Complete code for displaying a sprite
#include <huc.h>
#incspr(logo, "logo.png", 0, 0, 2, 12)
#incpal(logo_pal, "logo.png")
void main() {
load_palette(16, logo_pal, 1);
load_vram(0x5000, logo, 0x800);
init_satb();
spr_set(0);
spr_x(0);
spr_y(0);
spr_pattern(0x5000);
spr_ctrl(FLIP_MAS|SIZE_MAS, NO_FLIP|SZ_32x32);
spr_pal(0);
spr_pri(0);
satb_update();
}
## Animating a Sprite
With our sprite displayed on screen, let's have some fun with it.
We'll want to make it bounce around the screen and change frame when it hits a side of the screen.
Let's add some constants and variables in our `main` above where we draw the sprite:
```c
#define SCREEN_WIDTH 232
#define SCREEN_HEIGHT 184
int speedx = 1; // X velocity
int speedy = 1; // Y velocity
int logox = 100; // Starting x position
int logoy = 100; // Starting y position
int frame = 0; // Current animation frame
```
Following the last line of drawing the sprite we need a `while` loop and some conditions:
```c
while(1) {
// Update position
logox += speedx;
logoy += speedy;
// Bounce off screen edges
if(logox <= 0 || logox >= SCREEN_WIDTH-8) {
speedx = -speedx;
frame = (frame + 1) % 6;
}
if(logoy <= 0 || logoy >= SCREEN_HEIGHT+8) {
speedy = -speedy;
frame = (frame + 1) % 6;
}
// Update sprite
}
```
This is fairly basic stuff that adds the velocity to the position of the sprite so that it moves , then checks if it has collided with the bounds of the screen.
{% hint style="info" %}
We're adjusting the screen height and width by 8, to account for the sprite.
{% endhint %}
This line is how we update the frame of the animation, using a modulo to ensure that the number never exceeds the maximum number of frames, 6 in this case.
```c
frame = (frame + 1) % 6;
```
Now in the `while` loop we need to pass this to update the sprite.
First, again we need to say which sprite we are updating:
```c
spr_set(0);
```
Then set the x and y positions of the sprite again:
```c
spr_x(logox);
spr_y(logoy);
```
Here we update the data in the sprite pattern based on the frame, from the data in VRAM.
```c
spr_pattern(0x5000 + (frame * 0x100));
```
Now update the sprite:
```c
satb_update();
```
Finally, we need to add a `vsync()` so that we lock the rendering to 60fps.
Compile and run: