ebiten: Bug fix: Source regions should not be passed when not needed

The source region information affects the condition of merging graphics commands. To avoid performance issues by the big number of graphcis commands, do not pass the source region whenever possible. Fixes hajimehoshi#1293
ablegao · Aug 11, 2020 · d4042a5 · d4042a5
1 parent 95022ff
commit d4042a5
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Showing 2 changed files with 24 additions and 12 deletions.
diff --git a/image.go b/image.go
@@ -271,11 +271,15 @@ func (i *Image) DrawImage(img *Image, options *DrawImageOptions) error {
 	is := graphics.QuadIndices()
 
 	var sr driver.Region
-	sr = driver.Region{
-		X:      float32(bounds.Min.X),
-		Y:      float32(bounds.Min.Y),
-		Width:  float32(bounds.Dx()),
-		Height: float32(bounds.Dy()),
+	// Pass the source region only when the shader is used, since this affects the condition of merging graphics
+	// commands (#1293).
+	if options.Shader != nil {
+		sr = driver.Region{
+			X:      float32(bounds.Min.X),
+			Y:      float32(bounds.Min.Y),
+			Width:  float32(bounds.Dx()),
+			Height: float32(bounds.Dy()),
+		}
 	}
 
 	srcs := [graphics.ShaderImageNum]*mipmap.Mipmap{img.mipmap}
@@ -430,11 +434,15 @@ func (i *Image) DrawTriangles(vertices []Vertex, indices []uint16, img *Image, o
 
 	var sr driver.Region
 	b := img.Bounds()
-	sr = driver.Region{
-		X:      float32(b.Min.X),
-		Y:      float32(b.Min.Y),
-		Width:  float32(b.Dx()),
-		Height: float32(b.Dy()),
+	// Pass the source region only when the shader is used, since this affects the condition of merging graphics
+	// commands (#1293).
+	if options.Shader != nil || options.Address != AddressUnsafe {
+		sr = driver.Region{
+			X:      float32(b.Min.X),
+			Y:      float32(b.Min.Y),
+			Width:  float32(b.Dx()),
+			Height: float32(b.Dy()),
+		}
 	}
 
 	var srcs [graphics.ShaderImageNum]*mipmap.Mipmap

diff --git a/internal/shareable/image.go b/internal/shareable/image.go
@@ -337,8 +337,12 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderImageNum]*Image, vertices []f
 			vertices[i*graphics.VertexFloatNum+2] += oxf
 			vertices[i*graphics.VertexFloatNum+3] += oyf
 		}
-		sourceRegion.X += oxf
-		sourceRegion.Y += oyf
+		// sourceRegion can be delibarately empty when this is not needed in order to avoid unexpected
+		// performance issue (#1293).
+		if sourceRegion.Width != 0 && sourceRegion.Height != 0 {
+			sourceRegion.X += oxf
+			sourceRegion.Y += oyf
+		}
 	}
 
 	var offsets [graphics.ShaderImageNum - 1][2]float32