From 765a1e9710d8e2f61556a057bf324ffab48db071 Mon Sep 17 00:00:00 2001
From: Peter Spackman <peterspackman@fastmail.com>
Date: Thu, 29 Aug 2024 14:25:41 +0800
Subject: [PATCH] Fix fringes of text rendering

---
 shaders/billboard.frag               | 9 +++++++++
 src/graphics/scene.cpp               | 1 +
 src/graphics/signed_distance_field.h | 1 +
 3 files changed, 11 insertions(+)

diff --git a/shaders/billboard.frag b/shaders/billboard.frag
index 2f9bb0f..d73a27b 100644
--- a/shaders/billboard.frag
+++ b/shaders/billboard.frag
@@ -12,6 +12,8 @@ uniform float u_textSDFOutline;
 
 void main()
 {
+    vec2 clampedTexCoord = clamp(v_texcoord, 0.0, 1.0);
+
     float distance = texture(u_texture, v_texcoord).r;
     distance -= u_textSDFBuffer;
     float smoothing = u_textSDFSmoothing * fwidth(distance);
@@ -21,10 +23,17 @@ void main()
                                     distance);
     vec3 color = mix(u_textOutlineColor, u_textColor, textAlpha);
     float alpha = max(textAlpha, outlineAlpha);
+
+    // Additional alpha fade near texture edges
+    vec2 edgeDistance = min(clampedTexCoord, 1.0 - clampedTexCoord);
+    float edgeFade = smoothstep(0.0, 0.02, min(edgeDistance.x, edgeDistance.y));
+    alpha *= edgeFade;
+
     fragColor = vec4(color, alpha);
 
     // Discard nearly transparent fragments
     if (alpha < 0.01) {
         discard;
     }
+
 }
diff --git a/src/graphics/scene.cpp b/src/graphics/scene.cpp
index 467b317..29af5a1 100644
--- a/src/graphics/scene.cpp
+++ b/src/graphics/scene.cpp
@@ -44,6 +44,7 @@ void Scene::init() {
 
   screenGammaChanged();
   materialChanged();
+  textSettingsChanged();
   lightSettingsChanged();
 
   if (m_structure) {
diff --git a/src/graphics/signed_distance_field.h b/src/graphics/signed_distance_field.h
index bac5985..72970a6 100644
--- a/src/graphics/signed_distance_field.h
+++ b/src/graphics/signed_distance_field.h
@@ -31,6 +31,7 @@ QImage eigenMatrixToQImage(const Eigen::MatrixXf& matrix) {
     int height = matrix.rows();
     int width = matrix.cols();
     QImage result(width, height, QImage::Format_Grayscale8);
+    result.fill(Qt::white);
 
     float minVal = matrix.minCoeff();
     float maxVal = matrix.maxCoeff();