This commit is contained in:
Freya Murphy 2023-04-22 00:47:10 -04:00
commit 2a88947f03
7 changed files with 457 additions and 0 deletions

1
.gitignore vendored Normal file
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bin

42
Makefile Normal file
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CC = gcc
INCFLAGS = -Isrc
CCFLAGS = -std=c99 -Wall -Wextra -pedantic -O2
CCFLAGS += $(INCFLAGS)
LDFLAGS += $(INCFLAGS)
LDFLAGS += -lSDL2
LDFLAGS += -lm
BIN = bin
APP = $(BIN)/app
SRC = $(shell find src -name "*.c")
OBJ = $(SRC:%.c=$(BIN)/%.o)
.PHONY: dirs run clean build install uninstall
EOF: clean build
dirs:
mkdir -p ./$(BIN)
mkdir -p ./$(BIN)/src
run: build
$(APP)
build: dirs ${OBJ}
${CC} -o $(APP) $(filter %.o,$^) $(LDFLAGS)
$(BIN)/%.o: %.c
$(CC) -o $@ -c $< $(CCFLAGS)
clean:
rm -rf $(APP)
rm -rf $(BIN)
install:
cp $(APP) /usr/local/bin/wrapper
uninstall:
rm /usr/local/bin/wrapper

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src/main.c Normal file
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#include "renderer.h"
#include "screen.h"
int main (void) {
Screen screen;
init_screen(&screen, "test", 1920, 1080);
Camera camera;
init_camera(&camera);
while(screen.open) {
poll_screen(&screen);
draw_screen(&screen);
render(&screen, &camera);
update_camera(&camera, &screen);
}
free_screen(&screen);
return EXIT_SUCCESS;
}

