1 files changed, 30 insertions, 0 deletions
diff --git a/themes/src/_shaders/snowflake.vert b/themes/src/_shaders/snowflake.vert
new file mode 100644
index 0000000..7cbfb99
--- /dev/null
+++ b/themes/src/_shaders/snowflake.vert
@@ -0,0 +1,30 @@
+// Instanced snowflake vertex shader
+attribute vec2 position;        // Base quad vertex position
+attribute vec2 instancePos;     // Per-instance: snowflake center position
+attribute float instanceRot;    // Per-instance: rotation angle
+attribute float instanceScale;  // Per-instance: size scale
+attribute float instanceSeed;   // Per-instance: random seed for variation
+
+uniform mat4 projection;
+uniform mat4 model;
+
+varying lowp vec2 vUV;           // UV coordinates for fragment shader
+varying lowp float vSeed;        // Pass seed to fragment shader
+varying lowp float vScale;       // Pass scale to fragment shader
+
+void main() {
+    // Rotate and scale the base quad
+    float c = cos(instanceRot);
+    float s = sin(instanceRot);
+    mat2 rotation = mat2(c, s, -s, c);
+
+    vec2 rotatedPos = rotation * (position * instanceScale);
+    vec2 worldPos = instancePos + rotatedPos;
+
+    gl_Position = projection * model * vec4(worldPos, 0.0, 1.0);
+
+    // Pass UV in range [-1, 1] for procedural generation
+    vUV = position;
+    vSeed = instanceSeed;
+    vScale = instanceScale;
+}