pplugins/pui/knob.cpp

/*
  Copyright 2013 Peter Nelson

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <cmath>
#include <pugl/pugl.h>
#include "pui.h"

float Knob::GetNewValue(int x, int y)
{
	int dx = (this->x + this->w / 2) - x;
	int dy = (this->y + this->h / 2) - y;

	float a = .5f - (atan2(dx, dy) * .5f / M_PI) * 1.33f;
	if (a < 0) a = 0;
	if (a > 1) a = 1;

	return a * (max - min) + min;
}

static void DrawPartial(GLuint t1, GLuint t2, int seg, float x1, float y1, float x2, float y2, float r)
{
	float xc = .5f;
	float yc = .5f;

	if (r >= 0 && r <= .25f) {
		float t;
		if (r <= .125f) {
			t = .5 - tanf((.125f - r) * 2 * M_PI) * .5f;
		} else {
			t = .5 + tanf((r - .125f) * 2 * M_PI) * .5f;
		}
		float x, y;
		switch (seg) {
			default:
			case 0: x = x1; y = 1 - t; break;
			case 1: x = t; y = y1; break;
			case 2: x = x1; y = t; break;
			case 3: x = 1 - t; y = y1; break;
		}

		glBindTexture(GL_TEXTURE_2D, t2);
		glBegin(GL_TRIANGLES);
		glTexCoord2f(xc, yc);
		glVertex2f(xc, yc);
		glTexCoord2f(x1, y1);
		glVertex2f(x1, y1);
		glTexCoord2f(x, y);
		glVertex2f(x, y);
		glEnd();

		glBindTexture(GL_TEXTURE_2D, t1);
		glBegin(GL_TRIANGLES);
		glTexCoord2f(xc, yc);
		glVertex2f(xc, yc);
		glTexCoord2f(x, y);
		glVertex2f(x, y);
		glTexCoord2f(x2, y2);
		glVertex2f(x2, y2);
		glEnd();
	} else {
		glBindTexture(GL_TEXTURE_2D, r > 0 ? t2 : t1);
		glBegin(GL_TRIANGLES);
		glTexCoord2f(xc, yc);
		glVertex2f(xc, yc);
		glTexCoord2f(x1, y1);
		glVertex2f(x1, y1);
		glTexCoord2f(x2, y2);
		glVertex2f(x2, y2);
		glEnd();
	}
}

void Knob::OnPaint(const PUi *pui) const
{
	glEnable(GL_TEXTURE_2D);

	float mx = (w - pui->w[TEX_KNOB]) * 0.5f + x;
	float my = (h - pui->h[TEX_KNOB]) * 0.5f + y;

	float hw = pui->w[TEX_KNOB] * .5f;
	float hh = pui->h[TEX_KNOB] * .5f;

	glPushMatrix();
	glTranslatef(mx, my, 0);
	glColor3f(1, 1, 1);

	glScalef(pui->w[TEX_KNOB], pui->h[TEX_KNOB], 1);

	GLuint t1 = pui->tex[TEX_KNOB];
	GLuint t2 = pui->tex[TEX_KNOB_PRE];

	float r = (this->value - this->min) / (this->max - this->min) - .5f;
	r /= 1.3333f;
	r += .5f;

	r -= .125f;
	DrawPartial(t1, t2, 0, 0, 1, 0, 0, r);
	r -= .25f;
	DrawPartial(t1, t2, 1, 0, 0, 1, 0, r);
	r -= .25f;
	DrawPartial(t1, t2, 2, 1, 0, 1, 1, r);
	r -= .25f;
	DrawPartial(t1, t2, 3, 1, 1, 0, 1, r);

	glPopMatrix();
	r = (this->value - this->min) / (this->max - this->min) - .5f;

	glPushMatrix();
	glTranslatef(mx + hw, my + hw, 0);
	glRotatef(r * 270, 0, 0, 1);
	glBindTexture(GL_TEXTURE_2D, pui->tex[TEX_KNOB_SEL]);
	glBegin(GL_QUADS);
	glColor3f(1.0, 1.0, 1.0);
	glTexCoord2f(0, 0);
	glVertex2f(-hw, -hh);
	glTexCoord2f(0, 1);
	glVertex2f(-hw,  hh);
	glTexCoord2f(1, 1);
	glVertex2f( hw,  hh);
	glTexCoord2f(1, 0);
	glVertex2f( hw, -hh);
	glEnd();

	glPopMatrix();
	glDisable(GL_TEXTURE_2D);

	char tmp[128];
	snprintf(tmp, sizeof tmp, "%s: %06d", this->label, (int)(this->value * 44100));
	FTBBox box = pui->font->BBox(tmp);
	FTPoint p = box.Upper() - box.Lower();
	float cx = p.X();
	float cy = p.Y();

	float ox = -.5f;
	float oy = 0;

	glPushMatrix();
	glTranslatef(x + w * 0.5f, y - 4, 0);
	glScalef(.5f, -.5f, 1);
	glTranslatef(cx * ox, -cy * oy, 0);
	glColor4f(0, 0, 0, 1);
	pui->font->Render(tmp);
	glTranslatef(0, 2, 0);
	glColor4f(1, 1, 1, 1);
	pui->font->Render(tmp);
	glPopMatrix();

	Widget::OnPaint(pui);
}