Minecraft4K_JS_Port

// C++ port of Minecraft 4k JS (http://jsdo.it/notch/dB1E)
// By The8BitPimp
// See: the8bitpimp.wordpress.com

#define _SDL_main_h
#include <SDL\SDL.h>
#pragma comment( lib, "sdl.lib" )
#include <math.h>

const int w = 320;
const int h = 240;

SDL_Surface *screen = nullptr;

const float math_pi = 3.14159265359f;

static inline float math_sin( float x ) {
    return sinf( x );
}

static inline float math_cos( float x ) {
    return cosf( x );
}

// the texture map
int texmap[ 16 * 16 * 16 * 3 ];

// the voxel map
char map[ 64 * 64 * 64 ];

static inline int random( int max ) {
    return (rand()^(rand()<<16)) % max;
}

static inline void plot( int x, int y, int c ) {
    int *p = (int*) screen->pixels;
    p[ y * w + x ] = c;
}

static void makeTextures( void ) {

    // each texture
    for ( int j=0; j<16; j++ ) {

        int k = 255 - random(96);

        // each pixel in the texture
        for ( int m=0; m<16 * 3; m++ )
            for ( int n = 0; n<16; n++ ) {

                int i1 = 0x966C4A;
                int i2 = 0;
                int i3 = 0;

                if (j == 4)
                    i1 = 0x7F7F7F;
                if ((j != 4) || (random(3) == 0))
                    k = 255 - random(96);
                if ( j == 1 )
                {
                    if (m < (((n * n * 3 + n * 81) >> 2) & 0x3) + 18)
                        i1 = 0x6AAA40;
                    else if (m < (((n * n * 3 + n * 81) >> 2) & 0x3) + 19)
                        k = k * 2 / 3;
                }
                if (j == 7)
                {
                    i1 = 0x675231;
                    if ((n > 0) && (n < 15) && (((m > 0) && (m < 15)) || ((m > 32) && (m < 47))))
                    {
                        i1 = 0xBC9862;
                        i2 = n - 7;
                        i3 = (m & 0xF) - 7;
                        if (i2 < 0)
                            i2 = 1 - i2;

                        if (i3 < 0)
                            i3 = 1 - i3;

                        if (i3 > i2)
                            i2 = i3;

                        k = 196 - random(32) + i2 % 3 * 32;
                    }
                    else if (random(2) == 0)
                        k = k * (150 - (n & 0x1) * 100) / 100;
                }
                if (j == 5)
                {
                    i1 = 0xB53A15;
                    if (((n + m / 4 * 4) % 8 == 0) || (m % 4 == 0))
                        i1 = 0xBCAFA5;
                }
                i2 = k;
                if (m >= 32)
                    i2 /= 2;
                if (j == 8)
                {
                    i1 = 5298487;
                    if (random(2) == 0)
                    {
                        i1 = 0;
                        i2 = 255;
                    }
                }

                // fixed point colour multiply between i1 and i2
                i3 =
                    ((((i1 >> 16) & 0xFF) * i2 / 255) << 16) |
                    ((((i1 >>  8) & 0xFF) * i2 / 255) <<  8) |
                      ((i1        & 0xFF) * i2 / 255);
                // pack the colour away
                texmap[ n + m * 16 + j * 256 * 3 ] = i3;
            }
    }
}

static void makeMap( void ) {
    // add random blocks to the map
    for ( int x = 0; x < 64; x++) {
        for ( int y = 0; y < 64; y++) {
            for ( int z = 0; z < 64; z++) {
                int i = (z << 12) | (y << 6) | x;
                float yd = (y - 32.5) * 0.4;
                float zd = (z - 32.5) * 0.4;
                map[i] = random( 16 );

                float th = random( 256 ) / 256.0f;

                if (th > sqrtf( sqrtf( yd * yd + zd * zd ) ) - 0.8f)
                    map[i] = 0;
            }
        }
    }
}

static void init( void ) {
    makeTextures( );
    makeMap( );
}

// fixed point byte byte multiply
static inline int fxmul( int a, int b ) {
    return (a*b)>>8;
}

