graphics: Delete programs and buffers when resuming

internal/graphics/opengl/context_desktop.go

@@ -394,6 +394,13 @@ func (c *Context) UseProgram(p Program) {
 	})
 }
 
+func (c *Context) DeleteProgram(p Program) {
+	c.RunOnContextThread(func() error {
+		gl.DeleteProgram(uint32(p))
+		return nil
+	})
+}
+
 func (c *Context) getUniformLocationImpl(p Program, location string) uniformLocation {
 	uniform := uniformLocation(gl.GetUniformLocation(uint32(p), gl.Str(location+"\x00")))
 	if uniform == -1 {
@@ -491,6 +498,14 @@ func (c *Context) BufferSubData(bufferType BufferType, data []int16) {
 	})
 }
 
+func (c *Context) DeleteBuffer(b Buffer) {
+	c.RunOnContextThread(func() error {
+		bb := uint32(b)
+		gl.DeleteBuffers(1, &bb)
+		return nil
+	})
+}
+
 func (c *Context) DrawElements(mode Mode, len int, offsetInBytes int) {
 	c.RunOnContextThread(func() error {
 		gl.DrawElements(uint32(mode), int32(len), gl.UNSIGNED_SHORT, gl.PtrOffset(offsetInBytes))

internal/graphics/opengl/context_js.go

@@ -321,6 +321,11 @@ func (c *Context) UseProgram(p Program) {
 	gl.UseProgram(p.Object)
 }
 
+func (c *Context) DeleteProgram(p Program) {
+	gl := c.gl
+	gl.DeleteProgram(p.Object)
+}
+
 func (c *Context) getUniformLocationImpl(p Program, location string) uniformLocation {
 	gl := c.gl
 	return uniformLocation{gl.GetUniformLocation(p.Object, location)}
@@ -386,6 +391,11 @@ func (c *Context) BufferSubData(bufferType BufferType, data []int16) {
 	gl.BufferSubData(int(bufferType), 0, data)
 }
 
+func (c *Context) DeleteBuffer(b Buffer) {
+	gl := c.gl
+	gl.DeleteBuffer(b.Object)
+}
+
 func (c *Context) DrawElements(mode Mode, len int, offsetInBytes int) {
 	gl := c.gl
 	gl.DrawElements(int(mode), len, gl.UNSIGNED_SHORT, offsetInBytes)

internal/graphics/opengl/context_mobile.go

@@ -295,6 +295,11 @@ func (c *Context) UseProgram(p Program) {
 	gl.UseProgram(mgl.Program(p))
 }
 
+func (c *Context) DeleteProgram(p Program) {
+	gl := c.gl
+	gl.DeleteProgram(mgl.Program(p))
+}
+
 func (c *Context) getUniformLocationImpl(p Program, location string) uniformLocation {
 	gl := c.gl
 	u := uniformLocation(gl.GetUniformLocation(mgl.Program(p), location))
@@ -392,6 +397,11 @@ func (c *Context) BufferSubData(bufferType BufferType, data []int16) {
 	gl.BufferSubData(mgl.Enum(bufferType), 0, int16ToBytes(data))
 }
 
+func (c *Context) DeleteBuffer(b Buffer) {
+	gl := c.gl
+	gl.DeleteBuffer(mgl.Buffer(b))
+}
+
 func (c *Context) DrawElements(mode Mode, len int, offsetInBytes int) {
 	gl := c.gl
 	gl.DrawElements(mgl.Enum(mode), len, mgl.UNSIGNED_SHORT, offsetInBytes)

internal/graphics/program.go

@@ -21,6 +21,7 @@ import (
 )
 
 type openGLState struct {
+	arrayBuffer      opengl.Buffer
 	indexBufferQuads opengl.Buffer
 	programTexture   opengl.Program
 
@@ -32,8 +33,10 @@ type openGLState struct {
 	lastTexture                opengl.Texture
 }
 
-var theOpenGLState openGLState
 var (
+	theOpenGLState openGLState
+
+	zeroBuffer  opengl.Buffer
 	zeroProgram opengl.Program
 	zeroTexture opengl.Texture
 )
@@ -63,7 +66,15 @@ func (s *openGLState) initialize(context *opengl.Context) error {
 	s.lastColorMatrixTranslation = nil
 	s.lastTexture = zeroTexture
 
-	// TODO: Remove the old programs when resuming?
+	if s.arrayBuffer != zeroBuffer {
+		context.DeleteBuffer(s.arrayBuffer)
+	}
+	if s.indexBufferQuads != zeroBuffer {
+		context.DeleteBuffer(s.indexBufferQuads)
+	}
+	if s.programTexture != zeroProgram {
+		context.DeleteProgram(s.programTexture)
+	}
 
 	shaderVertexModelviewNative, err := context.NewShader(opengl.VertexShader, shader(context, shaderVertexModelview))
 	if err != nil {
@@ -85,10 +96,8 @@ func (s *openGLState) initialize(context *opengl.Context) error {
 		return err
 	}
 
-	// TODO: Remove the old buffers when resuming?
-
 	const stride = 8 // (2 [vertices] + 2 [texels]) * 2 [sizeof(int16)/bytes]
-	context.NewBuffer(opengl.ArrayBuffer, 4*stride*MaxQuads, opengl.DynamicDraw)
+	s.arrayBuffer = context.NewBuffer(opengl.ArrayBuffer, 4*stride*MaxQuads, opengl.DynamicDraw)
 
 	indices := make([]uint16, 6*MaxQuads)
 	for i := uint16(0); i < MaxQuads; i++ {