CODEWITHSUNDEEP
c#xna
Jancis
Jancis

Reputation: 97

Xna studio 4. Pixel drawing

1 ) Hey. I need help with pixels... How can i draw pixels with less lagg in draw function? While i am drawing them then my processor usage is 40%, it's too much for that.

protected override void Draw(GameTime gameTime)
        {
                spriteBatch.Begin(SpriteSortMode.BackToFront, BlendState.AlphaBlend);
                spriteBatch.Draw(grasspixel, screenpos, Color.Red);
                GraphicsDevice.Clear(Color.CornflowerBlue);
                DrawGround(spriteBatch, 1024, 768, screenpos, grasspixel);
                spriteBatch.End();

                base.Draw(gameTime);            
        }

Here is DrawGround function:

public void DrawGround(SpriteBatch spriteBatch, int screen_X, int screen_Y, Vector2 screenPosition, Texture2D texture)
        {
            Vector2 tempVector = Vector2.Zero;
            for (int i = 1; i <= screen_X; i++)
            {
                for (int j = 1; j <= screen_Y; j++)
                {
                    if (earth[i, j] == 1)
                    {
                        tempVector.X = i;
                        tempVector.Y = j;
                        spriteBatch.Draw(texture, tempVector, Color.Blue);
                    }
                }
            }
        }

In DrawGround I get pixel locations from an array and then return them to Vector2.

2 ) Do I need to draw my map every frame?

Is there a special buffer or something like that to do this? Sorry if I ask something stupid, but I'm new to XNA. Sorry for my bad english.

Upvotes: 0

Views: 232

Answers (1)

Lucius
Lucius

Reputation: 3745

The problem is that you are drawing 786432 (1024*768) sprites per frame. Each sprite consists of 2 triangles, that need to be streched and positioned, not to forget all the texture sampling. SpriteBatch is fast, but not that fast.

Normally you would draw your grass texture over a larger area, using a sprite that is more than 1*1 pixels in size. Drawing one sprite for every pixel on screen really defeats the whole purpose of it.

So combine your grass pixels in an image editing program to a texture and use a few large sprites to draw your ground. That should bring your FPS to a reasonable rate.

If you really need to write data to a texture on a per pixel basis, use the Texture2D.SetData method.

Upvotes: 2

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