glViewport(0,0,width,height);
glFrustum(1.0,1.0,1.0,1.0,1.0,10000.0);
glMatrixMode(GL_PROJECTION);
bool loop=1;
while(loop)
{
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glTranslatef(0.0,0.0,-4.0);
glBegin(GL_TRIANGLES);
glVertex3f(0.0,1.0,0.0);
glVertex3f(1.0,-1.0,0.0);
glVertex3f(-1.0,-1.0,0.0);
glEnd();
glFlush();(Solved) Need help with glTranslate()
Author
When I use it the triangle disappears:
You might be moving it 4 units towards the camera, try changing:
glTranslatef(0.0,0.0,-4.0);
to
glTranslatef(0.0,0.0,4.0);
also, try putting glPushMatrix(), glPopMatrix() functions in there like so:
glTranslatef(0.0,0.0,-4.0);
to
glTranslatef(0.0,0.0,4.0);
also, try putting glPushMatrix(), glPopMatrix() functions in there like so:
glPushMatrix();glTranslatef(0.0,0.0,-4.0); glBegin(GL_TRIANGLES); glVertex3f(0.0,1.0,0.0); glVertex3f(1.0,-1.0,0.0); glVertex3f(-1.0,-1.0,0.0); glEnd();glPopMatrix();
Author
Tried it and still shows blank screen.
??? I thought OpenGL has Z axis positive going out of the screen. So moving it (-4) would move it into screen. I was learning from the NeHe tutorials.
??? I thought OpenGL has Z axis positive going out of the screen. So moving it (-4) would move it into screen. I was learning from the NeHe tutorials.
I just looked in one of my projects, and the negative Z pulled back towards the screen.
Lemme look at our code again...
EDIT: I just compiled it, and it worked for me. Try using a smaller number(like 0.1) and see if it shows up then or not.
Lemme look at our code again...
EDIT: I just compiled it, and it worked for me. Try using a smaller number(like 0.1) and see if it shows up then or not.
You are using the wrong matrixmode.
glViewport(0,0,width,height);glFrustum(1.0,1.0,1.0,1.0,1.0,10000.0);glMatrixMode(GL_MODELVIEW);bool loop=1;while(loop){ glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); glLoadIdentity(); glTranslatef(0.0,0.0,-4.0); glBegin(GL_TRIANGLES); glVertex3f(0.0,1.0,0.0); glVertex3f(1.0,-1.0,0.0); glVertex3f(-1.0,-1.0,0.0); glEnd();glFlush();
Author
glFrustum(1.0,1.0,1.0,1.0,1.0,10000.0);
The 2 numbers at the end are the clipping plane. (1-10,000)
Alright. Here's the full code. Copy/pasted it straight from the testing program and the screen is blank. (Rebuilt project to make sure) Also I compiled Lesson 2 from NeHe and it works but this doesn't:
The 2 numbers at the end are the clipping plane. (1-10,000)
Alright. Here's the full code. Copy/pasted it straight from the testing program and the screen is blank. (Rebuilt project to make sure) Also I compiled Lesson 2 from NeHe and it works but this doesn't:
#include <SDL/SDL.h>#include <gl/gl.h>//Initalize variablesint width=800,height=600;SDL_Event event;int main(int argc, char *argv[]){ SDL_Init(SDL_INIT_VIDEO); SDL_SetVideoMode(width,height,0,SDL_OPENGL|SDL_HWSURFACE); //Setup OpenGL glViewport(0,0,width,height); glFrustum(1.0,1.0,1.0,1.0,1.0,10000.0); glMatrixMode(GL_MODELVIEW); bool loop=1; while(loop) { glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); glLoadIdentity(); glPushMatrix(); glTranslatef(0.0,0.0,-4.0); glBegin(GL_TRIANGLES); glVertex3f(0.0,1.0,0.0); glVertex3f(1.0,-1.0,0.0); glVertex3f(-1.0,-1.0,0.0); glEnd(); glPopMatrix(); glFlush(); if(SDL_PollEvent(&event)) switch(event.type) { case SDL_QUIT: loop=0; break; case SDL_KEYDOWN: switch(event.key.keysym.sym) { case SDLK_ESCAPE: loop=0; break; } } SDL_GL_SwapBuffers(); } SDL_Quit(); return(0);}
The default matrix mode is GL_MODELVIEW, so you are calling glFrustum on the ModelView matrix, which you probably don't want to do. You should have glMatrixMode(GL_PROJECTION) somewhere before you call glFrustum, then set it back to GL_MODELVIEW afterwards.
Author
Blank screen!
//Setup OpenGL glViewport(0,0,width,height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glFrustum(1.0,1.0,1.0,1.0,1.0,10000.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); bool loop=1; while(loop) { glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); glLoadIdentity(); glTranslatef(0.0,0.0,-2.0); glBegin(GL_TRIANGLES); glVertex3f(0.0,1.0,0.0); glVertex3f(1.0,-1.0,0.0); glVertex3f(-1.0,-1.0,0.0); glEnd(); glFlush();
oh,what a terrible word "while(loop)" here. There will be some problem here:
first, it will finish or refresh the screen very fastly,so you can see nothing.
second,you LoadIdentity(),and then translate() with a same number"-4", that mean you do not move a little;
maybe you can do it like this;
float Z_TRANSLATE = -4.0f;
while(loop)
{
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glTranslatef(0.0,0.0,Z_TRANSLATE);
glBegin(GL_TRIANGLES);
glVertex3f(0.0,1.0,0.0);
glVertex3f(1.0,-1.0,0.0);
glVertex3f(-1.0,-1.0,0.0);
glEnd();
glFlush();
Z_TRANSLATE -=5.0f; ///////////////////////////////////////
sleep(1000);///////////////////////////////
.....
}
first, it will finish or refresh the screen very fastly,so you can see nothing.
second,you LoadIdentity(),and then translate() with a same number"-4", that mean you do not move a little;
maybe you can do it like this;
float Z_TRANSLATE = -4.0f;
while(loop)
{
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glTranslatef(0.0,0.0,Z_TRANSLATE);
glBegin(GL_TRIANGLES);
glVertex3f(0.0,1.0,0.0);
glVertex3f(1.0,-1.0,0.0);
glVertex3f(-1.0,-1.0,0.0);
glEnd();
glFlush();
Z_TRANSLATE -=5.0f; ///////////////////////////////////////
sleep(1000);///////////////////////////////
.....
}
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