I have a simple SDL2 window that i'm trying to draw a path on.
I can click ten times and draw out a line with this code
if (button == SDL_BUTTON_LEFT)
{
if (Path.size() == Clicks) return;
// Clicks is set by the initializer
// Path is a vector of SDL_Points
SDL_Point p;
p.x = x;
p.y = y;
Path.push_back(p);
}
SDL_Point *points = new SDL_Point[Clicks];
for (int i = 0; i < Path.size(); i++)
{
if (i == Clicks) break;
points[i] = Path[i];
}
SDL_RenderClear(ren);
SDL_SetRenderDrawColor(ren, 0, 255, 0, 255);
SDL_RenderDrawLines(ren, points, Clicks);
Which works fine, it allows me to draw a path with no issue, however, it creates a sort of ghost line that flies off the top of the screen.
Here's a picture of the line.
Is there anything I can do to get rid of this line and use SDL_RenderDrawLines? If not what call should I use?
to me it looks more like a problem with the parameters for SDL_RenderDrawLines()
Have you checked the size of points and the value of Clicks?
Related
I have a grid of 300x300 cells. I am checking each cell individually which means I am checking 90000 cells atleast every second. Now, I know, one second is pretty fast considering the cpu is going through 300^2 different cells. But this stuff just isn't fast enough. I watched a guy on youtube who got his simulation to update every 20 ms. And he was running 512^2 cells. How is this possible? Optimizations? Is my computer a potato? I'll show my code if anyone wants to see exactly what i'm doing.
for (int y = GY; y >= 0; y--)
for (int x = 0; x < GX; x++) {
cell* cell_pointer = &grid[x][y];
if (grid[x][y].CellT == type::SAND) {
if (grid[x][y+1].CellT == type::AIR) {
if (y+1 > GY-1) {
continue;
}
cell* cell_below = &grid[x][y+1];
cell_below->Color ={ 255,0,0 };
cell_below->CellT = type::SAND;
cell_pointer->Color ={ 0,0,0 };
cell_pointer->CellT = type::AIR;
}
else if (grid[x+1][y+1].CellT == type::AIR) {
cell* cell_below = &grid[x+1][y+1];
cell_below->Color ={ 255,0,0 };
cell_below->CellT = type::SAND;
cell_pointer->Color ={ 0,0,0 };
cell_pointer->CellT = type::AIR;
}
else if (grid[x-1][y+1].CellT == type::AIR) {
cell* cell_below = &grid[x-1][y+1];
cell_below->Color ={ 255,0,0 };
cell_below->CellT = type::SAND;
cell_pointer->Color ={ 0,0,0 };
cell_pointer->CellT = type::AIR;
}
}
}
The code above is my update function. I am updating the cells bottom to top, left to right. It's a sand simulation which is why we're checking the bottom left, bottom right as well as the bottom neighboring cells.
//Square//
SDL_SetRenderDrawColor(renderer, 0, 0, 255, 255);
SDL_RenderClear(renderer);
//////////
int X = floor(mousePos.x/r.w);
int Y = floor(mousePos.y/r.h);
if (left) {
grid[X][Y].CellT = type::SAND;
grid[X][Y].Color ={ 255,0,0 };
}
if (right) {
grid[X][Y].CellT = type::WALL;
grid[X][Y].Color ={ 0,255,0 };
}
for (int y = 0; y < GY; y++)
for (int x = 0; x < GX; x++) {
cell* cell_pointer = &grid[x][y];
SDL_SetRenderDrawColor(renderer, cell_pointer->Color.r, cell_pointer->Color.g, cell_pointer->Color.b, 255);
r.x = cell_pointer->PosG.x;
r.y = cell_pointer->PosG.y;
SDL_RenderFillRect(renderer, &r);
}
SDL_RenderPresent(renderer);
SDL_UpdateWindowSurface(window);
The code above is my draw function. I am using SDL as my graphics API. I am getting the mouse position relative to the grids so that when I click left or right mouse buttons I can draw a sand cell or a wall cell. So I am checking each cell individually top to bottom and left to right and then drawing a square individually where the cell's position is.
