Merge pull request #4 from hajimehoshi/remove-glget

Remove unnecessary glGet* in the render loop

graphics/opengl/context.go

@@ -22,7 +22,7 @@ func flush() {
 
 type Context struct {
 	screenId     graphics.RenderTargetId
-	mainId       graphics.RenderTargetId
+	defaultId    graphics.RenderTargetId
 	currentId    graphics.RenderTargetId
 	ids          *ids
 	screenWidth  int
@@ -37,10 +37,13 @@ func newContext(ids *ids, screenWidth, screenHeight, screenScale int) *Context {
 		screenHeight: screenHeight,
 		screenScale:  screenScale,
 	}
-	mainRenderTarget := newRTWithCurrentFramebuffer(
-		screenWidth*screenScale,
-		screenHeight*screenScale)
-	context.mainId = context.ids.addRenderTarget(mainRenderTarget)
+	defaultRenderTarget := &RenderTarget{
+		framebuffer: C.GLuint(0),
+		width:       screenWidth * screenScale,
+		height:      screenHeight * screenScale,
+		flipY:       true,
+	}
+	context.defaultId = context.ids.addRenderTarget(defaultRenderTarget)
 
 	var err error
 	context.screenId, err = ids.createRenderTarget(
@@ -57,7 +60,7 @@ func newContext(ids *ids, screenWidth, screenHeight, screenScale int) *Context {
 }
 
 func (c *Context) Dispose() {
-	// TODO: remove main framebuffer?
+	// TODO: remove the default framebuffer?
 	c.ids.deleteRenderTarget(c.screenId)
 }
 
@@ -67,7 +70,7 @@ func (c *Context) Update(draw func(graphics.Context)) {
 
 	draw(c)
 
-	c.SetOffscreen(c.mainId)
+	c.SetOffscreen(c.defaultId)
 	c.Clear()
 
 	scale := float64(c.screenScale)

graphics/opengl/ids.go

@@ -1,9 +1,15 @@
 package opengl
 
+// #cgo LDFLAGS: -framework OpenGL
+//
+// #include <OpenGL/gl.h>
+import "C"
 import (
 	"github.com/hajimehoshi/go-ebiten/graphics"
 	"github.com/hajimehoshi/go-ebiten/graphics/matrix"
+	"github.com/hajimehoshi/go-ebiten/graphics/opengl/shader"
 	"image"
+	"math"
 	"sync"
 )
 
@@ -30,6 +36,7 @@ type ids struct {
 	renderTargets         map[graphics.RenderTargetId]*RenderTarget
 	renderTargetToTexture map[graphics.RenderTargetId]graphics.TextureId
 	counts                chan int
+	currentRenderTargetId graphics.RenderTargetId
 	sync.RWMutex
 }
 
@@ -39,6 +46,7 @@ func newIds() *ids {
 		renderTargets:         map[graphics.RenderTargetId]*RenderTarget{},
 		renderTargetToTexture: map[graphics.RenderTargetId]graphics.TextureId{},
 		counts:                make(chan int),
+		currentRenderTargetId: -1,
 	}
 	go func() {
 		for i := 1; ; i++ {
@@ -88,6 +96,8 @@ func (i *ids) createRenderTarget(width, height int, filter graphics.Filter) (
 		return 0, err
 	}
 	framebuffer := createFramebuffer(texture.native)
+	// The current binded framebuffer can be changed.
+	i.currentRenderTargetId = -1
 	renderTarget := &RenderTarget{framebuffer, texture.width, texture.height, false}
 
 	textureId := graphics.TextureId(<-i.counts)
@@ -130,13 +140,39 @@ func (i *ids) deleteRenderTarget(id graphics.RenderTargetId) {
 }
 
 func (i *ids) fillRenderTarget(id graphics.RenderTargetId, r, g, b uint8) {
-	i.renderTargetAt(id).fill(r, g, b)
+	i.setViewportIfNeeded(id)
+	const max = float64(math.MaxUint8)
+	C.glClearColor(
+		C.GLclampf(float64(r)/max),
+		C.GLclampf(float64(g)/max),
+		C.GLclampf(float64(b)/max),
+		1)
+	C.glClear(C.GL_COLOR_BUFFER_BIT)
 }
 
