Hi,
I have converted my terrain to use multiple stream to allow me to have a bigger landscape. I've manage to make it work. However, after a few frames a rendering bug is showing up. Some triangle start to flicker and they seems to change over time or when i move the camera.
I've tried to debug the problem using PIX, but everytimes a take a snapshot everythings is fine (image is ok).
This is the relevent part of my shader:
struct VS_INPUT
{
float2 Position : TEXCOORD0;
float2 TexCoord : TEXCOORD1;
float1 HeightPosition : TEXCOORD2;
};
VS_OUTPUT VS(VS_INPUT input)
{
VS_OUTPUT output = (VS_OUTPUT)0;
float4 position = float4(input.Position.x, input.HeightPosition.x, input.Position.y, 1);
output.Position = mul(position, g_WorldViewProjection);
output.TexCoord = input.TexCoord;
return output;
}
And the relevent part from my code
public struct TerrainVertex
{
public float x, z;
public float u1, v1;
}
public struct TerrainHeightVertex
{
public float y;
}
VertexElement[] vertexDeclaration = new VertexElement[]
{
new VertexElement(0, 0, DeclarationType.Float2, DeclarationMethod.Default, DeclarationUsage.TextureCoordinate, 0),
new VertexElement(0, 8, DeclarationType.Float2, DeclarationMethod.Default, DeclarationUsage.TextureCoordinate, 1),
new VertexElement(1, 16, DeclarationType.Float1, DeclarationMethod.Default, DeclarationUsage.TextureCoordinate, 2),
VertexElement.VertexDeclarationEnd,
};
public void Draw(Matrix viewMatrix, Matrix projectionMatrix)
{
_graphicsDevice.RenderState.ZBufferEnable = true;
_graphicsDevice.RenderState.ZBufferWriteEnable = true;
_graphicsDevice.RenderState.CullMode = Cull.CounterClockwise;
// disabled alpha-blending and alpha testing
_graphicsDevice.RenderState.AlphaBlendEnable = false;
_graphicsDevice.RenderState.AlphaTestEnable = false;
_graphicsDevice.SetStreamSource(0, _gridVertexBuffer, 0, Marshal.SizeOf(typeof(TerrainVertex)));
_graphicsDevice.SetStreamSource(1, _heightVertexBuffer, 0, Marshal.SizeOf(typeof(TerrainHeightVertex)));
_graphicsDevice.Indices = _indexBuffer;
_graphicsDevice.VertexDeclaration = _vertexDeclaration;
int passCount = _effect.Begin(FX.None);
for (int iPass = 0; iPass < passCount; iPass++)
{
_effect.BeginPass(iPass);
_graphicsDevice.DrawIndexedPrimitives(PrimitiveType.TriangleStrip, 0, 0, _vertexCount, 0, _primitiveCount);
_effect.EndPass();
}
_effect.End();
}
And the results:
So i'm asking here, since i dont have any good ideas on what could cause this strange behaviour. If i didnt post enought, just ask me the relevent part missing.
Thanks to look into it with me ;)
Lowrad
