I see. In that case, using D3DXSPRITE_OBJECTSPACE should work. Where is your camera? I think that the sprites will be drawn at the origin with this flag (You could check with PIX to see what information is being written to the ID3DXSprite vertex buffer).

My view is set by default (I didn't set it). I use an ortho projection defined as follows :

D3DXMatrixOrthoLH(
&proj,
4.0f, // width
4.0f, // height
1.0f, // near plane
1000.0f);// far plane

I have tried to play a bit with PIX, but I've never used it before. I captured calls on a given frame and have the following kind of information

<0x04FE4258> ID3DXSprite::Draw(0x04FED200, 0x0012FAAC, 0x0012FA90, 0x0012FA7C, D3DCOLOR_ARGB(0xff,0x9b,0x1e,0xc8))

That's pretty useless for me, I can only recognize the color, but not the vertex coordinates ...

I also tried to set the camera position to look along the z axis with :

D3DXVECTOR3 position(0.0f,0.0f,0.0f);
D3DXVECTOR3 target(0.0f,0.0f,100.0f);
D3DXVECTOR3 worldup(0.0f,1.0f,0.0f);
D3DXMATRIX V;
D3DXMatrixLookAtLH(&V, &position, &target, &worldup);
Device->SetTransform(D3DTS_VIEW,&V);

but no more results, the text is not visible ...

Your camera is at (0, 0, 0) looking at +Z, with your near clip set at Z=1, but ID3DXSprite is probably drawing at Z=0, meaning it's obscured by the near clip plane.

What if you move your camera further back, or change the translation matrix to move the sprite to Z += 5 or so?

I just tried that, no way !
Playing with the camera position or near clipping plane had no effect.

Oliver

Running a test app I have through Pix as "A replayable Direct3D call stream", and then inspecting a frame (And clicking on the "Render" tab to allow me to view objects), I see:
6991 <0x04D75190> IDirect3DDevice9::SetVertexDeclaration(0x04D76E98)
Selecting the 0x04D76E98 part shows a vertex format of float3, D3DCOLOR, float2 for position, colour and texture coordinates.
A little further down, there's a call to:
<0x04D676F8> IDirect3DVertexBuffer9::Lock(0, 0, 0x0012F758, D3DLOCK_NOOVERWRITE)
That shows that the sprite is locking the vertex buffer at offset 0. Scrolling down to the unlock line and double clicking on the vertex buffer object pointer then shows the buffer contents.
Filling in the vertex format above as:

float3 position;int color;float2 tex0;

then going to the "buffer" tab shows that the text is being drawn as it would be in screen coordinates:

If you draw a quad near the origin (Not using ID3DXSprite or ID3DXFont), can you see it? You need to make sure your camera is where you think it is before you can go much further.

Hi Steve,

First, a lot of thanks for all your efforts to help me !

I have tried to draw a triangle in the xy plane, at z=0. It is defined as :

Triangle->Lock(0, 0, (void**)&vertices, 0);
vertices[0] = Vertex(-1.0f, 0.0f, 0.0f, D3DCOLOR_XRGB(255,0,0));
vertices[1] = Vertex( 0.0f, 1.0f, 0.0f,D3DCOLOR_XRGB(255,0,0));
vertices[2] = Vertex(1.0f, 0.0f, 0.0f,D3DCOLOR_XRGB(255,0,0));
Triangle->Unlock();

Then, the projection and view are defined by :

D3DXMatrixOrthoLH(
&proj, // proj matrix
4.0f, // width
4.0f, // height
-1.0f, // near plane
1000.0f); // far plane
Device->SetTransform(D3DTS_PROJECTION, &proj);
D3DXVECTOR3 position(0.0f,0.0f,0.0f);
D3DXVECTOR3 target(0.0f,0.0f,100.0f);
D3DXVECTOR3 worldup(0.0f,1.0f,0.0f);
D3DXMATRIX V;
D3DXMatrixLookAtLH(&V, &position, &target, &worldup);
Device->SetTransform(D3DTS_VIEW,&V);

Finally, the drawing code is :

D3DXMATRIX WorldMatrix;

Device->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, D3DCOLOR_XRGB(10,0,10), 1.0f, 0);
Device->BeginScene();
Device->SetStreamSource(0, Triangle, 0, sizeof(Vertex));
Device->SetFVF(D3DFVF_XYZ | D3DFVF_DIFFUSE);
// Draw one triangle.
Device->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);

pD3DXSprite->Begin(D3DXSPRITE_OBJECTSPACE);
//pD3DXSprite->Begin(D3DXSPRITE_ALPHABLEND);
D3DXMatrixTranslation(&WorldMatrix, 1.0f, 1.0f, 0.0f);
char Text[] = "Test String";
pD3DXSprite->SetTransform(&WorldMatrix);
Font->DrawText(pD3DXSprite,Text(int(strlen(Text)),&font_rect,DT_LEFT|DT_EXPANDTABS,D3DCOLOR_XRGB(155,30,200));
pD3DXSprite->End();

Device->EndScene();
Device->Present(0, 0, 0, 0);

The triangle is correctly drawn, but not the text.
If I comment out Begin(D3DXSPRITE_OBJECTSPACE); and use Begin(D3DXSPRITE_ALPHABLEND); or whatever, then the text is drawn near the origin

Drives me mad !!

Oliver

The following works for me:
I think the problem is that your camera is still way too close - the text is pretty large. With the camera at -500 on Z, the text still takes up about a quarter of the width of the screen.

Hi Steve,

I have tried your small code, without success. However I'm still using the ortho projection and that's the point I think.

I tried to reduce the size of the font to a minimum, and got big blocks drawn; looks like they're part of a huge font drawing.

I think the whole story is a matter of coordinates - using PIX as you previously mentionned, I examined the data corresponding to the vertex for the font elements, they have the format (float3, D3DCOLOR, float2). For the float3 representing the XYZ coordinates, I find from pix that integer values up to 12 are produced, which is far out of my window extent (defined as -2,2 both on X and Y axis). So it seems that the font elements vertices still make use of screen coordinates.

I think you observe the same thing, a very large font size but you are able to see the text because you use perspective projection and a far away point of view, making the text appear smaller.

Still not clear to me ...

Quote:Original post by oliver_mpt
I have tried your small code, without success. However I'm still using the ortho projection and that's the point I think.

Yes, you'll need to adjust your coordinate range to see the text, or set a scaling transform before rendering it.

Quote:Original post by oliver_mpt
I tried to reduce the size of the font to a minimum, and got big blocks drawn; looks like they're part of a huge font drawing.

That sounds like you don't have the D3DXSPRITE_ALPHABLEND flag; you need both that and D3DXSPRITE_OBJECTSPACE.

Quote:Original post by oliver_mpt
I think the whole story is a matter of coordinates - using PIX as you previously mentionned, I examined the data corresponding to the vertex for the font elements, they have the format (float3, D3DCOLOR, float2). For the float3 representing the XYZ coordinates, I find from pix that integer values up to 12 are produced, which is far out of my window extent (defined as -2,2 both on X and Y axis). So it seems that the font elements vertices still make use of screen coordinates.

I think you observe the same thing, a very large font size but you are able to see the text because you use perspective projection and a far away point of view, making the text appear smaller.

Well, the font vertices aren't going to change - you need to accommodate for the range of values you can expect from the text.
There's two options:
1. Change your coordinate range from -2..+2 to -200..+200 or something else large so you can see the text clearly
2. Set a scaling transform as part of the world matrix to scale the text down to a reasonable size.

Hi Steve,

It's clearer now. I see the whole thing.

Thanks a lot for all your input - I learned a lot.

Oliver