Files
QuaternionEngine/shaders/particles.frag
2025-12-18 17:32:30 +09:00

103 lines
2.9 KiB
GLSL

#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;
void main()
{
// Soft circular sprite.
vec2 p = v_uv * 2.0 - 1.0;
float r = length(p);
float mask = smoothstep(1.0, 0.0, r);
vec4 c = v_color;
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;
}
outColor = c;
}