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base_rand refactor

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This commit is contained in:
jacob 2025-07-30 15:03:15 -05:00
parent d2e1be0df9
commit 380f63cacf
8 changed files with 66 additions and 57 deletions
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38
src/base/base_rand.c
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@ -1,44 +1,42 @@
/* TODO: Use a value that gives good precision when dividing into range 0 -> 1 */ ////////////////////////////////
#define F64_RAND_MAX U64Max //~ True randomness
#if PlatformIsWindows #if PlatformIsWindows
# define BCRYPT_RNG_ALG_HANDLE ((void *)0x00000081) # define BCRYPT_RNG_ALG_HANDLE ((void *)0x00000081)
u32 BCryptGenRandom(void *algorithm, u8 *buffer, u32 buffer_size, u32 flags); u32 BCryptGenRandom(void *algorithm, u8 *buffer, u32 buffer_size, u32 flags);
void rand_true(String buffer) void TrueRand(String buffer)
{ {
BCryptGenRandom(BCRYPT_RNG_ALG_HANDLE, (u8 *)buffer.text, buffer.len, 0); BCryptGenRandom(BCRYPT_RNG_ALG_HANDLE, (u8 *)buffer.text, buffer.len, 0);
} }
#else #else
# error rand_true not implemented for this platform # error TrueRand not implemented for this platform
#endif #endif
/* ========================== * ////////////////////////////////
* Stateful prng //~ Stateful randomness
* ========================== */
u64 rand_u64_from_state(RandState *state) u64 RandU64FromState(RandState *state)
{ {
u64 seed = state->seed; u64 seed = state->seed;
if (seed == 0) { if (seed == 0) {
rand_true(STRING_FROM_STRUCT(&seed)); TrueRand(STRING_FROM_STRUCT(&seed));
state->seed = seed; state->seed = seed;
} }
return seed ^ rand_u64_from_seed(++state->counter); return seed ^ RandU64FromSeed(++state->counter);
} }
f64 rand_f64_from_state(RandState *state, f64 range_start, f64 range_end) f64 RandF64FromState(RandState *state, f64 range_start, f64 range_end)
{ {
return range_start + (range_end - range_start) * ((f64)(rand_u64_from_state(state) % F64_RAND_MAX) / (f64)F64_RAND_MAX); return range_start + (range_end - range_start) * ((f64)(RandU64FromState(state) % RandMaxF64) / (f64)RandMaxF64);
} }
/* ========================== * ////////////////////////////////
* Seeded prng //~ Seeded randomness
* ========================== */
/* Based on Jon Maiga's "mx3" /* Based on Jon Maiga's "mx3"
* https://jonkagstrom.com/mx3/mx3_rev2.html * https://jonkagstrom.com/mx3/mx3_rev2.html
*/ */
u64 rand_u64_from_seed(u64 seed) u64 RandU64FromSeed(u64 seed)
{ {
seed = (seed ^ (seed >> 32)) * 0xbea225f9eb34556d; seed = (seed ^ (seed >> 32)) * 0xbea225f9eb34556d;
seed = (seed ^ (seed >> 29)) * 0xbea225f9eb34556d; seed = (seed ^ (seed >> 29)) * 0xbea225f9eb34556d;
@ -47,12 +45,12 @@ u64 rand_u64_from_seed(u64 seed)
return seed; return seed;
} }
u64 rand_u64_from_seeds(u64 seed_a, u64 seed_b) u64 RandU64FromSeeds(u64 seed_a, u64 seed_b)
{ {
return rand_u64_from_seed((seed_a * 3) + seed_b); return RandU64FromSeed((seed_a * 3) + seed_b);
} }
f64 rand_f64_from_seed(u64 seed, f64 range_start, f64 range_end) f64 RandF64FromSeed(u64 seed, f64 range_start, f64 range_end)
{ {
return range_start + (range_end - range_start) * ((f64)(rand_u64_from_seed(seed) % F64_RAND_MAX) / (f64)F64_RAND_MAX); return range_start + (range_end - range_start) * ((f64)(RandU64FromSeed(seed) % RandMaxF64) / (f64)RandMaxF64);
} }

