OpenGL GLFW入門篇 - 畫矩形

效果圖

主體代碼

void DrawRectangle(void)
{
    GLfloat xl, yt, xr, yb, w, h;

    glPushMatrix();
	glLoadIdentity();
	glTranslatef(0.0, 0.0, 0.f);

	w = 1.2;
	h = 1.0;
    xl = -0.8;
    yt = -0.8;
    yb = yt + h;
    xr = xl + w;

    // 紅色
	glColor3f(1.f, 0.f, 0.f);
    glRectf(xl, yt, xr, yb);

	// 綠色
	glColor3f(0.f, 1.f, 0.f);
    xl += 0.2;
    xr += 0.2;
    yt += 0.2;
    yb += 0.2;
    glRectf(xl, yt, xr, yb);

	// 藍色
	glColor3f(0.f, 0.f, 1.f);
	xl += 0.2;
	xr += 0.2;
	yt += 0.2;
	yb += 0.2;
    glRectf(xl, yt, xr, yb);

	glEnd();
	glPopMatrix();
}