6 files changed, 196 insertions, 10 deletions
diff --git a/themes/src/_shaders/grass.frag b/themes/src/_shaders/grass.frag
new file mode 100644
index 0000000..a72f078
--- /dev/null
+++ b/themes/src/_shaders/grass.frag
@@ -0,0 +1,11 @@
+varying lowp vec2 vUV;
+
+void main() {
+    lowp float halfWidth = 0.5 * (1.0 - vUV.y);
+    lowp float distFromCenter = abs(vUV.x - 0.5);
+    if (distFromCenter > halfWidth) discard;
+
+    lowp vec3 baseColor = vec3(0.15, 0.45, 0.10);
+    lowp vec3 tipColor  = vec3(0.40, 0.75, 0.20);
+    gl_FragColor = vec4(mix(baseColor, tipColor, vUV.y), 1.0);
+}
diff --git a/themes/src/_shaders/grass.vert b/themes/src/_shaders/grass.vert
new file mode 100644
index 0000000..0cf0285
--- /dev/null
+++ b/themes/src/_shaders/grass.vert
@@ -0,0 +1,25 @@
+attribute vec2 position;        // Local quad vertex: x in [-0.5, 0.5], y in [0, 1]
+attribute vec3 instancePos;     // Per-instance: world-space base of blade
+attribute float instancePhase;  // Per-instance: random phase offset for sway
+attribute float instanceHeight; // Per-instance: height scale multiplier
+
+uniform mat4 projection;
+uniform mat4 view;
+uniform float time;
+uniform float bladeWidth;
+uniform float bladeHeight;
+uniform float swayAmount;
+
+varying lowp vec2 vUV;
+
+void main() {
+    vec3 cameraRight = vec3(view[0][0], view[1][0], view[2][0]);
+    float h = bladeHeight * instanceHeight;
+    float sway = sin(time * 1.5 + instancePhase) * swayAmount * position.y;
+    vec3 worldPos = instancePos
+                  + cameraRight * (position.x + sway) * bladeWidth
+                  + vec3(0.0, 1.0, 0.0) * position.y * h;
+
+    gl_Position = projection * view * vec4(worldPos, 1.0);
+    vUV = vec2(position.x + 0.5, position.y);
+}
diff --git a/themes/src/_shaders/snowflake.frag b/themes/src/_shaders/snowflake.frag
new file mode 100644
index 0000000..d887cf5
--- /dev/null
+++ b/themes/src/_shaders/snowflake.frag
@@ -0,0 +1,73 @@
+// Procedural star fragment shader
+varying lowp vec2 vUV;
+varying lowp float vSeed;
+varying lowp float vScale;
+
+const lowp float PI = 3.14159265359;
+
+// Simple hash function for deterministic randomness
+lowp float hash(lowp float n) {
+    return fract(sin(n) * 43758.5453123);
+}
+
+// Generate star pattern procedurally
+lowp float starPattern(lowp vec2 uv) {
+    lowp float dist = length(uv);
+    lowp float angle = atan(uv.y, uv.x);
+
+    // Number of star points (4 or 5)
+    lowp float numPoints = 4.0 + floor(hash(vSeed) * 2.0);
+
+    // Create sharp star with triangular points
+    lowp float angleStep = 2.0 * PI / numPoints;
+    lowp float currentAngle = mod(angle + PI / numPoints, angleStep) - angleStep * 0.5;
+
+    // Create triangular points - distance from center to edge varies linearly with angle
+    lowp float normalizedAngle = abs(currentAngle) / (angleStep * 0.5);
+
+    // Outer tip radius and inner valley radius
+    lowp float tipRadius = 0.5;
+    lowp float valleyRadius = 0.15;
+
+    // Linear interpolation creates sharp triangular points
+    lowp float rayEdge = mix(tipRadius, valleyRadius, normalizedAngle);
+
+    // Hard cutoff for sharp edges
+    lowp float star = step(dist, rayEdge);
+
+    return star;
+}
+
+void main() {
+    lowp float pattern = starPattern(vUV);
+
+    // Color variation based on seed - white and blue tints
+    lowp float colorVar = hash(vSeed * 3.0);
+    lowp vec3 starColor;
+
+    if (colorVar < 0.5) {
+        // Pure white
+        starColor = vec3(1.0, 1.0, 1.0);
+    } else if (colorVar < 0.75) {
+        // Light blue tint
+        starColor = vec3(0.9, 0.95, 1.0);
+    } else {
+        // Stronger blue tint
+        starColor = vec3(0.85, 0.92, 1.0);
+    }
+
+    // Scale alpha based on size - smaller stars are more transparent
+    // Normalize scale from range [16, 48] to [0, 1]
+    lowp float sizeRatio = (vScale - 16.0) / (48.0 - 16.0);
+    // Map to alpha range [0.3, 1.0] - smaller stars at 30% opacity, larger at 100%
+    lowp float alpha = mix(0.3, 1.0, sizeRatio);
+
+    lowp vec4 color = vec4(starColor, pattern * alpha);
+
+    // Discard fully transparent pixels for performance
+    if (color.a < 0.01) {
+        discard;
+    }
+
+    gl_FragColor = color;
+}
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;
+}
diff --git a/themes/src/_shaders/sun.frag b/themes/src/_shaders/sun.frag
index 8463e06..2170b39 100644
--- a/themes/src/_shaders/sun.frag
+++ b/themes/src/_shaders/sun.frag
@@ -1,5 +1,43 @@
 varying lowp vec4 VertexColor;
+varying lowp vec2 TexCoord;
+uniform lowp float time;
+
+// Simple noise function for edge distortion
+lowp float noise(lowp vec2 p) {
+    return sin(p.x * 10.0 + time) * cos(p.y * 10.0 + time * 0.5) * 0.5 + 0.5;
+}
 
