feature: improve snowflake rendererHEADmaster

1 files changed, 76 insertions, 0 deletions

diff --git a/themes/src/shaders/snowflake_frag.cpp b/themes/src/shaders/snowflake_frag.cpp
new file mode 100644
index 0000000..52d535d
--- /dev/null
+++ b/themes/src/shaders/snowflake_frag.cpp
@@ -0,0 +1,76 @@
+#include "snowflake_frag.h"
+
+const char* shader_snowflake_frag = "// Procedural star fragment shader \n"
+"varying lowp vec2 vUV; \n"
+"varying lowp float vSeed; \n"
+"varying lowp float vScale; \n"
+" \n"
+"const lowp float PI = 3.14159265359; \n"
+" \n"
+"// Simple hash function for deterministic randomness \n"
+"lowp float hash(lowp float n) { \n"
+"    return fract(sin(n) * 43758.5453123); \n"
+"} \n"
+" \n"
+"// Generate star pattern procedurally \n"
+"lowp float starPattern(lowp vec2 uv) { \n"
+"    lowp float dist = length(uv); \n"
+"    lowp float angle = atan(uv.y, uv.x); \n"
+" \n"
+"    // Number of star points (4 or 5) \n"
+"    lowp float numPoints = 4.0 + floor(hash(vSeed) * 2.0); \n"
+" \n"
+"    // Create sharp star with triangular points \n"
+"    lowp float angleStep = 2.0 * PI / numPoints; \n"
+"    lowp float currentAngle = mod(angle + PI / numPoints, angleStep) - angleStep * 0.5; \n"
+" \n"
+"    // Create triangular points - distance from center to edge varies linearly with angle \n"
+"    lowp float normalizedAngle = abs(currentAngle) / (angleStep * 0.5); \n"
+" \n"
+"    // Outer tip radius and inner valley radius \n"
+"    lowp float tipRadius = 0.5; \n"
+"    lowp float valleyRadius = 0.15; \n"
+" \n"
+"    // Linear interpolation creates sharp triangular points \n"
+"    lowp float rayEdge = mix(tipRadius, valleyRadius, normalizedAngle); \n"
+" \n"
+"    // Hard cutoff for sharp edges \n"
+"    lowp float star = step(dist, rayEdge); \n"
+" \n"
+"    return star; \n"
+"} \n"
+" \n"
+"void main() { \n"
+"    lowp float pattern = starPattern(vUV); \n"
+" \n"
+"    // Color variation based on seed - white and blue tints \n"
+"    lowp float colorVar = hash(vSeed * 3.0); \n"
+"    lowp vec3 starColor; \n"
+" \n"
+"    if (colorVar < 0.5) { \n"
+"        // Pure white \n"
+"        starColor = vec3(1.0, 1.0, 1.0); \n"
+"    } else if (colorVar < 0.75) { \n"
+"        // Light blue tint \n"
+"        starColor = vec3(0.9, 0.95, 1.0); \n"
+"    } else { \n"
+"        // Stronger blue tint \n"
+"        starColor = vec3(0.85, 0.92, 1.0); \n"
+"    } \n"
+" \n"
+"    // Scale alpha based on size - smaller stars are more transparent \n"
+"    // Normalize scale from range [16, 48] to [0, 1] \n"
+"    lowp float sizeRatio = (vScale - 16.0) / (48.0 - 16.0); \n"
+"    // Map to alpha range [0.3, 1.0] - smaller stars at 30% opacity, larger at 100% \n"
+"    lowp float alpha = mix(0.3, 1.0, sizeRatio); \n"
+" \n"
+"    lowp vec4 color = vec4(starColor, pattern * alpha); \n"
+" \n"
+"    // Discard fully transparent pixels for performance \n"
+"    if (color.a < 0.01) { \n"
+"        discard; \n"
+"    } \n"
+" \n"
+"    gl_FragColor = color; \n"
+"} \n"
+" \n";