1 files changed, 27 insertions, 0 deletions
diff --git a/shaders/circles.fs b/shaders/circles.fs
new file mode 100644
index 0000000..5d504d8
--- /dev/null
+++ b/shaders/circles.fs
@@ -0,0 +1,27 @@
+#version 330
+
+// Input vertex attributes (from vertex shader)
+in vec2 fragTexCoord;
+in vec4 fragColor;
+
+// Output fragment color
+out vec4 finalColor;
+
+void main()
+{
+    float radius = 0.1;
+    vec2 distance_from_center = fragTexCoord - vec2(0.5);
+// s <= 0 -> inside circle
+// s > 0  -> outside circle
+    if (length(distance_from_center) <= 0.5) {
+        float s = length(distance_from_center) - radius;
+        if (s <= 0) {
+            finalColor = fragColor*1.5;
+        } else {
+            float t = 1 - s / (0.5 - radius);
+            finalColor = vec4(fragColor.xyz, t*t);
+        }
+    } else {
+        finalColor = vec4(0);
+    }
+}