TechArtLife's blog

Appearance

【PyOpenGL】4.变换 ​

1.准备数据 ​

  • 创建Actor

  • 添加Transform组件

    python
        def init(self):
        transform_comp = TransformComponent()
        transform_comp.position = glm.vec3(0, 0, 0)
        transform_comp.rotation = glm.vec3(0, 0, 1.0)
        transform_comp.scale = glm.vec3(0.5, 0.5, 0.5)
        transform_comp.update_matrix()
        self._main_actor.add_component(transform_comp)

    Actor-Component架构非常方便。

  • 在vs shader中添加uniform transform

    glsl
    #version 330
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
layout (location = 2) in vec2 aTexCoord;

uniform mat4 transform;

out vec3 ourColor;
out vec2 TexCoord;

void main()
{
    gl_Position = transform * vec4(aPos, 1.0);
    ourColor = aColor;
    TexCoord = aTexCoord;
}

  • 绑定Transform矩阵到Shader的transform上

    python
    mat_comp.bind_param('transform', 'mat4', transform_comp)

  • 在Game的update中更新transform的position, rotation, scale信息，更新transform矩阵信息。

    python
        def __init__(self, title='') -> None:
        self._title: str = title
        self._is_running: bool = False
        self._main_window: Window = None
        self._asset_manager: AssetManager = None
        self._main_actor: Actor = None

        self._frame_time = 0
        self._last_frame_time_point = 0

        self.pos_index = 0
        self.pos_flag = 1
        self.rotation_index = 0
        self.scale_index = 0
        self.scale_flag = 1    
   
    def _update(self):
        cur_time_point = time.perf_counter_ns() / 1000000  # ns -> ms
        self._frame_time = cur_time_point - self._last_frame_time_point
        self._last_frame_time_point = cur_time_point

        frame_time_ms = round(self._frame_time, 2)
        self._main_window.set_title(self._title + ' ' + str(frame_time_ms) + 'ms')

        transform: TransformComponent = self._main_actor.get_component('TransformComponent')
        transform.position = glm.vec3(self.pos_index, 0, 0)
        transform.angle = - self.rotation_index
        transform.scale = glm.vec3((self.scale_index % 150) * 0.01)
        transform.update_matrix()
        self._main_actor.update()

        if self.scale_index >= 149:  # 注意：这里比上面小1。因为等于时，scale会突变为0
            self.scale_flag = -1
        elif self.scale_index <= 20:
            self.scale_flag = 1
        self.scale_index += self.scale_flag * 0.07 * self._frame_time

        if self.pos_index - 1.0 > 0.001:
            self.pos_index = 1.0
            self.pos_flag = -1
        elif self.pos_index + 1.0 < -0.001:
            self.pos_index = -1.0
            self.pos_flag = 1
        self.pos_index += self.pos_flag * 0.001 * self._frame_time

        self.rotation_index += 1 * 0.08 * self._frame_time

2.渲染过程 ​

  • 在MeshRenderer的render中添加材质Material的uniform绑定过程。将mat中的参数传递到shader中。

  • 其他和《3.绘制图片》中过程相同。

3.结果展示 ​

alt text