Add radial mode, UI controls, front camera, update to API 35

- Add radial/elliptical blur mode with aspect ratio control
- Add UI sliders for blur intensity, falloff, and shape
- Add front camera support with flip button
- Update minimum SDK to API 35 (Android 15)
- Enable landscape orientation (fullSensor)
- Rename app to "Naiv Tilt Shift Camera"
- Set APK output name to naiv-tilt-shift
- Add project specification document

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/src/main/res/raw/tiltshift_fragment.glsl

@@ -1,7 +1,7 @@
 #extension GL_OES_EGL_image_external : require
 
 // Fragment shader for tilt-shift effect
-// Applies gradient blur based on distance from focus line
+// Supports both linear and radial blur modes
 
 precision mediump float;
 
@@ -9,17 +9,20 @@ precision mediump float;
 uniform samplerExternalOES uTexture;
 
 // Effect parameters
+uniform int uMode;              // 0 = linear, 1 = radial
 uniform float uAngle;           // Rotation angle in radians
 uniform float uPositionX;       // Horizontal center of focus (0-1)
 uniform float uPositionY;       // Vertical center of focus (0-1)
 uniform float uSize;            // Size of in-focus region (0-1)
 uniform float uBlurAmount;      // Maximum blur intensity (0-1)
+uniform float uFalloff;         // Transition sharpness (0-1, higher = more gradual)
+uniform float uAspectRatio;     // Ellipse aspect ratio for radial mode
 uniform vec2 uResolution;       // Texture resolution for proper sampling
 
 varying vec2 vTexCoord;
 
-// Calculate signed distance from the focus line
-float focusDistance(vec2 uv) {
+// Calculate signed distance from the focus region for LINEAR mode
+float linearFocusDistance(vec2 uv) {
     // Center point of the focus region
     vec2 center = vec2(uPositionX, uPositionY);
     vec2 offset = uv - center;
@@ -35,18 +38,45 @@ float focusDistance(vec2 uv) {
     return abs(rotatedY);
 }
 
+// Calculate signed distance from the focus region for RADIAL mode
+float radialFocusDistance(vec2 uv) {
+    // Center point of the focus region
+    vec2 center = vec2(uPositionX, uPositionY);
+    vec2 offset = uv - center;
+
+    // Adjust for aspect ratio to create ellipse
+    // Correct for screen aspect ratio first
+    float screenAspect = uResolution.x / uResolution.y;
+    offset.x *= screenAspect;
+
+    // Apply rotation
+    float adjustedAngle = uAngle - 1.5707963;
+    float cosA = cos(adjustedAngle);
+    float sinA = sin(adjustedAngle);
+    vec2 rotated = vec2(
+        offset.x * cosA - offset.y * sinA,
+        offset.x * sinA + offset.y * cosA
+    );
+
+    // Apply ellipse aspect ratio
+    rotated.x /= uAspectRatio;
+
+    // Distance from center (elliptical)
+    return length(rotated);
+}
+
 // Calculate blur factor based on distance from focus
 float blurFactor(float dist) {
-    // Smooth transition from in-focus to blurred
     float halfSize = uSize * 0.5;
-    float transitionSize = halfSize * 0.5;
+    // Falloff range scales with the falloff parameter
+    float transitionSize = halfSize * uFalloff;
 
     if (dist < halfSize) {
         return 0.0;  // In focus region
     }
 
     // Smooth falloff using smoothstep
-    float normalizedDist = (dist - halfSize) / transitionSize;
+    float normalizedDist = (dist - halfSize) / max(transitionSize, 0.001);
     return smoothstep(0.0, 1.0, normalizedDist) * uBlurAmount;
 }
 
@@ -72,9 +102,24 @@ vec4 sampleBlurred(vec2 uv, float blur) {
     vec4 color = vec4(0.0);
     vec2 texelSize = 1.0 / uResolution;
 
-    // Blur direction perpendicular to focus line (adjusted for portrait texture rotation)
-    float blurAngle = uAngle; // Already perpendicular after -90 adjustment in focusDistance
-    vec2 blurDir = vec2(cos(blurAngle), sin(blurAngle));
+    // For radial mode, blur in radial direction from center
+    // For linear mode, blur perpendicular to focus line
+    vec2 blurDir;
+    if (uMode == 1) {
+        // Radial: blur away from center
+        vec2 center = vec2(uPositionX, uPositionY);
+        vec2 toCenter = uv - center;
+        float len = length(toCenter);
+        if (len > 0.001) {
+            blurDir = toCenter / len;
+        } else {
+            blurDir = vec2(1.0, 0.0);
+        }
+    } else {
+        // Linear: blur perpendicular to focus line
+        float blurAngle = uAngle;
+        blurDir = vec2(cos(blurAngle), sin(blurAngle));
+    }
 
     // Scale blur radius by blur amount
     float radius = blur * 20.0;
@@ -90,7 +135,12 @@ vec4 sampleBlurred(vec2 uv, float blur) {
 }
 
 void main() {
-    float dist = focusDistance(vTexCoord);
+    float dist;
+    if (uMode == 1) {
+        dist = radialFocusDistance(vTexCoord);
+    } else {
+        dist = linearFocusDistance(vTexCoord);
+    }
     float blur = blurFactor(dist);
 
     gl_FragColor = sampleBlurred(vTexCoord, blur);