commit ebbb377ce8a51152e3586309505b2d8441b72939
Author: samstalhandske <samstalhandske@hotmail.com>
Date:   Fri Nov 14 11:56:14 2025 +0100

    Initial commit.

diff --git a/renderer.odin b/renderer.odin
new file mode 100644
index 0000000..08a016f
--- /dev/null
+++ b/renderer.odin
@@ -0,0 +1,90 @@
+package renderer
+
+import "core:fmt"
+
+RENDER_BACKEND_OPENGL       :: #config(RENDER_BACKEND_OPENGL,       false)
+RENDER_BACKEND_VULKAN       :: #config(RENDER_BACKEND_VULKAN,       false)
+RENDER_BACKEND_DIRECTX11    :: #config(RENDER_BACKEND_DIRECTX11,    false)
+RENDER_BACKEND_METAL        :: #config(RENDER_BACKEND_METAL,        false)
+
+Renderer :: struct {
+    api: Renderer_API,
+
+    viewport: Viewport,
+    surface_ptr: rawptr,
+    backend: rawptr,
+}
+
+Viewport :: struct {
+    x, y, width, height: u16,
+}
+
+Renderer_API :: enum {
+    OpenGL,
+    Vulkan,
+    DirectX11,
+    Metal,
+}
+
+
+create :: proc(surface_ptr: rawptr) -> (^Renderer, bool) {
+    renderer := new(Renderer)
+    renderer.surface_ptr = surface_ptr
+
+    when RENDER_BACKEND_OPENGL {
+        if !opengl_init(renderer) {
+            fmt.printfln("Failed to initialize OpenGL.")
+            destroy(renderer)
+            return nil, false
+        }
+    }
+    else {
+        destroy(renderer)
+        
+        fmt.printfln("Unhandled backend or no backend selected.")
+        return nil, false
+    }
+    
+    // TODO: SS - Init renderer using 'api'.
+    return renderer, true
+}
+
+set_viewport :: proc(renderer: ^Renderer, x, y, width, height: u16) {
+    fmt.printfln("Setting viewport to %v:%v, %vx%v.", x, y, width, height)
+
+    renderer.viewport = {
+        x = x,
+        y = y,
+        width = width,
+        height = height,
+    }
+
+    when RENDER_BACKEND_OPENGL {
+        opengl_viewport_changed(renderer)
+    }
+}
+
+set_clear_color :: proc(renderer: ^Renderer, color: [3]u8) {
+    when RENDER_BACKEND_OPENGL {
+        opengl_set_clear_color(renderer, color)
+    }
+}
+
+render_frame :: proc(renderer: ^Renderer) {
+    
+}
+
+swap_buffers :: proc(renderer: ^Renderer) {
+    when RENDER_BACKEND_OPENGL {
+        opengl_swap_buffers(renderer)
+    }
+}
+
+destroy :: proc(renderer: ^Renderer) {
+    when RENDER_BACKEND_OPENGL {
+        opengl_destroy(renderer)
+    }
+    
+    free(renderer)
+    renderer^ = {}
+}
\ No newline at end of file
diff --git a/renderer_backend_opengl_windows.odin b/renderer_backend_opengl_windows.odin
new file mode 100644
index 0000000..3ec2e15
--- /dev/null
+++ b/renderer_backend_opengl_windows.odin
@@ -0,0 +1,93 @@
+package renderer
+
+import "core:fmt"
+import gl "vendor:OpenGL"
+import win "core:sys/windows"
+
+
+when RENDER_BACKEND_OPENGL {
+    Backend_OpenGL_Windows :: struct {
+        hwnd: win.HWND,
+        hdc: win.HDC,
+        gl_context: win.HGLRC,
+    }
+
+    backend: Backend_OpenGL_Windows
+    
+    opengl_init :: proc(renderer: ^Renderer) -> bool {
+        renderer.backend = &backend
+
+        backend.hwnd = win.HWND(renderer.surface_ptr)
+        backend.hdc = win.GetDC(backend.hwnd)
+
+        pfd := win.PIXELFORMATDESCRIPTOR {
+            nSize = size_of(win.PIXELFORMATDESCRIPTOR),
+            nVersion = 1,
+            dwFlags = win.PFD_DRAW_TO_WINDOW | win.PFD_SUPPORT_OPENGL | win.PFD_DOUBLEBUFFER,
+            iPixelType = win.PFD_TYPE_RGBA,
+            cColorBits = 32,
+            cDepthBits = 24,
+            cStencilBits = 8,
+            iLayerType = win.PFD_MAIN_PLANE,
+        }
+
+        format_index := win.ChoosePixelFormat(backend.hdc, &pfd)
+        assert(format_index != 0, "ChoosePixelFormat failed")
+
+        set_pixel_format_ok := win.SetPixelFormat(backend.hdc, format_index, &pfd)
+        assert(set_pixel_format_ok == win.TRUE, "SetPixelFormat failed")
+
+        backend.gl_context = win.wglCreateContext(backend.hdc)
+        assert(backend.gl_context != nil, "Failed to create OpenGL context")
+
+        win.wglMakeCurrent(backend.hdc, backend.gl_context)
+        // fmt.printfln("GL Context: %v", backend.gl_context)
+
+        gl.load_up_to(3, 3, proc(p: rawptr, name: cstring) {
+            addr := win.wglGetProcAddress(name)
+            if addr == nil {
+                dll := win.LoadLibraryW(win.utf8_to_wstring("opengl32.dll"))
+                addr = win.GetProcAddress(dll, name)
+            }
+            (^rawptr)(p)^ = addr
+        })
+
+
+        opengl_swap_buffers(renderer)
+
+        return true
+    }
+
+    opengl_viewport_changed :: proc(renderer: ^Renderer) {
+        gl.Clear(gl.COLOR_BUFFER_BIT)
+
+        gl.Viewport(
+            i32(renderer.viewport.x),
+            i32(renderer.viewport.y),
+            i32(renderer.viewport.width),
+            i32(renderer.viewport.height)
+        )
+    }
+
+    opengl_set_clear_color :: proc(renderer: ^Renderer, color: [3]u8) {
+        gl.ClearColor(
+            f32(color.r) / f32(max(u8)),
+            f32(color.g) / f32(max(u8)),
+            f32(color.b) / f32(max(u8)),
+            1.0
+        )
+    }
+
+    opengl_swap_buffers :: proc(renderer: ^Renderer) {
+        gl.Clear(gl.COLOR_BUFFER_BIT)
+        win.SwapBuffers(backend.hdc)
+    }
+
+    opengl_destroy :: proc(renderer: ^Renderer) {
+        win.wglMakeCurrent(nil, nil)
+        win.wglDeleteContext(backend.gl_context)
+        win.ReleaseDC(backend.hwnd, backend.hdc)
+
+        backend = {}
+    }
+}
\ No newline at end of file