Hi,
I just want to share this to the community.
This is a basic raycaster ported to SFML. The original article below is written in SDL. And because the code uses vertices, the walls are drawn by the cpu.
http://lodev.org/cgtutor/raycasting.htmlSave as main.cpp and then build and run. Walk around by using the arrow keys.
#include <SFML/Graphics.hpp>
#include <SFML/Window.hpp>
#include <stdlib.h>
#include <math.h>
#include <iostream>
#include <sstream>
#define mapWidth 24
#define mapHeight 24
std::string ConvertToString(int number){
std::ostringstream buff;
buff<<number;
return buff.str();
}
int worldMap[mapWidth][mapHeight]=
{
{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,2,2,2,2,2,0,0,0,0,3,0,3,0,3,0,0,0,1},
{1,0,0,0,0,0,2,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,2,0,0,0,2,0,0,0,0,3,0,0,0,3,0,0,0,1},
{1,0,0,0,0,0,2,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,2,2,0,2,2,0,0,0,0,3,0,3,0,3,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,4,4,4,4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,4,0,4,0,0,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,4,0,0,0,0,5,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,4,0,4,0,0,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,4,0,4,4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,4,4,4,4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1},
{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1}
};
int main()
{
int w = 1024, h = 576;
double posX = 22, posY = 12; //x and y start position
double dirX = -1, dirY = 0; //initial direction vector
double planeX = 0, planeY = 0.66; //the 2d raycaster version of camera plane
double time = 0; //time of current frame
double oldTime = 0; //time of previous frame
// Create the main window
sf::RenderWindow window(sf::VideoMode(w, h), "SFML window");
window.setFramerateLimit(60);
sf::Clock clock = sf::Clock();
sf::Time fps;
// Start the game loop
while (window.isOpen()) {
// Process events
sf::Event event;
while (window.pollEvent(event))
{
// Close window: exit
if (event.type == sf::Event::Closed)
window.close();
// Escape key: exit
if ((event.type == sf::Event::KeyPressed) && (event.key.code == sf::Keyboard::Escape))
window.close();
}
window.clear();
for(int x = 0; x < w; x++)
{
//calculate ray position and direction
double cameraX = 2 * x / double(w) - 1; //x-coordinate in camera space
double rayPosX = posX;
double rayPosY = posY;
double rayDirX = dirX + planeX * cameraX;
double rayDirY = dirY + planeY * cameraX;
//which box of the map we're in
int mapX = int(rayPosX);
int mapY = int(rayPosY);
//length of ray from current position to next x or y-side
double sideDistX;
double sideDistY;
//length of ray from one x or y-side to next x or y-side
double deltaDistX = sqrt(1 + (rayDirY * rayDirY) / (rayDirX * rayDirX));
double deltaDistY = sqrt(1 + (rayDirX * rayDirX) / (rayDirY * rayDirY));
double perpWallDist;
//what direction to step in x or y-direction (either +1 or -1)
int stepX;
int stepY;
int hit = 0; //was there a wall hit?
int side; //was a NS or a EW wall hit?
//calculate step and initial sideDist
if (rayDirX < 0)
{
stepX = -1;
sideDistX = (rayPosX - mapX) * deltaDistX;
}
else
{
stepX = 1;
sideDistX = (mapX + 1.0 - rayPosX) * deltaDistX;
}
if (rayDirY < 0)
{
stepY = -1;
sideDistY = (rayPosY - mapY) * deltaDistY;
}
else
{
stepY = 1;
sideDistY = (mapY + 1.0 - rayPosY) * deltaDistY;
}
//perform DDA
while (hit == 0)
{
//jump to next map square, OR in x-direction, OR in y-direction
if (sideDistX < sideDistY)
{
sideDistX += deltaDistX;
mapX += stepX;
side = 0;
}
else
{
sideDistY += deltaDistY;
mapY += stepY;
side = 1;
}
//Check if ray has hit a wall
if (worldMap[mapX][mapY] > 0) hit = 1;
}
//Calculate distance projected on camera direction (oblique distance will give fisheye effect!)
if (side == 0)
perpWallDist = fabs((mapX - rayPosX + (1 - stepX) / 2) / rayDirX);
else
perpWallDist = fabs((mapY - rayPosY + (1 - stepY) / 2) / rayDirY);
//Calculate height of line to draw on screen
int lineHeight = abs(int(h / perpWallDist));
//calculate lowest and highest pixel to fill in current stripe
int drawStart = -lineHeight / 2 + h / 2;
if(drawStart < 0)drawStart = 0;
int drawEnd = lineHeight / 2 + h / 2;
if(drawEnd >= h)drawEnd = h - 1;
//choose wall color
sf::Color color;
switch(worldMap[mapX][mapY])
{
case 1: color = sf::Color::Red; break; //red
case 2: color = sf::Color::Green; break; //green
case 3: color = sf::Color::Blue; break; //blue
case 4: color = sf::Color::White; break; //white
default: color = sf::Color::Yellow; break; //yellow
}
//give x and y sides different brightness
if (side == 1) {
color = sf::Color(color.r/2, color.g/2, color.b/2);
}
//draw the pixels of the stripe as a vertical line
//verLine(x, drawStart, drawEnd, color);
sf::Vertex line[2] =
{
sf::Vertex(sf::Vector2f(x, drawStart), color),
sf::Vertex(sf::Vector2f(x, drawEnd), color)
};
window.draw(line , 2, sf::Lines);
}
fps = clock.getElapsedTime();
float fpsValue = 1000000/fps.asMicroseconds();
clock.restart();
double moveSpeed = fps.asSeconds() * 5.0; //the constant value is in squares/second
double rotSpeed = fps.asSeconds() * 3.0; //the constant value is in radians/second
if (sf::Keyboard::isKeyPressed(sf::Keyboard::Left)) {
//both camera direction and camera plane must be rotated
double oldDirX = dirX;
dirX = dirX * cos(rotSpeed) - dirY * sin(rotSpeed);
dirY = oldDirX * sin(rotSpeed) + dirY * cos(rotSpeed);
double oldPlaneX = planeX;
planeX = planeX * cos(rotSpeed) - planeY * sin(rotSpeed);
planeY = oldPlaneX * sin(rotSpeed) + planeY * cos(rotSpeed);
}
else if (sf::Keyboard::isKeyPressed(sf::Keyboard::Right)) {
//both camera direction and camera plane must be rotated
double oldDirX = dirX;
dirX = dirX * cos(-rotSpeed) - dirY * sin(-rotSpeed);
dirY = oldDirX * sin(-rotSpeed) + dirY * cos(-rotSpeed);
double oldPlaneX = planeX;
planeX = planeX * cos(-rotSpeed) - planeY * sin(-rotSpeed);
planeY = oldPlaneX * sin(-rotSpeed) + planeY * cos(-rotSpeed);
}
else if (sf::Keyboard::isKeyPressed(sf::Keyboard::Up)) {
if(worldMap[int(posX + dirX * moveSpeed)][int(posY)] == false) posX += dirX * moveSpeed;
if(worldMap[int(posX)][int(posY + dirY * moveSpeed)] == false) posY += dirY * moveSpeed;
}
else if (sf::Keyboard::isKeyPressed(sf::Keyboard::Down)) {
if(worldMap[int(posX - dirX * moveSpeed)][int(posY)] == false) posX -= dirX * moveSpeed;
if(worldMap[int(posX)][int(posY - dirY * moveSpeed)] == false) posY -= dirY * moveSpeed;
}
window.display();
window.clear();
}
return EXIT_SUCCESS;
}
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