[core] Port "combine line-width and line-gap-width in shader"

https://github.com/mapbox/mapbox-gl-shaders/commit/a9559e911b11a155135888f733a96e5110f8cef6
https://github.com/mapbox/mapbox-gl-js/commit/fcb9bcebae6e00f24ebfde8d7ec09adb95f6b1a3

4 files changed, 18 insertions, 26 deletions

diff --git a/src/mbgl/renderer/painter_line.cpp b/src/mbgl/renderer/painter_line.cpp
index f1f8403a42..e0592b4bc1 100644
--- a/src/mbgl/renderer/painter_line.cpp
+++ b/src/mbgl/renderer/painter_line.cpp
@@ -33,20 +33,6 @@ void Painter::renderLine(LineBucket& bucket,
     bool wireframe = frame.debugOptions & MapDebugOptions::Wireframe;
 
     float blur = properties.lineBlur + antialiasing;
-    float edgeWidth = wireframe ? 1 : properties.lineWidth / 2.0;
-    float inset = -1;
-    float offset = 0;
-    float shift = 0;
-
-    if (properties.lineGapWidth != 0 && !wireframe) {
-        inset = properties.lineGapWidth / 2.0 + antialiasing * 0.5;
-        edgeWidth = properties.lineWidth;
-
-        // shift outer lines half a pixel towards the middle to eliminate the crack
-        offset = inset - antialiasing / 2.0;
-    }
-
-    float outset = offset + edgeWidth + antialiasing / 2.0 + shift;
 
     Color color = {{ 1.0f, 1.0f, 1.0f, 1.0f }};
     float opacity = 1.0f;
@@ -78,8 +64,9 @@ void Painter::renderLine(LineBucket& bucket,
         config.program = linesdfShader->getID();
 
         linesdfShader->u_matrix = vtxMatrix;
-        linesdfShader->u_exmatrix = extrudeMatrix;
-        linesdfShader->u_linewidth = {{ outset, inset }};
+        linesdfShader->u_linewidth = properties.lineWidth / 2;
+        linesdfShader->u_gapwidth = properties.lineGapWidth / 2;
+        linesdfShader->u_antialiasing = antialiasing / 2;
         linesdfShader->u_ratio = ratio;
         linesdfShader->u_blur = blur;
         linesdfShader->u_color = color;
@@ -122,8 +109,9 @@ void Painter::renderLine(LineBucket& bucket,
         config.program = linepatternShader->getID();
 
         linepatternShader->u_matrix = vtxMatrix;
-        linepatternShader->u_exmatrix = extrudeMatrix;
-        linepatternShader->u_linewidth = {{ outset, inset }};
+        linepatternShader->u_linewidth = properties.lineWidth / 2;
+        linepatternShader->u_gapwidth = properties.lineGapWidth / 2;
+        linepatternShader->u_antialiasing = antialiasing / 2;
         linepatternShader->u_ratio = ratio;
         linepatternShader->u_blur = blur;
 
@@ -157,8 +145,9 @@ void Painter::renderLine(LineBucket& bucket,
         config.program = lineShader->getID();
 
         lineShader->u_matrix = vtxMatrix;
-        lineShader->u_exmatrix = extrudeMatrix;
-        lineShader->u_linewidth = {{ outset, inset }};
+        lineShader->u_linewidth = properties.lineWidth / 2;
+        lineShader->u_gapwidth = properties.lineGapWidth / 2;
+        lineShader->u_antialiasing = antialiasing / 2;
         lineShader->u_ratio = ratio;
         lineShader->u_blur = blur;
         lineShader->u_extra = extra;
diff --git a/src/mbgl/shader/line_shader.hpp b/src/mbgl/shader/line_shader.hpp
index 4a6d86381c..7e38db1656 100644
--- a/src/mbgl/shader/line_shader.hpp
+++ b/src/mbgl/shader/line_shader.hpp
@@ -12,11 +12,12 @@ public:
     void bind(GLbyte *offset) final;
 
