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Managed Direct3D & ProcessVertices

Started by arkasizer Feb 28, 2004 at 7:21 PM 1 reply 500+ views

Original Post

Feb 28, 2004 at 7:21 PM

Hi everyone, I''ve been lurking around this forum for a while and have found it very informative. I am now in need of help on a topic that is rather new and I can''t seem to find info on it anywhere! I''m prototyping with Managed (C#) DirectX 9.0, and for batching purposes I want to use Device.ProcessVertices(). Whenever I call this function, however, I get a NullReferenceException from Direct3D.dll. Here is the code:

device.VertexFormat = CustomVertex.PositionTextured.Format;
				device.SetStreamSource(0, vertices, 0);
				device.SetTransform(
					TransformType.World,
					Matrix.Translation(10, 20, 0));

				/*** copied from MSDN documentation on VertexDeclaration: ***/
				// Create the vertex element array.

				VertexElement[] elements = new VertexElement[]
				{
					new VertexElement(0, 0, DeclarationType.Float3,
					DeclarationMethod.Default,
					DeclarationUsage.Position, 0),
					VertexElement.VertexDeclarationEnd 
				};

				// Use the vertex element array to create a vertex declaration.

				VertexDeclaration decl = new VertexDeclaration((device, elements);
				/*** End copy ***/

				device.ProcessVertices(
					0, 0, 4,
					Scene.transformedVB, 
					decl);					// null reference exception here

				device.VertexFormat = CustomVertex.TransformedTextured.Format;
				device.SetStreamSource(0, transformedVB, 0);
				device.DrawPrimitives(
					PrimitiveType.TriangleStrip,
					0,
					2);

I hope someone else has found a way to call ProcessVertices() from managed code. Any help appreciated. Thanks in advance.

Troj

Feb 29, 2004 at 2:15 AM

Hi there,

I;ve noticed that that MSDN documention for managed DirectX is poor at best, and I suggest that the problem with you code might be the VertexElement[] because it only has one entry.

You can change your VertexElement if you have a mesh in your code to this

VertexElement[] elements = Mesh.Declaration;

the Declaration returns a VertexElement[] describing all the vertices of the mesh.

Good luck with that !

arkasizer

Author

arkasizer

Feb 29, 2004 at 3:25 PM

Thanks for your reply. I don''t use meshes in my code as I am only working with individual primitives, or two primitives joined together to make a billboard. All my vertices use this same format so I don''t know what I would add to my array.

Defining a VertexElement array and using that to create a VertexDeclaration seems like an obscure way to simply describe a vertex format, when in all other cases you can use CustomVertex.PositionTextured.Format, etc.

I have also tried passing null to ProcessVertices instead of a VertexDeclaration, but I get the same error.

Beyond better documentation, MS should really take the time to flesh out their exception messages for the DirectX dll''s.

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