// Rusting shader language, version 1: the built-ins a `#rusting surface 1`
// shader sees. Fields are only ever added at the end, and a change that
// would break a version 1 shader bumps RUSTING_SHADER_VERSION.
#define RUSTING_SHADER_VERSION 1
// Surface.subsurface exists.
#define RUSTING_SURFACE_SUBSURFACE 1
// What the engine knows about the pixel before the shader runs.
struct SurfaceInput {
// Texture coordinates after the material's uv_scale and uv_offset.
vec2 uv;
vec3 world_position;
// Unit vector from the surface toward the camera.
vec3 view_direction;
// Vertex color times the material and per-object color.
vec4 vertex_color;
// Seconds since the game started.
float time;
// Bits 0-15 of the mesh vertex `data`: a block id.
uint block_id;
// The RUSTING_FLAG_* bits of the mesh vertex `data`, not shifted.
uint flags;
// The vertex tangent in world space (w: the bitangent's handedness),
// interpolated. A mesh drawn without a normal map may carry its own
// per-vertex data here, such as baked light.
vec4 tangent;
};
// SurfaceInput.tangent exists.
#define RUSTING_SURFACE_TANGENT 1
// The surface the engine lights. It starts as the material's own values,
// textures applied; the shader may change any of them.
struct Surface {
// Linear RGB and alpha; alpha drives Mask and Blend.
vec4 base_color;
// World-space normal; the engine normalizes it after the shader.
vec3 normal;
float metallic;
float roughness;
// Light given off, linear RGB.
vec3 emissive;
// Thin-surface transmission: rgb is the linear tint of directional
// light let through from behind (0, the default, is off), a the
// thickness in metres the shadow is looked up past the surface.
vec4 subsurface;
};
#ifndef RUSTING_CUSTOM_SURFACE
void surface(SurfaceInput i, inout Surface s) {}
#endif