static void Main(string[] args)
{
// Create the window and the graphics device
VeldridInit(out var window, out var graphicsDevice);
// Create a renderer that implements the OpenWheels.Rendering.IRenderer interface
// this guy actually draws everything to the backbuffer
var renderer = new VeldridRenderer(graphicsDevice);
// Our batcher lets use make calls to render lots of different primitive shapes and text.
// When we're done the batcher sends the draw calls to the renderer which will actually do the drawing.
// Alternatively to Batcher you can use StringIdBatcher so you can register and set the active texture
// and font with a string identifier.
var batcher = new Batcher(renderer);
var checkerBoardTextureId = batcher.LoadTexture("checkerboard.png");
// OpenWheels defines a sprite as an image that's part of a texture
// To create a sprite, we pass a texture and a region of that texture (in pixels) that contains the actual image
// let's add a sprite that draws 3/4th of the checkerboard
// So if our original texture looks like this:
// |## |
// |## |
// | ##|
// | ##|
// We'll create a sprite that looks like this:
// |## |
// |## |
// | #|
var cbSize = renderer.GetTextureSize(checkerBoardTextureId);
var subSpriteRect = new Rectangle(0, 0, (cbSize.Width * 3) / 4, (cbSize.Height * 3) / 4);
var checkerBoardSubSprite = new Sprite(checkerBoardTextureId, subSpriteRect);
var frame = 0;
// We run the game loop here and do our drawing inside of it.
VeldridRunLoop(window, graphicsDevice, () =>
{
renderer.Clear(Color.CornflowerBlue);
// Start a new batch
batcher.Start();
// we set the texture using the texture id we got back when registering the texture
// OpenWheels internally only works with sprites
// If you set a texture on a batcher it will convert it to a sprite with the region being the
// entire texture bounds
batcher.SetTexture(checkerBoardTextureId);
// The Batcher API is stateful. Anything we render now will use the checkerboard texture.
// By default the UV coordinates 0, 0, 1, 1 are use, so our texture is stretched
batcher.FillRect(new RectangleF(50, 20, 100, 100), Color.White);
batcher.FillRect(new RectangleF(200, 20, 100, 200), Color.White);
// Let's draw our subsprite
batcher.Sprite = checkerBoardSubSprite;
batcher.FillRect(new RectangleF(350, 20, 100, 100), Color.White);
// We can only draw 1 texture in a single draw call, but since our subsprite actually uses the same
// texture as our full checkerboard the batcher can still combine the calls into a single batch.
batcher.SetTexture(checkerBoardTextureId);
// Most of the primitives support UV coordinates one way or another.
batcher.FillCircle(new Vector2(550, 70), 50, Color.White, .25f);
batcher.FillRoundedRect(new RectangleF(650, 20, 100, 100), 15, Color.White);
var v1 = new Vector2(50, 280);
var v2 = new Vector2(150, 380);
batcher.DrawLine(v1, v2, Color.White, 6f);
// Note that the texture rotates with the line
// This is different from the circle(segment) primitives where we draw a cutout of the active texture
// There are a lot of ways to UV-map shapes, but OpenWheels currently picks just one for each shape
// we can set a matrix to transform UV coordinates
// let's make our texture loop in length while keeping it's aspect ratio and UV across its width.
// The sampler should wrap to be able to loop the texture (the default sampler state is LinearClamp)
// This state sticks across frames, so we could set it before the render loop as well
batcher.SamplerState = SamplerState.LinearWrap;
var v3 = new Vector2(200, 280);
var v4 = new Vector2(300, 380);
const float lineWidth = 10f;
// we want our UV aspect ratio to be 1:1, but it's lineWidth:length and we want to use
// the coordinate system of the width, so we normalize height to get the right aspect ratio
// (note that height is defined as the forward direction of the line)
var uvHeight = Vector2.Distance(v3, v4) / lineWidth;
batcher.UvTransform = Matrix3x2.CreateScale(1f, uvHeight);
batcher.DrawLine(v3, v4, Color.White, lineWidth);
// Reset the uv transform
batcher.UvTransform = Matrix3x2.Identity;
// The color value we can pass to these methods is multiplied with our texture color at each pixel.
batcher.FillRect(new RectangleF(350, 280, 100, 100), Color.Red);
// Finish the batch and let the renderer draw everything to the back buffer.
batcher.Finish();
if (frame < 2)
{
// Note that the first frame renders in two batches because we change the sampler state
// halfway through.
// Every subsequent frame render in a single batch because the sampler state stays at LinearClamp
Console.WriteLine("Frame " + frame);
Console.WriteLine("Vertices: " + batcher.VerticesSubmitted);
Console.WriteLine("Indices: " + batcher.IndicesSubmitted);
Console.WriteLine("Batches: " + batcher.BatchCount);
Console.WriteLine();
frame++;
}
});
renderer.Dispose();
graphicsDevice.Dispose();
}