我正在玩一些 OpenGL 和 SDL。目前，我正在尝试让 HUD 显示在一些 3D 旋转立方体上。但是，当我在 3d 形状之后添加代码以绘制 2d 四边形时，我得到了黑屏死机。现在根本没有渲染，包括以前工作的 3d 形状，所以这似乎不是深度问题。
我在做什么：
_SETUP_
Make a new SDL window.
Enable lighting and make a new light.
Enable depth.
_GAMELOOP_
Switch the matrix to GL_PROJECTION and make a new perspective view.
Switch back to the GL_MODELVIEW matrix.
Draw some shapes.
Switch the matrix back to GL_PROJECTION and make a new ortho view.
Switch back to the GL_MODELVIEW matrix.
Draw a 2d shape.
代码（有点乱，我很抱歉）绘制了一个 10x10 的旋转立方体墙并让它们改变颜色：
int main(int argc, char **argv)
{
srand(12);
int x = 0, i, j, k;
Coordinate ang, pos;
Color color, colorMod;
SDL_Event event;
bool quit = false;
color.r = 0;
color.g = 0;
color.b = 0;
colorMod.r = .01;
colorMod.g = .05;
colorMod.b = .03;
pos.x = -5;
pos.y = -5;
pos.z = -40.0f;
SDL_Init(SDL_INIT_EVERYTHING);
SDL_SetVideoMode(800, 600, 32, SDL_OPENGL);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glClearColor(0, 0, 0, 0);
glClearDepth(1.0f);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
GLfloat lightpos[] = {10, 10, 10, 1};
glLightfv(GL_LIGHT0, GL_POSITION, lightpos);
glEnable(GL_COLOR_MATERIAL);
while(quit == false)
{
//Draw some cubes
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(40.0, 800.0/600.0, 0.5, 20.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
for(i=0;i<10;i++)
{
pos.x += 2;
for(j=0;j<10;j++)
{
pos.y += 2;
glPushMatrix();
drawACube(ang, pos, color);
glPopMatrix();
}
pos.y = -10;
}
pos.x = -10;
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, 800, 600, 0, -1, 1);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glPushMatrix();
glBegin(GL_QUADS);
glColor3f(color.r, color.g, color.b);
glVertex3f(-1.0f, 1.0f, 1.0f);
glVertex3f(-1.0f, 1.0f, -1.0f);
glVertex3f(1.0f, 1.0f, -1.0f);
glVertex3f(1.0f, 1.0f, 1.0f);
glEnd();
glPopMatrix();
//Swap and FPS delay
SDL_GL_SwapBuffers();
SDL_Delay(10);
//Makes the rotation happen
ang.x += .7;
ang.y += .1;
ang.z += .1;
//Monitor for a quit event
while(SDL_PollEvent(&event))
{
if(event.type == SDL_QUIT)
{
quit = true;
}
}
//Do the color stuff
if(color.r > 1)
colorMod.r = -.01;
else if(color.r < 0)
colorMod.r = .01;
if(color.g > 1)
colorMod.g = -.05;
else if(color.g < 0)
colorMod.g = .05;
if(color.b > 1)
colorMod.b = -.03;
else if(color.b < 0)
colorMod.b = .03;
color.r += colorMod.r;
color.g += colorMod.g;
color.b += colorMod.b;
}
SDL_Quit();
return 0;
}
void drawACube(Coordinate ang, Coordinate pos, Color color)
{
glTranslatef(pos.x, pos.y, pos.z);
glRotatef(ang.x, 1.0f, 0.0f, 0.0f);
glRotatef(ang.y, 0.0f, 1.0f, 0.0f);
glRotatef(ang.z, 0.0f, 0.0f, 1.0f);
glBegin(GL_QUADS);
//Top
glNormal3d(0, 1, 0);
glColor3f(color.r, color.g, color.b);
glVertex3f(-1.0f, 1.0f, 1.0f);
glVertex3f(-1.0f, 1.0f, -1.0f);
glVertex3f(1.0f, 1.0f, -1.0f);
glVertex3f(1.0f, 1.0f, 1.0f);
//Bottom
glNormal3d(0, -1, 0);
glColor3f(color.r, color.g, color.b);
glVertex3f(-1.0f, -1.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, -1.0f);
glVertex3f(1.0f, -1.0f, -1.0f);
glVertex3f(1.0f, -1.0f, 1.0f);
//Front
glNormal3d(0, 0, 1);
glColor3f(color.r, color.g, color.b);
glVertex3f(-1.0f, 1.0f, 1.0f);
glVertex3f(1.0f, 1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, 1.0f);
//Back
glNormal3d(0, 0, -1);
glColor3f(color.r, color.g, color.b);
glVertex3f(-1.0f, 1.0f, -1.0f);
glVertex3f(1.0f, 1.0f, -1.0f);
glVertex3f(1.0f, -1.0f, -1.0f);
glVertex3f(-1.0f, -1.0f, -1.0f);
//Left side
glNormal3d(-1, 0, 0);
glColor3f(color.r, color.g, color.b);
glVertex3f(-1.0f, 1.0f, -1.0f);
glVertex3f(-1.0f, 1.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, 1.0f);
glVertex3f(-1.0f, -1.0f, -1.0f);
//Right side
glNormal3d(1, 0, 0);
glColor3f(color.r, color.g, color.b);
glVertex3f(1.0f, 1.0f, -1.0f);
glVertex3f(1.0f, 1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, 1.0f);
glVertex3f(1.0f, -1.0f, -1.0f);
glEnd();
}
编辑：我尝试注释掉 2d 部分，并遇到了上述相同的问题。还更改了上面的代码以删除颜色缓冲区的错误清除（没有解决问题，但以后可能会出现问题
解决方案：在顶部有一个不正确的 gluPerspective 行，它搞砸了一切。感谢您的快速回复，我为错误道歉