3. Knobs Helper Functions

3.1. Drawing the value of a "lane"

A lane is considered to be 1/4th sized 4x8 strip of values, assigned to a particular knob.

<<knobs_function_declarations>>=

static void knobs_draw_lane(page_knobs_d *knobs, int lane);

<<knobs_functions>>=

static void knobs_draw_lane(page_knobs_d *knobs, int lane)
{
    int x, y;
    GFFLT val;
    int sel;
    int pos;
    int c;

    sel = knobs->selected[lane];

    if (sel < 0) return;

    x = (sel % 4);
    y = (sel / 4);

    pos = (y * 16) + (lane * 4 + x);

    val = knobs->vals[pos];

    for (c = 0; c < 4; c++) {
        if (c == x) {
            int ival;
            ival = 1 << y;
            monolith_page_mstate_led_col(knobs->mstate,
                                         (lane * 4) + c, 0,
                                         ival);
        } else {
            monolith_page_mstate_led_col(knobs->mstate,
                                         (lane * 4) + c, 0,
                                         0);
        }
    }

    monolith_arcstate_mapval(knobs->astate, lane, val);
}

3.2. Redraw

Will redraw values on all lanes.

<<knobs_function_declarations>>=

static void knobs_redraw(page_knobs_d *knobs);

<<knobs_functions>>=

static void knobs_redraw(page_knobs_d *knobs)
{
    int i;
    for (i = 0; i < 4; i++) {
        knobs_draw_lane(knobs, i);
    }
}

3.3. get knob values

You'll need to know the lane (0-4), and the local position (x, y) relative to the lane. Top left is 0,0 for each lane.

<<knobs_function_declarations>>=

static GFFLT * knobs_val(page_knobs_d *knobs,
                         int lane,
                         int x, int y);

<<knobs_functions>>=

static GFFLT * knobs_val(page_knobs_d *knobs,
                         int lane,
                         int x, int y)
{
    int pos;

    if (lane < 0 || lane >= 4) return NULL;
    if (x < 0 || x >= 4) return NULL;
    if (y < 0 || y >= 8) return NULL;

    pos = ((4 * lane) + x) + y * 16;

    if (pos < 0 || pos >= 128) return NULL;

    return &knobs->vals[pos];
}

3.4. selecting a knob in a lane

Selects + displays a knob at a lane.

<<knobs_function_declarations>>=

static void knobs_select(page_knobs_d *knobs,
                         int lane,
                         int x, int y);

<<knobs_functions>>=

static void knobs_select(page_knobs_d *knobs,
                         int lane,
                         int x, int y)
{
    knobs->selected[lane] = y * 4 + x;
}

3.5. Incrementing selected value

Increments current value. Should definitely handle clamping here. Lane is specified, along with how many clicks via delta, which can be positive + negative.

<<knobs_function_declarations>>=

static void knobs_increment(page_knobs_d *knobs,
                            int lane, int delta);

<<knobs_functions>>=

static void knobs_increment(page_knobs_d *knobs,
                            int lane, int delta)
{
    GFFLT val;
    int sel;
    int x, y;
    int pos;

    sel = knobs->selected[lane];

    if (sel < 0) return;

    x = (sel % 4);
    y = (sel / 4);

    pos = (y * 16) + (lane * 4 + x);

    val = knobs->vals[pos];

    val += knobs->inc * delta;

    if (val < 0) val = 0;
    if (val > 1) val = 1;

    knobs->vals[pos] = val;
}

3.6. Grid to knobs

Will convert grid XY location to knobs lane and local XY position.

<<knobs_function_declarations>>=

static void grid2knobs(int grid_x, int grid_y,
                       int *lane, int *knob_x, int *knob_y);

<<knobs_functions>>=

static void grid2knobs(int grid_x, int grid_y,
                       int *lane, int *knob_x, int *knob_y)
{
    *lane = 0;
    *knob_x = 0;
    *knob_y = 0;
    if (grid_x < 0 || grid_x >= 16) return;
    if (grid_y < 0 || grid_y >= 8) return;

    *lane = grid_x / 4;
    *knob_x = grid_x % 4;
    *knob_y = grid_y;
}

prev | home | next