+
+/*
+int pnpoly(int npol, float *xp, float *yp, float x, float y) {
+  int i, j, c = 0;
+  for (i = 0, j = npol-1; i < npol; j = i++) {
+    if ((((yp[i] <= y) && (y < yp[j])) ||
+         ((yp[j] <= y) && (y < yp[i]))) &&
+        (x < (xp[j] - xp[i]) * (y - yp[i]) / (yp[j] - yp[i]) + xp[i]))
+      c = !c;
+  }
+  return c;
+}
+*/
+
+bool pnpoly(vec2 p) {
+  bool c = false;
+  int i, j;
+  for (i = 0, j = points_in_count-1; i < points_in_count; j = i++) {
+    if ((((points_in[i].y <= p.y) && (p.y < points_in[j].y)) ||
+         ((points_in[j].y <= p.y) && (p.y < points_in[i].y))) &&
+        (p.x < (points_in[j].x - points_in[i].x) * (p.y - points_in[i].y) / (points_in[j].y - points_in[i].y) + points_in[i].x))
+      c = !c;
+  }
+  return c;
+}
+
+void main(void) {
+    if (points_in_count > 0 && pnpoly(ove_texcoord * ove_resolution)) {
+        fragColor = color_in;
+    } else {
+        fragColor = vec4(0.0, 0.0, 0.0, 0.0);
+    }
+}

app/shaders/shaders.qrc

@@ -12,6 +12,7 @@
         <file>dropshadow.xml</file>
         <file>diptoblack.frag</file>
         <file>diptoblack.xml</file>
+        <file>polygon.frag</file>
         <file>rgbwaveform.frag</file>
         <file>solid.frag</file>
         <file>solid.xml</file>