ENH: wireframe: refine the rendering logic under paint

1. remove wireframe in 3d view, only keep in paint;
2. pass barycentric_coordinates from outside
3. add shortcut hints

Change-Id: I911e5cdf3475926d9527dc0839fdce072ed54746
(cherry picked from commit 6e16d0ccfb71741e55daabd757be9f9e7613e695)

resources/shaders/mm_gouraud_wireframe.fs

@@ -1,4 +1,4 @@
-#version 130
+#version 110
 
 #define INTENSITY_CORRECTION 0.6
 
@@ -45,6 +45,10 @@ float edgeFactor(float lineWidth) {
 
 vec3 wireframe(vec3 fill, vec3 stroke, float lineWidth) {
     return mix(stroke, fill, edgeFactor(lineWidth));
+	//if (any(lessThan(barycentric_coordinates, vec3(0.005, 0.005, 0.005))))
+	//	return vec3(1.0, 0.0, 0.0);
+	//else
+	//	return fill;
 }
 
 vec3 getWireframeColor(vec3 fill) {

resources/shaders/mm_gouraud_wireframe.vs

@@ -1,7 +1,10 @@
-#version 130
+#version 110
 
 const vec3 ZERO = vec3(0.0, 0.0, 0.0);
 
+attribute vec3 v_position;
+attribute vec3 v_barycentric;
+
 uniform mat4 volume_world_matrix;
 // Clipping plane, x = min z, y = max z. Used by the FFF and SLA previews to clip with a top / bottom plane.
 uniform vec2 z_range;
@@ -22,15 +25,19 @@ struct SlopeDetection
 uniform SlopeDetection slope;
 void main()
 {
-    model_pos = gl_Vertex;
+    //model_pos = gl_Vertex;
+	model_pos = vec4(v_position, 1.0);
     // Point in homogenous coordinates.
-    vec4 world_pos = volume_world_matrix * gl_Vertex;
+    //vec4 world_pos = volume_world_matrix * gl_Vertex;
+	vec4 world_pos = volume_world_matrix * model_pos;
 
-    gl_Position = ftransform();
+    //gl_Position = ftransform();
+	gl_Position = gl_ModelViewProjectionMatrix * vec4(v_position.x, v_position.y, v_position.z, 1.0);
     // Fill in the scalars for fragment shader clipping. Fragments with any of these components lower than zero are discarded.
     clipping_planes_dots = vec3(dot(world_pos, clipping_plane), world_pos.z - z_range.x, z_range.y - world_pos.z);
 	
     //compute the Barycentric Coordinates
-    int vertexMod3 = gl_VertexID % 3;
-    barycentric_coordinates = vec3(float(vertexMod3 == 0), float(vertexMod3 == 1), float(vertexMod3 == 2));
+    //int vertexMod3 = gl_VertexID % 3;
+    //barycentric_coordinates = vec3(float(vertexMod3 == 0), float(vertexMod3 == 1), float(vertexMod3 == 2));
+	barycentric_coordinates = v_barycentric;
 }