Initial pipeline work

engine/sprite.odin

@@ -1,5 +1,6 @@
 package engine
 
+import "core:mem"
 import sdl "vendor:sdl3"
 
 Vec2 :: [2]f32
@@ -26,26 +27,105 @@ update_sprite :: proc(sprite: ^Sprite, dt: f32) {
 	_ = dt
 }
 
-draw_sprite :: proc(renderer: ^sdl.Renderer, sprite: ^Sprite) {
-	assert(sprite.data != nil)
+to_clip :: proc(px, py, sw, sh: f32) -> [2]f32 {
+	return {
+		px / sw * 2 - 1,
+		1 - py / sh * 2, // flip y (window pixels are y-down)
+	}
+}
+
+draw_sprite :: proc(app: ^App, sprite: ^Sprite) {
+	if app.render_pass == nil || app.cmd == nil || app.swapchain_texture == nil {
+		return // begin_frame may have skipped (minimized window, etc.)
+	}
+	if sprite == nil || sprite.data == nil || sprite.data.texture == nil {
+		return
+	}
+
 	rect, ok := character_frame_rect(sprite.data, sprite.clip, sprite.frame)
 	if !ok {
 		return
 	}
 
-	w := f32(rect[2])
-	h := f32(rect[3])
-	dst := sdl.FRect {
-		x = sprite.position.x - w * 0.5,
-		y = sprite.position.y - h,
-		w = w,
-		h = h,
+	fw := f32(rect[2])
+	fh := f32(rect[3])
+
+	// Feet-centered placement, same as renderer version
+	x0_px := sprite.position.x - fw * 0.5
+	y0_px := sprite.position.y - fh
+	x1_px := x0_px + fw
+	y1_px := y0_px + fh
+
+	sw := f32(app.swapchain_w)
+	sh := f32(app.swapchain_h)
+	p0 := to_clip(x0_px, y0_px, sw, sh) // top-left
+	p1 := to_clip(x1_px, y0_px, sw, sh) // top-right
+	p2 := to_clip(x1_px, y1_px, sw, sh) // bottom-right
+	p3 := to_clip(x0_px, y1_px, sw, sh) // bottom-left
+
+	tex_w := f32(sprite.data.width)
+	tex_h := f32(sprite.data.height)
+	u0 := f32(rect[0]) / tex_w
+	v0 := f32(rect[1]) / tex_h
+	u1 := f32(rect[0] + rect[2]) / tex_w
+	v1 := f32(rect[1] + rect[3]) / tex_h
+
+	// Two triangles: (0,1,2) and (0,2,3)
+	verts := [6]Vertex {
+		{pos = p0, uv = {u0, v0}},
+		{pos = p1, uv = {u1, v0}},
+		{pos = p2, uv = {u1, v1}},
+		{pos = p0, uv = {u0, v0}},
+		{pos = p2, uv = {u1, v1}},
+		{pos = p3, uv = {u0, v1}},
 	}
-	src := sdl.FRect {
-		x = f32(rect[0]),
-		y = f32(rect[1]),
-		w = w,
-		h = h,
+
+	map_ptr := sdl.MapGPUTransferBuffer(app.device, app.transfer_buffer, false)
+	if map_ptr == nil {
+		return
 	}
-	sdl.RenderTexture(renderer, sprite.data.texture, &src, &dst)
+	mem.copy(map_ptr, raw_data(verts[:]), size_of(verts))
+	sdl.UnmapGPUTransferBuffer(app.device, app.transfer_buffer)
+
+	// IMPORTANT: SDL does not allow beginning a copy pass while a render pass
+	// is active on the same command buffer. Upload on a separate command buffer.
+	copy_cmd := sdl.AcquireGPUCommandBuffer(app.device)
+	if copy_cmd == nil {
+		return
+	}
+	copy_pass := sdl.BeginGPUCopyPass(copy_cmd)
+
+	src := sdl.GPUTransferBufferLocation {
+		transfer_buffer = app.transfer_buffer,
+		offset          = 0,
+	}
+	dst := sdl.GPUBufferRegion {
+		buffer = app.vertex_buffer,
+		offset = 0,
+		size   = u32(size_of(verts)),
+	}
+	sdl.UploadToGPUBuffer(copy_pass, src, dst, false)
+	sdl.EndGPUCopyPass(copy_pass)
+	fence := sdl.SubmitGPUCommandBufferAndAcquireFence(copy_cmd)
+	if fence == nil {
+		return
+	}
+	defer sdl.ReleaseGPUFence(app.device, fence)
+	if !sdl.WaitForGPUFences(app.device, true, &fence, 1) {
+		return
+	}
+
+	sampler_binding := sdl.GPUTextureSamplerBinding {
+		texture = sprite.data.texture,
+		sampler = app.sampler,
+	}
+	sdl.BindGPUFragmentSamplers(app.render_pass, 0, &sampler_binding, 1)
+
+	vb_binding := sdl.GPUBufferBinding {
+		buffer = app.vertex_buffer,
+		offset = 0,
+	}
+	sdl.BindGPUVertexBuffers(app.render_pass, 0, &vb_binding, 1)
+
+	sdl.DrawGPUPrimitives(app.render_pass, 6, 1, 0, 0)
 }