c – OpenGL位图程序只显示白色,黑色和黄色？

2023年9月25日 221次阅读

我在
http://partow.net/programming/bitmap/index.html和OpenGL上使用库来创建一个在我的屏幕上加载位图的功能.图像加载但只显示黑色,白色和黄色.我在Windows 7上使用Dev C.这是我的代码：

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.
}

关于什么是错的任何想法？
谢谢！

最佳答案 红色,绿色,蓝色的颜色值为unsigned char类型,范围为0..255. glColor的浮点变量glColor3f但是要求输入值在0..1范围内.尝试使用glColor3ub()代替.

更新：我的原始答案建议glColor3b()但它应该是无符号变量glColor3ub().

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