27
src/base/base_rand.h
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@ -1,14 +1,25 @@
////////////////////////////////
//~ Rand types
Struct(RandState) { Struct(RandState) {
/* If a state's seed == 0 upon a call to a related function, it will be initialized using platform's true rng source */ u64 seed; /* If a state's seed == 0 upon a call to a related function, it will be initialized using platform's true rng source */
u64 seed;
u64 counter; u64 counter;
}; };
void rand_true(String buffer); /* TODO: Use a value that gives good precision when dividing into range 0 -> 1 */
#define RandMaxF64 U64Max
u64 rand_u64_from_state(RandState *state); ////////////////////////////////
f64 rand_f64_from_state(RandState *state, f64 range_start, f64 range_end); //~ Rand operations
u64 rand_u64_from_seed(u64 seed); //- True randomness
u64 rand_u64_from_seeds(u64 seed_a, u64 seed_b); void TrueRand(String buffer);
f64 rand_f64_from_seed(u64 seed, f64 range_start, f64 range_end);
//- Stateful randomness
u64 RandU64FromState(RandState *state);
f64 RandF64FromState(RandState *state, f64 range_start, f64 range_end);
//- Seeded randomness
u64 RandU64FromSeed(u64 seed);
u64 RandU64FromSeeds(u64 seed_a, u64 seed_b);
f64 RandF64FromSeed(u64 seed, f64 range_start, f64 range_end);

6
src/base/base_uid.c
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@ -2,7 +2,7 @@
UID uid_true_rand(void) UID uid_true_rand(void)
{ {
UID res = ZI; UID res = ZI;
rand_true(STRING_FROM_STRUCT(&res)); TrueRand(STRING_FROM_STRUCT(&res));
return res; return res;
} }
@ -14,8 +14,8 @@ UID uid_combine(UID a, UID b)
res.lo = (a.lo * 3) + b.lo; res.lo = (a.lo * 3) + b.lo;
res.hi += res.lo; res.hi += res.lo;
res.lo += res.hi; res.lo += res.hi;
res.hi = rand_u64_from_seed(res.hi); res.hi = RandU64FromSeed(res.hi);
res.lo = rand_u64_from_seed(res.lo); res.lo = RandU64FromSeed(res.lo);
res.hi += res.lo; res.hi += res.lo;
res.lo += res.hi; res.lo += res.hi;
return res; return res;

10
src/gp/gp_core_dx12.c
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@ -2035,7 +2035,7 @@ internal struct command_descriptor_heap *command_list_push_descriptor_heap(struc
internal u64 command_buffer_hash_from_size(u64 size) internal u64 command_buffer_hash_from_size(u64 size)
{ {
u64 hash = rand_u64_from_seed(size); u64 hash = RandU64FromSeed(size);
return hash; return hash;
} }
@ -3003,10 +3003,10 @@ G_Resource *gp_run_render(G_RenderSig *gp_render_sig, G_RenderParams params)
sig.flags = K_UintFromU32(shade_flags); sig.flags = K_UintFromU32(shade_flags);
sig.tex_width = K_UintFromU32(render_size.x); sig.tex_width = K_UintFromU32(render_size.x);
sig.tex_height = K_UintFromU32(render_size.y); sig.tex_height = K_UintFromU32(render_size.y);
sig.frame_seed = K_Uint4FromU32((u32)(rand_u64_from_state(&rsig->rand) & 0xFFFFFFFF), sig.frame_seed = K_Uint4FromU32((u32)(RandU64FromState(&rsig->rand) & 0xFFFFFFFF),
(u32)(rand_u64_from_state(&rsig->rand) & 0xFFFFFFFF), (u32)(RandU64FromState(&rsig->rand) & 0xFFFFFFFF),
(u32)(rand_u64_from_state(&rsig->rand) & 0xFFFFFFFF), (u32)(RandU64FromState(&rsig->rand) & 0xFFFFFFFF),
(u32)(rand_u64_from_state(&rsig->rand) & 0xFFFFFFFF)); (u32)(RandU64FromState(&rsig->rand) & 0xFFFFFFFF));
sig.frame_index = K_UintFromU32(rsig->frame_index); sig.frame_index = K_UintFromU32(rsig->frame_index);
sig.camera_offset = K_Float2FromV2(world_to_render_xf.og); sig.camera_offset = K_Float2FromV2(world_to_render_xf.og);
sig.albedo_tex_urid = K_UintFromU32(rsig->albedo->srv_descriptor->index); sig.albedo_tex_urid = K_UintFromU32(rsig->albedo->srv_descriptor->index);

2
src/sim/sim_ent.c
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@ -293,7 +293,7 @@ EntId sim_ent_tile_chunk_id_from_tile_chunk_index(Vec2I32 chunk_index)
{ {
EntId res = ZI; EntId res = ZI;
res.uid = SIM_ENT_TILE_CHUNK_BASIS_UID; res.uid = SIM_ENT_TILE_CHUNK_BASIS_UID;
res.uid = uid_combine(res.uid, MakeUID(rand_u64_from_seed(chunk_index.x), rand_u64_from_seed(chunk_index.y))); res.uid = uid_combine(res.uid, MakeUID(RandU64FromSeed(chunk_index.x), RandU64FromSeed(chunk_index.y)));
return res; return res;
} }

