# Terrain and camera problems

Hi! I’m having some difficulties with camera position in my scene. I’ve read the pixels from 128x128 bitmap and set it to the matrix height_field

``````
for(int i = 0; i < AREA_SIZE; i++)
{
for(int j = 0; j < AREA_SIZE; j++)
{
height_field[i][j][0]= float(j)*step;
height_field[i][j][1]= (float)GetRValue(bitmap->Canvas->Pixels[j][i]);//[(i*(AREA_SIZE+j)*3];
height_field[i][j][2]= -float(i)*step;
}
}

``````

then I have call a function that would draw triangle strip (maybe you have better solution)

``````
for (int z = 0; z < AREA_SIZE-1; z++)
{

glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texture1);

glBegin(GL_TRIANGLE_STRIP);
for (int x = 0; x < AREA_SIZE-1; x++)
{
// vertex 0
glColor3f(height_field[x][z][1]/255.0f, height_field[x][z][1]/255.0f, height_field[x][z][1]/255.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex3f(height_field[x][z][0], height_field[x][z][1], height_field[x][z][2]);

// vertex 1
glTexCoord2f(1.0f, 0.0f);
glColor3f(height_field[x+1][z][1]/255.0f, height_field[x+1][z][1]/255.0f, height_field[x+1][z][1]/255.0f);
glVertex3f(height_field[x+1][z][0], height_field[x+1][z][1], height_field[x+1][z][2]);

// vertex 2
glTexCoord2f(0.0f, 1.0f);
glColor3f(height_field[x][z+1][1]/255.0f, height_field[x][z+1][1]/255.0f, height_field[x][z+1][1]/255.0f);
glVertex3f(height_field[x][z+1][0], height_field[x][z+1][1], height_field[x][z+1][2]);

//vertex 3
glColor3f(height_field[x+1][z+1][1]/255.0f, height_field[x+1][z+1][1]/255.0f, height_field[x+1][z+1][1]/255.0f);
glTexCoord2f(1.0f, 1.0f);
glVertex3f(height_field[x+1][z+1][0], height_field[x+1][z+1][1], height_field[x+1][z+1][2]);
}
glEnd();
}
}
``````

And at the end I would like to point my camera in the center of the map

``````
glMatrixMode(GL_PROJECTION);

gluPerspective(60.0f,(GLfloat)w/(GLfloat)h,0.1f,1000.0f);
float temp = (AREA_SIZE*step)*0.5;
glTranslatef(-temp,
-height_field[AREA_SIZE/2][AREA_SIZE/2][1]-10,
-temp);

glTranslatef(XP2, YP2, ZP2);

glRotatef(XO2,1.0,0.0,0.0);
glRotatef(YO2,0.0,1.0,0.0);
glRotatef(ZO2,0.0,0.0,1.0);

glMatrixMode(GL_MODELVIEW);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);

``````

where step is a distance between 2 coordinates x and z, XP2, YP2, ZP2, XO2, YO2, ZO2 are assigned to some sliders so i can move my terrain around.

The problem is that I can’t see my terrain. It’s somewhere outside the window. I tried to change everything, but the problem is always the same. Could you tell me where is the bug?

Piotr

Hi !

You say “at the end” you would like to setup the camera, I hope this does not mean that you try to render the triangles first and then setup the camera in your code ? because that will not work.

Mikael

Hi! I tried to do many things. When I don’t do anything with camera settings - just leave a perspective, the terrain is rendering from the center of a screen. So I want to move camera first to the oposite direction that terrain is build. so i should see the terrain. right? but i can’t see anything

I think I have found what was the problem… I moved the terrain to far

``````
float temp = (AREA_SIZE*step)*0.5;

glTranslatef(-temp,
-height_field[AREA_SIZE/2][AREA_SIZE/2][1]-10,
-temp);

``````

when I put

``````
float temp = (AREA_SIZE*step)*0.5;

glTranslatef(-temp,
-height_field[AREA_SIZE/2][AREA_SIZE/2][1]-10,
-10);

``````

I can see the terrain

Thanks anyway!