#version 300 es
layout(location = 0) in vec2 aQuadPos;      // shared unit quad, centered (-0.5..+0.5)
layout(location = 1) in vec2 aTexCoord;     // quad-corner uv; v=0 = image top (same mapping as sprites)
layout(location = 2) in vec3 aPos;          // per-instance: world center
layout(location = 3) in float aSize;        // per-instance: world diameter
layout(location = 4) in vec4 aColor;
layout(location = 5) in vec4 aUVRect;       // per-instance: uvMin.xy, uvMax.zw (atlas region)
layout(location = 6) in vec2 aCosSin;       // per-instance: in-plane rotation (the uv stays put, so the image spins)
#include "_graphics_uniforms.glsl"
#include "_billboard.glsl"
#include "_fog.glsl"
out vec2 vTexCoord;
out vec4 vColor;
void main() {
    vec3 world = billboardWorld(aPos, aQuadPos, aCosSin, aSize);
    gl_Position = u_viewProjection * vec4(world, 1.0);
    // additive fog fades the added light, RGB only — alpha isn't light
    vTexCoord = mix(aUVRect.xy, aUVRect.zw, aTexCoord);
    vColor = vec4(aColor.rgb * (1.0 - fogFactor(aPos)), aColor.a);
}