Start working on the raytracer

.gitignore

@@ -1 +1,3 @@
+.cache
+build_dir
 compile_commands.json

.gitmodules

@@ -0,0 +1,4 @@
+[submodule "include/c_cpp_aliases"]
+	path = include/c_cpp_aliases
+	url = https://git.thewizardapprentice.com/abdelrahman/c-cpp-aliases.git
+	branch = main

build

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+bear -- ./compile "$@"

compile

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+CC=clang
+CFLAGS="-g -Wall -Werror -pedantic -Iinclude $(pkg-config --cflags sdl2)"
+LIBS="$(pkg-config --libs sdl2)"
+
+RAYTRACER_SRC="src/window/*.c \
+	src/raytracer/*.c \
+"
+
+BUILD=build_dir
+RAYTRACER_OUT="$BUILD/raytracer"
+
+mkdir -p $BUILD
+
+(set -x ; $CC $CFLAGS $LIBS $RAYTRACER_SRC -o $RAYTRACER_OUT)

include/c_cpp_aliases

@@ -0,0 +1 @@
+Subproject commit f95f3aa499910286876c1f2cdceea8146ebcf7b1

include/window/window.h

@@ -0,0 +1,31 @@
+#ifndef WINDOW_H
+#define WINDOW_H
+
+#include "c_cpp_aliases/aliases.h"
+#include <SDL2/SDL_video.h>
+#include <stdbool.h>
+
+typedef struct {
+  u8 r;
+  u8 g;
+  u8 b;
+  u8 a;
+} colour_t;
+
+typedef struct {
+  u64 width;
+  u64 height;
+  const char *title;
+  SDL_Window *window;
+  SDL_Surface *front_buffer;
+  SDL_Surface *back_buffer;
+} window_t;
+
+bool init_window(window_t *wnd, u64 width, u64 height, const char *title);
+void close_window(window_t *wnd);
+
+void clear_window(window_t *wnd, colour_t colour);
+void set_pixel(window_t *wnd, f32 x, f32 y, colour_t colour);
+void swap_buffers(window_t *wnd);
+
+#endif // !WINDOW_H

run

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+USAGE="Usage: run (raytracer | rasteriser)"
+
+if [[ $# == 0 ]]; then
+	echo $USAGE
+	exit 1
+fi
+
+while [[ $# -gt 0 ]]; do
+  case $1 in
+    raytracer)
+      RENDERER="raytracer"
+      shift # past argument
+      ;;
+    -*|--*|*)
+			echo $USAGE
+      exit 1
+      ;;
+  esac
+done
+
+./build_dir/$RENDERER

src/raytracer/main.c

@@ -0,0 +1,37 @@
+#include "SDL_events.h"
+#include "c_cpp_aliases/aliases.h"
+#include "window/window.h"
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char *argv[]) {
+  colour_t bg = (colour_t){.r = 128, .g = 128, .b = 128, .a = 255};
+
+  window_t window = {0};
+
+  if (!init_window(&window, 1000, 800, "CG From Scratch")) {
+    return EXIT_FAILURE;
+  }
+
+  bool running = true;
+  SDL_Event event = {0};
+
+  while (running) {
+    while (SDL_PollEvent(&event)) {
+      switch (event.type) {
+      case SDL_QUIT:
+        running = false;
+        break;
+      }
+    }
+
+    clear_window(&window, bg);
+
+    swap_buffers(&window);
+  }
+
+  close_window(&window);
+
+  return EXIT_SUCCESS;
+}