     UniformMatrix<4>                 u_matrix    = {"u_matrix",    *this};
-    UniformMatrix<4>                 u_exmatrix  = {"u_exmatrix",  *this};
     Uniform<std::array<GLfloat, 4>>  u_color     = {"u_color",     *this};
     Uniform<GLfloat>                 u_opacity   = {"u_opacity",   *this};
-    Uniform<std::array<GLfloat, 2>>  u_linewidth = {"u_linewidth", *this};
     Uniform<GLfloat>                 u_ratio     = {"u_ratio",     *this};
+    Uniform<GLfloat>                 u_linewidth = {"u_linewidth", *this};
+    Uniform<GLfloat>                 u_gapwidth  = {"u_gapwidth",  *this};
+    Uniform<GLfloat>                 u_antialiasing = {"u_antialiasing",  *this};
     Uniform<GLfloat>                 u_blur      = {"u_blur",      *this};
     Uniform<GLfloat>                 u_extra     = {"u_extra",     *this};
     Uniform<GLfloat>                 u_offset    = {"u_offset",    *this};
diff --git a/src/mbgl/shader/linepattern_shader.hpp b/src/mbgl/shader/linepattern_shader.hpp
index 98280af971..3cb91eae9d 100644
--- a/src/mbgl/shader/linepattern_shader.hpp
+++ b/src/mbgl/shader/linepattern_shader.hpp
@@ -12,8 +12,9 @@ public:
     void bind(GLbyte *offset) final;
 
     UniformMatrix<4>                u_matrix         = {"u_matrix",         *this};
-    UniformMatrix<4>                u_exmatrix       = {"u_exmatrix",       *this};
-    Uniform<std::array<GLfloat, 2>> u_linewidth      = {"u_linewidth",      *this};
+    Uniform<GLfloat>                u_linewidth      = {"u_linewidth",      *this};
+    Uniform<GLfloat>                u_gapwidth       = {"u_gapwidth",       *this};
+    Uniform<GLfloat>                u_antialiasing   = {"u_antialiasing",   *this};
     Uniform<std::array<GLfloat, 2>> u_pattern_size_a = {"u_pattern_size_a", *this};
     Uniform<std::array<GLfloat, 2>> u_pattern_tl_a   = {"u_pattern_tl_a",   *this};
     Uniform<std::array<GLfloat, 2>> u_pattern_br_a   = {"u_pattern_br_a",   *this};
diff --git a/src/mbgl/shader/linesdf_shader.hpp b/src/mbgl/shader/linesdf_shader.hpp
index 65d8e74b3a..8465952dac 100644
--- a/src/mbgl/shader/linesdf_shader.hpp
+++ b/src/mbgl/shader/linesdf_shader.hpp
@@ -12,10 +12,11 @@ public:
     void bind(GLbyte *offset) final;
 
     UniformMatrix<4>                 u_matrix    = {"u_matrix",    *this};
-    UniformMatrix<4>                 u_exmatrix  = {"u_exmatrix",  *this};
     Uniform<std::array<GLfloat, 4>>  u_color     = {"u_color",     *this};
     Uniform<GLfloat>                 u_opacity   = {"u_opacity",   *this};
-    Uniform<std::array<GLfloat, 2>>  u_linewidth = {"u_linewidth", *this};
+    Uniform<GLfloat>                 u_linewidth = {"u_linewidth", *this};
+    Uniform<GLfloat>                 u_gapwidth  = {"u_gapwidth",  *this};
+    Uniform<GLfloat>                 u_antialiasing = {"u_antialiasing",  *this};
     Uniform<GLfloat>                 u_ratio     = {"u_ratio",     *this};
     Uniform<GLfloat>                 u_blur      = {"u_blur",      *this};
     Uniform<std::array<GLfloat, 2>>  u_patternscale_a = { "u_patternscale_a", *this};