graphics: Add logging when 'ebitendebug' tag is specified

Fixes #563

internal/graphics/command.go

@@ -29,6 +29,8 @@ import (
 // A command is not immediately executed after created. Instaed, it is queued after created,
 // and executed only when necessary.
 type command interface {
+	fmt.Stringer
+
 	Exec(indexOffsetInBytes int) error
 	NumVertices() int
 	NumIndices() int
@@ -147,6 +149,9 @@ func (q *commandQueue) Flush() {
 	opengl.GetContext().ResetViewportSize()
 	es := q.indices
 	vs := q.vertices
+	if recordLog() {
+		fmt.Println("--")
+	}
 	for len(q.commands) > 0 {
 		nv := 0
 		ne := 0
@@ -177,6 +182,9 @@ func (q *commandQueue) Flush() {
 				q.err = err
 				return
 			}
+			if recordLog() {
+				fmt.Printf("%s\n", c)
+			}
 			// TODO: indexOffsetInBytes should be reset if the command type is different
 			// from the previous one. This fix is needed when another drawing command is
 			// introduced than drawImageCommand.
@@ -221,6 +229,10 @@ func VertexSizeInBytes() int {
 	return theArrayBufferLayout.totalBytes()
 }
 
+func (c *drawImageCommand) String() string {
+	return fmt.Sprintf("draw-image: dst: %p <- src: %p, colorm: %v, mode %d, filter: %d", c.dst, c.src, c.color, c.mode, c.filter)
+}
+
 // Exec executes the drawImageCommand.
 func (c *drawImageCommand) Exec(indexOffsetInBytes int) error {
 	f, err := c.dst.createFramebufferIfNeeded()
@@ -292,6 +304,10 @@ type replacePixelsCommand struct {
 	height int
 }
 
+func (c *replacePixelsCommand) String() string {
+	return fmt.Sprintf("replace-pixels: dst: %p, x: %d, y: %d, width: %d, height: %d", c.dst, c.x, c.y, c.width, c.height)
+}
+
 // Exec executes the replacePixelsCommand.
 func (c *replacePixelsCommand) Exec(indexOffsetInBytes int) error {
 	// glFlush is necessary on Android.
@@ -339,6 +355,10 @@ func (c *pixelsCommand) Exec(indexOffsetInBytes int) error {
 	return nil
 }
 
+func (c *pixelsCommand) String() string {
+	return fmt.Sprintf("pixels: img: %p", c.img)
+}
+
 func (c *pixelsCommand) NumVertices() int {
 	return 0
 }
@@ -362,6 +382,10 @@ type disposeCommand struct {
 	target *Image
 }
 
+func (c *disposeCommand) String() string {
+	return fmt.Sprintf("dispose: target: %p", c.target)
+}
+
 // Exec executes the disposeCommand.
 func (c *disposeCommand) Exec(indexOffsetInBytes int) error {
 	if c.target.framebuffer != nil &&
@@ -415,6 +439,10 @@ func checkSize(width, height int) {
 	}
 }
 
+func (c *newImageCommand) String() string {
+	return fmt.Sprintf("new-image: result: %p, width: %d, height: %d", c.result, c.width, c.height)
+}
+
 // Exec executes a newImageCommand.
 func (c *newImageCommand) Exec(indexOffsetInBytes int) error {
 	w := emath.NextPowerOf2Int(c.width)
@@ -455,6 +483,10 @@ type newScreenFramebufferImageCommand struct {
 	height int
 }
 
+func (c *newScreenFramebufferImageCommand) String() string {
+	return fmt.Sprintf("new-screen-framebuffer-image: result: %p, width: %d, height: %d", c.result, c.width, c.height)
+}
+
 // Exec executes a newScreenFramebufferImageCommand.
 func (c *newScreenFramebufferImageCommand) Exec(indexOffsetInBytes int) error {
 	checkSize(c.width, c.height)

internal/graphics/debug_ebitendebug.go

@@ -0,0 +1,21 @@
+// Copyright 2018 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build ebitendebug
+
+package graphics
+
+func recordLog() bool {
+	return recordLog
+}

internal/graphics/debug_notebitendebug.go

@@ -0,0 +1,21 @@
+// Copyright 2018 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !ebitendebug
+
+package graphics
+
+func recordLog() bool {
+	return false
+}