I'm working on a small game for school. I tiled an image on screen, but every time my character moves I have to re-tile it (the tiles are behind the character, because it's a grid and the character moves in the cells). I tried to tile everything onto a different surface, and then have that surface blit onto my screen surface to avoid having to retile it every single time and save on process time.
It didn't really work, it's like the surface that I tile on forgets what was tiled onto it. It doesn't error it, it just doesn't display the tiled surface on my window surface.
Here's my code (the relevant part at least)
void postaviTiles() {
SDL_BlitSurface(cell, NULL, polje, &offsetcell); //cell
for (int i = 0; i < 89; i++) {
SDL_Delay(5);
if (offsetcell.x < 450) {
offsetcell.x += 50;
SDL_BlitSurface(cell, NULL, polje, &offsetcell);
}
else {
offsetcell.x = 9;
offsetcell.y += 50;
SDL_BlitSurface(cell, NULL, polje, &offsetcell);
}
SDL_UpdateWindowSurface(okno);
}
poljezrisano = true;
}
//--------------------------------------------------------------//
void tileCells() {
if (poljezrisano == false) {
postaviTiles();}
SDL_BlitSurface(polje, NULL, oknoSurface, NULL); //cell
SDL_UpdateWindowSurface(okno);
}
//--------------------------------------------------------------//
Worth mentioning is that tiling it every single time works fine, but I want to tile it once, have that on a surface and then just blit that surface onto my screen surface.
P.S.: Sorry about most of the variables and function names not being in English
The SDL_BlitSurface takes in a source surface, a clip of that source surface, then the destination surface and a position where you want to display (blit) your source.
The last parameter thats passed to SDL_BlitSurface ignores the width and height, it just takes in the x an y.
Here is a quote from the documentation:
The width and height in srcrect determine the size of the copied rectangle. Only the position is used in the dstrect (the width and height are ignored).
And the prototype for the function:
int SDL_BlitSurface(SDL_Surface* src,
const SDL_Rect* srcrect,
SDL_Surface* dst,
SDL_Rect* dstrect)
That's one thing to keep in mind, not sure if that applies to your case, since your variable names aren't English.
But essentially with this line:
SDL_BlitSurface(cell, NULL, polje, &offsetcell);
You are telling SDL that you want all of cell placed inside polje at the position offsetcell.x and offsetcell.y with the width of cell.w and the height of cell.h.
If you wanted to place cell inside polje using the width and height of offsetcell then you would have to use another blit function, namely SDL_BlitScaled
Here is how I would blit tiles inside a grid (map).
SDL_Surface* grid; // assuming this is the new grid surface that holds the blited tiles
SDL_Surface* tile; // assuming this is a single tile of width 50, height 50
SDL_Surface* windowSurface;
SDL_Window* window;
int TileWidth = 50;
int TileHeight = 50;
int NumTiles = 90;
int TileColumns = 450 / TileWidth; // = 9, so we have a grid of 9X10
bool isFillGridTiles = false;
void FillGridTiles()
{
for (int i = 0;i < NumTiles; i++)
{
auto y = i / TileColumns; // divide to get the y position and...
auto x = i % TileColumns; // the remainder is the x position inside the grid
SDL_Rect srcClip;
srcClip.x = 0;
srcClip.y = 0;
srcClip.w = TileWidth;
srcClip.h = TileHeight;
SDL_Rect dstClip;
dstClip.x = x * TileWidth;
dstClip.y = y * TileHeight;
dstClip.w = TileWidth;
dstClip.h = TileHeight;
SDL_BlitSurface(tile, &srcClip, grid, &dstClip); //since we have the same width and height, we can use SDL_BlitSurface instead of SDL_BlitScaled
}
isFillGridTiles = true;
}
void BlitOnScreen()
{
if(!isFillGridTiles)
{
FillGridTiles();
}
SDL_BlitSurface(grid, NULL, windowSurface, NULL);
SDL_UpdateWindowSurface(window);
}
Not sure if the code is complete as posted, but it seems you are not initializing offsetcell. That fits the symptom of having nothing show up. Explicit definition of offsetcell might be better than the incremental method you've provided. For example:
for( offsetcell.x = 0; offsetcell.x < 450; offsetcell.x += 50) {
for( offsetcell.y = 0; offsetcell.y < 450; offsetcell.y += 50) {
...
