Does the OpenGL raster program display only white, black, and yellow?

Question

I use the library at http://partow.net/programming/bitmap/index.html and OpenGL to make the function of loading a bitmap on my screen. The image is loading, but it only displays black, white, and yellow. I am using Dev C ++ on Windows 7. Here is my code:

void Load_Image(HDC hDC, string File_Name, int x_position, int y_position, int length, int height)
{     
bitmap_image image(File_Name);      // Open the bitmap
unsigned char red;
unsigned char green;
unsigned char blue;
restart:
image.get_pixel(x_position, y_position, red, green, blue);     // Get the red green and blue from x_position and y_position and store it in red green and blue. 
glBegin (GL_TRIANGLES);                                        // Make a pixel at x_position and y_position with red green and blue.
glColor3f (red, green, blue);
glVertex2f (-1 + 0.0015 * x_position, 1 - 0.003 * y_position);
glVertex2f (-1 + 0.0015 * x_position, 0.997 - 0.003 * y_position);
glVertex2f (-0.9985 + 0.0015 * x_position, 1 - 0.003 * y_position);
glEnd();
glBegin (GL_TRIANGLES);
glColor3f (red, green, blue);
glVertex2f (-1 + 0.0015 * x_position, 0.997 - 0.003 * y_position);
glVertex2f (-0.9985 + 0.0015 * x_position, 1 - 0.003 * y_position);
glVertex2f (-0.9985 + 0.0015 * x_position, 0.997 - 0.003 * y_position);
glEnd();
if (x_position==length)      // If x_position equals to length of bmp set x_position to 0 and add 1 to y_position.
{
if (y_position==height)      // If bmp is done loading go to done.
{
goto done;
}
x_position = 0;
y_position = y_position + 1;
}
x_position = x_position + 1;
goto restart;
done:         
SwapBuffers(hDC);            // Put it on the screen.
}

Any ideas on what's wrong? Thanks!

Answer 1

Color values red, green, blueare of the type unsigned charand in the range 0..255. The floating point variant glColor, glColor3fhowever, expects input values ​​in the range 0..1. Use instead glColor3ub().

: glColor3b(), glColor3ub().