/* reinhard@finalmedia.de Do 30. Jul 02:23:12 CEST 2026 Public Domain fretina v0.27 Filesystem Retina Gaussian Splat RGBA Renderer im djb codestil. Gibt rgba frames auf stdout aus und liest Kamerabefehle auf stdin. musl-gcc Q -O3 -march=x86-64 -static-pie -fPIE -fstack-protector-strong -D_FORTIFY_SOURCE=2 -Wl,-z,relro -Wl,-z,now -o retina retina.c */ #include #include #include #include #define MAX_W 3840 #define MAX_H 2160 #define SEC_SZ 500 #define SPL_SZ 16 #define P_SZ 4194304 #define TOT_SPL (P_SZ / SPL_SZ) #define M_SZ 262144 #define TPF 100 #define W_OFF 5000 #define IN_SZ 4096 static int32_t scr_w = 640; static int32_t scr_h = 480; static uint8_t ret_o[MAX_H * MAX_W]; static uint8_t ret_r[MAX_H * MAX_W]; static uint8_t ret_g[MAX_H * MAX_W]; static uint8_t ret_b[MAX_H * MAX_W]; static int16_t ret_z[MAX_H * MAX_W]; static uint8_t fb[MAX_H * MAX_W * 4]; struct __attribute__((packed)) Splat { int16_t x, y, z; uint16_t t0; uint8_t dt; uint8_t op; uint8_t r, g, b, pad; }; static struct Splat p_pool[TOT_SPL]; static int8_t m_pool[TOT_SPL]; static const int16_t INT_SIN[64] = { 0, 25, 49, 73, 96, 118, 139, 159, 177, 193, 208, 220, 231, 239, 245, 249, 251, 249, 245, 239, 231, 220, 208, 193, 177, 159, 139, 118, 96, 73, 49, 25, 0, -25, -49, -73, -96, -118, -139, -159, -177, -193, -208, -220, -231, -239, -245, -249, -251, -249, -245, -239, -231, -220, -208, -193, -177, -159, -139, -118, -96, -73, -49, -25 }; static int16_t get_sin(int32_t angle) { return INT_SIN[angle & 63]; } static int16_t get_cos(int32_t angle) { return INT_SIN[(angle + 16) & 63]; } static int32_t get_atan2(int32_t y, int32_t x) { if (x == 0 && y == 0) return 0; int32_t abs_x = (x < 0) ? -x : x; int32_t abs_y = (y < 0) ? -y : y; int32_t angle; if (abs_x >= abs_y) { angle = (abs_y * 8) / (abs_x + 1); if (x < 0) angle = 32 - angle; } else { angle = 16 - (abs_x * 8) / (abs_y + 1); if (x < 0) angle = 16 + angle; } if (y < 0) return 64 - angle; return angle; } static const char LUT[100][2] = { {'0','0'},{'0','1'},{'0','2'},{'0','3'},{'0','4'},{'0','5'},{'0','6'},{'0','7'},{'0','8'},{'0','9'}, {'1','0'},{'1','1'},{'1','2'},{'1','3'},{'1','4'},{'1','5'},{'1','6'},{'1','7'},{'1','8'},{'1','9'}, {'2','0'},{'2','1'},{'2','2'},{'2','3'},{'2','4'},{'2','5'},{'2','6'},{'2','7'},{'2','8'},{'2','9'}, {'3','0'},{'3','1'},{'3','2'},{'3','3'},{'3','4'},{'3','5'},{'3','6'},{'3','7'},{'3','8'},{'3','9'}, {'4','0'},{'4','1'},{'4','2'},{'4','3'},{'4','4'},{'4','5'},{'4','6'},{'4','7'},{'4','8'},{'4','9'}, {'5','0'},{'5','1'},{'5','2'},{'5','3'},{'5','4'},{'5','5'},{'5','6'},{'5','7'},{'5','8'},{'5','9'}, {'6','0'},{'6','1'},{'6','2'},{'6','3'},{'6','4'},{'6','5'},{'6','6'},{'6','7'},{'6','8'},{'6','9'}, {'7','0'},{'7','1'},{'7','2'},{'7','3'},{'7','4'},{'7','5'},{'7','6'},{'7','7'},{'7','8'},{'7','9'}, {'8','0'},{'8','1'},{'8','2'},{'8','3'},{'8','4'},{'8','5'},{'8','6'},{'8','7'},{'8','8'},{'8','9'}, {'9','0'},{'9','1'},{'9','2'},{'9','3'},{'9','4'},{'9','5'},{'9','6'},{'9','7'},{'9','8'},{'9','9'} }; static void gen_path(char *buf, int32_t cx, int32_t cy, int32_t cz, uint16_t gt, char sfx) { uint32_t tb = (gt / TPF) * TPF; int32_t ax = cx + W_OFF; if (ax < 0) ax = 0; else if (ax > 9999) ax = 9999; int32_t ay = cy + W_OFF; if (ay < 