C++ - Blocks don't move and my array does not work - c++

Question

I'm trying to make a game using C++ in SFML for the first time.
Want : 6 blocks fall from random top to bottom.
Result : 1 block stay at the top.
How should I fix in this code?
#include <SFML/Graphics.hpp>
#include <vector>
#include <time.h>
using namespace sf;
using namespace std;
struct Position{
int x;
int y;
};
int main()
{
srand(time(NULL));
RenderWindow window(VideoMode(600, 480), "AVOID BLOCKS");
window.setFramerateLimit(60);
Texture t1, t2;
t1.loadFromFile("images/block.png");
t2.loadFromFile("images/cha2.png");
Sprite block(t1), cha2(t2);
Position blockPos;
blockPos.y = 0 + t1.getSize().y;
cha2.setPosition(300, 400);
float blockSpeed = 4;
const int size = 6;
vector<Sprite> blocks(6);
int n = 0;
auto bsize = t1.getSize();
for (int i = 0; i < 6; i++) {
blocks[n].setTexture(t1);
blocks[n].setPosition(rand()%10*bsize.x, 0);
n++;
}
while (window.isOpen())
{
Event e;
while (window.pollEvent(e)) {
if (e.type == Event::Closed)
window.close();
}
auto cha2_pos = cha2.getPosition();
if (Keyboard::isKeyPressed(Keyboard::Left)) {
if (cha2.getPosition().x < 0)
continue;
cha2.move(-5.0, 0.0);
}
if (Keyboard::isKeyPressed(Keyboard::Right)) {
if (cha2.getPosition().x > 600)
continue;
cha2.move(5.0, 0.0);
}
if (blockPos.y >= 480) {
blockPos.y = 0 + t1.getSize().y;
blockSpeed = blockSpeed + 0.2;
}
else
blockPos.y += blockSpeed;
for (int i = 0; i < blocks.size(); i++) {
if (FloatRect(cha2_pos.x + 3, cha2_pos.y + 3, 10, 10).
intersects(blocks[i].getGlobalBounds())) {
window.close();
}
}
window.clear();
window.draw(block);
window.draw(cha2);
window.display();
}
return 0;
}
The character at the bottom moves well.
I have no idea why block doesn't move and there's only one.
I think there's something wrong in the part starts "const int size".

Answer 1

Your program have two main problems. First of all, you don't draw all the blocks in the vector but you draw only the particular block you have made. This is why you see only one block on screen and not all the blocks you have create. The solution for this is:
for(auto& blk : blocks)
window.draw(blk);
The second problem affects the movement of the blocks. You have create a struct Position but you never associated with the blocks. So after you increase blockPos.y, you must move the blocks at that new blockPos.y. Explicit:
for(auto& blk : blocks)
blk.setPosition(blockPos.x, blockPos.y);
In this way you will have the problem that every block will be in the exact same position with the others because the blockPos variable is common for all blocks. A good idea is to make a class Block so which block to have his own position and movement. An example to what I say is:
class Block {
private:
Sprite block;
Position blockPos;
public:
Block(Texture& texture, int x, int y)
{
block.setTexture(texture);
blockPos.y = y;
blockPos.x = x; // save this value because you will need it
// every time you move the block
}
void setBlockPosition(float y)
{
blockPos.y = y;
}
Vector2<float> getBlockPosition()
{
return Vector2f(blockPos.x, blockPos.y);
}
void blockMovement(int y)
{
blockPos.y += y;
block.setPosition(blockPos.x, blockPos.y);
}
Sprite getSprite()
{
return block;
}
void Draw(RenderWindow& window)
{
window.draw(block);
}
};
After that I declare a vector with the new dynamic objects:
vector<Block*> blocks(6);
for(unsigned int i = 0; i < blocks.size(); i++)
{
blocks[i] = new Block(t1, rand()%10*t1.getSize().x ,0 - t1.getSize().y);
}
I change your if statements also:
for(unsigned int i = 0; i < blocks.size(); i++) //check for which block in the vector
{
if (blocks[i]->getBlockPosition().y >= 480) {
blocks[i]->setBlockPosition(0 - 200);
blockSpeed = blockSpeed + 0.2;
}
else {
blocks[i]->blockMovement(blockSpeed);
}
}
for (unsigned int i = 0; i < blocks.size(); i++) {
if (FloatRect(cha2_pos.x + 3, cha2_pos.y + 3, 10, 10)
.intersects(blocks[i]->getSprite().getGlobalBounds())) {
window.close();
}
}
Don't forget at the end to delete the objects because they was allocate dynamically:
for(unsigned int i = 0; i < blocks.size(); i++)
delete blocks[i];
return 0;