implement functions for line-image

2 files changed, 19 insertions, 12 deletions

diff --git a/src/mbgl/shader/linepattern.fragment.glsl b/src/mbgl/shader/linepattern.fragment.glsl
index 45be7c8c2f..08feff4396 100644
--- a/src/mbgl/shader/linepattern.fragment.glsl
+++ b/src/mbgl/shader/linepattern.fragment.glsl
@@ -2,9 +2,12 @@ uniform vec2 u_linewidth;
 uniform float u_point;
 uniform float u_blur;
 
-uniform vec2 u_pattern_size;
-uniform vec2 u_pattern_tl;
-uniform vec2 u_pattern_br;
+uniform vec2 u_pattern_size_a;
+uniform vec2 u_pattern_tl_a;
+uniform vec2 u_pattern_br_a;
+uniform vec2 u_pattern_size_b;
+uniform vec2 u_pattern_tl_b;
+uniform vec2 u_pattern_br_b;
 uniform float u_fade;
 uniform float u_opacity;
 
@@ -24,13 +27,14 @@ void main() {
     // (v_linewidth.s)
     float alpha = clamp(min(dist - (u_linewidth.t - u_blur), u_linewidth.s - dist) / u_blur, 0.0, 1.0);
 
-    float x = mod(v_linesofar / u_pattern_size.x, 1.0);
-    float y = 0.5 + (v_normal.y * u_linewidth.s / u_pattern_size.y);
-    vec2 pos = mix(u_pattern_tl, u_pattern_br, vec2(x, y));
-    float x2 = mod(x * 2.0, 1.0);
-    vec2 pos2 = mix(u_pattern_tl, u_pattern_br, vec2(x2, y));
+    float x_a = mod(v_linesofar / u_pattern_size_a.x, 1.0);
+    float y_a = 0.5 + (v_normal.y * u_linewidth.s / u_pattern_size_a.y);
+    vec2 pos_a = mix(u_pattern_tl_a, u_pattern_br_a, vec2(x_a, y_a));
+    float x_b = mod(v_linesofar / u_pattern_size_b.x, 1.0);
+    float y_b = 0.5 + (v_normal.y * u_linewidth.s / u_pattern_size_b.y);
+    vec2 pos_b = mix(u_pattern_tl_b, u_pattern_br_b, vec2(x_b, y_b));
 
-    vec4 color = texture2D(u_image, pos) * (1.0 - u_fade) + u_fade * texture2D(u_image, pos2);
+    vec4 color = mix(texture2D(u_image, pos_a), texture2D(u_image, pos_b), u_fade);
 
     alpha *= u_opacity;
 
diff --git a/src/mbgl/shader/linepattern_shader.hpp b/src/mbgl/shader/linepattern_shader.hpp
index 388cff17d2..16d9ff8be7 100644
--- a/src/mbgl/shader/linepattern_shader.hpp
+++ b/src/mbgl/shader/linepattern_shader.hpp
@@ -15,9 +15,12 @@ public:
     UniformMatrix<4>              u_matrix       = {"u_matrix",       *this};
     UniformMatrix<4>              u_exmatrix     = {"u_exmatrix",     *this};
     Uniform<std::array<float, 2>> u_linewidth    = {"u_linewidth",    *this};
-    Uniform<std::array<float, 2>> u_pattern_size = {"u_pattern_size", *this};
-    Uniform<std::array<float, 2>> u_pattern_tl   = {"u_pattern_tl",   *this};
-    Uniform<std::array<float, 2>> u_pattern_br   = {"u_pattern_br",   *this};
+    Uniform<std::array<float, 2>> u_pattern_size_a = {"u_pattern_size_a", *this};
+    Uniform<std::array<float, 2>> u_pattern_tl_a   = {"u_pattern_tl_a",   *this};
+    Uniform<std::array<float, 2>> u_pattern_br_a   = {"u_pattern_br_a",   *this};
+    Uniform<std::array<float, 2>> u_pattern_size_b = {"u_pattern_size_b", *this};
+    Uniform<std::array<float, 2>> u_pattern_tl_b   = {"u_pattern_tl_b",   *this};
+    Uniform<std::array<float, 2>> u_pattern_br_b   = {"u_pattern_br_b",   *this};
     Uniform<float>                u_ratio        = {"u_ratio",        *this};
     Uniform<float>                u_point        = {"u_point",        *this};
     Uniform<float>                u_blur         = {"u_blur",         *this};