Color circle

color_circle.cpp

static float colorCirclePos[512];
static vg::Color colorCircleColor[256];
static uint16_t colorCircleIndices[765];
static bool colorCircleReady = false;
if (!colorCircleReady) {
	// Center of the circle
	colorCirclePos[0] = 0.0f;
	colorCirclePos[1] = 0.0f;
	colorCircleColor[0] = vg::ColorRGBA::White;

	// the rest of the circle
	float* pos = &colorCirclePos[2];
	vg::Color* col = &colorCircleColor[1];
	for (uint32_t i = 0; i < 255; ++i) {
		const float ang = (i / 255.0f) * bx::kPi2;
		pos[0] = 100.0f * bx::cos(ang);
		pos[1] = 100.0f * bx::sin(ang);
		col[0] = vg::ColorRGBA::fromHSB(i / 255.0f, 1.0f, 1.0f);

    pos += 2;
		col++;
	}

	uint16_t* id = colorCircleIndices;
	for (uint32_t i = 1; i < 255; ++i) {
		id[0] = 0;
		id[1] = i;
		id[2] = i + 1;

    id += 3;
	}
	id[0] = 0;
	id[1] = 254;
	id[2] = 1;

	colorCircleReady = true;
}

// vg::Context* vgr = ...;
vg::indexedTriList(vgr, colorCirclePos, nullptr, 256, colorCircleColor, 256, colorCircleIndices, 765, VG_INVALID_HANDLE);