src/window/window.c

@@ -0,0 +1,144 @@
+#include "window/window.h"
+#include "c_cpp_aliases/aliases.h"
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_error.h>
+#include <SDL2/SDL_pixels.h>
+#include <SDL2/SDL_surface.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#define NORMALISED_MIN -1.0f
+#define NORMALISED_MAX 1.0f
+
+u32 colour_to_u32(colour_t colour);
+u32 index_from_coordinates(window_t *wnd, u32 x, u32 y);
+i32 denormalise(f32 value, u32 max);
+void set_screen_pixel(window_t *wnd, u32 x, u32 y, colour_t colour);
+
+bool init_window(window_t *wnd, u64 width, u64 height, const char *title) {
+  if (SDL_Init(SDL_INIT_EVERYTHING) != 0) {
+    printf("Failed to initialise SDL: %s\n", SDL_GetError());
+
+    return false;
+  }
+
+  wnd->window = SDL_CreateWindow(title, SDL_WINDOWPOS_CENTERED,
+                                 SDL_WINDOWPOS_CENTERED, width, height, 0);
+  if (!(wnd->window)) {
+    printf("Failed to create window: %s\n", SDL_GetError());
+
+    close_window(wnd);
+
+    return false;
+  }
+
+  wnd->front_buffer = SDL_GetWindowSurface(wnd->window);
+  if (!(wnd->front_buffer)) {
+    printf("Failed to get front buffer: %s\n", SDL_GetError());
+
+    close_window(wnd);
+
+    return false;
+  }
+
+  wnd->back_buffer = SDL_CreateRGBSurfaceWithFormat(0, width, height, 32,
+                                                    SDL_PIXELFORMAT_ABGR32);
+  if (!(wnd->back_buffer)) {
+    printf("Failed to create back buffer: %s\n", SDL_GetError());
+
+    close_window(wnd);
+
+    return false;
+  }
+
+  wnd->width = width;
+  wnd->height = height;
+  wnd->title = title;
+
+  return true;
+}
+
+void close_window(window_t *wnd) {
+  if (wnd) {
+    wnd->width = 0;
+    wnd->height = 0;
+    wnd->title = "";
+
+    if (wnd->window) {
+      SDL_DestroyWindow(wnd->window);
+
+      wnd->window = NULL;
+    }
+
+    if (wnd->back_buffer) {
+      SDL_FreeSurface(wnd->back_buffer);
+
+      wnd->back_buffer = NULL;
+    }
+  }
+
+  SDL_Quit();
+}
+
+void clear_window(window_t *wnd, colour_t colour) {
+  SDL_LockSurface(wnd->back_buffer);
+
+  u32 c = colour_to_u32(colour);
+
+  u32 *pixels = (u32 *)(wnd->back_buffer->pixels);
+  u32 count = wnd->back_buffer->w * wnd->back_buffer->h;
+
+  for (u32 i = 0; i < count; ++i) {
+    pixels[i] = c;
+  }
+
+  SDL_UnlockSurface(wnd->back_buffer);
+}
+
+void set_pixel(window_t *wnd, f32 x, f32 y, colour_t colour) {
+  i32 screen_x = denormalise(x, wnd->width);
+  i32 screen_y = denormalise(-y, wnd->height);
+
+  if (screen_x < 0 || screen_y < 0) {
+    return;
+  }
+
+  SDL_LockSurface(wnd->back_buffer);
+
+  set_screen_pixel(wnd, screen_x, screen_y, colour);
+
+  SDL_UnlockSurface(wnd->back_buffer);
+}
+
+void swap_buffers(window_t *wnd) {
+  SDL_BlitSurface(wnd->back_buffer, NULL, wnd->front_buffer, NULL);
+
+  SDL_UpdateWindowSurface(wnd->window);
+}
+
+u32 colour_to_u32(colour_t colour) {
+  return ((u32)(colour.r) << 24) | ((u32)(colour.g) << 16) |
+         ((u32)(colour.b) << 8) | (u32)(colour.a);
+}
+
+u32 index_from_coordinates(window_t *wnd, u32 x, u32 y) {
+  return y * wnd->width + x;
+}
+
+i32 denormalise(f32 value, u32 max) {
+  if (max == 0 || value < NORMALISED_MIN || value >= NORMALISED_MAX) {
+    return -1;
+  }
+
+  return (i32)(((value - NORMALISED_MIN) * max) /
+               (NORMALISED_MAX - NORMALISED_MIN));
+}
+
+void set_screen_pixel(window_t *wnd, u32 x, u32 y, colour_t colour) {
+  u32 index = index_from_coordinates(wnd, x, y);
+  u32 c = colour_to_u32(colour);
+
+  u32 *pixels = (u32 *)(wnd->back_buffer->pixels);
+
+  pixels[index] = c;
+}