Cleanup

examples/mrt/main.go

@@ -15,11 +15,13 @@
 package main
 
 import (
+	"fmt"
 	"image"
 	_ "image/jpeg"
 	"log"
 
 	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
 )
 
 const (
@@ -71,11 +73,9 @@ func init() {
 }
 
 type Game struct {
-	count int
 }
 
 func (g *Game) Update() error {
-	g.count++
 	return nil
 }
 
@@ -114,6 +114,8 @@ func (g *Game) Draw(screen *ebiten.Image) {
 	opts.GeoM.Reset()
 	opts.GeoM.Translate(dstSize, dstSize)
 	screen.DrawImage(dsts[3], opts)
+
+	ebitenutil.DebugPrint(screen, fmt.Sprintf("FPS: %.2f", ebiten.ActualFPS()))
 }
 
 func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
@@ -122,9 +124,10 @@ func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
 
 func main() {
 	ebiten.SetWindowSize(screenWidth, screenHeight)
+	ebiten.SetVsyncEnabled(false)
 	ebiten.SetWindowTitle("MRT (Ebitengine Demo)")
 	if err := ebiten.RunGameWithOptions(&Game{}, &ebiten.RunGameOptions{
-		GraphicsLibrary: ebiten.GraphicsLibraryDirectX,
+		GraphicsLibrary: ebiten.GraphicsLibraryOpenGL,
 	}); err != nil {
 		log.Fatal(err)
 	}

internal/graphicsdriver/opengl/context.go

@@ -396,7 +396,7 @@ func (c *context) newShader(shaderType uint32, source string) (shader, error) {
 	return shader(s), nil
 }
 
-func (c *context) newProgram(shaders []shader, attributes []string) (program, error) {
+func (c *context) newProgram(shaders []shader, attributes, fragData []string) (program, error) {
 	p := c.ctx.CreateProgram()
 	if p == 0 {
 		return 0, errors.New("opengl: glCreateProgram failed")
@@ -410,6 +410,10 @@ func (c *context) newProgram(shaders []shader, attributes []string) (program, er
 		c.ctx.BindAttribLocation(p, uint32(i), name)
 	}
 
+	for i, name := range fragData {
+		c.ctx.BindFragDataLocation(p, uint32(i), name)
+	}
+
 	c.ctx.LinkProgram(p)
 	if c.ctx.GetProgrami(p, gl.LINK_STATUS) == gl.FALSE {
 		info := c.ctx.GetProgramInfoLog(p)

internal/graphicsdriver/opengl/gl/debug.go

@@ -61,6 +61,14 @@ func (d *DebugContext) BindBuffer(arg0 uint32, arg1 uint32) {
 	}
 }
 
+func (d *DebugContext) BindFragDataLocation(arg0 uint32, arg1 uint32, arg2 string) {
+	d.Context.BindFragDataLocation(arg0, arg1, arg2)
+	fmt.Fprintln(os.Stderr, "BindFragDataLocation")
+	if e := d.Context.GetError(); e != NO_ERROR {
+		panic(fmt.Sprintf("gl: GetError() returned %d at BindFragDataLocation", e))
+	}
+}
+
 func (d *DebugContext) BindFramebuffer(arg0 uint32, arg1 uint32) {
 	d.Context.BindFramebuffer(arg0, arg1)
 	fmt.Fprintln(os.Stderr, "BindFramebuffer")

internal/graphicsdriver/opengl/gl/default_purego.go

@@ -28,6 +28,7 @@ type defaultContext struct {
 	gpAttachShader             uintptr
 	gpBindAttribLocation       uintptr
 	gpBindBuffer               uintptr
+	gpBindFragDataLocation     uintptr
 	gpBindFramebuffer          uintptr
 	gpBindRenderbuffer         uintptr
 	gpBindTexture              uintptr
@@ -140,6 +141,12 @@ func (c *defaultContext) BindBuffer(target uint32, buffer uint32) {
 	purego.SyscallN(c.gpBindBuffer, uintptr(target), uintptr(buffer))
 }
 
+func (c *defaultContext) BindFragDataLocation(program uint32, index uint32, name string) {
+	cname, free := cStr(name)
+	defer free()
+	purego.SyscallN(c.gpBindFragDataLocation, uintptr(program), uintptr(index), uintptr(unsafe.Pointer(cname)))
+}
+
 func (c *defaultContext) BindFramebuffer(target uint32, framebuffer uint32) {
 	purego.SyscallN(c.gpBindFramebuffer, uintptr(target), uintptr(framebuffer))
 }
@@ -483,6 +490,7 @@ func (c *defaultContext) LoadFunctions() error {
 	c.gpAttachShader = g.get("glAttachShader")
 	c.gpBindAttribLocation = g.get("glBindAttribLocation")
 	c.gpBindBuffer = g.get("glBindBuffer")
+	c.gpBindFragDataLocation = g.get("glBindFragDataLocation")
 	c.gpBindFramebuffer = g.get("glBindFramebuffer")
 	c.gpBindRenderbuffer = g.get("glBindRenderbuffer")
 	c.gpBindTexture = g.get("glBindTexture")

