draw.c

#include "draw.h"
#include "string.h"

// Set a single voxel to ON
void setvoxel(int x, int y, int z)
{
    if (inrange(x,y,z))
        cube[z][y] |= (1 << x);
}

// Set a single voxel in the temporary cube buffer to ON
void tmpsetvoxel(int x, int y, int z)
{
    if (inrange(x,y,z))
        fb[z][y] |= (1 << x);
}

// Set a single voxel to OFF
void clrvoxel(int x, int y, int z)
{
    if (inrange(x,y,z))
        cube[z][y] &= ~(1 << x);
}

// Set a single voxel to OFF
void tmpclrvoxel(int x, int y, int z)
{
    if (inrange(x,y,z))
        fb[z][y] &= ~(1 << x);
}

// This function validates that we are drawing inside the cube.
unsigned char inrange(int x, int y, int z)
{
    if (x >= 0 && x < CUBE_SIZE && y >= 0 && y < CUBE_SIZE && z >= 0 && z < CUBE_SIZE)
    {
        return 1;
    } else
    {
        // One of the coordinates was outside the cube.
        return 0;
    }
}

// Get the current status of a voxel
unsigned char getvoxel(int x, int y, int z)
{
    if (inrange(x,y,z))
    {
        if (cube[z][y] & (1 << x))
        {
            return 1;
        } else
        {
            return 0;
        }
    } else
    {
        return 0;
    }
}

// In some effect we want to just take bool and write it to a voxel
// this function calls the apropriate voxel manipulation function.
void altervoxel(int x, int y, int z, int state)
{
    if (state == 1)
    {
        setvoxel(x,y,z);
    } else
    {
        clrvoxel(x,y,z);
    }
}

// Flip the state of a voxel.
// If the voxel is 1, its turned into a 0, and vice versa.
void flpvoxel(int x, int y, int z)
{
    if (inrange(x, y, z))
        cube[z][y] ^= (1 << x);
}

// Makes sure x1 is alwas smaller than x2
// This is usefull for functions that uses for loops,
// to avoid infinite loops
void argorder(int ix1, int ix2, int *ox1, int *ox2)
{
    if (ix1>ix2)
    {
        int tmp;
        tmp = ix1;
        ix1= ix2;
        ix2 = tmp;
    }
    *ox1 = ix1;
    *ox2 = ix2;
}

// Sets all voxels along a X/Y plane at a given point
// on axis Z
void setplane_z (int z)
{
    int i;
    if (z>=0 && z<CUBE_SIZE)
    {
        for (i=0;i<CUBE_SIZE;i++)
            cube[z][i] = 0xff;
    }
}

// Clears voxels in the same manner as above
void clrplane_z (int z)
{
    int i;
    if (z>=0 && z<CUBE_SIZE)
    {
        for (i=0;i<CUBE_SIZE;i++)
            cube[z][i] = 0x00;
    }
}

void setplane_x (int x)
{
    int z;
    int y;
    if (x>=0 && x<CUBE_SIZE)
    {
        for (z=0;z<CUBE_SIZE;z++)
        {
            for (y=0;y<CUBE_SIZE;y++)
            {
                cube[z][y] |= (1 << x);
            }
        }
    }
}

void clrplane_x (int x)
{
    int z;
    int y;
    if (x>=0 && x<CUBE_SIZE)
    {
        for (z=0;z<CUBE_SIZE;z++)
        {
            for (y=0;y<CUBE_SIZE;y++)
            {
                cube[z][y] &= ~(1 << x);
            }
        }
    }
}

void setplane_y (int y)
{
    int z;
    if (y>=0 && y<CUBE_SIZE)
    {
        for (z=0;z<CUBE_SIZE;z++)
            cube[z][y] = 0xff;
    }
}

void clrplane_y (int y)
{
    int z;
    if (y>=0 && y<CUBE_SIZE)
    {
        for (z=0;z<CUBE_SIZE;z++)
            cube[z][y] = 0x00;
    }
}

void setplane (char axis, unsigned char i)
{
    switch (axis)
    {
        case AXIS_X:
            setplane_x(i);
            break;

       case AXIS_Y:
            setplane_y(i);
            break;

       case AXIS_Z:
            setplane_z(i);
            break;
    }
}

void clrplane (char axis, unsigned char i)
{
    switch (axis)
    {
        case AXIS_X:
            clrplane_x(i);
            break;

       case AXIS_Y:
            clrplane_y(i);
            break;

       case AXIS_Z:
            clrplane_z(i);
            break;
    }
}

// Fill a value into all 64 byts of the cube buffer
// Mostly used for clearing. fill(0x00)
// or setting all on. fill(0xff)
void fill (unsigned char pattern)
{
    int z;
    int y;
    for (z=0;z<CUBE_SIZE;z++)
    {
        for (y=0;y<CUBE_SIZE;y++)
        {
            cube[z][y] = pattern;
        }
    }
}

void tmpfill (unsigned char pattern)
{
    int z;
    int y;
    for (z=0;z<CUBE_SIZE;z++)
    {
        for (y=0;y<CUBE_SIZE;y++)
        {
            fb[z][y] = pattern;
        }
    }
}

