[core] improve legibility of labels that follow lines

port https://github.com/mapbox/mapbox-gl-js/pull/4781

This improves legibility of labels that follow lines in pitched views.
The previous approach used the limited information in the shader to
calculate put the glyph in approximatelyright place. The new approach
does this more accurately by doing it on the cpu where we have access to
the entire line geometry.

2 files changed, 12 insertions, 26 deletions

diff --git a/test/programs/symbol_program.test.cpp b/test/programs/symbol_program.test.cpp
index ef1e71c269..62a2e58d7b 100644
--- a/test/programs/symbol_program.test.cpp
+++ b/test/programs/symbol_program.test.cpp
@@ -10,7 +10,6 @@ TEST(SymbolProgram, SymbolSizeBinder) {
     EXPECT_EQ(uniformValues.get<uniforms::u_is_size_zoom_constant>().t, true);
     EXPECT_EQ(uniformValues.get<uniforms::u_is_size_feature_constant>().t, true);
     EXPECT_EQ(uniformValues.get<uniforms::u_size>().t, 12.0f);
-    EXPECT_EQ(uniformValues.get<uniforms::u_layout_size>().t, 12.0f);
 
     binder = SymbolSizeBinder::create(1.0f, style::CameraFunction<float>(style::ExponentialStops<float>({
         {0.0f, 8.0f},
@@ -20,7 +19,6 @@ TEST(SymbolProgram, SymbolSizeBinder) {
     EXPECT_EQ(uniformValues.get<uniforms::u_is_size_zoom_constant>().t, false);
     EXPECT_EQ(uniformValues.get<uniforms::u_is_size_feature_constant>().t, true);
     EXPECT_EQ(uniformValues.get<uniforms::u_size>().t, 9.5f);
-    EXPECT_EQ(uniformValues.get<uniforms::u_layout_size>().t, 10.0f);
     
     binder = SymbolSizeBinder::create(0.0f, style::CameraFunction<float>(style::ExponentialStops<float>({
         {1.0f, 8.0f},
@@ -30,7 +28,6 @@ TEST(SymbolProgram, SymbolSizeBinder) {
     EXPECT_EQ(uniformValues.get<uniforms::u_is_size_zoom_constant>().t, false);
     EXPECT_EQ(uniformValues.get<uniforms::u_is_size_feature_constant>().t, true);
     EXPECT_EQ(uniformValues.get<uniforms::u_size>().t, 8.0f);
-    EXPECT_EQ(uniformValues.get<uniforms::u_layout_size>().t, 8.0f);
     
     binder = SymbolSizeBinder::create(12.0f, style::CameraFunction<float>(style::ExponentialStops<float>({
         {1.0f, 8.0f},
@@ -40,7 +37,6 @@ TEST(SymbolProgram, SymbolSizeBinder) {
     EXPECT_EQ(uniformValues.get<uniforms::u_is_size_zoom_constant>().t, false);
     EXPECT_EQ(uniformValues.get<uniforms::u_is_size_feature_constant>().t, true);
     EXPECT_EQ(uniformValues.get<uniforms::u_size>().t, 18.0f);
-    EXPECT_EQ(uniformValues.get<uniforms::u_layout_size>().t, 18.0f);
     
     binder = SymbolSizeBinder::create(0.0f, style::SourceFunction<float>("x", style::ExponentialStops<float>({
         {1.0f, 8.0f},
diff --git a/test/text/quads.test.cpp b/test/text/quads.test.cpp
index efc3912aaa..f24b01ca87 100644
--- a/test/text/quads.test.cpp
+++ b/test/text/quads.test.cpp
@@ -23,10 +23,8 @@ TEST(getIconQuads, normal) {
     Shaping shapedText;
 
     SymbolQuad quad =
-        getIconQuad(anchor, shapedIcon, line, layout, 16.0f, SymbolPlacementType::Point, shapedText);
+        getIconQuad(shapedIcon, layout, 16.0f, shapedText);
 
-    EXPECT_EQ(quad.anchorPoint.x, 2);
-    EXPECT_EQ(quad.anchorPoint.y, 3);
     EXPECT_EQ(quad.tl.x, -14);
     EXPECT_EQ(quad.tl.y, -10);
     EXPECT_EQ(quad.tr.x, 1);
@@ -35,9 +33,6 @@ TEST(getIconQuads, normal) {
     EXPECT_EQ(quad.bl.y, 1);
     EXPECT_EQ(quad.br.x, 1);
     EXPECT_EQ(quad.br.y, 1);
-    EXPECT_EQ(quad.anchorAngle, 0.0f);
-    EXPECT_EQ(quad.glyphAngle, 0.0f);
-    EXPECT_EQ(quad.minScale, 0.5f);
 }
 
 TEST(getIconQuads, style) {
@@ -61,10 +56,8 @@ TEST(getIconQuads, style) {
     {
         SymbolLayoutProperties::Evaluated layout;
         SymbolQuad quad =
-            getIconQuad(anchor, shapedIcon, line, layout, 12.0f, SymbolPlacementType::Point, shapedText);
+            getIconQuad(shapedIcon, layout, 12.0f, shapedText);
 
-        EXPECT_EQ(quad.anchorPoint.x, 0);
-        EXPECT_EQ(quad.anchorPoint.y, 0);
         EXPECT_EQ(quad.tl.x, -19.5);
         EXPECT_EQ(quad.tl.y, -19.5);
         EXPECT_EQ(quad.tr.x, 0.5);
@@ -73,9 +66,6 @@ TEST(getIconQuads, style) {
         EXPECT_EQ(quad.bl.y, 0.5);
         EXPECT_EQ(quad.br.x, 0.5);
         EXPECT_EQ(quad.br.y, 0.5);
-        EXPECT_EQ(quad.anchorAngle, 0.0f);
-        EXPECT_EQ(quad.glyphAngle, 0.0f);
-        EXPECT_EQ(quad.minScale, 0.5f);
     }
 
