feat: adding shaders

Author: JeremyMeissner

FreeFrame/FreeFrame.csproj

@@ -11,4 +11,8 @@
     <PackageReference Include="OpenTK" Version="4.7.1" />
   </ItemGroup>
 
+  <Target Name="PostBuild" AfterTargets="PostBuildEvent">
+    <Exec Command="if not exist $(ProjectDir)$(OutDir)Shaders mkdir $(ProjectDir)$(OutDir)Shaders&#xD;&#xA;copy &quot;$(ProjectDir)Shaders\*&quot; &quot;$(ProjectDir)$(OutDir)Shaders\&quot;" />
+  </Target>
+
 </Project>

FreeFrame/Shaders/shader.frag

@@ -0,0 +1,8 @@
+#version 330
+
+layout(location = 0) out vec4 color;
+
+void main()
+{
+	color = vec4(0.5, 0.5, 0.5, 1.0);
+}

FreeFrame/Shaders/shader.vert

@@ -0,0 +1,8 @@
+#version 330 core
+
+layout(location = 0) in vec4 position;
+
+void main()
+{
+	gl_Position = position;
+}

FreeFrame/Window.cs

@@ -13,24 +13,75 @@ class Window : GameWindow
     {
         int _vertexBuffer;
 
+        int _vertexArray;
+
+        int _shader;
+
         public readonly float[] _vertices =
         {
-             0.0f, -0.5f, 0.0f, // Top
-            -0.5f,  0.5f, 0.0f, // Bottom-Left
-             0.5f,  0.5f, 0.0f  // Bottom-Right
+             0.0f, 0.5f, 0.0f, // Top
+            -0.5f,  -0.5f, 0.0f, // Bottom-Left
+             0.5f,  -0.5f, 0.0f  // Bottom-Right
         };
         public Window(GameWindowSettings gameWindowSettings, NativeWindowSettings nativeWindowSettings) : base(gameWindowSettings, nativeWindowSettings) { }
+        
+        static int CompileShader(string uri, ShaderType type)
+        {
+            int shader = GL.CreateShader(type);
+
+            GL.ShaderSource(shader, File.ReadAllText(uri)); // Import the source code of the shader
+            GL.CompileShader(shader);
+
+            GL.GetShader(shader, ShaderParameter.CompileStatus, out int compileStatus); // compileStatus is 0 if compile error
+            if (compileStatus == 0)
+            {
+                Console.WriteLine("{0}: {1}", type.ToString(), GL.GetShaderInfoLog(shader));
+                throw new Exception(); // TODO: Remove this exception
+            }
+
+            return shader;
+        }
+
+        static int CreateShader(string uriVertexShader, string uriFragementShader)
+        {
+            int program = GL.CreateProgram();
+
+            int vertexShader = CompileShader(uriVertexShader, ShaderType.VertexShader);
+            int fragmentShader = CompileShader(uriFragementShader, ShaderType.FragmentShader);
+
+            // TODO: Handling error
+
+            GL.AttachShader(program, vertexShader);
+            GL.AttachShader(program, fragmentShader);
+
+            GL.LinkProgram(program); // Put the shaders in their respective processor
+            GL.ValidateProgram(program); // Check if everything correct and store the information on the logs 
+            // TODO: Explain what's the difference with GL.ShaderInfoLog
+
+            GL.DeleteShader(vertexShader);
+            GL.DeleteShader(fragmentShader);
+
+            return program;
+        }
         protected override void OnLoad()
         {
             base.OnLoad();
+
+            GL.ClearColor(0.1f, 0.1f, 0.1f, 1.0f);
+
             _vertexBuffer = GL.GenBuffer();
             GL.BindBuffer(BufferTarget.ArrayBuffer, _vertexBuffer);
-            
             GL.BufferData(BufferTarget.ArrayBuffer, _vertices.Length * sizeof(float), _vertices, BufferUsageHint.StaticDraw);
 
+            _vertexArray = GL.GenVertexArray(); // TODO: Why a vertex array is necessary ?
+            GL.BindVertexArray(_vertexArray);
+
             GL.VertexAttribPointer(0, 3, VertexAttribPointerType.Float, false, 3 * sizeof(float), 0);
             GL.EnableVertexAttribArray(0);
 
+            _shader = CreateShader("Shaders/shader.vert", "Shaders/shader.frag");
+
+            GL.UseProgram(_shader);
         }
         protected override void OnResize(ResizeEventArgs e)
         {
@@ -52,12 +103,28 @@ protected override void OnUpdateFrame(FrameEventArgs e)
         protected override void OnRenderFrame(FrameEventArgs e)
         {
             base.OnRenderFrame(e);
+
+            GL.Clear(ClearBufferMask.ColorBufferBit); // Clear the color
+
+            GL.UseProgram(_shader);
+            GL.BindVertexArray(_vertexArray);
+
             GL.DrawArrays(PrimitiveType.Triangles, 0, 3);
+
+            SwapBuffers();
         }
 
         protected override void OnUnload()
         {
             base.OnUnload();
+
+            GL.BindBuffer(BufferTarget.ArrayBuffer, 0);
+            GL.BindVertexArray(_vertexArray);
+            GL.UseProgram(0);
+
+            GL.DeleteProgram(_shader);
+            GL.DeleteBuffer(_vertexBuffer);
+            GL.DeleteVertexArray(_vertexArray);
         }
     }
 }