HiSilicon fix: software clipping of polygon outlines

maplibre · May 20, 2024 · 98167ba · 98167ba
1 parent 266897d
commit 98167ba
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Showing 4 changed files with 34 additions and 1 deletion.
diff --git a/src/shaders/fill_outline.fragment.glsl b/src/shaders/fill_outline.fragment.glsl
@@ -1,4 +1,7 @@
 in vec2 v_pos;
+#ifdef GLOBE
+in float v_depth;
+#endif
 
 #pragma mapbox: define highp vec4 outline_color
 #pragma mapbox: define lowp float opacity
@@ -11,6 +14,15 @@ void main() {
     float alpha = 1.0 - smoothstep(0.0, 1.0, dist);
     fragColor = outline_color * (alpha * opacity);
 
+    #ifdef GLOBE
+    if (v_depth > 1.0) {
+        // Hides polygon outlines that are visible on the backfacing side of the globe.
+        // This is needed, because some hardware seems to apply glDepthRange first and then apply clipping, which is the wrong order.
+        // Other layers fix this by using backface culling, but that is unavailable for line primitives, so we clip the lines in software here.
+        discard;
+    }
+    #endif
+
 #ifdef OVERDRAW_INSPECTOR
     fragColor = vec4(1.0);
 #endif

diff --git a/src/shaders/fill_outline.vertex.glsl b/src/shaders/fill_outline.vertex.glsl
@@ -4,6 +4,9 @@ uniform vec2 u_fill_translate;
 in vec2 a_pos;
 
 out vec2 v_pos;
+#ifdef GLOBE
+out float v_depth;
+#endif
 
 #pragma mapbox: define highp vec4 outline_color
 #pragma mapbox: define lowp float opacity
@@ -15,4 +18,7 @@ void main() {
     gl_Position = projectTile(a_pos + u_fill_translate);
 
     v_pos = (gl_Position.xy / gl_Position.w + 1.0) / 2.0 * u_world;
+    #ifdef GLOBE
+    v_depth = gl_Position.z / gl_Position.w;
+    #endif
 }
diff --git a/src/shaders/fill_outline_pattern.fragment.glsl b/src/shaders/fill_outline_pattern.fragment.glsl
@@ -6,6 +6,9 @@ uniform float u_fade;
 in vec2 v_pos_a;
 in vec2 v_pos_b;
 in vec2 v_pos;
+#ifdef GLOBE
+in float v_depth;
+#endif
 
 #pragma mapbox: define lowp float opacity
 #pragma mapbox: define lowp vec4 pattern_from
@@ -34,9 +37,15 @@ void main() {
     float dist = length(v_pos - gl_FragCoord.xy);
     float alpha = 1.0 - smoothstep(0.0, 1.0, dist);
 
-
     fragColor = mix(color1, color2, u_fade) * alpha * opacity;
 
+    #ifdef GLOBE
+    if (v_depth > 1.0) {
+        // See comment in fill_outline.fragment.glsl
+        discard;
+    }
+    #endif
+
 #ifdef OVERDRAW_INSPECTOR
     fragColor = vec4(1.0);
 #endif

diff --git a/src/shaders/fill_outline_pattern.vertex.glsl b/src/shaders/fill_outline_pattern.vertex.glsl
@@ -9,6 +9,9 @@ in vec2 a_pos;
 out vec2 v_pos_a;
 out vec2 v_pos_b;
 out vec2 v_pos;
+#ifdef GLOBE
+out float v_depth;
+#endif
 
 #pragma mapbox: define lowp float opacity
 #pragma mapbox: define lowp vec4 pattern_from
@@ -41,4 +44,7 @@ void main() {
     v_pos_b = get_pattern_pos(u_pixel_coord_upper, u_pixel_coord_lower, toScale * display_size_b, tileRatio, a_pos);
 
     v_pos = (gl_Position.xy / gl_Position.w + 1.0) / 2.0 * u_world;
+    #ifdef GLOBE
+    v_depth = gl_Position.z / gl_Position.w;
+    #endif
 }