ADD: HQ particles

shaders/particles.frag

@@ -1,7 +1,27 @@
 #version 450
 
+layout(set = 0, binding = 0) uniform SceneData
+{
+    mat4 view;
+    mat4 proj;
+    mat4 viewproj;
+} sceneData;
+
 layout(location = 0) in vec4 v_color;
 layout(location = 1) in vec2 v_uv;
+layout(location = 2) in float v_view_depth;
+layout(location = 3) in float v_seed;
+
+layout(set = 2, binding = 0) uniform sampler2D gbufPosTex;
+layout(set = 3, binding = 0) uniform sampler2D flipbookTex;
+layout(set = 3, binding = 1) uniform sampler2D noiseTex;
+
+layout(push_constant) uniform ParticlePush
+{
+    vec4 screen;   // x=invW, y=invH, z=softDepthDistance, w=timeSeconds
+    vec4 flipbook; // x=cols, y=rows, z=fps, w=intensity
+    vec4 noise;    // x=scale, y=strength, z=scrollX, w=scrollY
+} pc;
 
 layout(location = 0) out vec4 outColor;
 
@@ -16,6 +36,63 @@ void main()
     c.rgb *= mask;
     c.a *= mask;
 
+    // Flipbook sampling + noise UV distortion (atlas).
+    float cols = max(pc.flipbook.x, 1.0);
+    float rows = max(pc.flipbook.y, 1.0);
+    float frames = cols * rows;
+    float fps = max(pc.flipbook.z, 0.0);
+    float intensity = max(pc.flipbook.w, 0.0);
+
+    vec2 uv = v_uv;
+    float noiseScale = max(pc.noise.x, 0.0);
+    float noiseStrength = max(pc.noise.y, 0.0);
+    if (noiseScale > 0.0 && noiseStrength > 0.0)
+    {
+        vec2 nUV = uv * noiseScale + pc.screen.w * pc.noise.zw;
+        vec2 n = texture(noiseTex, nUV).rg * 2.0 - 1.0;
+        vec2 cell = vec2(1.0 / cols, 1.0 / rows);
+        uv = clamp(uv + n * noiseStrength * cell, 0.0, 1.0);
+    }
+
+    uint frame = 0u;
+    if (frames > 0.5 && fps > 0.0)
+    {
+        float ff = pc.screen.w * fps + v_seed * frames;
+        frame = uint(ff) % uint(frames);
+    }
+    uint cols_u = uint(cols);
+    uint rows_u = uint(rows);
+    uint fx = frame % cols_u;
+    // Flipbook sheets are usually laid out with row 0 at the top.
+    uint fy = (rows_u > 0u) ? (rows_u - 1u - (frame / cols_u)) : 0u;
+
+    vec2 cell = vec2(1.0 / cols, 1.0 / rows);
+    vec2 atlas_uv = uv * cell + vec2(float(fx), float(fy)) * cell;
+
+    vec3 flip = texture(flipbookTex, atlas_uv).rgb;
+    // BC6H has no alpha; approximate mask from luminance.
+    float flip_a = clamp(dot(flip, vec3(0.2126, 0.7152, 0.0722)), 0.0, 1.0);
+
+    c.rgb *= flip * intensity;
+    c.a *= flip_a;
+
+    // Soft particles: fade out near opaque geometry intersections.
+    float soft = 1.0;
+    float softDist = pc.screen.z;
+    if (softDist > 0.0)
+    {
+        vec2 suv = gl_FragCoord.xy * pc.screen.xy;
+        vec4 scenePos = texture(gbufPosTex, suv);
+        if (scenePos.w > 0.0)
+        {
+            float sceneDepth = -(sceneData.view * vec4(scenePos.xyz, 1.0)).z;
+            float delta = sceneDepth - v_view_depth;
+            soft = clamp(delta / softDist, 0.0, 1.0);
+        }
+    }
+    c.rgb *= soft;
+    c.a *= soft;
+
     if (c.a <= 0.001)
     {
         discard;
@@ -23,4 +100,3 @@ void main()
 
     outColor = c;
 }
-