// STEP 1 of 3
// Change the following defines for compatibility with the TTGO T-DISPLAY

#define EXAMPLE_LCD_BK_LIGHT_ON_LEVEL  1
#define EXAMPLE_PIN_NUM_DATA0          19
#define EXAMPLE_PIN_NUM_PCLK           18
#define EXAMPLE_PIN_NUM_CS             5
#define EXAMPLE_PIN_NUM_DC             16
#define EXAMPLE_PIN_NUM_RST            23
#define EXAMPLE_PIN_NUM_BK_LIGHT       4

#define EXAMPLE_LCD_H_RES              135
#define EXAMPLE_LCD_V_RES              240

// Step 2 of 3
// Change the "display_pretty_colors" near line 60 with the following code

static uint16_t *s_lines[2];
static int xoffset = 52; // EDIT: Add this
static int yoffset = 40; // EDIT: Add this
static void display_pretty_colors(esp_lcd_panel_handle_t panel_handle)
{
    int frame = 0;
    // Indexes of the line currently being sent to the LCD and the line we're calculating
    int sending_line = 0;
    int calc_line = 0;

    // After ROTATE_FRAME frames, the image will be rotated
    while (frame <= ROTATE_FRAME) {
        frame++;
        for (int y = 0; y < EXAMPLE_LCD_V_RES; y += PARALLEL_LINES) {
            // Calculate a line
            pretty_effect_calc_lines(s_lines[calc_line], y, frame, PARALLEL_LINES);
            sending_line = calc_line;
            calc_line = !calc_line;
            // Send the calculated data. EDIT: The line below is the only one that has changed
            esp_lcd_panel_draw_bitmap(panel_handle, xoffset + 0, yoffset + y, xoffset +  + EXAMPLE_LCD_H_RES, yoffset + y + PARALLEL_LINES, s_lines[sending_line]);
        }
    }
}

// Step 3 of 3
// Update the width and height to match the display 

#include <math.h>
#include "pretty_effect.h"
#include "sdkconfig.h"
#include "decode_image.h"

#define PIX_WIDTH 135
#define PIX_HEIGHT 240

uint16_t **pixels;

//Grab a rgb16 pixel from the esp32_tiles image
static inline uint16_t get_bgnd_pixel(int x, int y)
{
    //Image has an 8x8 pixel margin, so we can also resolve e.g. [-3, 243]
    x+=8;
    y+=8;
    return pixels[y][x];
}

//This variable is used to detect the next frame.
static int prev_frame=-1;

//Instead of calculating the offsets for each pixel we grab, we pre-calculate the valueswhenever a frame changes, then re-use
//these as we go through all the pixels in the frame. This is much, much faster.
static int8_t xofs[PIX_WIDTH], yofs[PIX_HEIGHT];
static int8_t xcomp[PIX_WIDTH], ycomp[PIX_HEIGHT];

//Calculate the pixel data for a set of lines (with implied line size of 320). Pixels go in dest, line is the Y-coordinate of the
//first line to be calculated, linect is the amount of lines to calculate. Frame increases by one every time the entire image
//is displayed; this is used to go to the next frame of animation.
void pretty_effect_calc_lines(uint16_t *dest, int line, int frame, int linect)
{
    if (frame!=prev_frame) {
        //We need to calculate a new set of offset coefficients. Take some random sines as offsets to make everything
        //look pretty and fluid-y.
        for (int x=0; x<PIX_WIDTH; x++) xofs[x]=sin(frame*0.15+x*0.06)*4;
        for (int y=0; y<PIX_HEIGHT; y++) yofs[y]=sin(frame*0.1+y*0.05)*4;
        for (int x=0; x<PIX_WIDTH; x++) xcomp[x]=sin(frame*0.11+x*0.12)*4;
        for (int y=0; y<PIX_HEIGHT; y++) ycomp[y]=sin(frame*0.07+y*0.15)*4;
        prev_frame=frame;
    }
    for (int y=line; y<line+linect; y++) {
        for (int x=0; x<PIX_WIDTH; x++) {
            *dest++=get_bgnd_pixel(x+yofs[y]+xcomp[x], y+xofs[x]+ycomp[y]);
        }
    }
}

esp_err_t pretty_effect_init(void)
{
    return decode_image(&pixels);
}