main.cpp

#include <cmath>
#include <string>
#include <vector>
#include <iostream>

#include "quickcg.h"
using namespace QuickCG;
using namespace std;


#define screenWidth 480
#define screenHeight 360
#define texWidth 64
#define texHeight 64
#define mapWidth 48
#define mapHeight 48

// int worldMap[mapWidth][mapHeight]=
// {
//   {4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,7,7,7,7,7,7,7,7,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,7,7,7,7,7,7,7,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,5,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,6,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,7},
//   {4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,7,7,7,7,7,7,7,7,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,7,7,7,7,7,7,7,7}
// };

int worldMap[mapWidth][mapHeight] =
{
	{4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 7, 7, 7, 7, 7, 7, 7, 7},
	{4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 7},
	{4, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7},
	{4, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7},
	{4, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 7},
	{4, 0, 4, 0, 0, 0, 0, 5, 5, 5, 5, 5, 5, 5, 5, 5, 7, 7, 0, 7, 7, 7, 7, 7},
	{4, 0, 5, 0, 0, 0, 0, 5, 0, 5, 0, 5, 0, 5, 0, 5, 7, 0, 0, 0, 7, 7, 7, 1},
	{4, 0, 6, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 5, 7, 0, 0, 0, 0, 0, 0, 8},
	{4, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 7, 7, 1},
	{4, 0, 8, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 5, 7, 0, 0, 0, 0, 0, 0, 8},
	{4, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 5, 7, 0, 0, 0, 7, 7, 7, 1},
	{4, 0, 0, 0, 0, 0, 0, 5, 5, 5, 5, 0, 5, 5, 5, 5, 7, 7, 7, 7, 7, 7, 7, 1},
	{6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 0, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6},
	{8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4},
	{6, 6, 6, 6, 6, 6, 0, 6, 6, 6, 6, 0, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6},
	{4, 4, 4, 4, 4, 4, 0, 4, 4, 4, 6, 0, 6, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3},
	{4, 0, 0, 0, 0, 0, 0, 0, 0, 4, 6, 0, 6, 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 2},
	{4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 2, 0, 0, 5, 0, 0, 2, 0, 0, 0, 2},
	{4, 0, 0, 0, 0, 0, 0, 0, 0, 4, 6, 0, 6, 2, 0, 0, 0, 0, 0, 2, 2, 0, 2, 2},
	{4, 0, 6, 0, 6, 0, 0, 0, 0, 4, 6, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 2},
	{4, 0, 0, 5, 0, 0, 0, 0, 0, 4, 6, 0, 6, 2, 0, 0, 0, 0, 0, 2, 2, 0, 2, 2},
	{4, 0, 6, 0, 6, 0, 0, 0, 0, 4, 6, 0, 6, 2, 0, 0, 5, 0, 0, 2, 0, 0, 0, 2},
	{4, 0, 0, 0, 0, 0, 0, 0, 0, 4, 6, 0, 6, 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 2},
	{4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3}
};

int main(int, char *[])
{
	double posX = 22, posY = 11.5;
	double dirX = -1, dirY = 0;
	double planeX = 0, planeY = 0.66;

	double time = 0;
	double oldTime = 0;
	double frameTime = 0;

	Uint32 buffer[screenHeight][screenWidth]; // y-coordinate first because it works per scanline
	std::vector<Uint32> texture[8];
	for (int i = 0; i < 8; i++) texture[i].resize(texWidth * texHeight);

	unsigned long tw, th;
	loadImage(texture[0], tw, th, "pics/eagle.png");
	loadImage(texture[1], tw, th, "pics/redbrick.png");
	loadImage(texture[2], tw, th, "pics/purplestone.png");
	loadImage(texture[3], tw, th, "pics/greystone.png");
	loadImage(texture[4], tw, th, "pics/bluestone.png");
	loadImage(texture[5], tw, th, "pics/mossy.png");
	loadImage(texture[6], tw, th, "pics/wood.png");
	loadImage(texture[7], tw, th, "pics/colorstone.png");

