graphics: Add a func to delete programs and buffers

internal/graphics/opengl/context_desktop.go

@@ -391,6 +391,13 @@ func (c *Context) DisableVertexAttribArray(p Program, location string) {
 	})
 }
 
+func (c *Context) DeleteProgram(p Program) {
+	c.RunOnContextThread(func() error {
+		gl.DeleteProgram(uint32(p))
+		return nil
+	})
+}
+
 func (c *Context) NewBuffer(bufferType BufferType, v interface{}, bufferUsage BufferUsage) Buffer {
 	var buffer Buffer
 	c.RunOnContextThread(func() error {
@@ -425,6 +432,14 @@ 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) {
 	c.RunOnContextThread(func() error {
 		gl.DrawElements(uint32(mode), int32(len), gl.UNSIGNED_SHORT, gl.PtrOffset(0))

internal/graphics/opengl/context_js.go

@@ -341,6 +341,11 @@ func (c *Context) DisableVertexAttribArray(p Program, location string) {
 	gl.DisableVertexAttribArray(int(l))
 }
 
+func (c *Context) DeleteProgram(p Program) {
+	gl := c.gl
+	gl.DeleteProgram(p.Object)
+}
+
 func (c *Context) NewBuffer(bufferType BufferType, v interface{}, bufferUsage BufferUsage) Buffer {
 	gl := c.gl
 	b := gl.CreateBuffer()
@@ -359,6 +364,11 @@ 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) {
 	gl := c.gl
 	gl.DrawElements(int(mode), len, gl.UNSIGNED_SHORT, 0)

internal/graphics/program.go

@@ -47,6 +47,10 @@ func Initialize(c *opengl.Context) error {
 	return theOpenGLState.initialize(c)
 }
 
+func Finalize(c *opengl.Context) error {
+	return theOpenGLState.finalize(c)
+}
+
 func (s *openGLState) initialize(c *opengl.Context) error {
 	var zeroProgram opengl.Program
 	s.lastProgram = zeroProgram
@@ -92,6 +96,17 @@ func (s *openGLState) initialize(c *opengl.Context) error {
 	return nil
 }
 
+func (s *openGLState) finalize(c *opengl.Context) error {
+	var zeroProgram opengl.Program
+	s.lastProgram = zeroProgram
+	s.lastProjectionMatrix = nil
+	s.lastModelviewMatrix = nil
+	s.lastColorMatrix = nil
+	c.DeleteBuffer(s.indexBufferQuads)
+	c.DeleteProgram(s.programTexture)
+	return nil
+}
+
 func areSameFloat32Array(a, b []float32) bool {
 	if len(a) != len(b) {
 		return false