28
src/sim/sim_step.c
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@ -270,9 +270,9 @@ internal void test_spawn_entities2(Ent *parent, Vec2 pos)
/* FIXME: Remove this */ /* FIXME: Remove this */
{ {
static RandState rand = ZI; static RandState rand = ZI;
f32 r = rand_f64_from_state(&rand, 1, 5); f32 r = RandF64FromState(&rand, 1, 5);
f32 g = rand_f64_from_state(&rand, 1, 5); f32 g = RandF64FromState(&rand, 1, 5);
f32 b = rand_f64_from_state(&rand, 1, 5); f32 b = RandF64FromState(&rand, 1, 5);
e->sprite_emittance = VEC3(r, g, b); e->sprite_emittance = VEC3(r, g, b);
e->sprite_tint = Rgba32F(r / 5, g / 5, b / 5, 1); e->sprite_tint = Rgba32F(r / 5, g / 5, b / 5, 1);
} }
@ -528,8 +528,8 @@ internal void test_generate_walls(Snapshot *world)
Vec2I32 end = sim_world_tile_index_from_local_tile_index(chunk_index, VEC2I32(wall_end, tile_y)); Vec2I32 end = sim_world_tile_index_from_local_tile_index(chunk_index, VEC2I32(wall_end, tile_y));
struct wall_node *node = 0; struct wall_node *node = 0;
if (wall_start == 0) { if (wall_start == 0) {
u64 start_hash = rand_u64_from_seed(*(u64 *)&start); u64 start_hash = RandU64FromSeed(*(u64 *)&start);
start_hash = rand_u64_from_seeds(start_hash, wall_dir); start_hash = RandU64FromSeeds(start_hash, wall_dir);
DictEntry *entry = dict_get_entry(horizontal_ends_dict, start_hash); DictEntry *entry = dict_get_entry(horizontal_ends_dict, start_hash);
if (entry) { if (entry) {
/* Existing wall exists accross chunk boundary */ /* Existing wall exists accross chunk boundary */
@ -546,8 +546,8 @@ internal void test_generate_walls(Snapshot *world)
} }
node->end = end; node->end = end;
if (wall_end == SIM_TILES_PER_CHUNK_SQRT) { if (wall_end == SIM_TILES_PER_CHUNK_SQRT) {
u64 end_hash = rand_u64_from_seed(*(u64 *)&end); u64 end_hash = RandU64FromSeed(*(u64 *)&end);
end_hash = rand_u64_from_seeds(end_hash, wall_dir); end_hash = RandU64FromSeeds(end_hash, wall_dir);
dict_set(scratch.arena, horizontal_ends_dict, end_hash, (u64)node); dict_set(scratch.arena, horizontal_ends_dict, end_hash, (u64)node);
} }
wall_start = -1; wall_start = -1;
@ -618,8 +618,8 @@ internal void test_generate_walls(Snapshot *world)
Vec2I32 end = sim_world_tile_index_from_local_tile_index(chunk_index, VEC2I32(tile_x, wall_end)); Vec2I32 end = sim_world_tile_index_from_local_tile_index(chunk_index, VEC2I32(tile_x, wall_end));
struct wall_node *node = 0; struct wall_node *node = 0;
if (wall_start == 0) { if (wall_start == 0) {
u64 start_hash = rand_u64_from_seed(*(u64 *)&start); u64 start_hash = RandU64FromSeed(*(u64 *)&start);
start_hash = rand_u64_from_seeds(start_hash, wall_dir); start_hash = RandU64FromSeeds(start_hash, wall_dir);
DictEntry *entry = dict_get_entry(vertical_ends_dict, start_hash); DictEntry *entry = dict_get_entry(vertical_ends_dict, start_hash);
if (entry) { if (entry) {
/* Existing wall exists accross chunk boundary */ /* Existing wall exists accross chunk boundary */
@ -636,8 +636,8 @@ internal void test_generate_walls(Snapshot *world)
} }
node->end = end; node->end = end;
if (wall_end == SIM_TILES_PER_CHUNK_SQRT) { if (wall_end == SIM_TILES_PER_CHUNK_SQRT) {
u64 end_hash = rand_u64_from_seed(*(u64 *)&end); u64 end_hash = RandU64FromSeed(*(u64 *)&end);
end_hash = rand_u64_from_seeds(end_hash, wall_dir); end_hash = RandU64FromSeeds(end_hash, wall_dir);
dict_set(scratch.arena, vertical_ends_dict, end_hash, (u64)node); dict_set(scratch.arena, vertical_ends_dict, end_hash, (u64)node);
} }
wall_start = -1; wall_start = -1;
@ -748,7 +748,7 @@ internal PHYS_COLLISION_CALLBACK_FUNC_DEF(on_collision, data, step_ctx)
/* Create test blood */ /* Create test blood */
/* TODO: Remove this */ /* TODO: Remove this */
{ {
Xform xf = XformFromTrs(TRS(.t = point, .r = rand_f64_from_state(&step_ctx->rand, 0, Tau))); Xform xf = XformFromTrs(TRS(.t = point, .r = RandF64FromState(&step_ctx->rand, 0, Tau)));
Ent *decal = sim_ent_alloc_sync_src(root); Ent *decal = sim_ent_alloc_sync_src(root);
decal->sprite = sprite_tag_from_path(LIT("sprite/blood.ase")); decal->sprite = sprite_tag_from_path(LIT("sprite/blood.ase"));
decal->sprite_tint = Rgba32F(1, 1, 1, 0.25f); decal->sprite_tint = Rgba32F(1, 1, 1, 0.25f);
@ -757,10 +757,10 @@ internal PHYS_COLLISION_CALLBACK_FUNC_DEF(on_collision, data, step_ctx)
f32 perp_range = 0.5; f32 perp_range = 0.5;
Vec2 linear_velocity = MulVec2(normal, 0.5); Vec2 linear_velocity = MulVec2(normal, 0.5);
linear_velocity = AddVec2(linear_velocity, MulVec2(PerpVec2(normal), rand_f64_from_state(&step_ctx->rand, -perp_range, perp_range))); linear_velocity = AddVec2(linear_velocity, MulVec2(PerpVec2(normal), RandF64FromState(&step_ctx->rand, -perp_range, perp_range)));
f32 angular_velocity_range = 5; f32 angular_velocity_range = 5;
f32 angular_velocity = rand_f64_from_state(&step_ctx->rand, -angular_velocity_range, angular_velocity_range); f32 angular_velocity = RandF64FromState(&step_ctx->rand, -angular_velocity_range, angular_velocity_range);
sim_ent_enable_prop(decal, SEPROP_KINEMATIC); sim_ent_enable_prop(decal, SEPROP_KINEMATIC);
sim_ent_set_linear_velocity(decal, linear_velocity); sim_ent_set_linear_velocity(decal, linear_velocity);