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src/renderer.c Normal file
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#include "renderer.h"
#include "screen.h"
#include <math.h>
#define PI 3.14159265358979323846
#define PIH 1.57079632679489661923
#define PI2 6.28318530718
void init_camera(Camera* camera) {
camera->x = 3;
camera->y = 3;
camera->angle = PI / 4;
}
typedef struct {
float x, y;
} v2;
typedef struct {
int x, y;
} v2i;
#define MOVE_SPEED 1
#define ROTATE_SPEED PI / 2
void update_camera(Camera* camera, Screen* screen) {
double rotate = 0;
if (key_pressed(screen, SDL_SCANCODE_LEFT))
rotate -= ROTATE_SPEED;
if (key_pressed(screen, SDL_SCANCODE_RIGHT))
rotate += ROTATE_SPEED;
rotate *= screen->delta;
rotate += camera->angle;
while (rotate >= PI2) rotate -= PI2;
while (rotate < 0) rotate += PI2;
camera->angle = rotate;
v2 forward = { cos(camera->angle), sin(camera->angle) };
v2 left = { forward.y, -forward.x };
v2 move = { 0, 0 };
if (key_pressed(screen, SDL_SCANCODE_W)) {
move.x += forward.x;
move.y += forward.y;
}
if (key_pressed(screen, SDL_SCANCODE_S)) {
move.x -= forward.x;
move.y -= forward.y;
}
if (key_pressed(screen, SDL_SCANCODE_A)) {
move.x += left.x;
move.y += left.y;
}
if (key_pressed(screen, SDL_SCANCODE_D)) {
move.x -= left.x;
move.y -= left.y;
}
camera->x += move.x * MOVE_SPEED * screen->delta;
camera->y += move.y * MOVE_SPEED * screen->delta;
}
#define MAP_SIZE 8
static uint8_t MAPDATA[MAP_SIZE * MAP_SIZE] = {
1, 1, 1, 1, 1, 1, 1, 1,
1, 0, 0, 0, 0, 0, 0, 1,
1, 0, 0, 0, 0, 3, 0, 1,
1, 0, 0, 0, 0, 0, 0, 1,
1, 0, 2, 0, 4, 4, 0, 1,
1, 0, 0, 0, 4, 0, 0, 1,
1, 0, 3, 0, 0, 0, 0, 1,
1, 1, 1, 1, 1, 1, 1, 1,
};
static void verline(Screen* screen, int x, int y0, int y1, uint32_t color) {
for (int y = y0; y <= y1; y++) {
screen->pixels[(y * screen->width) + x] = color;
}
}
static float v2_cross(v2 a, v2 b) {
return fabs(a.x * b.y - a.y * b.x);
}
static float v2_len(v2 a) {
return sqrt(a.x * a.x + a.y * a.y);
}
static float v2_square_dist(v2 a, v2 b) {
return pow(a.x - b.x, 2) + pow(a.y - b.y, 2);
}
#define min(a, b) ((a) < (b) ? (a) : (b))
#define max(a, b) ((a) > (b) ? (a) : (b))
#define sign(a) ((a) < 0 ? -1 : 1)
#define value(x, y) (MAPDATA[(x) + MAP_SIZE * (y)])
void render(Screen* screen, const Camera* camera) {
const double fov = PI / 3;
const v2 cam_right = {
-sin(camera->angle),
cos(camera->angle)
};
const v2 pos = {
camera->x,
camera->y
};
for (int sx = 0; sx < screen->width; sx++) {
const float xcam = (2 * (sx / (float) (screen->width))) - 1;
const float change = fov * atan(xcam);
const v2i move = {
sign(cos(camera->angle + change)),
sign(sin(camera->angle + change)),
};
const v2i offset = {
move.x == -1 ? 1 : 0,
move.y == -1 ? 1 : 0
};
const float tanc = tan(camera->angle + change);
const float cotc = tan(PIH - (camera->angle + change));
v2i posi = {
(int)pos.x + offset.x,
(int)pos.y + offset.y
};
bool fx = false;
uint32_t vx = 0;
float x;
while (!fx) {
posi.y += move.y;
x = cotc * (posi.y - pos.y) + pos.x;
if (fabs(x) - pos.x >= MAP_SIZE) break;
vx = value((int)x, posi.y - offset.y);
if (vx != 0) {
fx = true;
}
}
bool fy = false;
uint32_t vy = 0;
float y;
while (!fy) {
posi.x += move.x;
y = tanc * (posi.x - pos.x) + pos.y;
if (fabs(y) - pos.y >= MAP_SIZE) break;
vy = value(posi.x - offset.x, (int)y);
if (vy != 0) {
fy = true;
}
}
uint32_t hit;
if (!fx && !fy) {
hit = 0;
x = pos.x + 1000 * move.x;
y = pos.y + 1000 * move.y;
} else if (fx && !fy) {
hit = vx;
y = posi.y;
} else if (fy && !fx) {
hit = vy;
x = posi.x;
} else {
const v2 posx = {x, posi.y};
const v2 posy = {posi.x, y};
if (v2_square_dist(posx, pos) < v2_square_dist(posy, pos)) {
hit = vx;
y = posi.y;
} else {
hit = vy;
x = posi.x;
}
}
const v2 relative = {
x - pos.x,
y - pos.y
};
float len = v2_cross(relative, cam_right) / v2_len(cam_right);
if (len < 0.00001) len = 0.00001;
uint32_t color;
switch (hit) {
case 1: color = 0xFF0000FF; break;
case 2: color = 0x00FF00FF; break;
case 3: color = 0x0000FFFF; break;
case 4: color = 0xFF00FFFF; break;
case 5: color = 0x00FFFFFF; break;
default: color = 0x000000FF; break;
}
const int
h = (int) (screen->height / len),
y0 = max((screen->height / 2) - (h / 2), 0),
y1 = min((screen->height / 2) + (h / 2), screen->height - 1);
verline(screen, sx, 0, y0, 0x202020FF);
verline(screen, sx, y0, y1, color);
verline(screen, sx, y1, screen->height - 1, 0x505050FF);
}
}

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src/renderer.h Normal file
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#pragma once
#include "screen.h"
typedef struct {
float x, y;
float angle;
} Camera;
void init_camera(Camera* camera);
void update_camera(Camera* camera, Screen* screeen);
void render(Screen* screen, const Camera* camera);

