From 041bfdfd5522923fcb5edb361a93587baf36ee82 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Theo=20M=C3=BCller?= <theo.paul.mueller@googlemail.com>
Date: Fri, 1 Feb 2019 20:19:15 +0100
Subject: [PATCH] Make anti-aliasing work with invert

---
 shaders/graph/1.frag |  6 ++----
 shaders/graph/4.frag | 22 ++++++++++++++++++++++
 2 files changed, 24 insertions(+), 4 deletions(-)
 create mode 100644 shaders/graph/4.frag

diff --git a/shaders/graph/1.frag b/shaders/graph/1.frag
index 9b82d05..b52423f 100644
--- a/shaders/graph/1.frag
+++ b/shaders/graph/1.frag
@@ -107,11 +107,9 @@ void render_side(in sampler1D tex, float idx) {
     float s = get_line_height(tex, idx);
 
     /* and finally set fragment color if we are in range */
-    #if INVERT > 0
-    float pos = float(screen.y) - gl_FragCoord.y;
-    #else
+
     float pos = gl_FragCoord.y;
-    #endif
+
     if (pos + 1.5 <= s) {
         fragment = COLOR;
     } else {
diff --git a/shaders/graph/4.frag b/shaders/graph/4.frag
new file mode 100644
index 0000000..4630153
--- /dev/null
+++ b/shaders/graph/4.frag
@@ -0,0 +1,22 @@
+
+in vec4 gl_FragCoord;
+
+#request uniform "screen" screen
+uniform ivec2 screen; /* screen dimensions */
+
+#request uniform "prev" tex
+uniform sampler2D tex;    /* screen texture    */
+
+out vec4 fragment; /* output */
+
+#include "@graph.glsl"
+#include ":graph.glsl"
+
+void main() {
+    float newy = gl_FragCoord.y;
+    #if INVERT > 0
+    newy = float(screen.y + 1) - newy;
+    #endif
+
+    fragment = texelFetch(tex, ivec2(gl_FragCoord.x, newy), 0);
+}