2
src/sprite/sprite_core.c
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@ -276,7 +276,7 @@ b32 sprite_tag_eq(S_Tag t1, S_Tag t2)
internal struct cache_entry_hash cache_entry_hash_from_tag_hash(u64 tag_hash, enum cache_entry_kind kind) internal struct cache_entry_hash cache_entry_hash_from_tag_hash(u64 tag_hash, enum cache_entry_kind kind)
{ {
return (struct cache_entry_hash) { .v = rand_u64_from_seed(tag_hash + kind) }; return (struct cache_entry_hash) { .v = RandU64FromSeed(tag_hash + kind) };
} }
/* ========================== * /* ========================== *

4
src/user/user_core.c
View File

@ -846,8 +846,8 @@ internal void user_update(P_Window *window)
if (shake > 0) { if (shake > 0) {
u64 angle_seed0 = ent->id.uid.lo + (u64)(G.ss_blended->sim_time_ns / frequency_ns); u64 angle_seed0 = ent->id.uid.lo + (u64)(G.ss_blended->sim_time_ns / frequency_ns);
u64 angle_seed1 = angle_seed0 + 1; u64 angle_seed1 = angle_seed0 + 1;
f32 angle0 = rand_f64_from_seed(angle_seed0, 0, Tau); f32 angle0 = RandF64FromSeed(angle_seed0, 0, Tau);
f32 angle1 = rand_f64_from_seed(angle_seed1, 0, Tau); f32 angle1 = RandF64FromSeed(angle_seed1, 0, Tau);
Vec2 vec0 = Vec2WithLen(Vec2FromAngle(angle0), shake); Vec2 vec0 = Vec2WithLen(Vec2FromAngle(angle0), shake);
/* NOTE: vec1 not completely accurate since shake can change between frames, it's just a prediction */ /* NOTE: vec1 not completely accurate since shake can change between frames, it's just a prediction */