	for (size_t i = 0; i < 8; i++)
		for (size_t x = 0; x < texWidth; x++)
			for (size_t y = 0; y < x; y++)
				std::swap(texture[i][texWidth * y + x], texture[i][texHeight * x + y]);


	screen(screenWidth, screenHeight, 0, "Raycaster");
	int currentRay = 0;

	while (!done())
	{

		//FLOOR CASTING
		for (int y = 0; y < h; y++) {
			// rayDir for leftmost ray (x = 0) and rightmost ray (x = w)
			float rayDirX0 = dirX - planeX;
			float rayDirY0 = dirY - planeY;
			float rayDirX1 = dirX + planeX;
			float rayDirY1 = dirY + planeY;

			// Current y position compared to the center of the screen (the horizon)
			int p = y - screenHeight / 2;

			// Vertical position of the camera.
			float posZ = 0.5 * screenHeight;

			// Horizontal distance from the camera to the floor for the current row.
			// 0.5 is the z position exactly in the middle between floor and ceiling.
			float rowDistance = abs(posZ / p);

			// calculate the real world step vector we have to add for each x (parallel to camera plane)
			// adding step by step avoids multiplications with a weight in the inner loop
			float floorStepX = rowDistance * (rayDirX1 - rayDirX0) / screenWidth;
			float floorStepY = rowDistance * (rayDirY1 - rayDirY0) / screenWidth;

			// real world coordinates of the leftmost column. This will be updated as we step to the right.
			float floorX = posX + rowDistance * rayDirX0;
			float floorY = posY + rowDistance * rayDirY0;

			for (int x = 0; x < screenWidth; ++x) {
				// the cell coord is simply got from the integer parts of floorX and floorY
				int cellX = (int)(floorX);
				int cellY = (int)(floorY);

				// get the texture coordinate from the fractional part
				int tx = (int)(texWidth * (floorX - cellX)) & (texWidth - 1);
				int ty = (int)(texHeight * (floorY - cellY)) & (texHeight - 1);

				floorX += floorStepX;
				floorY += floorStepY;

				// choose texture and draw the pixel
				int floorTexture = 3;
				int ceilingTexture = 6;
				Uint32 color;

				// floor
				if (y > h / 2)
				{
					color = texture[floorTexture][texWidth * ty + tx];
					color = (color << 8) | 255;
					color = (color >> 1 & 2139062143) | 255; // make a bit darker
					buffer[y][x] = color;
				} else {
					color = texture[ceilingTexture][texWidth * ty + tx];
					color = (color << 8) | 255;
					color = (color >> 1 & 2139062143) | 255; // make a bit darker
					buffer[y][x] = color;
				}
			}
				
		}
		for (int x = 0; x < w; x++)
		{
			//currentRay = x;
			//if(currentRay % 2 == 0) continue;
			double cameraX = 2 * x / (double) (w) - 1;
			double rayDirX = dirX + planeX * cameraX;
			double rayDirY = dirY + planeY * cameraX;

			int mapX = (int)posX;
			int mapY = (int)posY;

			double sideDistX;
			double sideDistY;

			int stepX;
			int stepY;

			double deltaDistX = sqrt(1 + (rayDirY * rayDirY) / (rayDirX * rayDirX));
			double deltaDistY = sqrt(1 + (rayDirX * rayDirX) / (rayDirY * rayDirY));

			int hit = 0;
			int side;

			if (rayDirX < 0) {
				stepX = -1;
				sideDistX = (posX - mapX) * deltaDistX;
			} else {
				stepX = 1;
				sideDistX = (mapX + 1 - posX) * deltaDistX;
			}
			if (rayDirY < 0) {
				stepY = -1;
				sideDistY = (posY - mapY) * deltaDistY;
			} else {
				stepY = 1;
				sideDistY = (mapY + 1 - posY) * deltaDistY;
			}

