static pattern frame cache

internal/video/pattern.go

@@ -15,6 +15,7 @@ type PatternInfo struct {
 type pattern struct {
 	PatternInfo
 	kernelSource string
+	dynamic      bool
 }
 
 var patterns = map[string]pattern{
@@ -25,6 +26,7 @@ var patterns = map[string]pattern{
 	"ebu75-move": {
 		PatternInfo:  PatternInfo{Name: "ebu75-move", Description: "EBU 75% Color Bar Signal with moving square"},
 		kernelSource: mustReadKernel("dynamic/ebu75.wgsl"),
+		dynamic:      true,
 	},
 	"ebu100": {
 		PatternInfo:  PatternInfo{Name: "ebu100", Description: "EBU 100% Color Bar Signal"},
@@ -33,6 +35,7 @@ var patterns = map[string]pattern{
 	"ebu100-move": {
 		PatternInfo:  PatternInfo{Name: "ebu100-move", Description: "EBU 100% Color Bar Signal with moving square"},
 		kernelSource: mustReadKernel("dynamic/ebu100.wgsl"),
+		dynamic:      true,
 	},
 	"smpte": {
 		PatternInfo:  PatternInfo{Name: "smpte", Description: "SMPTE RP-219 Color Bar Signal"},
@@ -41,6 +44,7 @@ var patterns = map[string]pattern{
 	"smpte-move": {
 		PatternInfo:  PatternInfo{Name: "smpte-move", Description: "SMPTE RP-219 Color Bar Signal with moving square"},
 		kernelSource: mustReadKernel("dynamic/smpteBars.wgsl"),
+		dynamic:      true,
 	},
 	"gray-bars": {
 		PatternInfo:  PatternInfo{Name: "gray-bars", Description: "13-step grayscale bars (Y 64..940)"},
@@ -49,6 +53,7 @@ var patterns = map[string]pattern{
 	"gray-bars-move": {
 		PatternInfo:  PatternInfo{Name: "gray-bars-move", Description: "13-step grayscale bars (Y 64..940) with moving square"},
 		kernelSource: mustReadKernel("dynamic/yBars.wgsl"),
+		dynamic:      true,
 	},
 	"gray-ramp": {
 		PatternInfo:  PatternInfo{Name: "gray-ramp", Description: "Y gradient (black -> 100% white)"},
@@ -57,6 +62,7 @@ var patterns = map[string]pattern{
 	"gray-ramp-move": {
 		PatternInfo:  PatternInfo{Name: "gray-ramp-move", Description: "Y gradient with moving square"},
 		kernelSource: mustReadKernel("dynamic/yRamp.wgsl"),
+		dynamic:      true,
 	},
 }
 

internal/video/pattern_test.go

@@ -1,6 +1,9 @@
 package video
 
-import "testing"
+import (
+	"strings"
+	"testing"
+)
 
 func TestPatterns(t *testing.T) {
 	got := Patterns()
@@ -43,5 +46,9 @@ func TestPatternRegistryKeysMatchNames(t *testing.T) {
 		if pattern.kernelSource == "" {
 			t.Errorf("pattern %q has empty kernel source", name)
 		}
+		wantDynamic := strings.HasSuffix(name, "-move")
+		if pattern.dynamic != wantDynamic {
+			t.Errorf("pattern %q dynamic = %t, want %t", name, pattern.dynamic, wantDynamic)
+		}
 	}
 }

internal/video/runner.go

@@ -35,6 +35,21 @@ func Run(ctx context.Context, inst *mxl.Instance, cfg Config) (runErr error) {
 		return err
 	}
 
+	var staticFrame []byte
+	if !pattern.dynamic {
+		frameSize := int(cfg.Width()*cfg.Height()) * 8 / 3
+		staticFrame = make([]byte, frameSize)
+
+		if err := gen.GenerateFrame(staticFrame, 0); err != nil {
+			return fmt.Errorf("generate static frame: %w", err)
+		}
+		if overlay != nil {
+			if err := overlay.ApplyV210(staticFrame); err != nil {
+				return fmt.Errorf("apply text overlay to static frame: %w", err)
+			}
+		}
+	}
+
 	flowJSON, err := json.Marshal(cfg.Definition)
 	if err != nil {
 		return fmt.Errorf("marshal video flow definition: %w", err)
@@ -70,6 +85,16 @@ func Run(ctx context.Context, inst *mxl.Instance, cfg Config) (runErr error) {
 		if err != nil {
 			return fmt.Errorf("open video grain %d: %w", idx, err)
 		}
+		if staticFrame != nil {
+			if len(grain.Payload) != len(staticFrame) {
+				return cancelGrain(grain, fmt.Errorf(
+					"video grain payload size %d, expected %d",
+					len(grain.Payload),
+					len(staticFrame),
+				))
+			}
+			copy(grain.Payload, staticFrame)
+		} else {
 			if err := gen.GenerateFrame(grain.Payload, int(tick)); err != nil {
 				return cancelGrain(grain, fmt.Errorf("generate frame for grain %d: %w", idx, err))
 			}
@@ -78,13 +103,14 @@ func Run(ctx context.Context, inst *mxl.Instance, cfg Config) (runErr error) {
 					return cancelGrain(grain, fmt.Errorf("apply text overlay to grain %d: %w", idx, err))
 				}
 			}
+			tick++
+		}
 		if err := grain.Commit(grain.TotalSlices, 0); err != nil {
 			return fmt.Errorf("commit video grain %d: %w", idx, err)
 		}
 
 		grainsWritten++
 		idx++
-		tick++
 		if grainsWritten%100 == 0 {
 			log.Printf("video grains written=%d, next index=%d", grainsWritten, idx)
 		}