why are some of my lines yellow andd some white

[kacper130320]

when i draw some lines

game cpp (lesson 12 )

#include "Game.h"

Game::Game( HWND hWnd,const KeyboardServer& kServer )
: gfx ( hWnd ),
kbd( kServer )
{}
void Game::Go()
{
gfx.BeginFrame();
ComposeFrame();
gfx.EndFrame();
}

void Game::DrawGrid( int x,int y )
{
gfx.DrawLine( 0 + x,99 + y,299 + x,99 + y,255,255,255 );

gfx.DrawLine( 0 + x,199 + y,299 + x,199 + y,255,255,255 );

gfx.DrawLine( 99 + x,0 + y,99 + x,299 + y,255,255,255 );

gfx.DrawLine( 199 + x,0 + y,199 + x,299 + y,255,255,255 );

}

void Game::ComposeFrame()
{
DrawGrid(300,150 );
}

[LuX]

The code looks fine. Try to update your graphics card, info should be found on the website of the graphics card.

OR upload the project here, so we can look if the problem replicates with other people, otherwise its a local problem on your computer as I mentioned.

[chili]

What LuX said.

[kacper130320]

Chili DirectX Framework - Kopia.rar

(5.36 MiB) Downloaded 173 times

this is my code

[zentojamorn]

Problem is in DrawLine function. Your variable name is misleading.
You should use PutPixel(x,y,r,g,bl) instead of PutPixel(x,y,r,g,b).

[LuX]

It's a weird bunch of files you uploaded...

Problem is in DrawLine function. Your variable name is misleading.
You should use PutPixel(x,y,r,g,bl) instead of PutPixel(x,y,r,g,b).

Yup. Currently your code is saying that the color has to be: PutPixel(red, green, *line equation*)

Code: Select all

float m = (float)dx / (float)dy;
		float b = x1 - m*y1;                            // <--- note that "b" is declared as line equation
		for( int y = y1; y <= y2; y++ )
				{
					int x = m*y + b + 0.5f;
					PutPixel( x,y,r,g,b  );    // "b" is still line equation here

[chili]

Hehe, this is why I always ask people to post their entire solution. Very often the problem is not the part of the code that they copy and paste into their post.

As the guys above me pointed out, your b variable for the blue component is getting covered up by your b variable for the y-intercept of your straight line equation. You need to rename one of them, preferably the one for the blue component (which is what I do in the tutorial video if you look closely).

Good job guys in catching his error.

[kacper130320]

Thanks
very much guys
mission success hope it works

[kacper130320]

oh yeah and my other bug was in game.cpp when i tried to draw the X it said that it dosent recognise the "gfx." the code was gfx.DrawLine()
help please

[Asimov]

Hi kacper,

I have never had the problem using gfx.DrawLine in the main game.cpp.

The only time I had a problem was when I tried to make a function in game.cpp.

I called it

void star()
{
}

instead of

void Game::star()
{
}

Just a beginners mistake.
I wonder if that is your problem. If you don't define which Class the function is for I think it loses scope.

Asimov