I'm struggling to find discussion on how DrawPrimitives is intended to be used, particularly in complex uses with varied primitive types and am running into what looks like some depth issues
In my engine I'm batching together all primitives of a particular type and then passing each batch to DrawPrimitives. So all my texture+lighting polys get to DrawPrimitives in one batch, and then all my coloured polys in a separate call, and then all my coloured lines, and so on for each combination of primitive properties I could be using
As it stands my engine is putting out the following
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The lines are spatially above the textures but sometimes appear to be occluded, or even glitching like they're overlapping? The line flickering isn't the gif compression, it's like they're on the same plane but they're not
And I'm experiencing the same problem for polys too, not just lines
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When the other circles grow larger, they are spatially closer to the camera than the purple circle which should be completely occluded
I've tried a lot of different settings, trying all combinations of DepthBufferEnable and DepthBufferWriteEnable to no effect, so my assumption has become that I've misunderstood the way DrawPrimitives works and it does no batching behind the scenes. Therefore the separate calls render in the order they're called. But I'm unsure how to proceed in choosing an alternative
If I have to order every primitive manually then wouldn't I also have to roll my own shader as well or I'll get errors when polys intersect using BasicEffect?
But that would make BasicEffect kinda useless unless you were using only one primitive type that isn't textured? On account of having to set effect.Texture before each DrawPrimitive call. And that doesn't sound right to me so I must be missing something? Is that Texture setting behaviour even ordinary?
This is my main render method where I'm mostly just messing around with settings atm
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.DarkBlue);
GraphicsDevice.RasterizerState = new RasterizerState()
{
FillMode = FillMode.Solid,
//CullMode = CullMode.None
};
GraphicsDevice.BlendState = BlendState.AlphaBlend;
//GraphicsDevice.DepthStencilState = new DepthStencilState()
//{
// DepthBufferEnable = true,
// DepthBufferWriteEnable = true
// //DepthStencilState.Default;//new DepthStencilState()
//};
//Graphics.ApplyChanges();
//{
// DepthBufferEnable = false,
// DepthBufferWriteEnable = false,
// CounterClockwiseStencilFunction = CompareFunction.Always,
// StencilFunction = CompareFunction.Always,
// StencilFail = StencilOperation.IncrementSaturation,
// StencilPass = StencilOperation.IncrementSaturation,
// CounterClockwiseStencilFail = StencilOperation.IncrementSaturation,
// CounterClockwiseStencilPass = StencilOperation.IncrementSaturation,
// ReferenceStencil = 0,
// StencilEnable = true,
// StencilMask = 0,
//};
Renderer.Render(Graphics.GraphicsDevice);
base.Draw(gameTime);
}
And these are each snipped from where we render each primitive type batch
Polys that have texture, colour and normal properties
if (PolyTexturesPositionColourNormalTexture != null)
{
effect.TextureEnabled = true;
effect.LightingEnabled = true;
effect.VertexColorEnabled = true;
renderer.Indices = PolyIndicesPositionColourNormalTexture;
renderer.SetVertexBuffer(PolyVerticesPositionColourNormalTexture);
Nullable<TextureReference> currentTexture;
currentTexture = PolyTexturesPositionColourNormalTexture[0];
if (currentTexture.HasValue)
effect.Texture = currentTexture.Value.Texture;
int currentOffset = 0;
//renderer.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, PolyVerticesPositionColourNormalTexture.VertexCount, 0, PolyVerticesPositionColourNormalTexture.VertexCount / 3);
for (int i = 1; i < PolyTexturesPositionColourNormalTexture.Length; i++)
{
currentTexture = PolyTexturesPositionColourNormalTexture[i];
if (currentTexture.HasValue)
{
foreach (EffectPass pass in effect.CurrentTechnique.Passes)
{
pass.Apply();
renderer.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, currentOffset, (i - currentOffset) / 3);
}
effect.Texture = currentTexture.Value.Texture;
currentOffset = i;
}
}
}
Polys with just colour
if (PolyVerticesPositionColourCountSampled > 0)
{
effect.TextureEnabled = false;
effect.LightingEnabled = false;
effect.VertexColorEnabled = true;
renderer.Indices = PolyIndicesPositionColour;
renderer.SetVertexBuffer(PolyVerticesPositionColour);
//renderer.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, PolyVerticesPositionColour.VertexCount, 0, PolyVerticesPositionColour.VertexCount / 3);
foreach (EffectPass pass in effect.CurrentTechnique.Passes)
{
pass.Apply();
renderer.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, PolyVerticesPositionColourCountSampled / 3);
}
}
Lines with just colour
if (LineVerticesPositionColourCountSampled > 0)
{
effect.TextureEnabled = false;
effect.LightingEnabled = false;
effect.VertexColorEnabled = true;
renderer.Indices = LineIndicesPositionColour;
renderer.SetVertexBuffer(LineVerticesPositionColour);
//renderer.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, LineVerticesPositionColour.VertexCount, 0, LineVerticesPositionColour.VertexCount / 2);
foreach (EffectPass pass in effect.CurrentTechnique.Passes)
{
pass.Apply();
renderer.DrawIndexedPrimitives(PrimitiveType.LineList, 0, 0, LineVerticesPositionColourCountSampled / 2);
}
}
Is my use case roll-my-own-shader territory? Am I doing completely everything wrong? Is the problem elsewhere?
I'm not finding much material talking about using a lot of different primitive types in tandem so struggling to figure out the way forward. Thanks for any help
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