lane(RECT dim,float r,float g,float b,float alpha)
{
glLoadIdentity();
glTranslatef((float)dim.left,(float)dim.top,0.0f);
glColor4f(r,g,b,alpha);
glBegin(GL_QUADS);
glVertex2d(0,dim.bottom); // top left
glVertex2d(0,0); // bottom left
glVertex2d(dim.right,0); // top right
glVertex2d(dim.right,dim.bottom);
// bottom right
glEnd();
}
I''m calling the function with these params:
rc.left=0;
rc.top=0;
rc.right=640;
rc.bottom=480;
Sprite->Plane(rc,1.0f,1.0f,1.0f,0.0f);
thanks!
Bye,
Alex
GL_QUADS and a shiny black screen
Author
Hi people,
I''m using OpenGL ortho mode and wanna display a simple quad with a color and an alpha value. So far so good, but everything I get is a black screen. The code seems right to me....could anybode please help!??
void cSprite:lane(RECT dim,float r,float g,float b,float alpha)
{
glLoadIdentity();
glTranslatef((float)dim.left,(float)dim.top,0.0f);
glColor4f(r,g,b,alpha);
glBegin(GL_QUADS);
glVertex2d(0,dim.bottom); // top left
glVertex2d(0,0); // bottom left
glVertex2d(dim.right,0); // top right
glVertex2d(dim.right,dim.bottom);
// bottom right
glEnd();
}
I''m calling the function with these params:
rc.left=0;
rc.top=0;
rc.right=640;
rc.bottom=480;
Sprite->Plane(rc,1.0f,1.0f,1.0f,0.0f);
thanks!
Bye,
Alex
lane(RECT dim,float r,float g,float b,float alpha)
{
glLoadIdentity();
glTranslatef((float)dim.left,(float)dim.top,0.0f);
glColor4f(r,g,b,alpha);
glBegin(GL_QUADS);
glVertex2d(0,dim.bottom); // top left
glVertex2d(0,0); // bottom left
glVertex2d(dim.right,0); // top right
glVertex2d(dim.right,dim.bottom);
// bottom right
glEnd();
}
I''m calling the function with these params:
rc.left=0;
rc.top=0;
rc.right=640;
rc.bottom=480;
Sprite->Plane(rc,1.0f,1.0f,1.0f,0.0f);
thanks!
Bye,
Alex
Using 0.0f for an alpha value makes the object invisible. Also, you might want to set up a method of blending.
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[Resist Windows XP''s Invasive Production Activation Technology!]
glClearColor(1,0,0,1);
if u see a pure red screen then the object cant be seen
perhaps the cameras pointing the wrong way or the backface is facing the camera etc.
if u do see a black square perhaps u have lighting enabled
if u see a pure red screen then the object cant be seen
perhaps the cameras pointing the wrong way or the backface is facing the camera etc.
if u do see a black square perhaps u have lighting enabled
Author
Hi,
I set the background to red but I''m getting a black one -> the quad is drawn but don''t uses the color....
I set the background to red but I''m getting a black one -> the quad is drawn but don''t uses the color....
Try translating behind the front clipping plane. If your front clipping plane is at 1.0, translate to 1.1.
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