cvr-props/Assets/raymarched/lib/libgarbage.cginc

298 lines
6.8 KiB
HLSL

#ifndef LIBGARBAGE_INCLUDED
#define LIBGARBAGE_INCLUDED
#include "UnityCG.cginc"
/*
## defines with no defaults
# default is object space
USE_WORLD_SPACE
# renders missed rays as transparent
DISCARD_ON_MISS
# use if the shape of the scene is significnatly different from the shape of the material space
# will use SCENE_FN only for the final step, and DISTANCE_FN for raymarching
# DISTANCE_FN must return a float
SEPARATE_MATERIAL_AND_DIST_FUNCTIONS
# don't write depth (will have the depth defined by the original mesh)
DISABLE_DEPTH
# meant for frontface culled meshes, makes depth no further than the mesh edges
LIMIT_DEPTH_TO_MESH
START_RAYS_IN_BOX // TODO: implement
START_RAYS_IN_SPHERE // TODO: implement
*/
// sky used as background unless DISCARD_ON_MISS is set, and used in reflections
// TODO: implement
#ifndef SKY_FN
#define SKY_FN default_sky
#endif
// scene sdf that includes material data
#ifndef SCENE_FN
#define SCENE_FN default_material_sdf
#endif
#ifdef SEPARATE_MATERIAL_AND_DIST_FUNCTIONS
// scene sdf with only distance
#ifndef DISTANCE_FN
#define DISTANCE_FN default_distance_sdf
#endif
#else
#define DISTANCE_FN material_fn_as_dist
#endif
// calculates a color from a Ray
#ifndef LIGHT_FN
#define LIGHT_FN default_lighting
#endif
// set to less than one if there are artifacts in distorted sdfs
#ifndef STEP_MULTIPLIER
#define STEP_MULTIPLIER 1
#endif
// max ray steps, from last bounce (reset on each reflection)
#ifndef MAX_STEPS
#define MAX_STEPS 128
#endif
// max ray length, from last bounce (length is reset on each reflection)
#ifndef MAX_DIST
#define MAX_DIST 128
#endif
// the largest surface distance that is counted as a hit
#ifndef SURF_DIST
#define SURF_DIST 0.001
#endif
#ifndef REFLECTIONS
#define REFLECTIONS 0
#endif
#ifndef SCENE_SCALE
#define SCENE_SCALE 1
#endif
struct AppData {
float4 vertex : POSITION;
UNITY_VERTEX_INPUT_INSTANCE_ID
};
struct V2F {
float4 vertex : SV_POSITION;
float3 cam_pos : TEXCOORD0;
float3 hit_pos : TEXCOORD1;
UNITY_VERTEX_OUTPUT_STEREO
};
struct FragOut {
fixed3 col : SV_Target;
#ifndef DISABLE_DEPTH
float depth : SV_Depth;
#endif
};
struct Material {
float3 col;
float gloss;
};
#define DEFAULT_MAT {float3(1, 1, 1), 0}
Material mat(float3 col = float3(1, 1, 1), float gloss = 0) {
Material m;
m.col = col;
m.gloss = gloss;
return m;
}
Material mat(float r, float g, float b) {
return mat(float3(r, g, b));
}
Material mat(float r, float g, float b, float gloss) {
return mat(float3(r, g, b), gloss);
}
struct SurfacePoint {
float dist;
Material mat;
};
//used for lighting a point
struct Ray {
float dist;
int steps;
Material mat;
float3 start;
float3 dir;
float3 hit_pos;
float3 normal;
bool missed;
float min_dist; // smallest distance encountered along the path (only useful for misses; shadow calculations)
};
#define UP float3(0, 1, 0)
float DISTANCE_FN(float3 p);
SurfacePoint SCENE_FN(float3 p);
float3 LIGHT_FN(Ray ray);
float3 SKY_FN(float3 d);
Ray cast_ray(float3 p, float3 d, float startDist = 0);
#include "libgarbage_shapes.cginc"
#include "libgarbage_operations.cginc"
#include "libgarbage_lighting.cginc"
V2F vert (AppData v) {
V2F o;
UNITY_SETUP_INSTANCE_ID(v);
UNITY_INITIALIZE_OUTPUT(V2F, o);
UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(o);
o.vertex = UnityObjectToClipPos(v.vertex);
#ifdef USE_WORLD_SPACE
