trace.rgen

#version 460
#extension GL_EXT_ray_tracing: require

layout(set = 0, binding = 0) uniform View {
    mat4x4 viewInv;
    mat4x4 projInv;
    mat4x4 viewProjInv;
};
layout(set = 0, binding = 1) uniform accelerationStructureEXT topLevel;
layout(set = 1, binding = 0, rgba8) uniform writeonly image2D backBuffer;

layout(location = 0) rayPayloadEXT vec3 color;

void main()
{
    vec2 fragPos = gl_LaunchIDEXT.xy + 0.5;
    vec2 xy = fragPos / gl_LaunchSizeEXT.xy * 2 - 1;
    vec4 origin = viewInv * vec4(0, 0, 0, 1);
    vec4 dir = viewProjInv * vec4(xy, 0, 1);
    float tmin = 0, tmax = 10;

    traceRayEXT(topLevel,
        gl_RayFlagsOpaqueEXT,
        0xFF, // cullMask
        0, // sbtRecordOffset
        0, // sbtRecordStride
        0, // missIndex
        origin.xyz, tmin,
        normalize(dir.xyz), tmax,
        0); // payload

    imageStore(backBuffer, ivec2(gl_LaunchIDEXT.xy), vec4(color, 1));
}