CODEWITHSUNDEEP
vb.netimagexna
Christian Boman
Christian Boman

Reputation: 43

Drawing on an image before drawing on screen in XNA using VB.NET

I'm programming a game in XNA, using VB.NET. I want to create an intro to the game that zooms in/out the whole screen and scaling each image to accomplish this is cumbersome at best. I like to be able to draw a lot of .PNG's (or parts of them) onto a whole image, to then be able to manipulate (scale, turn etc) that whole image, before drawing it with the spriteBatch. The examples I can find use something like: 

dim bitmap as New Bitmap

or 

dim image as New Image

but these codes highlights the "Bitmap" or "Image" as red, and I cannot use them. I'd be thankful for any help on this issue!

Upvotes: 0

Views: 213

Answers (2)

Christian Boman
Christian Boman

Reputation: 43

So I've experimented with Petri Laarne's answer and finally come up with a workable code (most examples online are using C#, and doesn't explain the entire process). Trying to explain it here:

In Public Class Game1:

Private WithEvents graphics As GraphicsDeviceManager
Private WithEvents spriteBatch, spriteBatch2 As SpriteBatch

In Loadcontent:

Public render2 As RenderTarget2D
spriteBatch2 = New SpriteBatch(GraphicsDevice)
spriteBatch = New SpriteBatch(GraphicsDevice)
render2 = New RenderTarget2D(GraphicsDevice, 1024, 768)

In Draw:

spriteBatch2.GraphicsDevice.SetRenderTarget(render2)
        GraphicsDevice.Clear(Color.Black)
        srcRect = New Rectangle(440, 0, 440, 440) : destRect = New Rectangle(100, 335, 440, 440)
        spriteBatch2.Begin(SpriteSortMode.BackToFront, BlendState.AlphaBlend) : spriteBatch2.Draw(introNEWMirrorDecos, destRect, srcRect, Color.White) : spriteBatch2.End()
        destRect = New Rectangle(300, 335, 440, 440)
        spriteBatch2.Begin(SpriteSortMode.BackToFront, BlendState.AlphaBlend) : spriteBatch2.Draw(introNEWMirrorDecos, destRect, srcRect, Color.White) : spriteBatch2.End()
        spriteBatch2.GraphicsDevice.SetRenderTarget(Nothing)
        GraphicsDevice.Clear(Color.Black)
        destRect = New Rectangle(512, 384, 1024, 768) : srcRect = New Rectangle(0, 0, 1024, 768)
        spriteBatch.Begin(SpriteSortMode.BackToFront, BlendState.AlphaBlend) : spriteBatch.Draw(render2, destRect, srcRect, Color.White, PI / 12, New Vector2(512, 384), SpriteEffects.None, 0) : spriteBatch.End()

This is an example code from the actual game that worked like it was intended: drawing 2 things on the alternate rendering image and then drawing them as one single image (in this case being able to rotate it by pi/12).

Any comments on how to do this differently or more efficient is appreciated, and thank's for the initial answer @Petri Laarne

Upvotes: 0

Petri Laarne
Petri Laarne

Reputation: 421

SpriteBatch works with XNA Texture2D objects, whereas Bitmap and Image are System.Drawing types. They do not work together.

You can create a new RenderTarget2D, set it as active using GraphicsDevice.SetRenderTarget() and draw there using a SpriteBatch. You can then draw the stored render target to screen using a SpriteBatch, since render targets are a type of Texture2D.

Upvotes: 1

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