How to display a model on top of textures? [XNA]

MatsK · 2011-11-21T22:08:58

I'm trying to render a 3D mesh above a screen that consists of textures. Based on my research I figured I'd need a rendertarget and something called a "depth stencil buffer". So I found some code on MSDN for creating these; private RenderTarget2D CreateRenderTarget(GraphicsDevice device, int numberLevels, SurfaceFormat surface) { MultiSampleType type = device.PresentationParameters.MultiSampleType; // If the card can't use the surface format if (!GraphicsAdapter.DefaultAdapter.CheckDeviceFormat( DeviceType.Hardware, GraphicsAdapter.DefaultAdapter.CurrentDisplayMode.Format, TextureUsage.None, QueryUsages.None, ResourceType.RenderTarget, surface)) { // Fall back to current display format surface = device.DisplayMode.Format; } // Or it can't accept that surface format // with the current AA settings else if (!GraphicsAdapter.DefaultAdapter.CheckDeviceMultiSampleType( DeviceType.Hardware, surface, device.PresentationParameters.IsFullScreen, type)) { // Fall back to no antialiasing type = MultiSampleType.None; } int width, height; // See if we can use our buffer size as our texture CheckTextureSize(device.PresentationParameters.BackBufferWidth, device.PresentationParameters.BackBufferHeight, out width, out height); // Create our render target return new RenderTarget2D(device, width, height, numberLevels, surface, type, 0); } private bool CheckTextureSize(int width, int height, out int newwidth, out int newheight) { bool retval = false; GraphicsDeviceCapabilities Caps; Caps = GraphicsAdapter.DefaultAdapter.GetCapabilities( DeviceType.Hardware); // Check if Device requires Power2 textures if (Caps.TextureCapabilities.RequiresPower2) { retval = true; // Return true to indicate the numbers changed // Find the nearest base two log of the current width, // and go up to the next integer double exp = Math.Ceiling(Math.Log(width) / Math.Log(2)); // and use that as the exponent of the new width width = (int)Math.Pow(2, exp); // Repeat the process for height exp = Math.Ceiling(Math.Log(height) / Math.Log(2)); height = (int)Math.Pow(2, exp); } if (Caps.TextureCapabilities.RequiresSquareOnly) { retval = true; // Return true to indicate numbers changed width = Math.Max(width, height); height = width; } newwidth = Math.Min(Caps.MaxTextureWidth, width); newheight = Math.Min(Caps.MaxTextureHeight, height); return retval; } private DepthStencilBuffer CreateDepthStencil(RenderTarget2D target) { return new DepthStencilBuffer(target.GraphicsDevice, target.Width, target.Height, target.GraphicsDevice.DepthStencilBuffer.Format, target.MultiSampleType, target.MultiSampleQuality); } The problem is that even with these methods my rendered model isn't showing up! :\ Here's my rendering code: public override void Draw(SpriteBatch SBatch) { base.Draw(SBatch); RenderTarget2D RenderTarget = CreateRenderTarget(m_Screen.ScreenMgr.GraphicsDevice, 1, SurfaceFormat.Depth32); m_Screen.ScreenMgr.GraphicsDevice.SetRenderTarget(1, RenderTarget); m_Screen.ScreenMgr.GraphicsDevice.DepthStencilBuffer = CreateDepthStencil(RenderTarget); m_Effect.World = m_Screen.ScreenMgr.WorldMatrix; m_Effect.View = m_Screen.ScreenMgr.ViewMatrix; m_Effect.Projection = m_Screen.ScreenMgr.ProjectionMatrix; if (m_HeadTexture != null) { m_Effect.Texture = m_HeadTexture; m_Effect.TextureEnabled = true; m_Effect.EnableDefaultLighting(); } m_Effect.CommitChanges(); // Draw m_Effect.Begin(); m_Effect.Techniques[0].Passes[0].Begin(); if (m_HeadVerticies != null) { foreach (Face Fce in m_CurrentHeadMesh.Faces) { VertexPositionNormalTexture[] Vertex = new VertexPositionNormalTexture[3]; Vertex[0] = m_HeadVerticies[Fce.AVertexIndex]; Vertex[1] = m_HeadVerticies[Fce.BVertexIndex]; Vertex[2] = m_HeadVerticies[Fce.CVertexIndex]; Vertex[0].TextureCoordinate = m_HeadVerticies[Fce.AVertexIndex].TextureCoordinate; Vertex[1].TextureCoordinate = m_HeadVerticies[Fce.BVertexIndex].TextureCoordinate; Vertex[2].TextureCoordinate = m_HeadVerticies[Fce.CVertexIndex].TextureCoordinate; m_Screen.ScreenMgr.GraphicsDevice.DrawUserPrimitives<VertexPositionNormalTexture>( PrimitiveType.TriangleList, Vertex, 0, 1); } } m_Effect.Techniques[0].Passes[0].End(); m_Effect.End(); } Here's the code for rendering a screen: public virtual void Draw(SpriteBatch SBatch) { foreach (Texture2D Background in m_Backgrounds) { if (Background != null) { //Usually a screen only has 1 background, it should be drawn at 0, 0... SBatch.Draw(Background, new Rectangle(0, 0, Background.Width, Background.Height), Color.White); } } //Networked UI elements are usually dialogs, so for now it is //relatively safe to assume they can be drawn behind other elements. foreach (NetworkedUIElement Element in m_NetUIElements) Element.Draw(SBatch); foreach (UIElement Element in m_UIElements) { if (Element.DrawingLevel == DrawLevel.DontGiveAFuck) Element.Draw(SBatch); } foreach (UIElement Element in m_UIElements) { if (Element.DrawingLevel == DrawLevel.AlwaysOnTop) Element.Draw(SBatch); } for (int i = 0; i < m_Popups.Count; i++) m_Popups.Draw(SBatch); } What do I do to make my model show up? I know that the rendering code works, because I've tested it in a tool I made. So I'm thinking the reason the rendering isn't showing is because the model is rendered behind the textures...

