1 files changed, 53 insertions, 44 deletions

diff --git a/src/mbgl/shaders/symbol_icon.cpp b/src/mbgl/shaders/symbol_icon.cpp
index bc570cf361..f5c2bbe22d 100644
--- a/src/mbgl/shaders/symbol_icon.cpp
+++ b/src/mbgl/shaders/symbol_icon.cpp
@@ -7,17 +7,22 @@ namespace shaders {
 
 const char* symbol_icon::name = "symbol_icon";
 const char* symbol_icon::vertexSource = R"MBGL_SHADER(
+const float PI = 3.141592653589793;
 
 attribute vec4 a_pos_offset;
 attribute vec4 a_data;
+attribute vec3 a_projected_pos;
+attribute float a_fade_opacity;
 
-// icon-size data (see symbol_sdf.vertex.glsl for more)
-attribute vec3 a_size;
 uniform bool u_is_size_zoom_constant;
 uniform bool u_is_size_feature_constant;
-uniform mediump float u_size_t; // used to interpolate between zoom stops when size is a composite function
-uniform mediump float u_size; // used when size is both zoom and feature constant
-uniform mediump float u_layout_size; // used when size is feature constant
+uniform highp float u_size_t; // used to interpolate between zoom stops when size is a composite function
+uniform highp float u_size; // used when size is both zoom and feature constant
+uniform highp float u_camera_to_center_distance;
+uniform highp float u_pitch;
+uniform bool u_rotate_symbol;
+uniform highp float u_aspect_ratio;
+uniform float u_fade_change;
 
 
 #ifndef HAS_UNIFORM_u_opacity
@@ -28,84 +33,86 @@ varying lowp float opacity;
 uniform lowp float u_opacity;
 #endif
 
-// matrix is for the vertex position.
+
 uniform mat4 u_matrix;
+uniform mat4 u_label_plane_matrix;
+uniform mat4 u_gl_coord_matrix;
 
 uniform bool u_is_text;
-uniform mediump float u_zoom;
-uniform bool u_rotate_with_map;
-uniform vec2 u_extrude_scale;
+uniform bool u_pitch_with_map;
 
 uniform vec2 u_texsize;
 
 varying vec2 v_tex;
-varying vec2 v_fade_tex;
+varying float v_fade_opacity;
 
 void main() {
-
+    
 #ifndef HAS_UNIFORM_u_opacity
     opacity = unpack_mix_vec2(a_opacity, a_opacity_t);
 #else
     lowp float opacity = u_opacity;
 #endif
 
+
     vec2 a_pos = a_pos_offset.xy;
     vec2 a_offset = a_pos_offset.zw;
 
     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];
+    vec2 a_size = a_data.zw;
+
+    highp float segment_angle = -a_projected_pos[2];
 
     float size;
-    // In order to accommodate placing labels around corners in
-    // symbol-placement: line, each glyph in a label could have multiple
-    // "quad"s only one of which should be shown at a given zoom level.
-    // The min/max zoom assigned to each quad is based on the font size at
-    // the vector tile's zoom level, which might be different than at the
-    // currently rendered zoom level if text-size is zoom-dependent.
-    // Thus, we compensate for this difference by calculating an adjustment
-    // based on the scale of rendered text size relative to layout text size.
-    mediump float layoutSize;
     if (!u_is_size_zoom_constant && !u_is_size_feature_constant) {
         size = mix(a_size[0], a_size[1], u_size_t) / 10.0;
-        layoutSize = a_size[2] / 10.0;
     } else if (u_is_size_zoom_constant && !u_is_size_feature_constant) {
         size = a_size[0] / 10.0;
-        layoutSize = size;
     } else if (!u_is_size_zoom_constant && u_is_size_feature_constant) {
         size = u_size;
-        layoutSize = u_layout_size;
     } else {
         size = u_size;
-        layoutSize = u_size;
     }
 
