#version 450
#extension GL_GOOGLE_include_directive : require
#extension GL_EXT_nonuniform_qualifier : enable

#include "bindless.glsl"

layout(location = 0) in vec2 uv;      // from fullscreen triangle: 0..2 range
layout(location = 0) out vec4 outColor;

layout(push_constant) uniform SkyboxPC {
    mat4 invViewProj;        // inverse(Proj * View) (your current setup)
    vec4 cameraPos;          // xyz = camera world position
    uint skyboxTextureId;    // index into textureCubes[]
} pcs;

void main()
{
    // Fullscreen-triangle trick gives uv in [0..2]. Convert to [0..1].
    vec2 uv01 = uv * 0.5;

    // Build an NDC point on the far plane.
    // Vulkan NDC is x,y in [-1..1], z in [0..1]. Using z=1 means "far".
    vec4 ndc = vec4(uv01 * 2.0 - 1.0, 1.0, 1.0);

    // Unproject to world space
    vec4 world = pcs.invViewProj * ndc;
    vec3 worldPos = world.xyz / world.w;

    // Direction from camera through this pixel
    vec3 dir = normalize(worldPos - pcs.cameraPos.xyz);

    // Sample cubemap directly
    outColor = sampleTextureCubeLinear(pcs.skyboxTextureId, dir);
    // outColor = sampleTextureCubeNearest(pcs.skyboxTextureId, dir);
}