// fixed point 8bit packed colour multiply
static inline int rgbmul( int a, int b ) {
    int _r = (((a>>16) & 0xff) * b) >> 8;
    int _g = (((a>> 8) & 0xff) * b) >> 8;
    int _b = (((a    ) & 0xff) * b) >> 8;
    return (_r<<16) | (_g<<8) | _b;
}

static void render( void ) {


    float now = (float)(SDL_GetTicks( ) % 10000) / 10000.f;

    float xRot = math_sin(now * math_pi * 2) * 0.4 + math_pi / 2;
    float yRot = math_cos(now * math_pi * 2) * 0.4;
    float yCos = math_cos(yRot);
    float ySin = math_sin(yRot);
    float xCos = math_cos(xRot);
    float xSin = math_sin(xRot);

    float ox = 32.5 + now * 64.0;
    float oy = 32.5;
    float oz = 32.5;

    // for each column
    for ( int x = 0; x < w; x++) {
        // get the x axis delta
        float ___xd = ((float)x - (float)w / 2.f) / (float)h;
        // for each row
        for ( int y = 0; y < h; y++) {
            // get the y axis delta
            float  __yd = ((float)y - (float)h / 2.f) / (float)h;
            float  __zd = 1;
            float ___zd =  __zd * yCos +  __yd * ySin;
            float   _yd =  __yd * yCos -  __zd * ySin;
            float   _xd = ___xd * xCos + ___zd * xSin;
            float   _zd = ___zd * xCos - ___xd * xSin;

            int col = 0;
            int br = 255;
            float ddist = 0;

            float closest = 32.f;

            // for each principle axis  x,y,z
            for ( int d = 0; d < 3; d++) {
                float dimLength = _xd;
                if (d == 1)
                    dimLength = _yd;
                if (d == 2)
                    dimLength = _zd;

                float ll = 1.0f / (dimLength < 0.f ? -dimLength : dimLength);
                float xd = (_xd) * ll;
                float yd = (_yd) * ll;
                float zd = (_zd) * ll;

                float       initial = ox - floor(ox);
                if (d == 1) initial = oy - floor(oy);
                if (d == 2) initial = oz - floor(oz);

                if (dimLength > 0) initial = 1 - initial;

                float dist = ll * initial;

                float xp = ox + xd * initial;
                float yp = oy + yd * initial;
                float zp = oz + zd * initial;

                if (dimLength < 0) {
                    if (d == 0) xp--;
                    if (d == 1) yp--;
                    if (d == 2) zp--;
                }

                // while we are concidering a ray that is still closer then the best so far
                while (dist < closest) {

                    // quantize to the map grid
                    int tex = map[ (((int)zp & 63) << 12) | (((int)yp & 63) << 6) | ((int)xp & 63) ];

                    // if this voxel has a texture applied
                    if (tex > 0) {

                        // find the uv coordinates of the intersection point
                        int u = ((int)((xp + zp) * 16.f)) & 15;
                        int v = ((int) (yp       * 16.f)  & 15) + 16;

                        // fix uvs for alternate directions?
                        if (d == 1) {
                            u =  ((int)(xp * 16.f)) & 15;
                            v = (((int)(zp * 16.f)) & 15);
                            if (yd < 0)
                                v += 32;
                        }

                        // find the colour at the intersection point
                        int cc = texmap[ u + v * 16 + tex * 256 * 3 ];

                        // if the colour is not transparent
                        if (cc > 0) {
                            col = cc;
                            ddist = 255 - ((dist / 32 * 255));
                            br = 255 * (255 - ((d + 2) % 3) * 50) / 255;

                            // we now have the closest hit point (also terminates this ray)
                            closest = dist;
                        }
                    }

                    // advance the ray
                    xp += xd;
                    yp += yd;
                    zp += zd;
                    dist += ll;
                }
            }

            plot( x, y, rgbmul( col, fxmul( br, ddist ) ) );
        }
    }
}

int main( void ) {
    SDL_Init( SDL_INIT_VIDEO );
    screen = SDL_SetVideoMode( w, h, 32, 0 );
    if ( screen == nullptr )
        return -1;
    init( );
    bool running = true;
    while ( running ) {
        SDL_Event event;
        while ( SDL_PollEvent( &event ) ) {
            running &= (event.type != SDL_QUIT);
        }
        render( );
        SDL_Flip( screen );
    }
    return 0;
}