Add cursor shader

1 files changed, 148 insertions, 0 deletions

diff --git a/ghostty/shaders/sonic_boom_cursor.glsl b/ghostty/shaders/sonic_boom_cursor.glsl
new file mode 100644
index 0000000..39355d1
--- /dev/null
+++ b/ghostty/shaders/sonic_boom_cursor.glsl
@@ -0,0 +1,148 @@
+// CONFIGURATION
+const float DURATION = 0.15;               // How long the ripple animates (seconds)
+const float MAX_RADIUS = 0.06;             // Max radius in normalized coords (0.5 = 1/4 screen height)
+const float ANIMATION_START_OFFSET = 0.0;        // Start the ripple slightly progressed (0.0 - 1.0)
+vec4 COLOR = vec4(0.35, 0.36, 0.44, 1.0); // change to iCurrentCursorColor for your cursor's color
+const float CURSOR_WIDTH_CHANGE_THRESHOLD = 0.5; // Triggers ripple if cursor width changes by this fraction
+const float BLUR = 3.0;                    // Blur level in pixels
+
+
+// Easing functions
+float easeOutQuad(float t) {
+    return 1.0 - (1.0 - t) * (1.0 - t);
+}
+float easeInOutQuad(float t) {
+    return t < 0.5 ? 2.0 * t * t : 1.0 - pow(-2.0 * t + 2.0, 2.0) / 2.0;
+}
+float easeOutCubic(float t) {
+    return 1.0 - pow(1.0 - t, 3.0);
+}
+float easeOutQuart(float t) {
+    return 1.0 - pow(1.0 - t, 4.0);
+}
+float easeOutQuint(float t) {
+    return 1.0 - pow(1.0 - t, 5.0);
+}
+float easeOutExpo(float t) {
+    return t == 1.0 ? 1.0 : 1.0 - pow(2.0, -10.0 * t);
+}
+float easeOutCirc(float t) {
+    return sqrt(1.0 - pow(t - 1.0, 2.0));
+}
+float easeOutSine(float t) {
+    return sin((t * 3.1415916) / 2.0);
+}
+float easeOutElastic(float t) {
+    const float c4 = (2.0 * 3.1415916) / 3.0;
+    return t == 0.0 ? 0.0 : t == 1.0 ? 1.0 : pow(2.0, -10.0 * t) * sin((t * 10.0 - 0.75) * c4) + 1.0;
+}
+float easeOutBounce(float t) {
+    const float n1 = 7.5625;
+    const float d1 = 2.75;
+    if (t < 1.0 / d1) {
+        return n1 * t * t;
+    } else if (t < 2.0 / d1) {
+        return n1 * (t -= 1.5 / d1) * t + 0.75;
+    } else if (t < 2.5 / d1) {
+        return n1 * (t -= 2.25 / d1) * t + 0.9375;
+    } else {
+        return n1 * (t -= 2.625 / d1) * t + 0.984375;
+    }
+}
+float easeOutBack(float t) {
+    const float c1 = 1.70158;
+    const float c3 = c1 + 1.0;
+    return 1.0 + c3 * pow(t - 1.0, 3.0) + c1 * pow(t - 1.0, 2.0);
+}
+
+// Pulse fade functions
+float smoothstepPulse(float t) {
+    return 4.0 * t * (1.0 - t);
+}
+float easeOutPulse(float t) {
+    return t * (2.0 - t);
+}
+float powerCurvePulse(float t) {
+    float x = t * 2.0 - 1.0;
+    return 1.0 - x * x;
+}
+float doubleSmoothstepPulse(float t) {
+    return smoothstep(0.0, 0.5, t) * (1.0 - smoothstep(0.5, 1.0, t));
+}
+float exponentialDecayPulse(float t) {
+    return exp(-3.0 * t) * sin(t * 3.1415916);
+}
+float sinPulse(float t) {
+    return sin(t * 3.1415916);
+}
+
+vec2 normalize(vec2 value, float isPosition) {
+    return (value * 2.0 - (iResolution.xy * isPosition)) / iResolution.y;
+}
+
+void mainImage(out vec4 fragColor, in vec2 fragCoord){
+    #if !defined(WEB)
+    fragColor = texture(iChannel0, fragCoord.xy / iResolution.xy);
+    #endif
+
+    // Normalization & setup (-1 to 1 coords)
+    vec2 vu = normalize(fragCoord, 1.);
+    vec2 offsetFactor = vec2(-.5, 0.5);
+
+    vec4 currentCursor = vec4(normalize(iCurrentCursor.xy, 1.), normalize(iCurrentCursor.zw, 0.));
+    vec4 previousCursor = vec4(normalize(iPreviousCursor.xy, 1.), normalize(iPreviousCursor.zw, 0.));
+
+    vec2 centerCC = currentCursor.xy - (currentCursor.zw * offsetFactor);
+
+    float cellWidth = max(currentCursor.z, previousCursor.z); // width of the 'block' cursor
+    
+    // check for significant width change
+    float widthChange = abs(currentCursor.z - previousCursor.z);
+    float widthThresholdNorm = cellWidth * CURSOR_WIDTH_CHANGE_THRESHOLD;
+    float isModeChange = step(widthThresholdNorm, widthChange);
+
+
+    // ANIMATION
+    float rippleProgress = (iTime - iTimeCursorChange) / DURATION + ANIMATION_START_OFFSET;
+    // don't clamp yet; we need to know if it's > 1.0 (finished)
+     float isAnimating = 1.0 - step(1.0, rippleProgress); // progress < 1.0 ? 1.0: 0.0
+     
+     if (isModeChange > 0.0 && isAnimating > 0.0) {
+        // float easedProgress = rippleProgress;
+        // float easedProgress = easeOutQuad(rippleProgress);
+        // float easedProgress = easeInOutQuad(rippleProgress);
+        // float easedProgress = easeOutCubic(rippleProgress);
+        // float easedProgress = easeOutQuart(rippleProgress);
+        // float easedProgress = easeOutQuint(rippleProgress);
+        // float easedProgress = easeOutExpo(rippleProgress);
+        float easedProgress = easeOutCirc(rippleProgress);
+        // float easedProgress = easeOutSine(rippleProgress);
+        // float easedProgress = easeOutBack(rippleProgress);
+
+        // easedProgress = clamp(easedProgress, 0.0, 1.0);
+
+        // RIPPLE CALCULATION
+        float rippleRadius = easedProgress * MAX_RADIUS;
+        
+        // float fade = 1.0; // no fade
+        // float fade = 1.0 - easedProgress; // linear fade
+        // float fade = 1.0 - smoothstepPulse(rippleProgress);
+        float fade = 1.0 - easeOutPulse(rippleProgress);
+        // float fade = 1.0 - powerCurvePulse(rippleProgress);
+        // float fade = doubleSmoothstepPulse(rippleProgress);
+        // float fade = exponentialDecayPulse(rippleProgress);
+        // float fade = sinPulse(rippleProgress);
+        
+        // Calculate distance from frag to cursor center
+        float dist = distance(vu, centerCC);
+        
+        float sdfCircle = dist - rippleRadius;
+        
+        // Antialias (1-pixel width in normalized coords)
+        float antiAliasSize = normalize(vec2(BLUR, BLUR), 0.0).x;
+        float ripple = (1.0 - smoothstep(-antiAliasSize, antiAliasSize, sdfCircle)) * fade;
+        
+        // Apply ripple effect
+        fragColor = mix(fragColor, COLOR, ripple * COLOR.a);
+    }
+}