 void main() {
-    gl_FragColor = VertexColor;
+    // TexCoord is now normalized: center is (0,0), edges are at distance ~1
+    lowp float dist = length(TexCoord);
+
+    // Add animated noise to the edge
+    lowp float angle = atan(TexCoord.y, TexCoord.x);
+    lowp float wave = sin(angle * 8.0 + time * 2.0) * 0.05 + sin(angle * 4.0 - time * 1.5) * 0.03;
+    lowp float noiseValue = noise(TexCoord + time * 0.1) * 0.02;
+
+    // Create soft edge using smoothstep - ensure fade reaches zero at the actual edge
+    lowp float innerEdge = 0.8;
+    lowp float outerEdge = 1.0;
+    lowp float alpha = 1.0 - smoothstep(innerEdge, outerEdge, dist);
+
+    // Apply wave distortion to the edge
+    alpha *= 1.0 - smoothstep(0.85 + wave + noiseValue * 2.0, 1.0, dist);
+
+    // Make edges more transparent but not too much
+    alpha = alpha * alpha;
+
+    // Add slight glow effect at the edge
+    lowp float glow = smoothstep(0.5, 0.8, dist) * (1.0 - smoothstep(0.8, 1.0, dist));
+
+    // Create orange gradient from center
+    lowp vec3 orangeColor = vec3(1.0, 0.5, 0.1);
+    lowp float centerGradient = smoothstep(0.6, 0.0, dist);
+    lowp vec3 baseColor = mix(VertexColor.rgb, orangeColor, centerGradient * 0.6);
+
+    // Mix in the glow with a brighter color
+    lowp vec3 glowColor = baseColor * 1.3;
+    lowp vec3 finalColor = mix(baseColor, glowColor, glow * 0.5);
+
+    gl_FragColor = vec4(finalColor, VertexColor.a * alpha);
 }
diff --git a/themes/src/_shaders/sun.vert b/themes/src/_shaders/sun.vert
index 76150f0..5ed77d7 100644
--- a/themes/src/_shaders/sun.vert
+++ b/themes/src/_shaders/sun.vert
@@ -1,13 +1,22 @@
 
-attribute vec2 position; 
-attribute vec4 color; 
-attribute mat4 vMatrix; 
-uniform mat4 projection; 
-uniform mat4 model; 
+attribute vec2 position;
+attribute vec4 color;
+attribute mat4 vMatrix;
+uniform mat4 projection;
+uniform mat4 model;
 varying lowp vec4 VertexColor;
+varying lowp vec2 TexCoord;
 
-void main() { 
-    vec4 fragmentPosition = projection * model * vMatrix * vec4(position.x, position.y, 0, 1); 
-    gl_Position = fragmentPosition; 
-    VertexColor = color; 
+void main() {
+    vec4 fragmentPosition = projection * model * vMatrix * vec4(position.x, position.y, 0, 1);
+    gl_Position = fragmentPosition;
+    VertexColor = color;
+    // Normalize the position - the center is at (0,0) and edge vertices are at distance 'radius'
+    // We want TexCoord to be in the range roughly [-1, 1] at the edges
+    lowp float maxDist = length(position);
+    if (maxDist > 0.1) {
+        TexCoord = position / maxDist;
+    } else {
+        TexCoord = vec2(0.0, 0.0);
+    }
 }