diff --git a/client/index.html b/client/index.html
index f1c1760..2e8cb41 100644
--- a/client/index.html
+++ b/client/index.html
@@ -56,7 +56,7 @@
 
         <div class="sizer-wrapper">
             <div class="sizer">
-                <input type="range" class="slider" id="stroke-width" min="1" max="64">
+                <input type="range" class="slider" id="stroke-width" min="0.01" step="0.01" max="64">
             </div>
             <div id="stroke-preview" class="dhide"></div>
         </div>
diff --git a/client/index.js b/client/index.js
index 5fb5ae2..8a82057 100644
--- a/client/index.js
+++ b/client/index.js
@@ -19,8 +19,8 @@ const config = {
     second_finger_timeout: 500,
     buffer_first_touchmoves: 5,
     debug_print: false,
-    min_zoom: 0.0000005,
-    max_zoom: 10.0,
+    min_zoom: 1.0,
+    max_zoom: 1000,
     initial_offline_timeout: 1000,
     default_color: 0x00,
     default_width: 8,
diff --git a/client/math.js b/client/math.js
index 5d108e5..881ea28 100644
--- a/client/math.js
+++ b/client/math.js
@@ -7,7 +7,7 @@ function screen_to_canvas(state, p) {
 }
 
 function rdp_find_max(state, points, start, end) {
-    const EPS = 0.5 / Math.pow(state.canvas.zoom, 0.25);
+    const EPS = 1.0 / state.canvas.zoom;
     // const EPS = 10.0;
 
     let result = -1;
@@ -86,6 +86,7 @@ function process_ewmv(points, round = false) {
 function process_stroke(state, points) {
     // const result0 = process_ewmv(points);
     const result1 = process_rdp(state, points, true);
+    console.debug('simplified to', points.length, 'points to', result1.length);
     return result1;
 }
 
diff --git a/client/webgl_draw.js b/client/webgl_draw.js
index d3b81ec..60bee84 100644
--- a/client/webgl_draw.js
+++ b/client/webgl_draw.js
@@ -164,6 +164,18 @@ function draw(state, context) {
     const dynamic_points = context.dynamic_serializer.offset / config.bytes_per_point;
 
     if (dynamic_points > 0) {
+        gl.drawBuffers([gl.BACK]);
+
+        locations = context.locations['sdf'].main;
+
+        gl.useProgram(context.programs['sdf'].main);
+
+        gl.uniform2f(locations['u_res'], context.canvas.width, context.canvas.height);
+        gl.uniform2f(locations['u_scale'], state.canvas.zoom, state.canvas.zoom);
+        gl.uniform2f(locations['u_translation'], state.canvas.offset.x, state.canvas.offset.y);
+        gl.uniform1i(locations['u_stroke_count'], state.stroke_count);
+        gl.uniform1i(locations['u_debug_mode'], state.debug.red);
+
         gl.clear(gl.DEPTH_BUFFER_BIT);
         gl.bindBuffer(gl.ARRAY_BUFFER, buffers['b_packed_dynamic']);