o.cam_pos = _WorldSpaceCameraPos;
o.hit_pos = mul(unity_ObjectToWorld, v.vertex);
#else
o.cam_pos = mul(unity_WorldToObject, float4(_WorldSpaceCameraPos, 1));
o.hit_pos = v.vertex;
#endif
return o;
}
FragOut frag (V2F i) {
float ray_len = 0;
float3 ray_dir = normalize(i.hit_pos - i.cam_pos);
float3 ray_origin = i.cam_pos / SCENE_SCALE;
Ray ray;
float3 col_acc = 1;
float3 first_hit;
bool inside_shape;
int ray_num = 0;
for (; ray_num < REFLECTIONS + 1;) {
ray = cast_ray(ray_origin, ray_dir);
if (ray_num == 0) { // before any bounces
first_hit = ray.hit_pos;
inside_shape = ray.steps == 0;
}
float3 light = LIGHT_FN(ray);
col_acc *= ray.mat.col * lerp(light, 1, ray.mat.gloss);
ray_num++;
if (ray.missed || ray.mat.gloss < 0.01) {
break;
}
ray_dir = reflect(ray_dir, ray.normal);
ray_origin = ray.hit_pos + ray_dir * SURF_DIST * 2;
}
#ifdef DISCARD_ON_MISS
if (ray.missed && ray_num == 1) discard;
#endif
FragOut o;
// something something sRGB, colour space is annoying
col_acc = pow(col_acc, 2.2);
o.col = clamp(col_acc, 0, 1);
#ifndef DISABLE_DEPTH
float3 depth_point = first_hit * SCENE_SCALE;
if (ray.missed && ray_num == 1)
depth_point = i.hit_pos;
#ifdef LIMIT_DEPTH_TO_MESH
if (length(i.cam_pos - first_hit * SCENE_SCALE) > length(i.cam_pos - i.hit_pos))
depth_point = i.hit_pos;
#endif
if (inside_shape) {
depth_point = i.cam_pos + normalize(i.hit_pos - i.cam_pos) * 0.01;
}
#ifdef USE_WORLD_SPACE
float4 clip_pos = mul(UNITY_MATRIX_VP, float4(depth_point, 1));
#else
float4 clip_pos = mul(UNITY_MATRIX_VP, mul(unity_ObjectToWorld, float4(depth_point, 1)));
#endif
o.depth = clip_pos.z / clip_pos.w;
#ifndef UNITY_REVERSED_Z // basically only OpenGL (unity editor on linux)
o.depth = o.depth * 0.5 + 0.5; // remap -1 to 1 range to 0.0 to 1.0
#endif
#endif
return o;
}
inline float3 get_normal(float3 pos, float surface_distance, float epsilon = 0.001) {
// if epsilon is smaller than 0.001, there are often artifacts
const float2 e = float2(epsilon, 0);
float3 n = surface_distance - float3(
DISTANCE_FN(pos - e.xyy),
DISTANCE_FN(pos - e.yxy),
DISTANCE_FN(pos - e.yyx));
return normalize(n);
}
Ray cast_ray(float3 start, float3 dir, float start_len) {
float ray_len = start_len;
Ray ray;
ray.dir = dir;
ray.start = start;
ray.min_dist = 100100100; // budget "infinity"
ray.missed = true;
for (int i = 0; i < MAX_STEPS; i++) {
ray.hit_pos = start + ray_len * dir;
ray.dist = DISTANCE_FN(ray.hit_pos);
if (ray.dist < SURF_DIST) {
ray.missed = false;
break;
}
ray.min_dist = min(ray.min_dist, ray.dist);
ray_len += ray.dist * STEP_MULTIPLIER;
if (ray_len > MAX_DIST) break;
}
ray.steps = i;
if (ray.missed) {
ray.normal = float3(0, 0, 0);
ray.mat = mat();
} else {
ray.normal = get_normal(ray.hit_pos, ray.dist);
ray.mat = SCENE_FN(ray.hit_pos).mat;
}
return ray;
}
float3 default_sky(float3 dir) {
return lRenderSky(dir, normalize(float3(2, 1, 0)));
}
float default_distance_sdf(float3 p) {
return sdSphere(p, 0.5);
}
float material_fn_as_dist(float3 p) {
return SCENE_FN(p).dist;
}
SurfacePoint default_material_sdf(float3 p) {
return mSphere(p, 0.5);
}
float3 default_lighting(Ray ray) {
float3 sun_dir = normalize(float3(1, 0.5, -0.5));
if (ray.missed)
return SKY_FN(ray.dir);
float3 light = lSun(ray.normal, sun_dir);
light *= lShadow(ray.hit_pos + ray.normal * SURF_DIST, sun_dir, 50);
light += lSky(ray.normal);
return light;
}
#endif // LIBGARBAGE_INCLUDED