}
}
I'm writing a video poker game and I'm having a problem with a hand being drawn and then replaced when a new round is started.
The idea is you start with five cards, you select which cards to keep and then the others are switched out when you click "deal", you will then be shown your new cards and told what you've won, after that you will be asked to start a new round, when you click "new round" the deck that was used previously should be discarded, a new hand taken from that deck and then drawn onto the screen.
The first two things work, the problem is that when I click "new round" it very quickly draws the hand to the screen and then replaces it with another hand, this doesn't effect the players bet, the money they have, absolutely nothing, it took me a while to notice that it was actually happening.
I can't post a working example, that would require the entire game to be uploaded (my code isn't very elegant) but I will try to show the relevant text.
Main:
int main(int argc, char *argv[])
{
srand(time(NULL));
//load static cards
SDL_Surface* deal_card = load_surface("resources/images/cards/misc/deal.png");
SDL_Surface* round_card = load_surface("resources/images/cards/misc/new_round.png");
SDL_Surface* held = load_surface("resources/images/cards/effect/held.png");
//initiate standard sdl modules
if(!init())
{
printf("fail init");
}
//initiate SDL_ttf
else if(TTF_Init() == -1)
{
printf("TTF INit fail");
}
else
{
//should exit
bool quit = false;
//events
SDL_Event e;
//font and font colour to be used for rendering text1
TTF_Font* font = TTF_OpenFont("resources/fonts/OpenSans-Regular.ttf", 18);
SDL_Color text_colour = {236, 251, 100};
//create a new deck, draw out a hand, sort it numerically, setup images and positions for cards
vector<card>my_deck = new_shuffled_deck();
vector<card>my_hand = hand(my_deck);
sort_hand(my_hand);
setup_hand(my_hand);
//should switch cards that are not held and remove those used
//must be TRUE on start otherwise the first deal will duplicate cards
bool switch_hand = true;
int round_number = 1;
//get or set bet information
read_bet(player_pot, cash_borrowed);
while(!quit)
{
//starting mouse position
int mouse_x_pos = 0;
int mouse_y_pos = 0;
//push current mouse position to starting mouse positions
SDL_GetMouseState(&mouse_x_pos, &mouse_y_pos);
//set up to blit hold icon
update_hold_position(my_hand);
//check for winning hand
winning_hand hand_details = my_scores.card_check(my_hand, bet_amount);
//setup render and blit text
render_and_blit_text(font, hand_details, player_pot, cash_borrowed, text_colour);
scoring_text(font, hand_details, text_colour);
//switch out cards that are not held
if(switch_hand == true)
{
swap_cards(my_hand, my_deck);
}
switch_hand = false;
while(SDL_PollEvent(&e) != 0)
{
if(e.type == SDL_QUIT)
{
quit = true;
}
if(e.type == SDL_MOUSEBUTTONDOWN)
{
//set mouse position to carry over without resetting
int n_mouse_pos_x = mouse_x_pos;
int n_mouse_pos_y = mouse_y_pos;
//check if card is clicked, if is selected de-select, if not selected then select
for(size_t cpc = 0; cpc < my_hand.size(); cpc++)
{
// if mouse position is in range of left side of card and right side of card
if(n_mouse_pos_x > my_hand[cpc].position.x and n_mouse_pos_x < my_hand[cpc].position.x + my_hand[cpc].image->w &&
n_mouse_pos_y > my_hand[cpc].position.y and n_mouse_pos_y < my_hand[cpc].position.y + my_hand[cpc].image->h)
