I'm working on a space invaders clone and I decided to use opengl just for fun.
In the display I have a number of asteroids (with the x,y coordinates stored in a list) and I can draw them to the screen each step just fine. But when I try to rotate them (z axis, so they spin in place) they won't cooperate. Here's what I have so far, tell me what I'm doing wrong (this is in my function for drawing the scene):
// *** asteroids ***
glLoadIdentity(); // reset
glEnable(GL_TEXTURE_2D); // Enable Texture Mapping
for (ast = ast_list->begin(); ast != ast_list->end(); ast++)
{
glPushMatrix();
glTranslatef(ast->x(), ast->y(), 0);
glRotatef(ast_rot, 0.0f, 0.0f, 1.0f);
if (ast->destroyable())
glBindTexture(GL_TEXTURE_2D, texture[4]);
else
glBindTexture(GL_TEXTURE_2D, texture[5]);
glBegin(GL_QUADS);
glTexCoord2d(0.0,0.0); glVertex2d(ast->x()-16, ast->y()-16);
glTexCoord2d(1.0,0.0); glVertex2d(ast->x()+16, ast->y()-16);
glTexCoord2d(1.0,1.0); glVertex2d(ast->x()+16, ast->y()+16);
glTexCoord2d(0.0,1.0); glVertex2d(ast->x()-16, ast->y()+16);
glEnd();
glPopMatrix();
}
glDisable(GL_TEXTURE_2D);
ast_rot += 0.1f;
Now the problem is that they seem to rotate on a circle with the origin at 0,0 (the upper left of my screen). I don't want them to move on the screen, just rotate in place... Thanks guys.
Gamer-Insight.com
[edited by - powdahound on June 8, 2002 12:07:55 PM]