			while (hit == 0) {
				if (sideDistX > sideDistY) {
					mapY += stepY;
					sideDistY += deltaDistY;
					side = 1;
				} else {
					mapX += stepX;
					sideDistX += deltaDistX;
					side = 0;
				}
				if (worldMap[mapX][mapY] > 0) hit = 1;
			}
			double perpWallDist;
			if (side == 0) perpWallDist = (mapX - posX + (1 - stepX) / 2) / rayDirX;
			else           perpWallDist = (mapY - posY + (1 - stepY) / 2) / rayDirY;

			int lineHeight = (int)(h / perpWallDist);
			int drawStart = -lineHeight / 2 + h / 2;
			if (drawStart < 0) drawStart = 0;
			int drawEnd = lineHeight / 2 + h / 2;
			if (drawEnd >= h) drawEnd = h - 1;

			// if (side == 0) cout << sideDistX << "\n" << perpWallDist << "\n";


			//texturing calculations
			int texNum = worldMap[mapX][mapY] - 1; //1 subtracted from it so that texture 0 can be used!

			//calculate value of wallX
			double wallX; //where exactly the wall was hit
			if (side == 0) wallX = posY + perpWallDist * rayDirY;
			else           wallX = posX + perpWallDist * rayDirX;
			wallX -= floor((wallX));

			//x coordinate on the texture
			int texX = int(wallX * double(texWidth));
			if (side == 0 && rayDirX > 0) texX = texWidth - texX - 1;
			if (side == 1 && rayDirY < 0) texX = texWidth - texX - 1;

			// How much to increase the texture coordinate per screen pixel
			double step = 1.0 * texHeight / lineHeight;
			// Starting texture coordinate
			double texPos = (drawStart - h / 2 + lineHeight / 2) * step;
			for (int y = drawStart; y < drawEnd; y++)
			{
				// Cast the texture coordinate to integer, and mask with (texHeight - 1) in case of overflow
				int texY = (int)texPos & (texHeight - 1);
				texPos += step;
				Uint32 color = texture[texNum][texHeight * texX + texY];
				color = (color << 8) | 255;
				//make color darker for y-sides: R, G and B byte each divided through two with a "shift" and an "and"
				if (side == 1) color = ((color >> 1) & 2139062143) | 255;
				buffer[y][x] = color;
			}
		}

		drawBuffer(buffer[0]);
		for (int y = 0; y < h; y++) for (int x = 0; x < w; x++) buffer[y][x] = 0;

		//timing for input and FPS counter
		oldTime = time;
		time = getTicks();
		frameTime = (time - oldTime) / 1000.0; //frameTime is the time this frame has taken, in seconds
		print(1.0 / frameTime); //FPS counter
		redraw();


		double moveSpeed = frameTime * 5.0; //the constant value is in squares/second
		double rotSpeed = frameTime * 3.5; //the constant value is in radians/second


		readKeys();
		//move forward if no wall in front of you
		if (keyDown(SDL_SCANCODE_W))
		{
			if (worldMap[int(posX + dirX * moveSpeed)][int(posY)] == false) posX += dirX * moveSpeed;
			if (worldMap[int(posX)][int(posY + dirY * moveSpeed)] == false) posY += dirY * moveSpeed;
		}
		//move backwards if no wall behind you
		if (keyDown(SDL_SCANCODE_S))
		{
			if (worldMap[int(posX - dirX * moveSpeed)][int(posY)] == false) posX -= dirX * moveSpeed;
			if (worldMap[int(posX)][int(posY - dirY * moveSpeed)] == false) posY -= dirY * moveSpeed;
		}
		//rotate to the right
		if (keyDown(SDL_SCANCODE_D))
		{
			//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);
		}
		//rotate to the left
		if (keyDown(SDL_SCANCODE_A))
		{
			//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);
		}
	}
	return 0;
}