#2 Draw an image from a byte array

MathTypes.cs

@@ -0,0 +1,32 @@
+public struct float3(float x, float y, float z)
+{
+    public float x = x;
+    public float y = y;
+    public float z = z;
+    
+    public float r
+    {
+        get => x; set => x = value;
+    }
+    public float g
+    {
+        get => y; set => y = value;
+    }
+    public float b
+    {
+        get => z; set => z = value;
+    }
+
+    public static float3 operator -(float3 a, float3 b) => new float3(a.x - b.x, a.y - b.y, a.z - b.y);
+
+    public static float3 cross(float3 a, float3 b) => new float3(a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z, a.x * b.y - a.y * b.x);
+    
+    public static float dot(float3 a, float3 b) => a.x * b.x + a.y * b.y + a.z * b.z;
+
+}
+
+public struct float2(float x, float y)
+{
+    public float x = x;
+    public float y = y;
+}

README.md

@@ -5,7 +5,7 @@ Writing a simple 3D software renderer from scratch to understand the math behind
 
 ## 🎯 Milestones
 - [X]  Setup Raylib C# project
-- [ ]  Draw an image from a byte array
+- [X]  Draw an image from a byte array
 - [ ]  Draw a triangle
 - [ ]  Render Lots of triangles
 - [ ]  OBJ Loader

RenderDevice.cs

@@ -0,0 +1,57 @@
+using System.Numerics;
+using System.Runtime.InteropServices;
+using Raylib_cs;
+
+
+public class RenderDevice
+{
+    public int width { get; private set; }
+    public int height { get; private set; }
+    
+    private int screenWidth, screenHeight;
+    
+    private Texture2D renderTarget;
+    private IntPtr pixelPtr;
+    private byte[] pixelData;
+    public RenderDevice(int width, int height, int screenWidth, int screenHeight)
+    {
+        this.width = width;
+        this.height = height;
+        this.screenWidth = screenWidth;
+        this.screenHeight = screenHeight;
+        
+        Image image = Raylib.GenImageColor(width, height, Color.Black);
+        renderTarget = Raylib.LoadTextureFromImage(image);
+        Raylib.UnloadImage(image); 
+        
+        pixelData = new byte[width * height * 4];
+        pixelPtr = Marshal.AllocHGlobal(pixelData.Length);
+
+    }
+
+    public void render()
+    {
+        Marshal.Copy(pixelData, 0, pixelPtr, pixelData.Length);
+        unsafe
+        {
+            Raylib.UpdateTexture(renderTarget, (void*)pixelPtr);
+        }
+        
+        Raylib.DrawTexturePro(renderTarget, new Rectangle(0,0, width, height), new Rectangle(0, 0, screenWidth, screenHeight), Vector2.Zero, 0f, Color.White);
+    }
+    
+    public void SetPixel(int x, int y, float3 color)
+    {
+        int idx = (y * width + x) * 4;
+        pixelData[idx] = (byte)color.r;
+        pixelData[idx + 1] = (byte)color.g;
+        pixelData[idx + 2] = (byte)color.b;
+        pixelData[idx + 3] = 0xFF;
+    }
+
+    public void cleanup()
+    {
+        Raylib.UnloadTexture(renderTarget);
+        Marshal.FreeHGlobal(pixelPtr); // always free after upload
+    }
+}

SoftwareRasterizer.cs

@@ -2,22 +2,55 @@
 
 class SoftwareRasterizer
 {
+    
+    const int screenWidth = 1280 * 2;
+    const int screenHeight = 800 * 2;
+
+    const int scale = 8;
+
+    private RenderDevice renderer;
+    
     static void Main()
     {
-        const int screenWidth = 800;
-        const int screenHeight = 600;
+        SoftwareRasterizer sr = new SoftwareRasterizer();
+        sr.start();
+    }
+
+    public void start()
+    {
         
         Raylib.InitWindow(screenWidth, screenHeight, "Software Rasterizer");
-        Raylib.SetTargetFPS(60);
+        Raylib.SetTargetFPS(0);
+
+        renderer = new RenderDevice(screenWidth / scale, screenHeight / scale, screenWidth, screenHeight);
+
+        int frameCounter = 0;
+
+        Random rand = new Random();
         
         while (!Raylib.WindowShouldClose())
         {
+            for (int i = 0; i < renderer.height; i++)
+            {
+                for (int j = 0; j < renderer.width; j++)
+                {
+                    renderer.SetPixel(j, i, new float3((j / (float)(renderer.width)) * 255, (i / (float)(renderer.height)) * 255, rand.Next(1,256)));
+                }
+            }
+            // Render
             Raylib.BeginDrawing();
-            Raylib.ClearBackground(Color.LightGray);
-            Raylib.DrawText("Hello, Raylib-cs!", 190, 200, 50, Color.DarkGray);
+            Raylib.ClearBackground(Color.Black);
+            //
+            renderer.render();
+            //
+            Raylib.DrawText($"FPS: {Raylib.GetFPS()}", 10, 10, 20, Color.White);
             Raylib.EndDrawing();
+            frameCounter += 2;
         }
 
+        // Cleanup
+        renderer.cleanup();
         Raylib.CloseWindow();
     }
 }
+

SoftwareRasterizer.csproj

@@ -5,6 +5,7 @@
     <TargetFramework>net8.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
 
   <ItemGroup>