// Draw a box with all walls drawn and all voxels inside set
void box_filled(int x1, int y1, int z1, int x2, int y2, int z2)
{
    int iy;
    int iz;

    argorder(x1, x2, &x1, &x2);
    argorder(y1, y2, &y1, &y2);
    argorder(z1, z2, &z1, &z2);

    for (iz=z1;iz<=z2;iz++)
    {
        for (iy=y1;iy<=y2;iy++)
        {
            cube[iz][iy] |= byteline(x1,x2);
        }
    }

}

// Darw a hollow box with side walls.
void box_walls(int x1, int y1, int z1, int x2, int y2, int z2)
{
    int iy;
    int iz;

    argorder(x1, x2, &x1, &x2);
    argorder(y1, y2, &y1, &y2);
    argorder(z1, z2, &z1, &z2);

    for (iz=z1;iz<=z2;iz++)
    {
        for (iy=y1;iy<=y2;iy++)
        {
            if (iy == y1 || iy == y2 || iz == z1 || iz == z2)
            {
                cube[iz][iy] = byteline(x1,x2);
            } else
            {
                cube[iz][iy] |= ((0x01 << x1) | (0x01 << x2));
            }
        }
    }

}

// Draw a wireframe box. This only draws the corners and edges,
// no walls.
void box_wireframe(int x1, int y1, int z1, int x2, int y2, int z2)
{
    int iy;
    int iz;

    argorder(x1, x2, &x1, &x2);
    argorder(y1, y2, &y1, &y2);
    argorder(z1, z2, &z1, &z2);

    // Lines along X axis
    cube[z1][y1] = byteline(x1,x2);
    cube[z1][y2] = byteline(x1,x2);
    cube[z2][y1] = byteline(x1,x2);
    cube[z2][y2] = byteline(x1,x2);

    // Lines along Y axis
    for (iy=y1;iy<=y2;iy++)
    {
        setvoxel(x1,iy,z1);
        setvoxel(x1,iy,z2);
        setvoxel(x2,iy,z1);
        setvoxel(x2,iy,z2);
    }

    // Lines along Z axis
    for (iz=z1;iz<=z2;iz++)
    {
        setvoxel(x1,y1,iz);
        setvoxel(x1,y2,iz);
        setvoxel(x2,y1,iz);
        setvoxel(x2,y2,iz);
    }

}

// Returns a byte with a row of 1's drawn in it.
// byteline(2,5) gives 0b00111100
char byteline (int start, int end)
{
    return ((0xff<<start) & ~(0xff<<(end+1)));
}

// Flips a byte 180 degrees.
// MSB becomes LSB, LSB becomes MSB.
char flipbyte (char byte)
{
    char flop = 0x00;

    flop = (flop & 0b11111110) | (0b00000001 & (byte >> 7));
    flop = (flop & 0b11111101) | (0b00000010 & (byte >> 5));
    flop = (flop & 0b11111011) | (0b00000100 & (byte >> 3));
    flop = (flop & 0b11110111) | (0b00001000 & (byte >> 1));
    flop = (flop & 0b11101111) | (0b00010000 & (byte << 1));
    flop = (flop & 0b11011111) | (0b00100000 & (byte << 3));
    flop = (flop & 0b10111111) | (0b01000000 & (byte << 5));
    flop = (flop & 0b01111111) | (0b10000000 & (byte << 7));
    return flop;
}

// Draw a line between any coordinates in 3d space.
// Uses integer values for input, so dont expect smooth animations.
void line(int x1, int y1, int z1, int x2, int y2, int z2)
{
    float xy;    // how many voxels do we move on the y axis for each step on the x axis
    float xz;    // how many voxels do we move on the y axis for each step on the x axis
    unsigned char x,y,z;

