Hi,
I have been working on a small 3d engine for the last few weeks, no big plans for it or anything just doing it to teach myself.
Everything has been going ok so far, been working off internet tutorials and examples but i have run into a problem, everything in my viewpoint is backwards.
Screen Shot: www.turnipfan.com/screen_shot.jpg
I have tried changing all the settings but nothing seems to work, i was wondering if someone more experience could have a look at the code and tell me whats wrong.
Source Code (84kb): www.turnipfan.com/testapp.zip
Thanks for any help,
-Dave
Everything in viewpoint is backwards
A_S_G
acangialosi
When you draw in DX your faces have an orientation depending on the order of entry of your vertex
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a triangle 0,0,0 to 0,1,0 to 1,0,0
will be facing toward you
a triangle 0,0,0 to 1,0,0 to 0,1,0
is the very same triangle but this time it face the back of your screen
the ''normal'' is the direction the face of the triangle is pointing
In the first triangle the normal point to you
In the second triangle the normal point to the back of the screen
So the order you send the vertex to the system will give the orientation of your face (triangles)
Another problem might be that your texture coordinate are not in the good orientation
The texture coordinate work the same way, the order you send them is important
a triangle 0,0,0 to 0,1,0 to 1,0,0 must have (0,0) (0,1) and (1,0) texture for each respective vertex
Maybe your vertex are in the good order but your texture coordinate are not
If I do this :
a triangle 0,0,0 to 0,1,0 to 1,0,0 with (0,0) (1,0) and (0,1) texture for each respective vertex
I will get what you get...the texture will be backward...like seen in a mirror
When you plot those value on a sheet of paper, you can draw a circular arrow on the face
To show the order you should enter the vertex
Depending on the order your circular arrow will go clock wise ot not
If you use your left hand over that circular arrow your tumb will show the direction of your faces...
So maybe your vertex are enter in the bad order or it's your texture coodinate order
MattFunke
Thanks for the reply Etienne2005 but i think it has to be in the camera or the way my engine is getting declared, you see normally instead of a simple box mesh i have the app loading largers mesh data complete with normals, indices, vertex colors and texture coords and everything is backwards.
I have tried reversing my vertex data, indices and changind the normals with no luck so i posted the engines code here to see if someone could help.
Thanks though!
Mark Uniacke
Your matrix view seems a little complicated :-)
An easier way is to use the LookAt Function...
device.Transform.View = Matrix.LookAtLH(
new Vector3(0.0f, 3.0f, -5.0f),
new Vector3(0.0f, 0.0f, 0.0f),
new Vector3(0.0f, 1.0f, 0.0f));
It's a lot easier :-)
public void Render()
{
Matrix view = Matrix.Identity;
//cameraTarget = Vector3.Normalize(cameraTarget);
vRight = Vector3.Cross(cameraUp, cameraTarget);
vRight = Vector3.Normalize(vRight);
//cameraUp = Vector3.Cross(cameraTarget, vRight);
//Vector3.Normalize(cameraUp);
view.M11 = vRight.X;
view.M12 = cameraUp.X;
view.M13 = cameraTarget.X;
view.M14 = 0.0f;
view.M21 = vRight.Y;
view.M22 = cameraUp.Y;
view.M23 = cameraTarget.Y;
view.M24 = 0.0f;
view.M31 = vRight.Z;
view.M32 = cameraUp.Z;
view.M33 = cameraTarget.Z;
view.M34 = 0.0f;
view.M41 = -Vector3.Dot(cameraPos, vRight);
view.M42 = -Vector3.Dot(cameraPos, cameraUp);
view.M43 = -Vector3.Dot(cameraPos, cameraTarget);
view.M44 = 1.0f;
parentForm.device.Transform.View = view;
}
private void SetupMatrices()
{
// For our world matrix, we will just rotate
the object about the y-axis.
// Set up the rotation matrix to generate 1
full rotation (2*PI radians)
// every 1000 ms. To avoid the loss of
precision inherent in very high
// floating point numbers, the system time is
modulated by the rotation
// period before conversion to a radian
angle.
//float fangle;
//int iTime = Environment.TickCount % 1000;
//fangle = iTime * (2.0f * (float)Math.PI) /
1000.0f;
//device.Transform.World =
Matrix.RotationY(fangle);
device.Transform.World =
Matrix.RotationX(xRotate);
//device.Transform.World =
Matrix.RotationY(yRotate);
//device.Transform.World =
Matrix.RotationZ(zRotate);
// Set up our view matrix. A view matrix can
be defined given an eye
// point, a point to lookat, and a direction
for which way is up. Here,
// we set the eye five units back along the
z-axis and up three units,
// look at the origin, and define "up" to be
in the y-direction.
device.Transform.View = Matrix.LookAtLH(
new Vector3(0.0f, 3.0f, -5.0f),
new Vector3(0.0f, 0.0f, 0.0f),
new Vector3(0.0f, 1.0f, 0.0f));
// For the projection matrix, we set up a
perspective transform (which
// transforms geometry from 3D view space to
2D viewport space, with
// a perspective divide making objects
smaller in the distance). To build
// a perpsective transform, we need the field
of view (1/4 pi is common),
// the aspect ratio, and the near and far
clipping planes (which define
// at what distances geometry should be no
longer be rendered).
device.Transform.Projection =
Matrix.PerspectiveFovLH(
(float)Math.PI / 4,
1.0f,
0.4f,
10000.0f);
}