From 6de9e6696ed46be6632c2f1a8b29979098713f38 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sat, 29 Oct 2016 01:07:19 +0900
Subject: [PATCH] graphics: Cache total bytes

---
 internal/graphics/command.go |  2 +-
 internal/graphics/program.go | 13 +++++++++----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/internal/graphics/command.go b/internal/graphics/command.go
index 3926e2152..a73d8fd73 100644
--- a/internal/graphics/command.go
+++ b/internal/graphics/command.go
@@ -199,7 +199,7 @@ type drawImageCommand struct {
 }
 
 func QuadVertexSizeInBytes() int {
-	return 4 * theArrayBufferLayout.total()
+	return 4 * theArrayBufferLayout.totalBytes()
 }
 
 func (c *drawImageCommand) Exec(context *opengl.Context, indexOffsetInBytes int) error {
diff --git a/internal/graphics/program.go b/internal/graphics/program.go
index 0d6f72f96..5e3a2719d 100644
--- a/internal/graphics/program.go
+++ b/internal/graphics/program.go
@@ -30,25 +30,30 @@ type arrayBufferLayoutPart struct {
 
 type arrayBufferLayout struct {
 	parts []arrayBufferLayoutPart
+	total int
 }
 
-func (a *arrayBufferLayout) total() int {
+func (a *arrayBufferLayout) totalBytes() int {
+	if a.total != 0 {
+		return a.total
+	}
 	t := 0
 	for _, p := range a.parts {
 		t += p.dataType.SizeInBytes() * p.num
 	}
-	return t
+	a.total = t
+	return a.total
 }
 
 func (a *arrayBufferLayout) newArrayBuffer(c *opengl.Context) opengl.Buffer {
-	return c.NewBuffer(opengl.ArrayBuffer, a.total()*4*maxQuads, opengl.DynamicDraw)
+	return c.NewBuffer(opengl.ArrayBuffer, a.totalBytes()*4*maxQuads, opengl.DynamicDraw)
 }
 
 func (a *arrayBufferLayout) enable(c *opengl.Context, program opengl.Program) {
 	for _, p := range a.parts {
 		c.EnableVertexAttribArray(program, p.name)
 	}
-	total := a.total()
+	total := a.totalBytes()
 	offset := 0
 	for _, p := range a.parts {
 		c.VertexAttribPointer(program, p.name, p.num, p.dataType, p.normalize, total, offset)