{
//if clicked un-click, if un-clickde click
if(my_hand[cpc].selected == 0)
{
my_hand[cpc].selected = 1;
}
else if(my_hand[cpc].selected == 1)
{
my_hand[cpc].selected = 0;
}
}
}
//if deal is clicked
if(n_mouse_pos_x > deal_rect.x and n_mouse_pos_x < deal_rect.x + deal_card->w &&
n_mouse_pos_y > deal_rect.y and n_mouse_pos_y < deal_rect.y + deal_card->h)
{
//switch held cards, if last round switch entire hand, update cash
deal_clicked(switch_hand, round_number, my_hand, my_deck, cash_borrowed, player_pot, amount_won,
bet_amount, hand_details);
}
}
}
//blit section
//blit cards to screen
blit_cards(my_hand, round_number, held, screen_surface, deal_rect, round_card, deal_card);
SDL_Surface* fill_screen;
fill_screen = SDL_CreateRGBSurface(0, screen_width, screen_height, 32, 0, 0, 0, 0);
SDL_UpdateWindowSurface(window);
SDL_FillRect(screen_surface, 0, SDL_MapRGB(fill_screen->format, 18, 17, 233));
SDL_FreeSurface(fill_screen);
SDL_Delay(30);
}
}
close();
return 0;
}
Swap cards:
void swap_cards(vector<card>&my_hand, vector<card>&my_deck)
{
for(size_t b = 0; b < my_hand.size(); b++)
{
if(my_hand[b].selected == false)
{
SDL_FreeSurface(my_hand[b].image);
//replace card with card of the same index from the deck
my_hand[b] = my_deck[b];
// remove card from deck so it cannot be chosen again
my_deck.erase(my_deck.begin() + b);
}
else
{
// this prevents memory leak on held cards, no idea why.
SDL_FreeSurface(my_hand[b].image);
}
}
//set up images and position for cards again
setup_hand(my_hand);
}
Deal clicked:
void deal_clicked(bool &switch_hand, int &round_number, vector<card>&my_hand, vector<card>&my_deck,
int &cash_borrowed, int &player_pot, int &amount_won, int& bet_amount, winning_hand &hand_details)
{
switch_hand = true;
round_number++;
// aka if(round_number % 2 == 0 and round_number != 0)
if(round_number == 3)
{
//free card surface images
for(size_t d = 0; d < my_hand.size(); d++)
{
SDL_FreeSurface(my_hand[d].image);
}
vector<card>().swap(my_deck);
//replace deck with new deck
my_deck = new_shuffled_deck();
//draw new hand
vector<card>().swap(my_hand);
my_hand = hand(my_deck);
//sort hand by card number
sort_hand(my_hand);
//load images and position cards
setup_hand(my_hand);
//set round number back to beginning
round_number = 1;
//distribute winnings and take next bet amount
amount_won = hand_details.hand_score;
if(cash_borrowed > 0)
{
cash_borrowed -= amount_won;
}
else if(cash_borrowed < 0)
{
player_pot += abs(cash_borrowed);
cash_borrowed = 0;
}
else
{
player_pot += amount_won;
}
if(player_pot <= 0)
{
cash_borrowed +=5;
}
else
{
player_pot -= bet_amount;
}
write_bet(player_pot, cash_borrowed);
}
}
Hopefully that should be enough for someone to have an idea about where my problem is coming from.
If anyone wants more code I can post it, it jut gets even more messy, these are the only areas I think could be causing the problem, then again I can't figure out what it is.
EDIT:
Solved, duplicate call to the setup_hand function.
Duplicate call to setup_hand function.
I have this 800x600square I want to draw to the screen. I want to 'cut' circles in it (where alpha would be 0). Basically I'm drawing this whole rectangle over a map so in these 'circles' I drew, you can see the map, otherwise you see the grey square
So, I assume you're trying to add fog of war to one of you game?