 func (i *ids) drawTexture(
 	target graphics.RenderTargetId,
 	id graphics.TextureId,
-	parts []graphics.TexturePart, geo matrix.Geometry, color matrix.Color) {
+	parts []graphics.TexturePart,
+	geo matrix.Geometry,
+	color matrix.Color) {
 	texture := i.textureAt(id)
-	i.renderTargetAt(target).drawTexture(texture, parts, geo, color)
+	i.setViewportIfNeeded(target)
+	r := i.renderTargetAt(target)
+	projectionMatrix := r.projectionMatrix()
+	quads := graphics.TextureQuads(parts, texture.width, texture.height)
+	shader.DrawTexture(
+		shader.NativeTexture(texture.native),
+		glMatrix(projectionMatrix),
+		quads,
+		geo,
+		color)
+}
+
+func (i *ids) setViewportIfNeeded(id graphics.RenderTargetId) {
+	r := i.renderTargetAt(id)
+	if i.currentRenderTargetId != id {
+		r.setAsViewport()
+		i.currentRenderTargetId = id
+	}
 }

graphics/opengl/render_target.go

@@ -7,9 +7,6 @@ import "C"
 import (
 	"fmt"
 	"github.com/hajimehoshi/go-ebiten/graphics"
-	"github.com/hajimehoshi/go-ebiten/graphics/matrix"
-	"github.com/hajimehoshi/go-ebiten/graphics/opengl/shader"
-	"math"
 )
 
 func glMatrix(matrix [4][4]float64) [16]float32 {
@@ -29,21 +26,11 @@ type RenderTarget struct {
 	flipY       bool
 }
 
-func newRTWithCurrentFramebuffer(width, height int) *RenderTarget {
-	framebuffer := C.GLint(0)
-	C.glGetIntegerv(C.GL_FRAMEBUFFER_BINDING, &framebuffer)
-	return &RenderTarget{C.GLuint(framebuffer), width, height, true}
-}
-
 func createFramebuffer(nativeTexture C.GLuint) C.GLuint {
 	framebuffer := C.GLuint(0)
 	C.glGenFramebuffers(1, &framebuffer)
 
-	origFramebuffer := C.GLint(0)
-	C.glGetIntegerv(C.GL_FRAMEBUFFER_BINDING, &origFramebuffer)
-
 	C.glBindFramebuffer(C.GL_FRAMEBUFFER, framebuffer)
-	defer C.glBindFramebuffer(C.GL_FRAMEBUFFER, C.GLuint(origFramebuffer))
 
 	C.glFramebufferTexture2D(C.GL_FRAMEBUFFER, C.GL_COLOR_ATTACHMENT0,
 		C.GL_TEXTURE_2D, nativeTexture, 0)
@@ -61,12 +48,6 @@ func createFramebuffer(nativeTexture C.GLuint) C.GLuint {
 }
 
 func (r *RenderTarget) setAsViewport() {
-	current := C.GLint(0)
-	C.glGetIntegerv(C.GL_FRAMEBUFFER_BINDING, &current)
-	if C.GLuint(current) == r.framebuffer {
-		return
-	}
-
 	C.glFlush()
 
 	C.glBindFramebuffer(C.GL_FRAMEBUFFER, C.GLuint(r.framebuffer))
@@ -98,30 +79,3 @@ func (r *RenderTarget) projectionMatrix() [4][4]float64 {
 func (r *RenderTarget) dispose() {
 	C.glDeleteFramebuffers(1, &r.framebuffer)
 }
-
-func (r *RenderTarget) fill(red, green, blue uint8) {
-	r.setAsViewport()
-	const max = float64(math.MaxUint8)
-	C.glClearColor(
-		C.GLclampf(float64(red)/max),
-		C.GLclampf(float64(green)/max),
-		C.GLclampf(float64(blue)/max),
-		1)
-	C.glClear(C.GL_COLOR_BUFFER_BIT)
-}
-
-func (r *RenderTarget) drawTexture(
-	texture *Texture,
-	parts []graphics.TexturePart,
-	geometryMatrix matrix.Geometry,
-	colorMatrix matrix.Color) {
-	r.setAsViewport()
-	projectionMatrix := r.projectionMatrix()
-	quads := graphics.TextureQuads(parts, texture.width, texture.height)
-	shader.DrawTexture(
-		shader.NativeTexture(texture.native),
-		glMatrix(projectionMatrix),
-		quads,
-		geometryMatrix,
-		colorMatrix)
-}