Python OpenGL.GL.glVertexAttribPointer() Examples

def paintGL(self):
        self.makeCurrent()
        gl.glClear(gl.GL_COLOR_BUFFER_BIT | gl.GL_DEPTH_BUFFER_BIT)

        self.program.bind()

        self.program.enableAttributeArray("position")
        self.vbo.bind()
        gl.glVertexAttribPointer(self.program.attributeLocation("position"), 2, gl.GL_FLOAT, gl.GL_FALSE, 0, self.vbo)


        self.program.enableAttributeArray("normal")
        self.vbo_cols.bind()
        gl.glVertexAttribPointer(self.program.attributeLocation("normal"), 3, gl.GL_FLOAT, gl.GL_FALSE, 0, self.vbo_cols)


        gl.glDrawArrays(gl.GL_TRIANGLES, 0, len(self.data))



        print(self.context().format().majorVersion())
        print(self.context().format().minorVersion())


        print(gl.glGetString(gl.GL_VERSION)); 

def _init_shaders(self):
    """Initializes the shaders used to render the textures fullscreen quad."""
    vs = shaders.compileShader(_VERTEX_SHADER, GL.GL_VERTEX_SHADER)
    fs = shaders.compileShader(_FRAGMENT_SHADER, GL.GL_FRAGMENT_SHADER)
    self._shader = shaders.compileProgram(vs, fs)

    stride = _FLOATS_PER_VERTEX * _SIZE_OF_FLOAT
    var_position = GL.glGetAttribLocation(self._shader, _VAR_POSITION)
    GL.glVertexAttribPointer(
        var_position, 2, GL.GL_FLOAT, GL.GL_FALSE, stride, None)
    GL.glEnableVertexAttribArray(var_position)

    var_uv = GL.glGetAttribLocation(self._shader, _VAR_UV)
    uv_offset = ctypes.c_void_p(_FLOATS_PER_XY * _SIZE_OF_FLOAT)
    GL.glVertexAttribPointer(
        var_uv, 2, GL.GL_FLOAT, GL.GL_FALSE, stride, uv_offset)
    GL.glEnableVertexAttribArray(var_uv)

    self._var_texture_sampler = GL.glGetUniformLocation(
        self._shader, _VAR_TEXTURE_SAMPLER) 

def bindAttributeArray(self, shader, name, data, count):
        location = gl.glGetAttribLocation(shader.handle, name)
        if location != -1:
            gl.glVertexAttribPointer(location, count, gl.GL_FLOAT, False, 0, data)
            gl.glEnableVertexAttribArray(location) 

def paintGL(self):
        self.makeCurrent()
        gl.glClear(gl.GL_COLOR_BUFFER_BIT | gl.GL_DEPTH_BUFFER_BIT)

        self.program.bind()

        self.program.enableAttributeArray("position")
        self.vbo.bind()
        gl.glVertexAttribPointer(self.program.attributeLocation("position"), 2, gl.GL_FLOAT, gl.GL_FALSE, 0, self.vbo)


        self.program.enableAttributeArray("color")
        self.vbo_cols.bind()
        gl.glVertexAttribPointer(self.program.attributeLocation("color"), 3, gl.GL_FLOAT, gl.GL_FALSE, 0, self.vbo_cols)

        self.vbo_index.bind()

        #gl.glDrawArrays(gl.GL_TRIANGLES, 0, len(self.data))

        gl.glDrawElements(gl.GL_TRIANGLES, len(self.index), gl.GL_UNSIGNED_INT, None)

        print(self.context().format().majorVersion())
        print(self.context().format().minorVersion())


        print(gl.glGetString(gl.GL_VERSION)); 

def bind_attrib(self, attrib_id, size, data, storagetype=gl.GL_STATIC_DRAW, instance_divisor=0, datatype=gl.GL_FLOAT, stride=0, offset=None, normalize=False):
        if RenderObject.bound_vao is not self.vao_id:
            gl.glBindVertexArray(self.vao_id)
            RenderObject.bound_vao = self.vao_id

        # Keep track of max instance divisor
        self.max_instance_divisor = max(instance_divisor, self.max_instance_divisor)