    // We always want to draw the line from x=0 to x=7.
    // If x1 is bigget than x2, we need to flip all the values.
    if (x1>x2)
    {
        int tmp;
        tmp = x2; x2 = x1; x1 = tmp;
        tmp = y2; y2 = y1; y1 = tmp;
        tmp = z2; z2 = z1; z1 = tmp;
    }


    if (y1>y2)
    {
        xy = (float)(y1-y2)/(float)(x2-x1);
    } else
    {
        xy = (float)(y2-y1)/(float)(x2-x1);
    }

    if (z1>z2)
    {
        xz = (float)(z1-z2)/(float)(x2-x1);
    } else
    {
        xz = (float)(z2-z1)/(float)(x2-x1);
    }



    // For each step of x, y increments by:
    for (x = x1; x<=x2;x++)
    {
        y = (xy*(x-x1))+y1;
        z = (xz*(x-x1))+z1;
        setvoxel(x,y,z);
    }

}

// Delay loop.
// This is not calibrated to milliseconds,
// but we had allready made to many effects using this
// calibration when we figured it might be a good idea
// to calibrate it.
void delay_ms(uint16_t x)
{
  uint8_t y, z;
  for ( ; x > 0 ; x--){
    for ( y = 0 ; y < 90 ; y++){
      for ( z = 0 ; z < 12 ; z++){
        asm volatile ("nop");
      }
    }
  }
}

// Copies the contents of fb (temp cube buffer) into the rendering buffer
void tmp2cube (void)
{
    memcpy(cube, fb, 64); // copy the current cube into a buffer.
}

// Shift the entire contents of the cube along an axis
// This is great for effects where you want to draw something
// on one side of the cube and have it flow towards the other
// side. Like rain flowing down the Z axiz.
void shift (char axis, int direction)
{
    int i, x ,y;
    int ii, iii;
    int state;

    for (i = 0; i < CUBE_SIZE; i++)
    {
        if (direction == -1)
        {
            ii = i;
        } else
        {
            ii = (7-i);
        }


        for (x = 0; x < CUBE_SIZE; x++)
        {
            for (y = 0; y < CUBE_SIZE; y++)
            {
                if (direction == -1)
                {
                    iii = ii+1;
                } else
                {
                    iii = ii-1;
                }

                if (axis == AXIS_Z)
                {
                    state = getvoxel(x,y,iii);
                    altervoxel(x,y,ii,state);
                }

                if (axis == AXIS_Y)
                {
                    state = getvoxel(x,iii,y);
                    altervoxel(x,ii,y,state);
                }

                if (axis == AXIS_X)
                {
                    state = getvoxel(iii,y,x);
                    altervoxel(ii,y,x,state);
                }
            }
        }
    }

    if (direction == -1)
    {
        i = 7;
    } else
    {
        i = 0;
    }

    for (x = 0; x < CUBE_SIZE; x++)
    {
        for (y = 0; y < CUBE_SIZE; y++)
        {
            if (axis == AXIS_Z)
                clrvoxel(x,y,i);

            if (axis == AXIS_Y)
                clrvoxel(x,i,y);

            if (axis == AXIS_X)
                clrvoxel(i,y,x);
        }
    }
}

// Flip the cube 180 degrees along the y axis.
void mirror_y (void)
{
    unsigned char buffer[CUBE_SIZE][CUBE_SIZE];
    unsigned char x,y,z;

    memcpy(buffer, cube, CUBE_BYTES); // copy the current cube into a buffer.

    fill(0x00);
    for (z=0; z<CUBE_SIZE; z++)
    {
        for (y=0; y<CUBE_SIZE; y++)
        {
            for (x=0; x<CUBE_SIZE; x++)
            {
                if (buffer[z][y] & (0x01 << x))
                    setvoxel(x,CUBE_SIZE-1-y,z);
            }
        }
    }

}

// Flip the cube 180 degrees along the x axis
void mirror_x (void)
{
    unsigned char buffer[CUBE_SIZE][CUBE_SIZE];
    unsigned char y,z;

    memcpy(buffer, cube, CUBE_BYTES); // copy the current cube into a buffer.

    fill(0x00);

    for (z=0; z<CUBE_SIZE; z++)
    {
        for (y=0; y<CUBE_SIZE; y++)
        {
            // This will break with different buffer sizes..
            cube[z][y] = flipbyte(buffer[z][y]);
        }
    }
}

// flip the cube 180 degrees along the z axis
void mirror_z (void)
{
    unsigned char buffer[CUBE_SIZE][CUBE_SIZE];
    unsigned char z, y;

    memcpy(buffer, cube, CUBE_BYTES); // copy the current cube into a buffer.

    for (y=0; y<CUBE_SIZE; y++)
    {
        for (z=0; z<CUBE_SIZE; z++)
        {
            cube[CUBE_SIZE-1-z][y] = buffer[z][y];
        }
    }
}