Allegro Flickering Graphics
Hello. I am mostly new to programming, I have been learning straight C for about two months and I have been trying to apply what I am learning to simple game programming with Allegro. But, I have hit kind of a snag. I wrote the beginnings of a very basic "game" and I am trying to compartmentalize some of it into functions to start getting things out of main. My problem is that when I call the draw_platform function that should draw a rectangular platform from a set of variables I send it from main, (among other bad things that I will figure out later) the graphics flicker like crazy. I do not have this problem unless I call the draw_platform function. I am using a buffer and I have also tried other suggestions I have seem on this forum like using vsync(). But that didn't work. Here is the code.
Code:
#include <allegro.h>
int main(int argc, char *argv[])
{
allegro_init();
install_keyboard();
set_color_depth(16);
set_gfx_mode(GFX_AUTODETECT, 640,480,0,0);
BITMAP *cursor;
cursor = load_bitmap( "cursor.bmp", NULL);
BITMAP *buffer;
buffer = create_bitmap(640, 480);
int playerx = 320;//cursor origin
int playery = 240;
int moveright_p1 = 1;
int lp1_x = 250, rp1_x = 300;
int ground_collide = 0;
int ceiling_collide = 0;
int right_collide = 0;
int left_collide = 0;
int player_jump = 0;
int height = 470;
int jumpheight = 350;
int draw_platform( int, int, int, int, int, int, int, int, int, int, int, int);
while ( !key[KEY_ESC] )
{
int left_edge_p1 = lp1_x - 8;
clear_keybuf();
acquire_screen();
line( buffer, lp1_x, 380, lp1_x, 400, makecol( 255, 0, 0)); //left
line( buffer, rp1_x, 380, rp1_x, 400, makecol( 255, 0, 0)); //right
line( buffer, lp1_x, 380, rp1_x, 380, makecol( 255, 0, 0)); //top
line( buffer, lp1_x, 400, rp1_x, 400, makecol( 255, 0, 0)); //bottom
line( buffer, 0, 0, 0, 480, makecol( 255, 0, 0)); //border
line( buffer, 0, 0, 640, 0, makecol( 255, 0, 0));
line( buffer, 639, 0, 639, 480, makecol( 255, 0, 0)); //player
line( buffer, 0, 479, 640, 479, makecol( 255, 0, 0));
draw_platform( 100, 100, 50, 50, 620, 20, 1, 1, 0, 255, 0, 0);
masked_blit( cursor, buffer, 0, 0, playerx, playery, 8, 8 ); //buffer
blit( buffer, screen, 0, 0, 0, 0, 640, 480);
if( moveright_p1 == 1 ) //platform 1 movement
{
++lp1_x, ++rp1_x;
if( rp1_x == 620 ) moveright_p1 = 0;
}
else
{
--lp1_x, --rp1_x;
if( lp1_x == 20 ) moveright_p1 = 1;
}
ground_collide = 0; //ground collide
if ( (playery == 470) || ( (playery == 371) && (playerx > left_edge_p1) && (playerx < rp1_x) ) ) ground_collide = 1;
if ( ground_collide == 1 )
{
if (playery == 470) height = 0;
if ( (playery == 371) && (playerx > left_edge_p1 ) && (playerx < rp1_x) ) //platform 1 ground collision
{
if (moveright_p1 == 1) ++playerx;
else --playerx;
}
if (key[KEY_UP])
{
player_jump = 1;
ground_collide = 0;
}
}
else ++playery; //gravity
left_collide = 0; //left of object collide
if ( (playerx == 630) || ( (playerx >= left_edge_p1 ) && (playery < 401) && (playery > 371) && (playerx <= left_edge_p1 + 8) ) ) left_collide = 1;
if (left_collide == 1)
{
if ( (playerx >= left_edge_p1 ) && (playerx <= left_edge_p1 + 8) && (playery < 401) && (playery > 371) && (moveright_p1 == 0) ) --playerx;
}
else
if ( left_collide == 0 )
{
if (key[KEY_RIGHT])
{
playerx+=1;
}
}
right_collide = 0; //right of object collide
if ( (playerx == 1) || ( (playerx >= rp1_x - 1 ) && (playery < 401) && (playery > 371) && (playerx <= rp1_x + 7) ) ) right_collide = 1;
if (right_collide == 1)
{
if ( (playerx == rp1_x - 1 ) && (playery < 401) && (playery > 371) && (moveright_p1 == 1) ) ++playerx;
}
else
if ( right_collide == 0 )
{
if (key[KEY_LEFT])
{
playerx-=1;
}
}
if ( playery == 470 ) height = 470; //on ground
if ( player_jump == 1 ){}
else if ( (playery == 371) && (playerx > left_edge_p1) && (playerx < rp1_x) ) height = 371; //on platform 1
jumpheight = height - 120;
if ( player_jump == 1 ) //jump
{
playery-=2;
if ( playery == jumpheight ) player_jump = 0;
}
ceiling_collide = 0; //left of object collide
if ( (playery == 1) || ( (playerx >= left_edge_p1 + 1 ) && (playery == 400) && (playerx <= rp1_x - 1) ) ) ceiling_collide = 1;
if (ceiling_collide == 1 ) player_jump = 0;
release_screen();
clear_bitmap( buffer );
rest(10);
}
clear_bitmap( buffer );
clear_bitmap( cursor );
return 0;
}
END_OF_MAIN()
int draw_platform( int lp_x, int tp_y, int width, int height, int movebound1, int movebound2, int movement, int start_direction, int up_down, int color_r, int color_g, int color_b )
{ //origin x, origin y, width, height, left/bottom, right/top , movement(1 = yes, 0 = stationary), starting direction(1 = right/up, 0 = left/down), movement(1 = up/down, 0 = right/left), colors r, g ,b
int bp_y = height + tp_y;
int rp_x = width + lp_x;
BITMAP *buffer;
buffer = create_bitmap(640, 480);
line( buffer, lp_x, tp_y, lp_x, bp_y, makecol( color_r, color_g, color_b)); //left
line( buffer, rp_x, tp_y, rp_x, bp_y, makecol( color_r, color_g, color_b)); //right
line( buffer, lp_x, tp_y, rp_x, tp_y, makecol( color_r, color_g, color_b)); //top
line( buffer, lp_x, bp_y, rp_x, bp_y, makecol( color_r, color_g, color_b)); //bottom
if( movement == 1 )
{
if( (start_direction == 1) && (up_down == 0) ) //platform 1 movement
{
++lp_x, ++rp_x;
if( rp_x + width == movebound1 ) start_direction = 0; //620
}
if( (start_direction == 0) && (up_down == 0) )
{
--lp_x, --rp_x;
if( lp_x == movebound2 ) start_direction = 1; //20
}
if( (start_direction == 1) && (up_down == 1) )
{
++tp_y, ++bp_y;
if( tp_y == movebound1 ) start_direction = 0;
}
if( (start_direction == 0) && (up_down == 1) )
{
--tp_y, --bp_y;
if( bp_y + height == movebound2 ) start_direction = 1;
}
}
else{}
blit( buffer, screen, 0, 0, 0, 0, 640, 480);
return 0;
}
This is probably pretty sloppy code, but I am trying to clean it up a bit.
Any suggestions on how to fix my problem would be wonderful.
Thanks,
-Erlex