        # If the input is an array create a new GL buffer, otherwise assume the buffer already exists and a buffer ID is passed
        if type(data) is np.ndarray:
            # Get an index to one new buffer in GPU mem, bind it, and copy the array data to it
            buf_id = gl.glGenBuffers(1)
            gl.glBindBuffer(gl.GL_ARRAY_BUFFER, buf_id)
            gl.glBufferData(gl.GL_ARRAY_BUFFER, data.nbytes, data, storagetype)
        else:
            # Assume that a GLuint is passed which means that the buffer is already in GPU memory
            buf_id = data
            gl.glBindBuffer(gl.GL_ARRAY_BUFFER, buf_id)

        # Assign this buffer to one of the attributes in the shader
        gl.glEnableVertexAttribArray(attrib_id)
        gl.glVertexAttribPointer(attrib_id, size, datatype, normalize, stride, offset)
        # For instanced data, indicate per how many instances we move a step in the buffer (1=per instance)
        if instance_divisor > 0:
            gl.glVertexAttribDivisor(attrib_id, instance_divisor)
        # Clean up
        gl.glDisableVertexAttribArray(attrib_id)

        self.enabled_attributes[attrib_id] = [size, buf_id, instance_divisor, datatype]

        return buf_id 

def bind_attrib(self, attrib_id, size, data, storagetype=gl.GL_STATIC_DRAW, instance_divisor=0, datatype=gl.GL_FLOAT, stride=0, offset=None, normalize=False):
        if RenderObject.bound_vao is not self.vao_id:
            gl.glBindVertexArray(self.vao_id)
            RenderObject.bound_vao = self.vao_id

        # Keep track of max instance divisor
        self.max_instance_divisor = max(instance_divisor, self.max_instance_divisor)

        # If the input is an array create a new GL buffer, otherwise assume the buffer already exists and a buffer ID is passed
        if type(data) is np.ndarray:
            # Get an index to one new buffer in GPU mem, bind it, and copy the array data to it
            buf_id = gl.glGenBuffers(1)
            gl.glBindBuffer(gl.GL_ARRAY_BUFFER, buf_id)
            gl.glBufferData(gl.GL_ARRAY_BUFFER, data.nbytes, data, storagetype)
        else:
            # Assume that a GLuint is passed which means that the buffer is already in GPU memory
            buf_id = data
            gl.glBindBuffer(gl.GL_ARRAY_BUFFER, buf_id)

        # Assign this buffer to one of the attributes in the shader
        gl.glEnableVertexAttribArray(attrib_id)
        gl.glVertexAttribPointer(attrib_id, size, datatype, normalize, stride, offset)
        # For instanced data, indicate per how many instances we move a step in the buffer (1=per instance)
        if instance_divisor > 0:
            gl.glVertexAttribDivisor(attrib_id, instance_divisor)
        # Clean up
        gl.glDisableVertexAttribArray(attrib_id)

        self.enabled_attributes[attrib_id] = [size, buf_id, instance_divisor, datatype]

        return buf_id 

def set_up_scene(self):
        self.vertex_data = []
        v = self.scene_volume_init
        s = self.scale_spacing
        scale = 0.3
        mat_scale = numpy.diag(numpy.array([scale, scale, scale, 1], dtype=numpy.float32))
        t = -0.5 * v * s
        mat_translate = translate(t, t, t)
        mat = mat_translate @ mat_scale
        for z in range(v):
            for y in range(v):
                for x in range(v):
                    self.add_cube_to_scene(mat)
                    mat = translate(s, 0, 0) @ mat
                mat = translate(-v * s, s, 0) @ mat
            mat = translate(0, -v * s, s) @ mat
        vertex_data = numpy.array(self.vertex_data, dtype=numpy.float32).flatten()
        self.vert_count = len(vertex_data) / 5
        self.scene_vao = GL.glGenVertexArrays(1)
        GL.glBindVertexArray(self.scene_vao)
        self.scene_vert_buffer = GL.glGenBuffers(1)
        GL.glBindBuffer(GL.GL_ARRAY_BUFFER, self.scene_vert_buffer)
        GL.glBufferData(GL.GL_ARRAY_BUFFER, vertex_data, GL.GL_STATIC_DRAW)
        f_size = sizeof(c_float)
        stride = 5 * f_size
        GL.glEnableVertexAttribArray(0)
        GL.glVertexAttribPointer(0, 3, GL.GL_FLOAT, False, stride, cast(0 * f_size, c_void_p))
        GL.glEnableVertexAttribArray(1)
        GL.glVertexAttribPointer(1, 2, GL.GL_FLOAT, False, stride, cast(3 * f_size, c_void_p))
        GL.glBindVertexArray(0)
        GL.glDisableVertexAttribArray(0)
        GL.glDisableVertexAttribArray(1) 

