#version 430 core

// Unit quad vertex (XY -0.5..+0.5)
layout(location = 0) in vec2 aQuad;
layout(location = 1) in vec2 aTex;

// Per-instance: world-space center, authored sheet axes, color.
layout(location = 2) in vec4 aCenter;
layout(location = 3) in vec4 aAxisX;
layout(location = 4) in vec4 aAxisY;
layout(location = 5) in vec4 aColor;
// Campaign V slice V2c (2026-07-27): was uvec2 aTextureHandle (a raw
// ARB_bindless_texture handle); now a slot into the global texture table
// (ACDREAM_TEXTURE_HANDLE, injected by
// tools/ShaderCompiler/VulkanGlslPreamble.cs).
layout(location = 6) in uint aTextureIndex;

uniform mat4 uViewProjection;

out vec2 vTex;
out vec4 vColor;
// Campaign V slice V6e: was `flat uvec2 vTextureHandle`. A varying cannot carry
// a Vulkan descriptor, so the table SLOT crosses the stage boundary and
// particle.frag does the lookup at the sample site.
flat out uint vTextureIndex;

void main() {
    vec3 world = aCenter.xyz
               + aAxisX.xyz * aQuad.x
               + aAxisY.xyz * aQuad.y;

    vTex = aTex;
    vColor = aColor;
    // Slice V6e: forward the slot untouched; the lookup moved to the fragment
    // stage, which is the only form Vulkan can express.
    vTextureIndex = aTextureIndex;
    gl_Position = uViewProjection * vec4(world, 1.0);
}