The ray tracer function....

For David M.

float ct_trace(glm::vec3 from, glm::vec3 direction) {
    float distance_total = 0.0;
    int steps;
    for (steps = 0; steps < 64; steps++) {
        glm::vec3 p = from + distance_total * direction;
        float distance_sum = 9999.;

        glm::vec3 p_0 = p + glm::vec3(-3., 0., 0.);
        glm::vec3 p_1 = p + glm::vec3(3., 0., 0.);
        glm::vec3 p_2 = p + glm::vec3(0., 3., 0.);
        glm::vec3 p_3 = p + glm::vec3(0., -3., 0.);
        glm::vec3 p_4 = p + glm::vec3(0., .0, -3.);
        glm::vec3 p_5 = p + glm::vec3(0., .0, 3.);

        //float color_0 = ct_box(p_1, glm::vec3(1., 1., 1.));
        //float color_1 = ct_box(p_1, glm::vec3(1., 1., 1.));
        //float color_2 = ct_box(p_2, glm::vec3(1., 1., 1.));
        //float color_3 = ct_box(p_3, glm::vec3(1., 1., 1.));
        // float color_4 = ct_box(p_4, glm::vec3(1., 1., 1.));
        //float color_5 = ct_box(p_5, glm::vec3(1., 1., 1.));

        float color_0 = ct_torus(p_0, glm::vec2(1., 1.));
        float color_1 = ct_torus(p_1, glm::vec2(1., 1.));
        float color_2 = ct_torus(p_2, glm::vec2(1., 1.));
        float color_3 = ct_torus(p_3, glm::vec2(1., 1.));
        float color_4 = ct_torus(p_4, glm::vec2(1., 1.));
        float color_5 = ct_torus(p_4, glm::vec2(1., 1.));

        float color_6 = ct_box(p, glm::vec3(2., 2., 2.)); //ct_sphere_distance(p, 2.);
        float color_7 = ct_sphere_distance(p, 1.0);

        distance_sum = glm::min(distance_sum, color_0);
        distance_sum = glm::min(distance_sum, color_1);
        distance_sum = glm::min(distance_sum, color_2);
        distance_sum = glm::min(distance_sum, color_3);
        distance_sum = glm::min(distance_sum, color_4);
        distance_sum = glm::min(distance_sum, color_5);
        distance_sum = glm::min(distance_sum, color_6);
        //distance_sum = glm::min(distance_sum, color_7);

        distance_total += distance_sum;
        if (distance_sum < .001)
        {
            break;
        }
    }
    return 1.0 - float(steps) / float(64);
}