def set_up_companion_window(self):
        if not self.hmd:
            return
        verts = list()
        # left eye verts
        verts.append(((-1, -1), (0, 0)))
        verts.append(((0, -1), (1, 0)))
        verts.append(((-1, 1), (0, 1)))
        verts.append(((0, 1), (1, 1)))
        # right eye verts
        verts.append(((0, -1), (0, 0)))
        verts.append(((1, -1), (1, 0)))
        verts.append(((0, 1), (0, 1)))
        verts.append(((1, 1), (1, 1)))
        vIndices = numpy.array([0, 1, 3, 0, 3, 2, 4, 5, 7, 4, 7, 6], dtype=numpy.uint16)
        self.companion_window_index_size = len(vIndices)
        self.companion_window_vao = GL.glGenVertexArrays(1)
        GL.glBindVertexArray(self.companion_window_vao)
        #
        self.companion_window_id_vert_buffer = GL.glGenBuffers(1)
        GL.glBindBuffer(GL.GL_ARRAY_BUFFER, self.companion_window_id_vert_buffer)
        vVerts = numpy.array(verts, dtype=numpy.float32).flatten()
        GL.glBufferData(GL.GL_ARRAY_BUFFER, vVerts, GL.GL_STATIC_DRAW)
        #
        self.companion_window_id_index_buffer = GL.glGenBuffers(1)
        GL.glBindBuffer(GL.GL_ELEMENT_ARRAY_BUFFER, self.companion_window_id_index_buffer)
        GL.glBufferData(GL.GL_ELEMENT_ARRAY_BUFFER, vIndices, GL.GL_STATIC_DRAW)
        #
        f_size = sizeof(c_float)
        GL.glEnableVertexAttribArray(0)
        GL.glVertexAttribPointer(0, 2, GL.GL_FLOAT, False, 4 * f_size, cast(0 * f_size, c_void_p))
        #
        GL.glEnableVertexAttribArray(1)
        GL.glVertexAttribPointer(1, 2, GL.GL_FLOAT, False, 4 * f_size, cast(2 * f_size, c_void_p))
        #
        GL.glBindVertexArray(0)
        GL.glDisableVertexAttribArray(0)
        GL.glDisableVertexAttribArray(1)
        GL.glBindBuffer(GL.GL_ARRAY_BUFFER, 0)
        GL.glBindBuffer(GL.GL_ELEMENT_ARRAY_BUFFER, 0) 

def _create_device_objects(self):
        # save state
        last_texture = gl.glGetIntegerv(gl.GL_TEXTURE_BINDING_2D)
        last_array_buffer = gl.glGetIntegerv(gl.GL_ARRAY_BUFFER_BINDING)

        last_vertex_array = gl.glGetIntegerv(gl.GL_VERTEX_ARRAY_BINDING)

        self._shader_handle = gl.glCreateProgram()
        # note: no need to store shader parts handles after linking
        vertex_shader = gl.glCreateShader(gl.GL_VERTEX_SHADER)
        fragment_shader = gl.glCreateShader(gl.GL_FRAGMENT_SHADER)

        gl.glShaderSource(vertex_shader, self.VERTEX_SHADER_SRC)
        gl.glShaderSource(fragment_shader, self.FRAGMENT_SHADER_SRC)
        gl.glCompileShader(vertex_shader)
        gl.glCompileShader(fragment_shader)

        gl.glAttachShader(self._shader_handle, vertex_shader)
        gl.glAttachShader(self._shader_handle, fragment_shader)

        gl.glLinkProgram(self._shader_handle)