internal/graphicsdriver/opengl/gl/interface.go

@@ -31,6 +31,7 @@ type Context interface {
 	AttachShader(program uint32, shader uint32)
 	BindAttribLocation(program uint32, index uint32, name string)
 	BindBuffer(target uint32, buffer uint32)
+	BindFragDataLocation(program uint32, index uint32, name string)
 	BindFramebuffer(target uint32, framebuffer uint32)
 	BindRenderbuffer(target uint32, renderbuffer uint32)
 	BindTexture(target uint32, texture uint32)

internal/graphicsdriver/opengl/program.go

@@ -265,7 +265,7 @@ func (g *Graphics) colorBufferVariableName(idx int) string {
 	if g.colorBufferVariableNameCache == nil {
 		g.colorBufferVariableNameCache = map[int]string{}
 	}
-	name := fmt.Sprintf("gl_FragData[%d]", idx)
+	name := fmt.Sprintf("fragColor%d", idx)
 	g.colorBufferVariableNameCache[idx] = name
 	return name
 }

internal/graphicsdriver/opengl/shader.go

@@ -69,7 +69,11 @@ func (s *Shader) compile() error {
 	}
 	defer s.graphics.context.ctx.DeleteShader(uint32(fs))
 
-	p, err := s.graphics.context.newProgram([]shader{vs, fs}, theArrayBufferLayout.names())
+	colorNames := make([]string, s.ir.ColorsOutCount)
+	for i := range colorNames {
+		colorNames[i] = s.graphics.colorBufferVariableName(i)
+	}
+	p, err := s.graphics.context.newProgram([]shader{vs, fs}, theArrayBufferLayout.names(), colorNames)
 	if err != nil {
 		return err
 	}

internal/shader/shader.go

@@ -822,7 +822,7 @@ func (cs *compileState) parseFunc(block *block, d *ast.FuncDecl) (function, bool
 				return function{}, false
 			}
 
-			// The first out-param is treated as gl_FragColor in GLSL.
+			// The first out-param is treated as fragColor0 in GLSL.
 			for i := range outParams {
 				if outParams[i].typ.Main != shaderir.Vec4 {
 					cs.addError(d.Pos(), "fragment entry point must only have vec4 return values for colors")

internal/shaderir/glsl/glsl.go

@@ -86,8 +86,7 @@ precision highp int;
 #define lowp
 #define mediump
 #define highp
-#endif
-`
+#endif`
 	if version == GLSLVersionDefault {
 		prelude += "\n\n" + utilFunctions
 	}
@@ -230,6 +229,9 @@ func Compile(p *shaderir.Program, version GLSLVersion) (vertexShader, fragmentSh
 				fslines = append(fslines, fmt.Sprintf("in %s;", c.varDecl(p, &t, fmt.Sprintf("V%d", i))))
 			}
 		}
+		for i := 0; i < p.ColorsOutCount; i++ {
+			fslines = append(fslines, fmt.Sprintf("out vec4 fragColor%d;", i))
+		}
 
 		var funcs []*shaderir.Func
 		if p.VertexFunc.Block != nil {
@@ -291,6 +293,8 @@ func Compile(p *shaderir.Program, version GLSLVersion) (vertexShader, fragmentSh
 	vs = strings.TrimSpace(vs) + "\n"
 	fs = strings.TrimSpace(fs) + "\n"
 
+	fmt.Println("FS:", fs)
+
 	return vs, fs
 }
 
@@ -419,7 +423,7 @@ func (c *compileContext) localVariableName(p *shaderir.Program, topBlock *shader
 		case idx < nv+1:
 			return fmt.Sprintf("V%d", idx-1)
 		default:
-			return fmt.Sprintf("gl_FragData[%d]", idx-(nv+1))
+			return fmt.Sprintf("fragColor%d", idx-(nv+1))
 		}
 	default:
 		return fmt.Sprintf("l%d", idx)

internal/shaderir/hlsl/hlsl.go

@@ -607,11 +607,6 @@ func adjustProgram(p *shaderir.Program) *shaderir.Program {
 	copy(newP.Funcs, p.Funcs)
 
 	// Create a new function whose body is the same is the fragment shader's entry point.
-	// The entry point will call this.
-	// This indirect call is needed for these issues:
-	// - Assignment to gl_FragColor doesn't work (#2245)
-	// - There are some odd compilers that don't work with early returns and gl_FragColor (#2247)
-
 	// Determine a unique index of the new function.
 	var funcIdx int
 	for _, f := range newP.Funcs {
@@ -659,7 +654,8 @@ func adjustProgram(p *shaderir.Program) *shaderir.Program {
 	// Replace the entry point with just calling the new function.
 	stmts := []shaderir.Stmt{
 		{
-			// Return: This will be replaced with assignment to gl_FragColor.
+			// Return: This will be replaced with a call to the new function.
+			// Then the output structure containing colors will be returned.
 			Type: shaderir.Return,
 			Exprs: []shaderir.Expr{
 				// The function call