import numpy as np

import moderngl
from _example import Example


class Fractal(Example):
    title = "Julia Fractal"
    gl_version = (3, 3)

    def __init__(self, **kwargs):
        super().__init__(**kwargs)

        self.prog = self.ctx.program(
            vertex_shader='''
                #version 330

                in vec2 in_vert;
                out vec2 v_text;

                void main() {
                    gl_Position = vec4(in_vert, 0.0, 1.0);
                    v_text = in_vert / 2.0 + 0.5;
                }
            ''',
            fragment_shader='''
                #version 330

                in vec2 v_text;
                out vec4 f_color;

                uniform vec2 Center;
                uniform int Iter;

                void main() {
                    vec2 z = vec2(5.0 * (v_text.x - 0.5), 3.0 * (v_text.y - 0.5));
                    vec2 c = Center;

                    int i;
                    for(i = 0; i < Iter; i++) {
                        vec2 v = vec2(
                            (z.x * z.x - z.y * z.y) + c.x,
                            (z.y * z.x + z.x * z.y) + c.y
                        );
                        if (dot(v, v) > 4.0) break;
                        z = v;
                    }

                    float cm = fract((i == Iter ? 0.0 : float(i)) * 10 / Iter);
                    f_color = vec4(
                        fract(cm + 0.0 / 3.0),
                        fract(cm + 1.0 / 3.0),
                        fract(cm + 2.0 / 3.0),
                        1.0
                    );
                }
            ''',
        )

        self.center = self.prog['Center']
        self.iter = self.prog['Iter']

        vertices = np.array([-1.0, -1.0, -1.0, 1.0, 1.0, -1.0, 1.0, 1.0])

        self.vbo = self.ctx.buffer(vertices.astype('f4'))
        self.vao = self.ctx.simple_vertex_array(self.prog, self.vbo, 'in_vert')

    def render(self, time, frame_time):
        self.ctx.clear(1.0, 1.0, 1.0)

        self.center.value = (0.49, 0.32)
        self.iter.value = 100

        self.vao.render(moderngl.TRIANGLE_STRIP)


if __name__ == '__main__':
    Fractal.run()