Fix rounding problems

Fragment shader does not know about the projection matrix, thus it has to take the pixel ratio into account.

src/ol/render/webgl/imagereplay/index.js

@@ -194,7 +194,7 @@ ol.render.webgl.Replay.prototype.replay = function(context,
       'indicesBuffer must not be null');
   context.bindBuffer(goog.webgl.ELEMENT_ARRAY_BUFFER, this.indicesBuffer_);
 
-  var locations = this.setUpProgram_(gl, context, size);
+  var locations = this.setUpProgram_(gl, context, size, pixelRatio);
 
   // set the "uniform" values
   var projectionMatrix = ol.transform.reset(this.projectionMatrix_);
@@ -657,9 +657,10 @@ ol.render.webgl.ImageReplay.prototype.createTextures_ = function(textures, image
  * @param {WebGLRenderingContext} gl gl.
  * @param {ol.webgl.Context} context Context.
  * @param {ol.Size} size Size.
+ * @param {number} pixelRatio Pixel ratio.
  * @return {ol.render.webgl.imagereplay.shader.Default.Locations} Locations.
  */
-ol.render.webgl.ImageReplay.prototype.setUpProgram_ = function(gl, context, size) {
+ol.render.webgl.ImageReplay.prototype.setUpProgram_ = function(gl, context, size, pixelRatio) {
   // get the program
   var fragmentShader = ol.render.webgl.imagereplay.defaultshader.fragment;
   var vertexShader = ol.render.webgl.imagereplay.defaultshader.vertex;
@@ -1335,9 +1336,10 @@ ol.render.webgl.LineStringReplay.prototype.getDeleteResourcesFunction = function
  * @param {WebGLRenderingContext} gl gl.
  * @param {ol.webgl.Context} context Context.
  * @param {ol.Size} size Size.
+ * @param {number} pixelRatio Pixel ratio.
  * @return {ol.render.webgl.linestringreplay.shader.Default.Locations} Locations.
  */
-ol.render.webgl.LineStringReplay.prototype.setUpProgram_ = function(gl, context, size) {
+ol.render.webgl.LineStringReplay.prototype.setUpProgram_ = function(gl, context, size, pixelRatio) {
   // get the program
   var fragmentShader, vertexShader;
   fragmentShader =
@@ -1384,6 +1386,7 @@ ol.render.webgl.LineStringReplay.prototype.setUpProgram_ = function(gl, context,
     gl.uniform1f(locations.u_miterLimit, this.state_.miterLimit);
   }
   gl.uniform2fv(locations.u_size, size);
+  gl.uniform1f(locations.u_pixelRatio, pixelRatio);
 
   return locations;
 };
@@ -1398,7 +1401,9 @@ ol.render.webgl.LineStringReplay.prototype.setUpProgram_ = function(gl, context,
  */
 ol.render.webgl.LineStringReplay.prototype.drawReplay_ = function(gl, context, skippedFeaturesHash, hitDetection) {
   //Save GL parameters.
+  /** @type {number} */
   var tmpDepthFunc = gl.getParameter(gl.DEPTH_FUNC);
+  /** @type {boolean} */
   var tmpDepthMask = gl.getParameter(gl.DEPTH_WRITEMASK);
 
   gl.enable(gl.DEPTH_TEST);

src/ol/render/webgl/webgllinestringdefault.glsl

@@ -4,7 +4,7 @@
 
 //! COMMON
 varying float v_round;
-varying vec4 v_roundVertex;
+varying vec2 v_roundVertex;
 varying float v_halfWidth;
 
 
@@ -26,20 +26,15 @@ void main(void) {
   v_round = 0.0;
   float direction = a_direction / abs(a_direction);
   vec4 projPos = u_projectionMatrix * vec4(a_position, 0., 1.);
+  v_roundVertex = projPos.xy;
   if (mod(a_direction, 3.0) == 0.0 || mod(a_direction, 17.0) == 0.0) {
     vec2 dirVect = a_nextPos - a_position;
     vec2 normal = normalize(vec2(-dirVect.y, dirVect.x));
     offset = v_halfWidth * normal * direction;
-    if (mod(a_direction, 2.0) == 0.0) {
-      v_roundVertex = projPos + u_offsetScaleMatrix * vec4(0., 0., 0., 0.);
-    }
   } else if (mod(a_direction, 5.0) == 0.0 || mod(a_direction, 13.0) == 0.0) {
     vec2 dirVect = a_lastPos - a_position;
     vec2 normal = normalize(vec2(dirVect.y, -dirVect.x));
     offset = v_halfWidth * normal * direction;
-    if (mod(a_direction, 2.0) == 0.0) {
-      v_roundVertex = projPos + u_offsetScaleMatrix * vec4(0., 0., 0., 0.);
-    }
   } else if (mod(a_direction, 19.0) == 0.0 || mod(a_direction, 23.0) == 0.0) {
     vec2 dirVect = a_nextPos - a_position;
     vec2 tmpNormal = normalize(vec2(-dirVect.y, dirVect.x));
@@ -50,7 +45,6 @@ void main(void) {
       offset = normal * direction * miterLength;
       if (mod(a_direction, 2.0) == 0.0) {
         v_round = 1.0;
-        v_roundVertex = projPos + u_offsetScaleMatrix * vec4(0., 0., 0., 0.);
       } else if (miterLength > u_miterLimit) {
         offset = tmpNormal * direction * v_halfWidth;
       }
@@ -106,7 +100,6 @@ void main(void) {
     offset = normal * length;
     if (mod(a_direction, 2.0) == 0.0) {
       v_round = 1.0;
-      v_roundVertex = projPos + u_offsetScaleMatrix * vec4(0., 0., 0., 0.);
     }
   }
   if (!degenerate) {
@@ -121,11 +114,13 @@ void main(void) {
 uniform float u_opacity;
 uniform vec4 u_color;
 uniform vec2 u_size;
+uniform float u_pixelRatio;
 
 void main(void) {
   if (v_round > 0.0) {
-    vec2 windowCoords = vec2((v_roundVertex.x + 1.0) / 2.0 * u_size.x, (v_roundVertex.y + 1.0) / 2.0 * u_size.y);
-    if (length(windowCoords - gl_FragCoord.xy) > v_halfWidth) {
+    vec2 windowCoords = vec2((v_roundVertex.x + 1.0) / 2.0 * u_size.x * u_pixelRatio,
+        (v_roundVertex.y + 1.0) / 2.0 * u_size.y * u_pixelRatio);
+    if (length(windowCoords - gl_FragCoord.xy) > v_halfWidth * u_pixelRatio) {
       discard;
     }
   }