I had a small demo I made for a local University a few weeks ago to show A* pathfinding, so I thought I could add fog of war to it for you. Here's the results:
Initial map
First, you start with a complete map, totally visible
Fog
Then, I added a surface to cover the entire screen (take note that my map is smaller than the screen, so for this case I just added fog of war on the screen, but if you have scrolling, make sure it covers each map pixel 1:1)
mFogOfWar = SDL_CreateRGBSurface(SDL_HWSURFACE, in_Width, in_Height, 32, 0x00ff0000, 0x0000ff00, 0x000000ff, 0xff000000);
SDL_Rect screenRect = {0, 0, in_Width, in_Height};
SDL_FillRect(mFogOfWar, &screenRect, 0xFF202020);
Then, you need to draw it... I added this call after drawing the game objects and before drawing the UI
DrawSurface(mFogOfWar, 0, 0);
Where
void RenderingManager::DrawSurface(SDL_Surface* in_Surface, int in_X, int in_Y)
{
SDL_Rect Dest = { in_X, in_Y, 0, 0 };
SDL_BlitSurface(in_Surface, NULL, mScreen, &Dest);
}
Which should give you the following result:
"Punch Surface"
I then created a 32 bits .png that looks like this (checkerboard shows alpha)
When rendering my main character, I added this call:
gRenderingManager.RemoveFogOfWar(int(mX) + SPRITE_X_OFFSET, int(mY) + SPRITE_Y_OFFSET);
The offset is only there to center the punch with the sprite, basically, what I'm passing to RemoveFogOfWar is the center of my sprite.
Remove Fog Of War
Now the meat of the fog of war. I did two versions, one where Fog of War is removed permanently and one where the fog of war is reset. My fog of war reset relies on my punch surface to have a contour where the alpha is reset to 0 and the fact that my character moves of less pixels than the contour contains per frame, otherwise I would keep the Rect where my punch was applied and I would refill it before drawing again the new punch.
Since I couldn't find a "multiply" blend with SDL, I decided to write a simple function that iterates on the punch surface and updates the alpha on the fog of war surface. The most important part is to make sure you stay within the bounds of your surfaces, so it takes up most of the code... there might be some crop functions but I didn't bother checking:
void RenderingManager::RemoveFogOfWar(int in_X, int in_Y)
{
const int halfWidth = mFogOfWarPunch->w / 2;
const int halfHeight = mFogOfWarPunch->h / 2;
SDL_Rect sourceRect = { 0, 0, mFogOfWarPunch->w, mFogOfWarPunch->h };
SDL_Rect destRect = { in_X - halfWidth, in_Y - halfHeight, mFogOfWarPunch->w, mFogOfWarPunch->h };
// Make sure our rects stays within bounds
if(destRect.x < 0)
{
sourceRect.x -= destRect.x; // remove the pixels outside of the surface
sourceRect.w -= sourceRect.x; // shrink to the surface, not to offset fog
destRect.x = 0;
destRect.w -= sourceRect.x; // shrink the width to stay within bounds
}
if(destRect.y < 0)
{
sourceRect.y -= destRect.y; // remove the pixels outside
sourceRect.h -= sourceRect.y; // shrink to the surface, not to offset fog
destRect.y = 0;
destRect.h -= sourceRect.y; // shrink the height to stay within bounds
}
int xDistanceFromEdge = (destRect.x + destRect.w) - mFogOfWar->w;
if(xDistanceFromEdge > 0) // we're busting
{
sourceRect.w -= xDistanceFromEdge;
destRect.w -= xDistanceFromEdge;
}
int yDistanceFromEdge = (destRect.y + destRect.h) - mFogOfWar->h;
if(yDistanceFromEdge > 0) // we're busting
{
sourceRect.h -= yDistanceFromEdge;
destRect.h -= yDistanceFromEdge;
}
SDL_LockSurface(mFogOfWar);
Uint32* destPixels = (Uint32*)mFogOfWar->pixels;
Uint32* srcPixels = (Uint32*)mFogOfWarPunch->pixels;
static bool keepFogRemoved = false;
for(int x = 0; x < destRect.w; ++x)
{
for(int y = 0; y < destRect.h; ++y)
{
Uint32* destPixel = destPixels + (y + destRect.y) * mFogOfWar->w + destRect.x + x;
Uint32* srcPixel = srcPixels + (y + sourceRect.y) * mFogOfWarPunch->w + sourceRect.x + x;
unsigned char* destAlpha = (unsigned char*)destPixel + 3; // fetch alpha channel
unsigned char* srcAlpha = (unsigned char*)srcPixel + 3; // fetch alpha channel
if(keepFogRemoved == true && *srcAlpha > 0)
{
continue; // skip this pixel
}
*destAlpha = *srcAlpha;
}
}
SDL_UnlockSurface(mFogOfWar);
}
Which then gave me this with keepFogRemoved = false even after the character had moved around
And this with keepFogRemoved = true
Validation
The important part is really to make sure you don't write outside of your pixel buffer, so watch out with negative offsets or offsets that would bring you out of the width or height. To validate my code, I added a simple call to RemoveFogOfWar when the mouse is clicked and tried corners and edges to make sure I didn't have a "off by one" problem
case SDL_MOUSEBUTTONDOWN:
{
if(Event.button.button == SDL_BUTTON_LEFT)
{
gRenderingManager.RemoveFogOfWar(Event.button.x, Event.button.y);
}
break;
}
Notes
Obviously, you don't need a 32 bits texture for the "punch", but it was the clearest way I could think of to show you how to do it. It could be done using as little as 1 bit per pixel (on / off). You can also add some gradient, and change the
if(keepFogRemoved == true && *srcAlpha > 0)
{
continue; // skip this pixel
}
To something like
if(*srcAlpha > *destAlpha)
{
continue;
}
To keep a smooth blend like this:
3 State Fog of War
I thought I should add this... I added a way to create a 3 state fog of war: visible, seen and fogged.
