Ok here is a quick demo I threw togther:
using System;using System.Windows.Forms;using Microsoft.DirectX;using Microsoft.DirectX.Direct3D;using System.Drawing;namespace TestConsole{ class CMain : System.Windows.Forms.Form { Device D3DDevice; Sprite SpriteDevice; Texture m_texture; VertexBuffer m_buffer; protected void InitGraphics() { PresentParameters pres = new PresentParameters (); pres.Windowed = true; pres.SwapEffect = SwapEffect.Discard ; pres.BackBufferCount = 1; pres.EnableAutoDepthStencil = true; pres.AutoDepthStencilFormat = DepthFormat.D16; D3DDevice = new Device(0, DeviceType.Hardware , this, CreateFlags.SoftwareVertexProcessing , pres); SpriteDevice = new Sprite(D3DDevice); m_texture = TextureLoader.FromFile(D3DDevice, "icons09.dds"); m_buffer = CreateVertexBuffer(D3DDevice); } protected VertexBuffer CreateVertexBuffer (Device device) { CustomVertex.TransformedColoredTextured [] verts = new CustomVertex.TransformedColoredTextured [6]; verts [0] = new CustomVertex.TransformedColoredTextured ( 0 + 64 + 256, 0, 0.1F, 0.1F, Color.White.ToArgb (), 0.0f, 0.0f); verts [1] = new CustomVertex.TransformedColoredTextured ( 256 + 64 + 256, 0, 0.1F, 0.1F, Color.White.ToArgb (), 1.0f, 0.0f); verts [2] = new CustomVertex.TransformedColoredTextured ( 0 + 64 + 256, 256, 0.1F, 0.1F, Color.White.ToArgb (), 0.0f, 1.0f); verts [3] = new CustomVertex.TransformedColoredTextured ( 0 + 64 + 256, 256, 0.1F, 0.1F, Color.White.ToArgb (), 0.0f, 1.0f); verts [4] = new CustomVertex.TransformedColoredTextured ( 256 + 64 + 256, 0, 0.1F, 0.1F, Color.White.ToArgb (), 1.0f, 0.0f); verts [5] = new CustomVertex.TransformedColoredTextured ( 256 + 64 + 256, 256, 0.1F, 0.1F, Color.White.ToArgb (), 1.0f, 1.0f); VertexBuffer buf = new VertexBuffer ( typeof ( CustomVertex.TransformedColoredTextured ), verts.Length , device, 0, CustomVertex.TransformedColoredTextured.Format , Pool.Default ); GraphicsStream stm = buf.Lock (0, 0, 0); stm.Write ( verts ); buf.Unlock (); return buf ; } protected void RenderGraphics() { D3DDevice.VertexFormat = CustomVertex.TransformedColoredTextured.Format; // alpha blending D3DDevice.RenderState.AlphaTestEnable = true; D3DDevice.RenderState.ReferenceAlpha = 0x01; D3DDevice.RenderState.AlphaFunction = Compare.GreaterEqual; D3DDevice.RenderState.AlphaBlendEnable = true; D3DDevice.RenderState.AlphaSourceBlend = Blend.SourceAlpha; D3DDevice.RenderState.AlphaDestinationBlend = Blend.InvSourceAlpha; D3DDevice.TextureState[0].ColorOperation = TextureOperation.Modulate; D3DDevice.TextureState[0].ColorArgument1 = TextureArgument.TextureColor; D3DDevice.TextureState[0].ColorArgument2 = TextureArgument.Diffuse; D3DDevice.TextureState[0].AlphaOperation = TextureOperation.Modulate; D3DDevice.TextureState[0].AlphaArgument1 = TextureArgument.TextureColor; D3DDevice.TextureState[0].AlphaArgument2 = TextureArgument.Diffuse; D3DDevice.RenderState.ZBufferEnable = true; D3DDevice.RenderState.ZBufferFunction = Compare.LessEqual; D3DDevice.BeginScene(); D3DDevice.Clear(ClearFlags.Target | ClearFlags.ZBuffer, Color.BlueViolet, 1.0f, 0); D3DDevice.SetTexture(0, m_texture); D3DDevice.SetStreamSource(0, m_buffer, 0); D3DDevice.DrawPrimitives(PrimitiveType.TriangleList, 0, 2); SpriteDevice.Begin(); SpriteDevice.Draw(m_texture, new Rectangle(0, 0, 256, 256), new Vector2(1.0f, 1.0f), new Vector2(0.0f, 0.0f), 0.0f, new Vector2(0.0f, 0.0f), Color.White); SpriteDevice.End(); D3DDevice.EndScene(); D3DDevice.Present(); } // Program Entrypoint static void Main() { CMain app = new CMain(); app.Width = 800; app.Height = 600; app.InitGraphics(); app.Text = "Managed DirectX Test Sample"; app.Show(); while(app.Created) { app.RenderGraphics(); Application.DoEvents(); }; } }}
That is my problem. Image 1 shows the output I see on screen. Image 2 is the DDS file viewed in Adobe Photoshop. Image 3 is the result of me selecting the alpha channel and copying it onto another image with Photoshop. This is the same result I get when I used the Sprite helper class. It works fine, but using my own rendering code with a VertexBuffer it doesn't blend properly.