     // width
@@ -84,7 +74,7 @@ TEST(getIconQuads, style) {
         layout.get<TextSize>() = 24.0f;
         layout.get<IconTextFit>() = IconTextFitType::Width;
         SymbolQuad quad =
-            getIconQuad(anchor, shapedIcon, line, layout, 24.0f, SymbolPlacementType::Point, shapedText);
+            getIconQuad(shapedIcon, layout, 24.0f, shapedText);
 
         EXPECT_EQ(quad.tl.x, -60);
         EXPECT_EQ(quad.tl.y, 0);
@@ -102,7 +92,7 @@ TEST(getIconQuads, style) {
         layout.get<TextSize>() = 12.0f;
         layout.get<IconTextFit>() = IconTextFitType::Width;
         SymbolQuad quad =
-            getIconQuad(anchor, shapedIcon, line, layout, 12.0f, SymbolPlacementType::Point, shapedText);
+            getIconQuad(shapedIcon, layout, 12.0f, shapedText);
 
         EXPECT_EQ(quad.tl.x, -30);
         EXPECT_EQ(quad.tl.y, -5);
@@ -124,7 +114,7 @@ TEST(getIconQuads, style) {
         layout.get<IconTextFitPadding>()[2] = 5.0f;
         layout.get<IconTextFitPadding>()[3] = 10.0f;
         SymbolQuad quad =
-            getIconQuad(anchor, shapedIcon, line, layout, 12.0f, SymbolPlacementType::Point, shapedText);
+            getIconQuad(shapedIcon, layout, 12.0f, shapedText);
 
         EXPECT_EQ(quad.tl.x, -40);
         EXPECT_EQ(quad.tl.y, -10);
@@ -142,7 +132,7 @@ TEST(getIconQuads, style) {
         layout.get<TextSize>() = 24.0f;
         layout.get<IconTextFit>() = IconTextFitType::Height;
         SymbolQuad quad =
-            getIconQuad(anchor, shapedIcon, line, layout, 24.0f, SymbolPlacementType::Point, shapedText);
+            getIconQuad(shapedIcon, layout, 24.0f, shapedText);
 
         EXPECT_EQ(quad.tl.x, -30);
         EXPECT_EQ(quad.tl.y, -10);
@@ -160,7 +150,7 @@ TEST(getIconQuads, style) {
         layout.get<TextSize>() = 12.0f;
         layout.get<IconTextFit>() = IconTextFitType::Height;
         SymbolQuad quad =
-            getIconQuad(anchor, shapedIcon, line, layout, 12.0f, SymbolPlacementType::Point, shapedText);
+            getIconQuad(shapedIcon, layout, 12.0f, shapedText);
 
         EXPECT_EQ(quad.tl.x, -20);
         EXPECT_EQ(quad.tl.y, -5);
@@ -182,7 +172,7 @@ TEST(getIconQuads, style) {
         layout.get<IconTextFitPadding>()[2] = 5.0f;
         layout.get<IconTextFitPadding>()[3] = 10.0f;
         SymbolQuad quad =
-            getIconQuad(anchor, shapedIcon, line, layout, 12.0f, SymbolPlacementType::Point, shapedText);
+            getIconQuad(shapedIcon, layout, 12.0f, shapedText);
 
         EXPECT_EQ(quad.tl.x, -30);
         EXPECT_EQ(quad.tl.y, -10);
@@ -200,7 +190,7 @@ TEST(getIconQuads, style) {
         layout.get<TextSize>() = 24.0f;
         layout.get<IconTextFit>() = IconTextFitType::Both;
         SymbolQuad quad =
-            getIconQuad(anchor, shapedIcon, line, layout, 24.0f, SymbolPlacementType::Point, shapedText);
+            getIconQuad(shapedIcon, layout, 24.0f, shapedText);
 
         EXPECT_EQ(quad.tl.x, -60);
         EXPECT_EQ(quad.tl.y, -10);
@@ -218,7 +208,7 @@ TEST(getIconQuads, style) {
         layout.get<TextSize>() = 12.0f;
         layout.get<IconTextFit>() = IconTextFitType::Both;
         SymbolQuad quad =
-            getIconQuad(anchor, shapedIcon, line, layout, 12.0f, SymbolPlacementType::Point, shapedText);
+            getIconQuad(shapedIcon, layout, 12.0f, shapedText);
 
         EXPECT_EQ(quad.tl.x, -30);
         EXPECT_EQ(quad.tl.y, -5);
@@ -240,7 +230,7 @@ TEST(getIconQuads, style) {
         layout.get<IconTextFitPadding>()[2] = 5.0f;
         layout.get<IconTextFitPadding>()[3] = 10.0f;
         SymbolQuad quad =
-            getIconQuad(anchor, shapedIcon, line, layout, 12.0f, SymbolPlacementType::Point, shapedText);
+            getIconQuad(shapedIcon, layout, 12.0f, shapedText);
 
         EXPECT_EQ(quad.tl.x, -40);
         EXPECT_EQ(quad.tl.y, -10);
@@ -262,7 +252,7 @@ TEST(getIconQuads, style) {
         layout.get<IconTextFitPadding>()[2] = 10.0f;
         layout.get<IconTextFitPadding>()[3] = 15.0f;
         SymbolQuad quad =
-            getIconQuad(anchor, shapedIcon, line, layout, 12.0f, SymbolPlacementType::Point, shapedText);
+            getIconQuad(shapedIcon, layout, 12.0f, shapedText);
 
         EXPECT_EQ(quad.tl.x, -45);
         EXPECT_EQ(quad.tl.y, -5);