Graphics and GPU Programming Programming

Started by MatsK November 17, 2011 04:19 PM

13 comments, last by kauna 12 years, 4 months ago

MatsK

395

Author

November 21, 2011 05:30 AM

Yup, and lighting seems to work fine when not using a rendetarget.

phil_t

8,087

November 21, 2011 07:22 AM

Take a step back for a minute. Do you really need to use a render target at all?

Just draw all your 2d GUI, then draw the models on top. That should work unless you're actually using the depth buffer when drawing your GUI. But assuming you're drawing it with SpriteBatch, depth-writing is disabled by default.

Once you've done drawing the GUI, then set the appropriate states for rendering 3d models (enable the depth buffer, enable depth writing, turn off alpha blending) and draw your model.

(btw, it looks like you're using XNA 3.0. I would consider upgrading to XNA 4.0. The API has had a number of improvements that make it more difficult to do the wrong thing :-)).

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kauna

2,925

November 21, 2011 01:28 PM

Take a step back for a minute. Do you really need to use a render target at all?
Just draw all your 2d GUI, then draw the models on top. That should work unless you're actually using the depth buffer when drawing your GUI. But assuming you're drawing it with SpriteBatch, depth-writing is disabled by default.
Once you've done drawing the GUI, then set the appropriate states for rendering 3d models (enable the depth buffer, enable depth writing, turn off alpha blending) and draw your model.
(btw, it looks like you're using XNA 3.0. I would consider upgrading to XNA 4.0. The API has had a number of improvements that make it more difficult to do the wrong thing :-)).

[font="Arial"]
[/font][font="Arial"]Otherwise, there is still some improvement for the code with render target :[/font]
[font="Arial"] [/font]
[font="Arial"]- you can clear your render target and depth buffer with one call. No need to call clear twice (this isn't an error though).[/font]
[font="Arial"]- Projection matrix : you have to calculate correct projection matrix to use with the render target. You may not use the same projection matrix as with the full screen since the aspect ratio is different.[/font]
[font="Arial"]- [color="#1C2837"]SurfaceFormat.Color should be the correct color buffer format[/font]
[color="#1C2837"][font="Arial"] [/font]
[color="#1C2837"][font="Arial"]However, I can't think why your model shows up black.[/font]
[color="#1C2837"][font="Arial"] [/font]
[color="#1C2837"][font="Arial"]Cheers![/font]

MatsK

395

Author

November 21, 2011 09:11 PM

[color="#1C2837"][font="Arial"]SurfaceFormat.Color should be the correct color buffer format[/quote][/font]
[color="#1C2837"][font="Arial"] [/font]
[font="Arial"][color="#1c2837"]What?[/font]
[font="Arial"] [/font]
[font="Arial"][color="#1c2837"]... I'm thinking that the current aspectratio might be banning me from using non-power-of-two-textures... but I'm not sure.[/font]

kauna

2,925

November 21, 2011 10:08 PM

[color="#1C2837"][font="Arial"]SurfaceFormat.Color should be the correct color buffer format
[/font]
[color="#1C2837"]
[font="Arial"][color="#1c2837"]What?[/font]
[font="Arial"] [/font]
[font="Arial"][color="#1c2837"]... I'm thinking that the current aspectratio might be banning me from using non-power-of-two-textures... but I'm not sure.[/font]
[/quote]

Well I guess it's my turn to say "what"?
[color=#1C2837][font=Arial][size=2]By saying "Color buffer format" I mean render target format. As you are storing color in it it is correct to say "color buffer". You'll need RGB channels for your render target and 8-bits per channel is enough. The closest thing to that is a surface format RGBA with 8-bits per channel. [/font][color=#1C2837][font=Arial][size=2]SurfaceFormat.Color[/font][color=#1C2837][font=Arial][size=2] stands for such surface format. [/font]
[color=#1C2837][font=Arial][size=2]
[/font]
[color=#1C2837][font=Arial][size=2]Nothing is banning you from using non-power-of-two-textures except the hardware if it doesn't support them (which is rare these days). [/font]
[font="Arial"][color="#1c2837"]Just calculate a correct projection matrix to reflect the size / aspect of the render target.[/font]
[font="Arial"][color="#1c2837"]
[/font]
[font="Arial"][color="#1c2837"]Cheers![/font]
[font="Arial"][color="#1c2837"]
[/font]

How to display a model on top of textures? [XNA]

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How to display a model on top of textures? [XNA]

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