To do this, I simply keep the SDL_Rect of where I last "punched" the fog of war, and if the alpha is lower than a certain value, I clamp it at that value.
So, by simply adding
for(int x = 0; x < mLastFogOfWarPunchPosition.w; ++x)
{
for(int y = 0; y < mLastFogOfWarPunchPosition.h; ++y)
{
Uint32* destPixel = destPixels + (y + mLastFogOfWarPunchPosition.y) * mFogOfWar->w + mLastFogOfWarPunchPosition.x + x;
unsigned char* destAlpha = (unsigned char*)destPixel + 3;
if(*destAlpha < 0x60)
{
*destAlpha = 0x60;
}
}
}
mLastFogOfWarPunchPosition = destRect;
right before the loop where the fog of war is "punched", I get a fog of war similar to what you could have in games like StarCraft:
Now, since the "seen" fog of war is semi transparent, you will need to tweak your rendering method to properly clip "enemies" that would be in the fog, so you don't see them but you still see the terrain.
Hope this helps!
I've recently tried making an inventory system in allegro 5, where I draw a grid of squares 20x20 and drag-drop items around. The problem is, I can see the item sprite going under the actual grid that I drew, which is an unwanted effect. Here's my code:
if(draw)
{
draw = false;
al_draw_bitmap(image, item.posx, item.posy, 0);
if(mouseKey)
{
grab = true;
item.posx = mouse.posx - (item.boundx-5);
item.posy = mouse.posy - (item.boundy-5);
}
else if(mouseKey == false && grab == true)
{
for(int i = 0; i < mouse.posx; i += 20)
{
if(i < mouse.posx)
item.posx = i;
}
for(int j = 0; j < mouse.posy; j += 20)
{
if(j < mouse.posy)
{
item.posy = j;
}
}
grab = false;
}
for(int i = 0; i <= width; i += 20)
{
al_draw_line(i, 0, i, height, al_map_rgb(0, 0, 0), 1);
al_draw_line(0, i, width, i, al_map_rgb(0, 0, 0), 1);
}
al_flip_display();
al_clear_to_color(al_map_rgb(40,40,40));
}
(I know it's terribly written and un-optimized but I wrote it in about 10 minutes simply as a test)
How can I make it so the item sprite does not display the lines over it? Here's an example of my problem if I was too vague:
I'm using Codeblocks IDE on windows XP
Unless you fiddle with OpenGL settings, you're going to always get the things you draw last on top. So in this case, simply move al_draw_bitmap(image, item.posx, item.posy, 0); to be directly above al_flip_display().
Note that you will have some problems because you are manipulating item.posx and item.posy in that section, so you'd have to first cache the results:
int x = item.posx;
int y = item.posy;
// ...
al_draw_bitmap(image, x, y, 0);
al_flip_display();
However, that's just a bandaid over the larger problem: you shouldn't be changing anything inside your drawing block. The entire if/else block should be elsewhere. i.e.:
if (event timer is a game tick)
{
do all logic stuff
draw = true
}
if (draw)
{
do all drawing stuff
draw = false;
}