SdlVulkan.Renderer

SDL3 + Vortice.Vulkan rendering library built on DIR.Lib primitives.

Types

• SdlVulkanWindow — SDL3 window with Vulkan instance and surface lifecycle. Creates maximized, resizable windows with Vulkan surface.
• VulkanContext — Vulkan device, swapchain, command buffers, sync management. MaxFramesInFlight = 2 with per-frame vertex buffers.
• VkRenderer — Renderer<VulkanContext> implementation with FillRectangle, DrawRectangle, FillEllipse, DrawText. Exposes FontAtlasDirty for callers to trigger redraws after glyph rasterization.
• VkPipelineSet — GLSL 450 shader compilation and Vulkan pipeline creation (flat, textured, ellipse)
• VkFontAtlas — Dynamic glyph atlas with FreeType2 rasterization and Vulkan texture upload. Supports grow (512→2048), deferred eviction, and skipUnflushed to prevent sampling stale GPU texture data.

Font Atlas Lifecycle

Per frame:

1. BeginFrame() — handles deferred eviction if atlas was full last frame
2. Flush(cmd) — uploads dirty staging region to GPU via vkCmdCopyBufferToImage
3. DrawText(...) → GetGlyph(...) — cache hit returns UV coords; miss rasterizes into staging
4. GetGlyph(..., skipUnflushed: true) — in draw loops, returns zero-width for glyphs not yet uploaded

Thread safety: vkDeviceWaitIdle() before reusing the shared upload buffer (prevents race with MaxFramesInFlight = 2).

Diagnostic logging (Console.Error): [FontAtlas] / [VkRenderer] prefixed lines for Flush, Grow, EvictAll, cache miss, Resize. Capture with 2>stderr.log.

Usage

using SdlVulkan.Renderer;

using var window = SdlVulkanWindow.Create("My App", 800, 600);
window.GetSizeInPixels(out var w, out var h);

var ctx = VulkanContext.Create(window.Instance, window.Surface, (uint)w, (uint)h);
var renderer = new VkRenderer(ctx, (uint)w, (uint)h);

while (running)
{
    if (!renderer.BeginFrame(bgColor)) { renderer.Resize(w, h); continue; }
    renderer.FillRectangle(rect, color);
    renderer.DrawText("Hello", fontPath, 14f, white, layout);
    renderer.EndFrame();
    if (renderer.FontAtlasDirty) needsRedraw = true;
}

Dependencies

• DIR.Lib — Rendering primitives + FreeType glyph rasterization
• SDL3-CS — SDL3 bindings
• Vortice.Vulkan — Vulkan bindings
• Vortice.ShaderCompiler — GLSL to SPIR-V

License

MIT