Add .gitignore

.gitignore

@@ -0,0 +1,4 @@
+.cache
+compile_commands.json
+outputs
+xorshift

aliases.h

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+#ifndef ALIASES_H
+#define ALIASES_H
+
+#include <stdint.h>
+
+#define u8 uint8_t
+#define u16 uint16_t
+#define u32 uint32_t
+#define u64 uint64_t
+
+#define i8 int8_t
+#define i16 int16_t
+#define i32 int32_t
+#define i64 int64_t
+
+#define f32 float
+#define f64 double
+#define f128 long double
+
+#define uptr uintptr_t
+#define iptr intptr_t
+
+#define internal static
+#define persistent static
+
+#ifdef __cplusplus
+#define class_mem static
+#endif // __cplusplus
+
+#endif // !ALIASES_H

build

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+#!/bin/bash
+
+bear -- ./compile

compile

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+#!/bin/bash
+
+CC=clang
+CFLAGS="-g -Wall -Werror "
+
+XORSHIFT_SRC="xorshift.c ppm.c"
+XORSHIFT_OUT=xorshift
+
+(set -x ; $CC $CFLAGS $XORSHIFT_SRC -o $XORSHIFT_OUT)

ppm.c

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+#include "ppm.h"
+#include "aliases.h"
+#include <stdio.h>
+#include <string.h>
+
+void write_p6_ppm(const char *filepath, u64 width, u64 height, Pixel *data) {
+  FILE *fp = fopen(filepath, "wb");
+  if (!fp) {
+    return;
+  }
+
+  char header[1024] = {0};
+  sprintf(header, "P6\n%lu %lu\n255\n", width, height);
+
+  u64 length = strlen(header);
+  fwrite(&header, length, 1, fp);
+
+  u64 pixel_count = width * height;
+  fwrite(data, sizeof(Pixel), pixel_count, fp);
+
+  fclose(fp);
+}

ppm.h

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+#include "aliases.h"
+
+typedef struct {
+  u8 r;
+  u8 g;
+  u8 b;
+} Pixel;
+
+void write_p6_ppm(const char *filepath, u64 width, u64 height, Pixel *data);

xorshift.c

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+#include "aliases.h"
+#include "ppm.h"
+#include <bits/time.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+typedef struct {
+  u64 x;
+  u64 y;
+  u64 z;
+  u64 w;
+} XORShiftBasic;
+
+u64 xor_shift_basic_generate(XORShiftBasic *state);
+
+int main(int argc, char *argv[]) {
+  struct timespec ts = {0};
+  clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
+
+  srand48(ts.tv_nsec);
+
+  XORShiftBasic state = {
+      .x = lrand48(),
+      .y = lrand48(),
+      .z = lrand48(),
+      .w = lrand48(),
+  };
+
+  u64 w = 1024;
+  u64 h = 1024;
+  u64 length = w * h;
+
+  Pixel data[length];
+  for (u64 y = 0; y < h; ++y) {
+    for (u64 x = 0; x < w; ++x) {
+      u64 i = y * w + x;
+
+      u8 pixel = xor_shift_basic_generate(&state) % UINT8_MAX;
+      data[i] = (Pixel){
+          .r = pixel,
+          .g = pixel,
+          .b = pixel,
+      };
+    }
+  }
+
+  write_p6_ppm("./outputs/xorshift.ppm", w, h, data);
+
+  return EXIT_SUCCESS;
+}
+
+u64 xor_shift_basic_generate(XORShiftBasic *state) {
+  u64 t = state->x ^ (state->x << 11);
+
+  state->x = state->y;
+  state->y = state->z;
+  state->z = state->w;
+  state->w = (state->w ^ (state->w >> 19)) ^ (t ^ (t >> 8));
+
+  return state->w;
+}