Не получается добавить прозрачность правильно

const GLchar* vertexShaderSource = "#version 330 core\n"
"layout(location = 0) in vec3 position;\n"
"layout(location = 1) in vec4 color;\n"
"layout(location = 2) in vec2 texCoord;\n"
"out vec4 ourColor;\n"
"out vec2 TexCoord;\n"
"uniform mat4 transform;\n"
"void main()\n"
"{\n"
"gl_Position = transform*vec4(position, 1.0f);\n"
"ourColor = color;\n"
"TexCoord = texCoord;\n"
"}\0";
const GLchar* fragmentShaderSource = "#version 330 core\n"
"in vec4 ourColor;\n"
"in vec2 TexCoord;\n"
"out vec4 color;\n"
"uniform sampler2D ourTexture;\n"
"void main()\n"
"{\n"
"color = texture(ourTexture, TexCoord);\n"
"}\0";
//...
void Scene1::LoadBorder(QOpenGLExtraFunctions* f)
{
	float buf2[] =
	{		// x,	y,	z,	 r,	  g,	b,   a,	  s,	t
			-1.0,  1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
			-1.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0,
			 1.0,  1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0,
			 1.0,  1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0,
			-1.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0,
			 1.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0
	};
	//	GLuint buffer2;
	f->glGenVertexArrays(1, &vao2);
	f->glGenBuffers(1, &buffer2);
	f->glBindVertexArray(vao2);
	f->glBindBuffer(GL_ARRAY_BUFFER, buffer2);
	f->glBufferData(GL_ARRAY_BUFFER, sizeof(buf2), buf2, GL_STATIC_DRAW);
	indices_2 = new GLuint[6];
	for (int i = 0; i < 6; i++)
		indices_2[i] = (GLuint)i;
	GLuint EBO2;
	f->glGenBuffers(1, &EBO2);
	f->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO2);
	f->glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices_2), indices_2, GL_STATIC_DRAW);
	// Position attribute
	f->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 9 * sizeof(GLfloat), (GLvoid*)0);
	f->glEnableVertexAttribArray(0);
	// Color attribute
	f->glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 9 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
	f->glEnableVertexAttribArray(1);
	// TexCoord attribute
	f->glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 9 * sizeof(GLfloat), (GLvoid*)(7 * sizeof(GLfloat)));
	f->glEnableVertexAttribArray(2);
	f->glEnableVertexAttribArray(0);
	f->glBindBuffer(GL_ARRAY_BUFFER, 0); // Note that this is allowed, the call to glVertexAttribPointer registered VBO as the currently bound vertex buffer object so afterwards we can safely unbind
	f->glBindVertexArray(0); // Unbind VAO (it's always a good thing to unbind any buffer/array to prevent strange bugs
	image2.load("content//border.png"); // загружаем изображение в переменную image1
	// конвертируем изображение в формат для работы с OpenGL:
	texture3 = new QOpenGLTexture(image2.mirrored());
	texture3->setMinificationFilter(QOpenGLTexture::LinearMipMapLinear);
	texture3->setMagnificationFilter(QOpenGLTexture::Linear);
	glGenTextures(1, &id3);
	glBindTexture(GL_TEXTURE_2D, id3);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image2.width(), image2.height(),
		0, GL_RGBA, GL_UNSIGNED_BYTE, image2.bits());
	glBindTexture(GL_TEXTURE_2D, 0);
}
void Scene1::ShowBorder(QOpenGLExtraFunctions* f, GLuint shaderProgram)
{
	f->glUseProgram(shaderProgram);
	//f->glBindBuffer(GL_ARRAY_BUFFER, buffer2);
	
	f->glBindVertexArray(vao2);
	glBindTexture(GL_TEXTURE_2D, id3);
	GLfloat trans2[16] =
	{
		1.0,0.0,0.0,0.0,
		0.0,1.0 /** cos(-rotate__ * 0.0175)*/,0.0/* - sin(-rotate__ * 0.0175)*/,0.0,
		0.0,0.0 /* + sin(-rotate__ * 0.0175) */ ,1.0/* * cos(-rotate__ * 0.0175)*/,0.0,
		0.0,0.0,0.0,1.0
	};
	unsigned int transformLoc = f->glGetUniformLocation(shaderProgram, "transform");
	f->glUniformMatrix4fv(transformLoc, 1, GL_FALSE, trans2);
	glEnable(GL_ALPHA_TEST);
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glTexEnvf(GL_TEXTURE_2D, GL_TEXTURE_ENV_MODE, GL_BLEND);
	f->glDrawArrays(GL_TRIANGLES, 0, 6);

	glDisable(GL_BLEND);
	glDisable(GL_ALPHA_TEST);
	f->glBindVertexArray(0);
}