        # note: after linking shaders can be removed
        gl.glDeleteShader(vertex_shader)
        gl.glDeleteShader(fragment_shader)

        self._attrib_location_tex = gl.glGetUniformLocation(self._shader_handle, "Texture")
        self._attrib_proj_mtx = gl.glGetUniformLocation(self._shader_handle, "ProjMtx")
        self._attrib_location_position = gl.glGetAttribLocation(self._shader_handle, "Position")
        self._attrib_location_uv = gl.glGetAttribLocation(self._shader_handle, "UV")
        self._attrib_location_color = gl.glGetAttribLocation(self._shader_handle, "Color")

        self._vbo_handle = gl.glGenBuffers(1)
        self._elements_handle = gl.glGenBuffers(1)

        self._vao_handle = gl.glGenVertexArrays(1)
        gl.glBindVertexArray(self._vao_handle)
        gl.glBindBuffer(gl.GL_ARRAY_BUFFER, self._vbo_handle)

        gl.glEnableVertexAttribArray(self._attrib_location_position)
        gl.glEnableVertexAttribArray(self._attrib_location_uv)
        gl.glEnableVertexAttribArray(self._attrib_location_color)

        gl.glVertexAttribPointer(self._attrib_location_position, 2, gl.GL_FLOAT, gl.GL_FALSE, imgui.VERTEX_SIZE, ctypes.c_void_p(imgui.VERTEX_BUFFER_POS_OFFSET))
        gl.glVertexAttribPointer(self._attrib_location_uv, 2, gl.GL_FLOAT, gl.GL_FALSE, imgui.VERTEX_SIZE, ctypes.c_void_p(imgui.VERTEX_BUFFER_UV_OFFSET))
        gl.glVertexAttribPointer(self._attrib_location_color, 4, gl.GL_UNSIGNED_BYTE, gl.GL_TRUE, imgui.VERTEX_SIZE, ctypes.c_void_p(imgui.VERTEX_BUFFER_COL_OFFSET))

        # restore state
        gl.glBindTexture(gl.GL_TEXTURE_2D, last_texture)
        gl.glBindBuffer(gl.GL_ARRAY_BUFFER, last_array_buffer)
        gl.glBindVertexArray(last_vertex_array) 

def _try_load_model(self):
        try:
            model = openvr.VRRenderModels().loadRenderModel_Async(self.model_name)
        except openvr.error_code.RenderModelError_Loading:
            return
        vertices0 = list()
        indices0 = list()
        if model is not None:
            for v in range(model.unVertexCount):
                vd = model.rVertexData[v]
                vertices0.append(float(vd.vPosition.v[0]))  # position X
                vertices0.append(float(vd.vPosition.v[1]))  # position Y
                vertices0.append(float(vd.vPosition.v[2]))  # position Z
                vertices0.append(float(vd.vNormal.v[0]))  # normal X
                vertices0.append(float(vd.vNormal.v[1]))  # normal Y
                vertices0.append(float(vd.vNormal.v[2]))  # normal Z
                vertices0.append(float(vd.rfTextureCoord[0]))  # texture coordinate U
                vertices0.append(float(vd.rfTextureCoord[1]))  # texture coordinate V
            for i in range(model.unTriangleCount * 3):
                index = model.rIndexData[i]
                indices0.append(int(index))
        vertices0 = numpy.array(vertices0, dtype=numpy.float32)
        indices0 = numpy.array(indices0, dtype=numpy.uint32)
        #
        self.vertexPositions = vbo.VBO(vertices0)
        self.indexPositions = vbo.VBO(indices0, target=GL.GL_ELEMENT_ARRAY_BUFFER)
        # http://stackoverflow.com/questions/14365484/how-to-draw-with-vertex-array-objects-and-gldrawelements-in-pyopengl
        self.vao = GL.glGenVertexArrays(1)
        GL.glBindVertexArray(self.vao)
        self.vertexPositions.bind()
        self.indexPositions.bind()
        # Vertices
        GL.glEnableVertexAttribArray(0)
        fsize = sizeof(c_float)
        GL.glVertexAttribPointer(0, 3, GL.GL_FLOAT, False, 8 * fsize, cast(0 * fsize, c_void_p))
        # Normals
        GL.glEnableVertexAttribArray(1)
        GL.glVertexAttribPointer(1, 3, GL.GL_FLOAT, False, 8 * fsize, cast(3 * fsize, c_void_p))
        # Texture coordinates    
        GL.glEnableVertexAttribArray(2)
        GL.glVertexAttribPointer(2, 2, GL.GL_FLOAT, False, 8 * fsize, cast(6 * fsize, c_void_p))
        GL.glBindVertexArray(0)
        self.model = model
        self.model_is_loaded = True
        self._try_load_texture() 

