fix picking bugs

Author: mikolalysenko

lib/shaders/pick-fragment.glsl

@@ -5,15 +5,21 @@ uniform vec4 pickOffset;
 varying vec4 pickA, pickB;
 
 void main() {
-  vec4 pick = vec4(pickA.xyz, 0);
+  vec4 fragId = vec4(pickA.xyz, 0.0);
   if(pickB.w > pickA.w) {
-    pick.xyz = pickB.xyz;
+    fragId.xyz = pickB.xyz;
   }
 
-  vec4 id = pick + pickOffset;
-  id.y += floor(id.x / 256.0);
-  id.z += floor(id.y / 256.0);
-  id.w += floor(id.z / 256.0);
-  id -= 256.0 * floor(id / 256.0);
-  gl_FragColor = id / 255.0;
+  fragId += pickOffset;
+
+  fragId.y += floor(fragId.x / 256.0);
+  fragId.x -= floor(fragId.x / 256.0) * 256.0;
+
+  fragId.z += floor(fragId.y / 256.0);
+  fragId.y -= floor(fragId.y / 256.0) * 256.0;
+
+  fragId.w += floor(fragId.z / 256.0);
+  fragId.z -= floor(fragId.z / 256.0) * 256.0;
+
+  gl_FragColor = fragId / 255.0;
 }

lib/shaders/pick-vertex.glsl

@@ -13,7 +13,7 @@ varying vec4 pickA, pickB;
 
 void main() {
   vec3 base = matrix * vec3(a, 1);
-  vec2 n = 0.5 * width *
+  vec2 n = width *
     normalize(screenShape.yx * vec2(d.y, -d.x)) / screenShape.xy;
   gl_Position = vec4(base.xy/base.z + n, 0, 1);
   pickA = pick0;

line.js

@@ -9,9 +9,6 @@ var ndarray = require('ndarray')
 var pool = require('typedarray-pool')
 
 var SHADERS = require('./lib/shaders')
-function compareScale(a, b) {
-  return b - a.pixelSize
-}
 
 function GLLine2D(
   plot,
@@ -85,8 +82,6 @@ return function() {
   var screenX = viewBox[2] - viewBox[0]
   var screenY = viewBox[3] - viewBox[1]
 
-  var pixelSize   = Math.max(dataX / screenX, dataY / screenY) / pixelRatio
-
   MATRIX[0] = 2.0 * boundX / dataX
   MATRIX[4] = 2.0 * boundY / dataY
   MATRIX[6] = 2.0 * (bounds[0] - dataBox[0]) / dataX - 1.0
@@ -199,21 +194,18 @@ proto.drawPick = (function() {
     var bounds    = this.bounds
     var count     = this.vertCount
 
-
     var gl        = plot.gl
     var viewBox   = plot.viewBox
     var dataBox   = plot.dataBox
-    var pixelRatio = plot.pixelRatio
+    var pixelRatio = plot.pickPixelRatio
 
-    var boundX  = bounds[2] - bounds[0]
-    var boundY  = bounds[3] - bounds[1]
+    var boundX  = bounds[2]  - bounds[0]
+    var boundY  = bounds[3]  - bounds[1]
     var dataX   = dataBox[2] - dataBox[0]
     var dataY   = dataBox[3] - dataBox[1]
     var screenX = viewBox[2] - viewBox[0]
     var screenY = viewBox[3] - viewBox[1]
 
-    var pixelSize   = Math.max(dataX / screenX, dataY / screenY) / pixelRatio
-
     this.pickOffset = pickOffset
 
     MATRIX[0] = 2.0 * boundX / dataX
@@ -249,7 +241,7 @@ proto.drawPick = (function() {
 
     gl.drawArrays(gl.TRIANGLES, 0, count)
 
-    return pickOffset+numPoints
+    return pickOffset + numPoints
   }
 })()
 
@@ -333,6 +325,13 @@ proto.update = function(options) {
     bounds[3] = Math.max(bounds[3], ay)
   }
 
+  if(bounds[0] === bounds[2]) {
+    bounds[2] += 1
+  }
+  if(bounds[3] === bounds[1]) {
+    bounds[3] += 1
+  }
+
   //Generate line data
   var lineData    = pool.mallocFloat32(24*(numPoints-1))
   var pickData    = pool.mallocUint32(12*(numPoints-1))