Pack texture and layout data into single attribute

src/data/bucket/symbol_bucket.js

@@ -5,6 +5,7 @@ const ArrayGroup = require('../array_group');
 const BufferGroup = require('../buffer_group');
 const createElementArrayType = require('../element_array_type');
 const EXTENT = require('../extent');
+const packUint8ToFloat = require('../../shaders/encode_attribute').packUint8ToFloat;
 const Anchor = require('../../symbol/anchor');
 const getAnchors = require('../../symbol/get_anchors');
 const resolveTokens = require('../../util/token');
@@ -32,8 +33,7 @@ const elementArrayType = createElementArrayType();
 
 const layoutAttributes = [
     {name: 'a_pos_offset',  components: 4, type: 'Int16'},
-    {name: 'a_texture_pos', components: 2, type: 'Uint16'},
-    {name: 'a_data',        components: 4, type: 'Uint8'}
+    {name: 'a_data',        components: 4, type: 'Uint16'}
 ];
 
 const symbolInterfaces = {
@@ -77,15 +77,18 @@ function addVertex(array, x, y, ox, oy, tx, ty, sizeData, minzoom, maxzoom, labe
         Math.round(ox * 64),
         Math.round(oy * 64),
 
-        // a_texture_pos
+        // a_data
         tx / 4, // x coordinate of symbol on glyph atlas texture
         ty / 4, // y coordinate of symbol on glyph atlas texture
+        packUint8ToFloat(
+            (labelminzoom || 0) * 10, // labelminzoom
+            labelangle // labelangle
+        ),
+        packUint8ToFloat(
+            (minzoom || 0) * 10, // minzoom
+            Math.min(maxzoom || 25, 25) * 10 // maxzoom
+        ),
 
-        // a_data
-        (labelminzoom || 0) * 10, // labelminzoom
-        labelangle, // labelangle
-        (minzoom || 0) * 10, // minzoom
-        Math.min(maxzoom || 25, 25) * 10, // maxzoom
         // a_size
         sizeData ? sizeData[0] : undefined,
         sizeData ? sizeData[1] : undefined,

src/shaders/symbol_icon.vertex.glsl

@@ -1,6 +1,5 @@
 
 attribute vec4 a_pos_offset;
-attribute vec2 a_texture_pos;
 attribute vec4 a_data;
 
 // icon-size data (see symbol_sdf.vertex.glsl for more)
@@ -32,9 +31,10 @@ void main() {
     vec2 a_pos = a_pos_offset.xy;
     vec2 a_offset = a_pos_offset.zw;
 
-    vec2 a_tex = a_texture_pos.xy;
-    mediump float a_labelminzoom = a_data[0];
-    mediump vec2 a_zoom = a_data.pq;
+    vec2 a_tex = a_data.xy;
+    mediump vec2 label_data = unpack_float(a_data[2]);
+    mediump float a_labelminzoom = label_data[0];
+    mediump vec2 a_zoom = unpack_float(a_data[3]);
     mediump float a_minzoom = a_zoom[0];
     mediump float a_maxzoom = a_zoom[1];
 

src/shaders/symbol_sdf.vertex.glsl

@@ -1,7 +1,6 @@
 const float PI = 3.141592653589793;
 
 attribute vec4 a_pos_offset;
-attribute vec2 a_texture_pos;
 attribute vec4 a_data;
 
 // contents of a_size vary based on the type of property value
@@ -54,9 +53,10 @@ void main() {
     vec2 a_pos = a_pos_offset.xy;
     vec2 a_offset = a_pos_offset.zw;
 
-    vec2 a_tex = a_texture_pos.xy;
-    mediump float a_labelminzoom = a_data[0];
-    mediump vec2 a_zoom = a_data.pq;
+    vec2 a_tex = a_data.xy;
+    mediump vec2 label_data = unpack_float(a_data[2]);
+    mediump float a_labelminzoom = label_data[0];
+    mediump vec2 a_zoom = unpack_float(a_data[3]);
     mediump float a_minzoom = a_zoom[0];
     mediump float a_maxzoom = a_zoom[1];
 
@@ -93,7 +93,7 @@ void main() {
     // pitch-alignment: map
     // rotation-alignment: map | viewport
     if (u_pitch_with_map) {
-        lowp float angle = u_rotate_with_map ? (a_data[1] / 256.0 * 2.0 * PI) : u_bearing;
+        lowp float angle = u_rotate_with_map ? (label_data[1] / 256.0 * 2.0 * PI) : u_bearing;
         lowp float asin = sin(angle);
         lowp float acos = cos(angle);
         mat2 RotationMatrix = mat2(acos, asin, -1.0 * asin, acos);
@@ -109,7 +109,7 @@ void main() {
         // it goes from 0% foreshortening to up to around 70% foreshortening
         lowp float pitchfactor = 1.0 - cos(u_pitch * sin(u_pitch * 0.75));
 
-        lowp float lineangle = a_data[1] / 256.0 * 2.0 * PI;
+        lowp float lineangle = label_data[1] / 256.0 * 2.0 * PI;
 
         // use the lineangle to position points a,b along the line
         // project the points and calculate the label angle in projected space