def __init__(self, name, vr_model, vr_diffuse_texture):
        self.name = name
        # create and bind a VAO to hold state for this model
        self.vertex_array = GL.glGenVertexArrays(1)
        GL.glBindVertexArray(self.vertex_array)
        # Populate a vertex buffer
        self.vertex_buffer = GL.glGenBuffers(1)
        GL.glBindBuffer(GL.GL_ARRAY_BUFFER, self.vertex_buffer)
        GL.glBufferData(GL.GL_ARRAY_BUFFER,
                        sizeof(openvr.RenderModel_Vertex_t) * vr_model.unVertexCount,
                        vr_model.rVertexData, GL.GL_STATIC_DRAW)
        # Identify the components in the vertex buffer
        GL.glEnableVertexAttribArray(0)
        hv3sz = sizeof(openvr.HmdVector3_t)
        GL.glVertexAttribPointer(0, 3, GL.GL_FLOAT, False, sizeof(openvr.RenderModel_Vertex_t),
                                 cast(0 * hv3sz, c_void_p))
        GL.glEnableVertexAttribArray(1)
        GL.glVertexAttribPointer(1, 3, GL.GL_FLOAT, False, sizeof(openvr.RenderModel_Vertex_t),
                                 cast(1 * hv3sz, c_void_p))
        GL.glEnableVertexAttribArray(2)
        GL.glVertexAttribPointer(2, 2, GL.GL_FLOAT, False, sizeof(openvr.RenderModel_Vertex_t),
                                 cast(2 * hv3sz, c_void_p))
        # Create and populate the index buffer
        self.index_buffer = GL.glGenBuffers(1)
        GL.glBindBuffer(GL.GL_ELEMENT_ARRAY_BUFFER, self.index_buffer)
        GL.glBufferData(GL.GL_ELEMENT_ARRAY_BUFFER,
                        sizeof(c_uint16) * vr_model.unTriangleCount * 3,
                        vr_model.rIndexData, GL.GL_STATIC_DRAW)
        GL.glBindVertexArray(0)
        # create and populate the texture
        self.texture = GL.glGenTextures(1)
        GL.glBindTexture(GL.GL_TEXTURE_2D, self.texture)
        GL.glTexImage2D(GL.GL_TEXTURE_2D, 0, GL.GL_RGBA, vr_diffuse_texture.unWidth, vr_diffuse_texture.unHeight,
                        0, GL.GL_RGBA, GL.GL_UNSIGNED_BYTE, vr_diffuse_texture.rubTextureMapData)
        # If this renders black ask McJohn what's wrong.
        GL.glGenerateMipmap(GL.GL_TEXTURE_2D)
        GL.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_S, GL.GL_CLAMP_TO_EDGE)
        GL.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_WRAP_T, GL.GL_CLAMP_TO_EDGE)
        GL.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_LINEAR)
        GL.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_LINEAR_MIPMAP_LINEAR)
        f_largest = GL.glGetFloatv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT)
        GL.glTexParameterf(GL.GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, f_largest)
        GL.glBindTexture(GL.GL_TEXTURE_2D, 0)
        self.vertex_count = vr_model.unTriangleCount * 3