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src/screen.c Normal file
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#include "screen.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
void init_screen(Screen* screen, const char* title, uint16_t width, uint16_t height) {
screen->width = width;
screen->height = height;
size_t pixel_count = screen->width * screen->height;
screen->pixels = malloc(pixel_count * sizeof(uint32_t));
memset(screen->pixels, 0, pixel_count * sizeof(uint32_t));
SDL_Init(SDL_INIT_VIDEO);
screen->window =
SDL_CreateWindow(
title,
SDL_WINDOWPOS_CENTERED_DISPLAY(0),
SDL_WINDOWPOS_CENTERED_DISPLAY(0),
screen->width,
screen->height,
0
);
if (!screen->window) {
printf("fatal: failed to create sdl window\n");
exit(EXIT_FAILURE);
}
screen->renderer =
SDL_CreateRenderer(
screen->window,
-1,
SDL_RENDERER_ACCELERATED
| SDL_RENDERER_PRESENTVSYNC
);
if (!screen->renderer) {
printf("fatal: failed to create sdl renderer\n");
exit(EXIT_FAILURE);
}
screen->texture =
SDL_CreateTexture(
screen->renderer,
SDL_PIXELFORMAT_RGBA8888,
SDL_TEXTUREACCESS_STREAMING,
screen->width,
screen->height
);
if (!screen->texture) {
printf("fatal: failed to create window texture\n");
exit(EXIT_FAILURE);
}
screen->open = true;
screen->delta = 0;
}
static long last = 0;
void poll_screen(Screen* screen) {
struct timespec spec;
clock_gettime(CLOCK_MONOTONIC, &spec);
long now = round(spec.tv_nsec / 1.0e6) + spec.tv_sec * 1000;
if (last == 0) {
screen->delta = 0;
} else {
screen->delta = (now - last) / 1000.0;
}
last = now;
SDL_Event ev;
while (SDL_PollEvent(&ev)) {
switch (ev.type) {
case SDL_QUIT:
screen->open = false;
break;
default:
break;
}
}
screen->key_state = SDL_GetKeyboardState(NULL);
}
void draw_screen(Screen* screen) {
void *px;
int pitch;
SDL_LockTexture(screen->texture, NULL, &px, &pitch);
{
for (uint16_t y = 0; y < screen->height; y++) {
memcpy(
&((uint8_t*) px)[y * pitch],
&screen->pixels[y * screen->width],
screen->width * sizeof(uint32_t)
);
}
}
SDL_UnlockTexture(screen->texture);
SDL_SetRenderTarget(screen->renderer, NULL);
SDL_SetRenderDrawColor(screen->renderer, 0, 0, 0, 0xFF);
SDL_SetRenderDrawBlendMode(screen->renderer, SDL_BLENDMODE_NONE);
SDL_RenderClear(screen->renderer);
SDL_RenderCopyEx(
screen->renderer,
screen->texture,
NULL,
NULL,
0.0,
NULL,
SDL_FLIP_VERTICAL);
SDL_RenderCopy(screen->renderer, NULL, NULL, &((SDL_Rect) { 0, 0, 512, 512 }));
SDL_RenderPresent(screen->renderer);
}
void free_screen(Screen* screen) {
SDL_DestroyTexture(screen->texture);
SDL_DestroyRenderer(screen->renderer);
SDL_DestroyWindow(screen->window);
}
bool key_pressed(Screen* screen, SDL_Scancode code) {
return screen->key_state[code & 0xFFFF];
}

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#pragma once
#define _POSIX_C_SOURCE 200809L
#include <SDL2/SDL.h>
#include <stdbool.h>
typedef struct {
uint16_t width;
uint16_t height;
SDL_Window* window;
SDL_Renderer* renderer;
SDL_Texture* texture;
uint32_t* pixels;
const uint8_t* key_state;
bool open;
float delta;
} Screen;
void init_screen(Screen* screen, const char* title, uint16_t width, uint16_t height);
void draw_screen(Screen* screen);
void poll_screen(Screen* screen);
void free_screen(Screen* screen);
bool key_pressed(Screen* screen, SDL_Scancode code);