godosa-engine: initial public history

1 files changed, 35 insertions, 0 deletions

diff --git a/src/Godosa.Desktop/GlProgram.cs b/src/Godosa.Desktop/GlProgram.cs
new file mode 100644
index 0000000..25ebe5c
--- /dev/null
+++ b/src/Godosa.Desktop/GlProgram.cs
@@ -0,0 +1,35 @@
+using Silk.NET.OpenGL;
+
+namespace Godosa.Desktop;
+
+/// <summary>Shader program helpers: compile + link with the driver's info log in the
+/// exception, so a bad shader fails loudly at startup instead of drawing nothing.</summary>
+public static class GlProgram
+{
+    public static uint Link(GL gl, string vertexSource, string fragmentSource)
+    {
+        uint vs = Compile(gl, ShaderType.VertexShader, vertexSource);
+        uint fs = Compile(gl, ShaderType.FragmentShader, fragmentSource);
+        uint program = gl.CreateProgram();
+        gl.AttachShader(program, vs);
+        gl.AttachShader(program, fs);
+        gl.LinkProgram(program);
+        gl.GetProgram(program, ProgramPropertyARB.LinkStatus, out int linkStatus);
+        if (linkStatus == 0)
+            throw new InvalidOperationException($"Shader link failed: {gl.GetProgramInfoLog(program)}");
+        gl.DeleteShader(vs);
+        gl.DeleteShader(fs);
+        return program;
+    }
+
+    public static uint Compile(GL gl, ShaderType type, string source)
+    {
+        uint shader = gl.CreateShader(type);
+        gl.ShaderSource(shader, source);
+        gl.CompileShader(shader);
+        gl.GetShader(shader, ShaderParameterName.CompileStatus, out int status);
+        if (status == 0)
+            throw new InvalidOperationException($"Shader compile failed: {gl.GetShaderInfoLog(shader)}");
+        return shader;
+    }
+}