0) ay = 0; else if (ay > 9999) ay = 9999; int32_t az = cz + W_OFF; if (az < 0) az = 0; else if (az > 9999) az = 9999; uint32_t ux = (uint32_t)ax, uy = (uint32_t)ay, uz = (uint32_t)az; uint32_t hx = ux / 100, lx = ux - (hx * 100); buf[16] = LUT[hx][0]; buf[17] = LUT[hx][1]; buf[18] = LUT[lx][0]; buf[19] = LUT[lx][1]; uint32_t hy = uy / 100, ly = uy - (hy * 100); buf[11] = LUT[hy][0]; buf[12] = LUT[hy][1]; buf[13] = LUT[ly][0]; buf[14] = LUT[ly][1]; uint32_t hz = uz / 100, lz = uz - (hz * 100); buf[6] = LUT[hz][0]; buf[7] = LUT[hz][1]; buf[8] = LUT[lz][0]; buf[9] = LUT[lz][1]; uint32_t ht = tb / 1000, rt = tb - (ht * 1000), mt = rt / 100, lt = rt - (mt * 100); buf[21] = LUT[ht][0]; buf[22] = LUT[ht][1]; buf[23] = '0' + mt; buf[24] = LUT[lt][0]; buf[25] = LUT[lt][1]; buf[27] = sfx; } int main(void) { char path[] = "W0000/5000/5000/5000/00000.?"; int32_t active_t = -1; uint16_t gt = 0; int32_t p[8]; int p_idx = 0, cur_v = 0, is_neg = 0, in_cmd = 0; static char in_buf[IN_SZ]; int in_bytes = 0, in_ptr = 0; char *w_env = getenv("SCREEN_WIDTH"), *h_env = getenv("SCREEN_HEIGHT"); if (w_env) { int32_t v = atoi(w_env); if (v > 0 && v <= MAX_W) scr_w = v; } if (h_env) { int32_t v = atoi(h_env); if (v > 0 && v <= MAX_H) scr_h = v; } size_t tot_px = (size_t)(scr_w * scr_h), fb_sz = tot_px * 4; while (1) { if (in_ptr >= in_bytes) { in_bytes = read(0, in_buf, IN_SZ); if (in_bytes <= 0) break; in_ptr = 0; } char c = in_buf[in_ptr++]; if (c == 'W') { in_cmd = 0; int valid = 1; char next_bytes[5]; for (int i = 0; i < 5; i++) { if (in_ptr >= in_bytes) { in_bytes = read(0, in_buf, IN_SZ); if (in_bytes <= 0) { valid = 0; break; } in_ptr = 0; } next_bytes[i] = in_buf[in_ptr++]; } if (valid && next_bytes[0] == ' ' && next_bytes[1] >= '0' && next_bytes[1] <= '9' && next_bytes[2] >= '0' && next_bytes[2] <= '9' && next_bytes[3] >= '0' && next_bytes[3] <= '9' && next_bytes[4] >= '0' && next_bytes[4] <= '9') { path[1] = next_bytes[1]; path[2] = next_bytes[2]; path[3] = next_bytes[3]; path[4] = next_bytes[4]; active_t = -1; } continue; } if (c == 'P') { in_cmd = 1; p_idx = 0; cur_v = 0; is_neg = 0; continue; } if (in_cmd) { if (c == '-') { is_neg = 1; continue; } if (c >= '0' && c <= '9') { cur_v = (cur_v * 10) + (c - '0'); continue; } if (c == ' ' || c == '\n') { if (is_neg) cur_v = -cur_v; if (p_idx < 7) p[p_idx++] = cur_v; cur_v = 0; is_neg = 0; if (c == '\n' || p_idx == 7) { in_cmd = 0; if (p_idx < 7) continue; int32_t cam_x = p[0] + 250, cam_y = p[1] + 250, cam_z = p[2]; int32_t pan = p[3], tilt = p[4], zoom = p[5], b_shift = p[6]; gt++; int req_t = gt / TPF; int32_t Sx = cam_x / SEC_SZ, Sy = cam_y / SEC_SZ, Sz = cam_z / SEC_SZ; int32_t key = (Sx * 73856093) ^ (Sy * 19349663) ^ (Sz * 83492791) ^ req_t; if (key != active_t) { gen_path(path, Sx, Sy, Sz, gt, 'p'); int fd = open(path, O_RDONLY); if (fd >= 0) { posix_fadvise(fd, 0, P_SZ, POSIX_FADV_WILLNEED | POSIX_FADV_SEQUENTIAL); size_t r = 0; while (r < P_SZ) { ssize_t n = read(fd, ((char*)p_pool) + r, P_SZ - r); if (n <= 0) break; r += n; } posix_fadvise(fd, 0, P_SZ, POSIX_FADV_DONTNEED); close(fd); } path[27] = 'm'; fd = open(path, O_RDONLY); if (fd >= 0) { posix_fadvise(fd, 0, M_SZ, POSIX_FADV_WILLNEED | POSIX_FADV_SEQUENTIAL); size_t r = 0; while (r < M_SZ) { ssize_t n = read(fd, ((char*)m_pool) + r, M_SZ - r); if (n <= 0) break; r += n; } posix_fadvise(fd, 0, M_SZ, POSIX_FADV_DONTNEED); close(fd); } active_t = key; } for (size_t i = 0; i < tot_px; i++) { ret_o[i] = 0; ret_r[i] = 0; ret_g[i] = 0; ret_b[i] = 0; ret_z[i] = 32767; } uint16_t relative_zeit = gt % TPF; int32_t live_phase_int = gt / 2; for (uint32_t i = 0; i < TOT_SPL; i++) { if (p_pool[i].op == 0) continue; if (p_pool[i].dt < 100 && (relative_zeit < p_pool[i].t0 || relative_zeit > (p_pool[i].t0 + p_pool[i].dt))) continue; int32_t px = p_pool[i].x; int32_t py = p_pool[i].y; int32_t pz = p_pool[i].z; if (p_pool[i].dt >= 100) { int32_t dx = px - 250; int32_t dy = py - 250; int32_t dz = pz - 250; int32_t angle_idx = get_atan2(dz, dx); int32_t s_wave = get_sin(dy / 8 + live_phase_int); int32_t c_wave = get_cos(angle_idx * 3); int32_t wave_scale = 1024 + ((s_wave * c_wave) >> 10); px = 250 + ((dx * wave_scale) >> 10); pz = 250 + ((dz * wave_scale) >> 10); } int32_t rx = px - cam_x, ry = py - cam_y, rz = pz - cam_z; if (rz <= 10) continue; rx += (pan * rz) >> 9; ry += (tilt * rz) >> 9; int32_t fl = 300 + zoom; int32_t sx = (rx * fl) / rz + (scr_w / 2), sy = (ry * fl) / rz + (scr_h / 2); sy = scr_h - sy; int32_t fr = (fl * 4) / rz; if (fr < 1) fr = 1; int32_t emaj = fr, emin = fr, sch = 0; if (p_pool[i].dt >= 100) { emaj = (fr * ((px % 4) + 2)) >> 1; sch = (rx * fr) / 400; } if (emaj > 24) emaj = 24; if (emin > 24) emin = 24; int32_t max_r = (emaj > emin) ? emaj : emin; int32_t x0 = sx - max_r; if (x0 < 0) x0 = 0; int32_t x1 = sx + max_r; if (x1 >= scr_w) x1 = scr_w - 1; int32_t y0 = sy - max_r; if (y0 < 0) y0 = 0; int32_t y1 = sy + max_r; if (y1 >= scr_h) y1 = scr_h - 1; if (x0 > x1 || y0 > y1) continue; int32_t v_dz = (500 - rz) >> 2, sh = ((int32_t)m_pool[i] * v_dz) >> 6; int32_t rf = p_pool[i].r + sh, gf = p_pool[i].g + sh, bf = p_pool[i].b + sh; if (rf > 255) rf = 255; else if (rf < 0) rf = 0; if (gf > 255) gf = 255; else if (gf < 0) gf = 0; if (bf > 255) bf = 255; else if (bf < 0) bf = 0; int32_t ia = (1048576 / (emin * emin + 1)), ic = (1048576 / (emaj * emaj + 1)), ib = (sch * 524288) / (max_r * max_r + 1); int32_t dx0 = x0 - sx, step_x0 = (2 * dx0 + 1) * ia, step_xy0 = 2 * ib; for (int32_t y = y0; y <= y1; y++) { int32_t dy = y - sy, row = y * scr_w, dx = dx0; int32_t ed = (dx * dx * ia) + (2 * dx * dy * ib) + (dy * dy * ic); int32_t st_x = step_x0, st_xy = dy * step_xy0; for (int32_t x = x0; x <= x1; x++) { int32_t cur_d = ed >> 10; ed += st_x + st_xy; st_x += (2 * ia); if (cur_d > 1024) continue; int32_t idx = row + x; if (rz > ret_z[idx]) continue; uint32_t ao = ret_o[idx]; if (ao >= 255) continue; uint32_t bo = (p_pool[i].op * (1024 - cur_d)) >> 10; if (bo == 0) continue; uint32_t ba = (bo * (255 - ao)) >> 8; ret_r[idx] += (rf * ba) >> 8; ret_g[idx] += (gf * ba) >> 8; ret_b[idx] += (bf * ba) >> 8; ret_o[idx] += ba; if (bo >= 230) ret_z[idx] = (int16_t)rz; } } } size_t f_idx = 0; for (size_t i = 0; i < tot_px; i++) { fb[f_idx++] = ret_r[i]; fb[f_idx++] = ret_g[i]; fb[f_idx++] = ret_b[i]; fb[f_idx++] = ret_o[i]; } size_t w_b = 0; while (w_b < fb_sz) { ssize_t res = write(1, fb + w_b, fb_sz - w_b); if (res < 0) exit(1); w_b += res; } } } } } return 0; }