Shmup/src/utilities/utilities.cpp

#include "../config.h"

#include <azur/azur.h>
#include <azur/gint/render.h>

#include "utilities.h"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fxlibc/printf.h>
#include <sys/types.h>


extern font_t milifont_prop;

void Azur_draw_text(int x, int y, char const *fmt, ...)
{
    char str[128];
    va_list args;
    va_start(args, fmt);
    vsnprintf(str, 128, fmt, args);
    va_end(args);

    dfont( &milifont_prop );

    azrp_text( x, y, C_WHITE, str );
}



bool AABB_Collision( SpriteLocator image1, SpriteLocator image2 )
{
    if(    (image2.x >= image1.x + image1.image->width)      
        || (image2.x + image2.image->width <= image1.x)     
        || (image2.y >= image1.y + image1.image->height)     
        || (image2.y + image2.image->height <= image1.y) )   
        return false;
    
    // no need to do pixel perfect detection
    return true;
}



bool Pixel_Perfect_Collision( SpriteLocator image1, SpriteLocator image2 )
{
    if( !AABB_Collision( image1, image2 ) )
        return false;                       // bounding boxes not overlapping, impossible to have collision

    /* if we reach that point, this means that we need to perform pixel perfect collsion detection */

    /* First we will calculate the corners of the zone to be tested for collision */
    /* as it is not usefull to check for all the surface of the image, only the */
    /* overlapping area will be verified */



    /* WARNING !! */
    /* P4 format is not supported yet has it is currently focused on use with Azur */
    /* that is mostly P8/RGB565 oriented for ultra fast performances */
    if ( IMAGE_IS_P4(image1.image->format) || IMAGE_IS_P4(image2.image->format) )
        return false;




    int astartx, aendx;
    int astarty, aendy;
    int adeltax, adeltay;
    
    int bstartx, bendx;
    int bstarty, bendy;
    int bdeltax, bdeltay;
    
    int rows, columns;

    if (image1.x <= image2.x)
    {
        adeltax = image2.x - image1.x;
        columns = MIN(image1.image->width - adeltax, image2.image->width);
        bdeltax = 0;
    }
    else
    {
        bdeltax = image1.x - image2.x;
        columns = MIN(image2.image->width - bdeltax, image1.image->width);
        adeltax = 0;
    }

    if (image1.y <= image2.y)
    {
        adeltay = image2.y - image1.y;
        rows = MIN(image1.image->height - adeltay, image2.image->height);
        bdeltay = 0;
    }
    else
    {
        bdeltay = image1.y - image2.y;
        rows = MIN(image2.image->height - bdeltay, image1.image->height);
        adeltay = 0;
    }

    /* if BOTH images are in a 16bits color format, we will not use masks and will quicken the process */
    if ( IMAGE_IS_RGB16(image1.image->format) && IMAGE_IS_RGB16(image2.image->format) )
    {
        void *data1 = image1.image->data + adeltay * image1.image->stride;
        void *data2 = image2.image->data + bdeltay * image2.image->stride;

        uint16_t *data_u16_1 = (uint16_t *) data1;
        uint16_t *data_u16_2 = (uint16_t *) data2;

        int transp1 = image_alpha(image1.image->format);
        int transp2 = image_alpha(image2.image->format);

        for( int j=0; j<rows; j++)
        {
            for (int i=0; i<columns; i++)
            {
                if(  (data_u16_1[ adeltax + i ] != transp1 )
                  && (data_u16_2[ bdeltax + i ] != transp2 ) )
                  return true;
            }
            data1 += image1.image->stride;
            data_u16_1 = (uint16_t *) data1;
            data2 += image2.image->stride;
            data_u16_2 = (uint16_t *) data2;
        }
        return false;
    }

    /* if BOTH images are in a 8bits color format, we will not use masks and will quicken the process */

    if ( IMAGE_IS_P8(image1.image->format) && IMAGE_IS_P8(image2.image->format) )
    {
        void *data1 = image1.image->data + adeltay * image1.image->stride;
        void *data2 = image2.image->data + bdeltay * image2.image->stride;

        int8_t *data_u8_1 = (int8_t *) data1;
        int8_t *data_u8_2 = (int8_t *) data2;

        int transp1 = image_alpha(image1.image->format);
        int transp2 = image_alpha(image2.image->format);

        for( int j=0; j<rows; j++)
        {
            for (int i=0; i<columns; i++)
            {
                if(  (data_u8_1[ adeltax + i ] != transp1 )
                  && (data_u8_2[ bdeltax + i ] != transp2 ) )
                  return true;
            }
            data1 += image1.image->stride;
            data_u8_1 = (int8_t *) data1;
            data2 += image2.image->stride;
            data_u8_2 = (int8_t *) data2;
        }
        return false;
    }

    /* if we reach that point, this means that images have differnt format and we need to manage this */

    uint8_t d1;
    uint8_t d2;

    void *data1 = image1.image->data + adeltay * image1.image->stride;
    void *data2 = image2.image->data + bdeltay * image2.image->stride;
    
    int8_t *data_u8_1 = (int8_t *) data1;
    uint16_t *data_u16_1 = (uint16_t *) data1;

    int8_t *data_u8_2 = (int8_t *) data2;
    uint16_t *data_u16_2 = (uint16_t *) data2;

    int transp1 = image_alpha(image1.image->format);
    int transp2 = image_alpha(image2.image->format);

    bool im1_P16 = IMAGE_IS_RGB16(image1.image->format);
    bool im1_P8  = IMAGE_IS_P8(image1.image->format);

    bool im2_P16 = IMAGE_IS_RGB16(image2.image->format);
    bool im2_P8  = IMAGE_IS_P8(image2.image->format);

    for( int j=0; j<rows; j++)
    {
        for (int i=0; i<columns; i++)
        {
            /* d1 is set to 1 if pixel of image1 is not transparent and to 0 if transparent */
            /* need to be format dependant here so quite time consumming test at each loop :( )*/
            if (im1_P16)
                d1 = data_u16_1[ adeltax + i ] == transp1 ? 0 : 1;
            else if (im1_P8)
                d1 = data_u8_1[ adeltax + i ] == transp1 ? 0 : 1;
        
            /* d2 is set to 1 if pixel of image2 is not transparent and to 0 if transparent */
            /* need to be format dependant here so quite time consumming test at each loop :( )*/
            if (im2_P16)
                d2 = data_u16_2[ bdeltax + i ] == transp2 ? 0 : 1;
            else if (im2_P8)
                d2 = data_u8_2[ bdeltax + i ] == transp2 ? 0 : 1;

            /* if d1 + d2 = 2 means that both coincident pixels are not transparent and then we have collision*/
            if (d1 + d2 == 2) return true;
        }
        /* we move the pointer to the next line of both images */
        data1 += image1.image->stride;
        data2 += image2.image->stride;
        data_u8_1 = (int8_t *) data1;
        data_u8_2 = (int8_t *) data2;
        data_u16_1 = (uint16_t *) data1;
        data_u16_2 = (uint16_t *) data2;
    }
    return false;
}