Tunnel.c

#include <os.h>
#include "utils.c"
#include "graphics3.c"
#include "touchpad.c"

uint16_t* loadBMP(char *path)
{
    int size, offset, i;
    uint16_t *returnValue, color;
    FILE *temp = fopen(path, "rb");

    // Check if the file's 2 first char are BM (indicates bitmap)
    if(!(fgetc(temp) == 0x42 && fgetc(temp) == 0x4d))
    {
        printf("Image is not a bitmap\n");
        fclose(temp);
        return NULL;
    }

    // Check if the file is in 16-bits-per-pixel format
    fseek(temp, 0x1c, SEEK_SET);
    if(!(fgetc(temp) == 16))
    {
        printf("Wrong format\n");
        fclose(temp);
        return NULL;
    }

    // Gets the 4-bytes raw pixels size, situated at 0x22
    fseek(temp, 0x22, SEEK_SET);
    size = fgetc(temp) | (fgetc(temp) << 8) | (fgetc(temp) << 16) | (fgetc(temp) << 24);
    size >>= 1;

    // Gets the 4-bytes offset to the start of the pixel table, situated at 0x0a
    fseek(temp, 0x0a, SEEK_SET);
    offset = fgetc(temp) | (fgetc(temp) << 8) | (fgetc(temp) << 16) | (fgetc(temp) << 24);

    fseek(temp, offset, SEEK_SET);

    returnValue = malloc(size * sizeof(int));
    if(!returnValue)
    {
        printf("Couldn't allocate memory\n");
        fclose(temp);
        return NULL;
    }

    for(i = size - 1; i >= 0; i--)
    {
        color = (uint16_t)(fgetc(temp) | (fgetc(temp) << 8));
        returnValue[i] = (is_cx ? color : ((int)( 0.229 * (color >> 11) + 0.587 * ((color >> 6) & 0x1f) + 0.114 * (color & 0x1f)) >> 1));
    }
    fclose(temp);
    return returnValue;
}

#define texWidth 256
#define texHeight 256
#define screenWidth 240
#define screenHeight 240

int w = 240, h = 240, x, y;

uint16_t *texture;

int distanceTable[screenWidth][screenHeight];
int angleTable[screenWidth][screenHeight];
int buffer[screenWidth][screenHeight];

void masksprite(void *buffer, int *data, int x, int y, int width, int height, int mask){
    int i, j;
    for(i = 0; i < height; i++){
        for(j = 0; j < width; j++){
            if(data[i*width+j] != mask && x+j < 320 && x+j > 0 && y+i < 240 && y+i > 0){
                setPixelBuf(buffer, x+j, y+i, data[i*width+j]);
            }
        }
    }
}

uint16_t RGBColor(uint8_t r, uint8_t g, uint8_t b)
{
  return ((r / 8) << 11) | ((g / 4) << 5) | (b / 8);
}

int main(void) {
    char *screen;
    screen = (char*)malloc(SCREEN_BYTES_SIZE * sizeof(char));     // just a buffer
    if(!screen)
    {
        exit(0);
    }
    texture = loadBMP("/documents/ndless/texture.bmp.tns");
    if(!texture)
    {
        free(screen);
        exit(0);
    }
    initTP();
    lcd_ingray();
    for(x = 0; x < w; x++)
    for(y = 0; y < h; y++)
    {
        int angle, distance;
        float ratio = 32.0;
        distance = (unsigned int)(ratio * texHeight / sqrt((x - w / 2.0) * (x - w / 2.0) + (y - h / 2.0) * (y - h / 2.0))) % texHeight;
        angle = (unsigned int)(0.5 * texWidth * atan2(y - h / 2.0, x - w / 2.0) / M_PI);
        distanceTable[x][y] = distance;
        angleTable[x][y] = angle;
    }
    float animation = 0;
    int shiftY = (unsigned int)(texHeight * 0.25);
    //begin the loop
    while(!isKeyPressed(KEY_NSPIRE_ESC))
    {
        animation = animation+0.02;
        readTP();
        int TZ = getTouchedZone4();
        //calculate the shift values out of the animation value
        int shiftX = (unsigned int)(texWidth * 1.0 * animation);
        if(isKeyPressed(KEY_NSPIRE_RIGHT) || TZ==6)
            shiftY++;
        if(isKeyPressed(KEY_NSPIRE_LEFT) || TZ==4)
            shiftY--;
        for(x = 0; x < w; x++)
        for(y = 0; y < h; y++)
        {
            //get the texel from the texture by using the tables, shifted with the animation values
            int color = texture[(abs(angleTable[x][y] + shiftY) % texHeight)*texWidth+(abs(distanceTable[x][y] + shiftX)  % texWidth)];
            buffer[x][y] = color;
        }
        masksprite(screen, buffer[0], 0, 0, 240, 240, 0xf800);
        refresh(screen);
        clearBuf(screen);
    }
    free(screen);
    endTP();
    return 0;
}