OpenGL位图程序只显示白色，黑色和黄色

OpenGL bitmap program only displaying white, black, and yellow?

本文关键字：黑色 黄色 白色 显示 位图 程序 OpenGL      更新时间：2023-10-16

我正在使用http://partow.net/programming/bitmap/index.html和OpenGL的库来制作一个函数来加载我屏幕上的位图。图像加载，但它只显示黑色，白色和黄色。我在Windows 7上使用Dev c++。下面是我的代码:

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.
}

有什么问题吗?谢谢!

red、green、blue的颜色值类型为unsigned char，取值范围为0 ~ 255。glColor、glColor3f的浮点变体期望输入值在0..1的范围内。试着用glColor3ub()代替。

更新:我原来的答案建议glColor3b()，但它应该是无符号的变体glColor3ub()。

相关文章：