safely stage video frames

internal/renderer/renderer.go

@@ -3,17 +3,20 @@ package renderer
 import (
 	"errors"
 	"fmt"
-	"mxl-player/internal/sdl"
 	"unsafe"
 
+	"mxl-player/internal/sdl"
+
 	"github.com/christerso/vulkan-go/vk"
 )
 
-// Raises by swapchain creation, whem windos is minimized
-var ErrMinimized = errors.New("window minimized")
-
-// ErrOutOfDate is returned by DrawFrame when the swapchain needs recreation.
-var ErrOutOfDate = errors.New("swapchain out of date")
+var (
+	// Raises by swapchain creation, whem windos is minimized
+	ErrMinimized = errors.New("window minimized")
+	// ErrOutOfDate is returned by DrawFrame when the swapchain needs recreation.
+	ErrOutOfDate         = errors.New("swapchain out of date")
+	ErrInvalidVideoFrame = errors.New("invalid video frame")
+)
 
 // shader push-constants block
 type PushConstants struct {
@@ -392,6 +395,64 @@ func (r *Renderer) RecreateBuffers(newSize vk.DeviceSize) error {
 	return nil
 }
 
+func (r *Renderer) StageFrame(
+	payload []byte,
+	width uint32,
+	height uint32,
+	stride uint32,
+) error {
+	frameSize, err := validateFramePayload(len(payload), width, height, stride)
+	if err != nil {
+		return err
+	}
+
+	if frameSize != r.FrameSize() {
+		// RecreateBuffers waits for the device to become idle.
+		if err := r.RecreateBuffers(frameSize); err != nil {
+			return fmt.Errorf("resize video buffers: %w", err)
+		}
+	} else {
+		// The previous submitted frame may still read the mapped staging buffer.
+		if err := r.dev.WaitFence(r.inFlight, ^uint64(0)); err != nil {
+			return fmt.Errorf("wait before staging video: %w", err)
+		}
+	}
+
+	vk.CopyToMapped(
+		r.StagingMapped(),
+		payload[:int(frameSize)],
+	)
+	return nil
+}
+
+func validateFramePayload(
+	payloadLen int,
+	width uint32,
+	height uint32,
+	stride uint32,
+) (vk.DeviceSize, error) {
+	if width == 0 || height == 0 || stride == 0 {
+		return 0, fmt.Errorf(
+			"%w: dimensions=%dx%d stride=%d",
+			ErrInvalidVideoFrame,
+			width,
+			height,
+			stride,
+		)
+	}
+
+	requiredSize := uint64(stride) * uint64(height)
+	if payloadLen < 0 || requiredSize > uint64(payloadLen) {
+		return 0, fmt.Errorf(
+			"%w: payload=%d required=%d",
+			ErrInvalidVideoFrame,
+			payloadLen,
+			requiredSize,
+		)
+	}
+	return vk.DeviceSize(requiredSize), nil
+}
+
 // DrawFrame acquires an image, records commands, submits, and presents.
 // Returns ErrOutOfDate if the swapchain needs recreation
 func (r *Renderer) DrawFrame(videoW, videoH, stride uint32) error {

internal/renderer/renderer_test.go

@@ -0,0 +1,122 @@
+package renderer
+
+import (
+	"errors"
+	"strconv"
+	"testing"
+
+	"github.com/christerso/vulkan-go/vk"
+)
+
+func TestValidateFramePayload(t *testing.T) {
+	tests := []struct {
+		name       string
+		payloadLen int
+		width      uint32
+		height     uint32
+		stride     uint32
+		wantSize   vk.DeviceSize
+		wantErr    bool
+	}{
+		{
+			name:       "valid frame",
+			payloadLen: 5120 * 1080,
+			width:      1920,
+			height:     1080,
+			stride:     5120,
+			wantSize:   vk.DeviceSize(5120 * 1080),
+		},
+		{
+			name:       "payload may be larger than frame",
+			payloadLen: 5120*1080 + 128,
+			width:      1920,
+			height:     1080,
+			stride:     5120,
+			wantSize:   vk.DeviceSize(5120 * 1080),
+		},
+		{
+			name:       "zero width",
+			payloadLen: 100,
+			height:     10,
+			stride:     10,
+			wantErr:    true,
+		},
+		{
+			name:       "zero height",
+			payloadLen: 100,
+			width:      10,
+			stride:     10,
+			wantErr:    true,
+		},
+		{
+			name:       "zero stride",
+			payloadLen: 100,
+			width:      10,
+			height:     10,
+			wantErr:    true,
+		},
+		{
+			name:       "payload is too small",
+			payloadLen: 99,
+			width:      10,
+			height:     10,
+			stride:     10,
+			wantErr:    true,
+		},
+		{
+			name:       "negative payload length",
+			payloadLen: -1,
+			width:      10,
+			height:     10,
+			stride:     10,
+			wantErr:    true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := validateFramePayload(
+				tt.payloadLen,
+				tt.width,
+				tt.height,
+				tt.stride,
+			)
+
+			if tt.wantErr {
+				if !errors.Is(err, ErrInvalidVideoFrame) {
+					t.Fatalf("validateFramePayload() error = %v, want %v", err, ErrInvalidVideoFrame)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("validateFramePayload() error = %v, want nil", err)
+			}
+			if got != tt.wantSize {
+				t.Errorf("validateFramePayload() size = %d, want %d", got, tt.wantSize)
+			}
+		})
+	}
+}
+
+func TestValidateFramePayloadUses64BitSize(t *testing.T) {
+	if strconv.IntSize < 64 {
+		t.Skip("test requires a 64-bit int")
+	}
+
+	stride := ^uint32(0)
+	height := uint32(2)
+	required := uint64(stride) * uint64(height)
+
+	got, err := validateFramePayload(
+		int(required),
+		1,
+		height,
+		stride,
+	)
+	if err != nil {
+		t.Fatalf("validateFramePayload() error = %v, want nil", err)
+	}
+	if uint64(got) != required {
+		t.Fatalf("validateFramePayload() size = %d, want %d", got, required)
+	}
+}