+    vec4 projectedPoint = u_matrix * vec4(a_pos, 0, 1);
+    highp float camera_to_anchor_distance = projectedPoint.w;
+    // See comments in symbol_sdf.vertex
+    highp float distance_ratio = u_pitch_with_map ?
+        camera_to_anchor_distance / u_camera_to_center_distance :
+        u_camera_to_center_distance / camera_to_anchor_distance;
+    highp float perspective_ratio = 0.5 + 0.5 * distance_ratio;
+
+    size *= perspective_ratio;
+
     float fontScale = u_is_text ? size / 24.0 : size;
 
-    mediump float zoomAdjust = log2(size / layoutSize);
-    mediump float adjustedZoom = (u_zoom - zoomAdjust) * 10.0;
-    // result: z = 0 if a_minzoom <= adjustedZoom < a_maxzoom, and 1 otherwise
-    mediump float z = 2.0 - step(a_minzoom, adjustedZoom) - (1.0 - step(a_maxzoom, adjustedZoom));
+    highp float symbol_rotation = 0.0;
+    if (u_rotate_symbol) {
+        // See comments in symbol_sdf.vertex
+        vec4 offsetProjectedPoint = u_matrix * vec4(a_pos + vec2(1, 0), 0, 1);
 
-    vec2 extrude = fontScale * u_extrude_scale * (a_offset / 64.0);
-    if (u_rotate_with_map) {
-        gl_Position = u_matrix * vec4(a_pos + extrude, 0, 1);
-        gl_Position.z += z * gl_Position.w;
-    } else {
-        gl_Position = u_matrix * vec4(a_pos, 0, 1) + vec4(extrude, 0, 0);
+        vec2 a = projectedPoint.xy / projectedPoint.w;
+        vec2 b = offsetProjectedPoint.xy / offsetProjectedPoint.w;
+
+        symbol_rotation = atan((b.y - a.y) / u_aspect_ratio, b.x - a.x);
     }
 
+    highp float angle_sin = sin(segment_angle + symbol_rotation);
+    highp float angle_cos = cos(segment_angle + symbol_rotation);
+    mat2 rotation_matrix = mat2(angle_cos, -1.0 * angle_sin, angle_sin, angle_cos);
+
+    vec4 projected_pos = u_label_plane_matrix * vec4(a_projected_pos.xy, 0.0, 1.0);
+    gl_Position = u_gl_coord_matrix * vec4(projected_pos.xy / projected_pos.w + rotation_matrix * (a_offset / 64.0 * fontScale), 0.0, 1.0);
+
     v_tex = a_tex / u_texsize;
-    v_fade_tex = vec2(a_labelminzoom / 255.0, 0.0);
+    vec2 fade_opacity = unpack_opacity(a_fade_opacity);
+    float fade_change = fade_opacity[1] > 0.5 ? u_fade_change : -u_fade_change;
+    v_fade_opacity = max(0.0, min(1.0, fade_opacity[0] + fade_change));
 }
 
 )MBGL_SHADER";
 const char* symbol_icon::fragmentSource = R"MBGL_SHADER(
 uniform sampler2D u_texture;
-uniform sampler2D u_fadetexture;
 
 
 #ifndef HAS_UNIFORM_u_opacity
@@ -114,16 +121,18 @@ varying lowp float opacity;
 uniform lowp float u_opacity;
 #endif
 
+
 varying vec2 v_tex;
-varying vec2 v_fade_tex;
+varying float v_fade_opacity;
 
 void main() {
-
+    
 #ifdef HAS_UNIFORM_u_opacity
     lowp float opacity = u_opacity;
 #endif
 
-    lowp float alpha = texture2D(u_fadetexture, v_fade_tex).a * opacity;
+
+    lowp float alpha = opacity * v_fade_opacity;
     gl_FragColor = texture2D(u_texture, v_tex) * alpha;
 
 #ifdef OVERDRAW_INSPECTOR