本节来看一下在cocos2d-x中，常用的一些绘图api；
先来看一个工具类，以便于快速指定游戏窗口的一些位置，如左上，右上等；
VisibleRect.h
#ifndef __VISIBLERECT_H__
#define __VISIBLERECT_H__#include "cocos2d.h"
class VisibleRect
{
public:
static cocos2d::Rect getVisibleRect();static cocos2d::Vec2 left();
static cocos2d::Vec2 right();
static cocos2d::Vec2 top();
static cocos2d::Vec2 bottom();
static cocos2d::Vec2 center();
static cocos2d::Vec2 leftTop();
static cocos2d::Vec2 rightTop();
static cocos2d::Vec2 leftBottom();
static cocos2d::Vec2 rightBottom();
private:
static void lazyInit();
static cocos2d::Rect s_visibleRect;
};#endif /* __VISIBLERECT_H__ */
VisibleRect.cpp实现
#include "VisibleRect.h"USING_NS_CC;
Rect VisibleRect::s_visibleRect;
void VisibleRect::lazyInit()
{
// no lazy init
// Useful if we change the resolution in runtime
s_visibleRect = Director::getInstance()->getOpenGLView()->getVisibleRect();
}Rect VisibleRect::getVisibleRect()
{
lazyInit();
return s_visibleRect;
}Vec2 VisibleRect::left()
{
lazyInit();
return Vec2(s_visibleRect.origin.x, s_visibleRect.origin.y+s_visibleRect.size.height/2);
}Vec2 VisibleRect::right()
{
lazyInit();
return Vec2(s_visibleRect.origin.x+s_visibleRect.size.width, s_visibleRect.origin.y+s_visibleRect.size.height/2);
}Vec2 VisibleRect::top()
{
lazyInit();
return Vec2(s_visibleRect.origin.x+s_visibleRect.size.width/2, s_visibleRect.origin.y+s_visibleRect.size.height);
}Vec2 VisibleRect::bottom()
{
lazyInit();
return Vec2(s_visibleRect.origin.x+s_visibleRect.size.width/2, s_visibleRect.origin.y);
}Vec2 VisibleRect::center()
{
lazyInit();
return Vec2(s_visibleRect.origin.x+s_visibleRect.size.width/2, s_visibleRect.origin.y+s_visibleRect.size.height/2);
}Vec2 VisibleRect::leftTop()
{
lazyInit();
return Vec2(s_visibleRect.origin.x, s_visibleRect.origin.y+s_visibleRect.size.height);
}Vec2 VisibleRect::rightTop()
{
lazyInit();
return Vec2(s_visibleRect.origin.x+s_visibleRect.size.width, s_visibleRect.origin.y+s_visibleRect.size.height);
}Vec2 VisibleRect::leftBottom()
{
lazyInit();
return s_visibleRect.origin;
}Vec2 VisibleRect::rightBottom()
{
lazyInit();
return Vec2(s_visibleRect.origin.x+s_visibleRect.size.width, s_visibleRect.origin.y);
}
上面的代码不再过多解释，比较简单，也就是获取一些Rect的位置；
下面主要展示两种种形式，一是直接在Layer的构造方法中通过api绘制，另一种是在继承Layer的draw,onDraw方法进行绘制；
一、直接在Layer类构造方法里面绘制图形
DrawNodeTest::DrawNodeTest()
{
auto s = Director::getInstance()->getWinSize();auto draw = DrawNode::create();
addChild(draw, 10);// 画10个圆，实际上是画了10个点，指定点的大小，所以看起来就是圆；
for( int i=0; i < 10; i++)
{
draw->drawDot(Vec2(s.width/2, s.height/2), 10*(10-i), Color4F(CCRANDOM_0_1(), CCRANDOM_0_1(), CCRANDOM_0_1(), 1));
}// 画多边形
Vec2 points[] = { Vec2(s.height/4,0), Vec2(s.width,s.height/5), Vec2(s.width/3*2,s.height) };
draw->drawPolygon(points, sizeof(points)/sizeof(points[0]), Color4F(1,0,0,0.5), 4, Color4F(0,0,1,1));// 多边形(注意，这里会有一些bug)
{
const float o=80;
const float w=20;
const float h=50;
Vec2 star[] = {
Vec2(o+w,o-h), Vec2(o+w*2, o), // lower spike
Vec2(o + w*2 + h, o+w ), Vec2(o + w*2, o+w*2), // right spike
// {o +w, o+w*2+h}, {o,o+w*2}, // top spike
// {o -h, o+w}, {o,o}, // left spike
};draw->drawPolygon(star, sizeof(star)/sizeof(star[0]), Color4F(1,0,0,0.5), 1, Color4F(0,0,1,1));
}// 多边形，此处正常显示，注意此处与上一个多边形的区别:按规律指定点的顺序，相反，上一个多边形的顶点顺序是乱的，所以会有一些bug；
{
const float o=180;
const float w=20;
const float h=50;
Vec2 star[] = {
Vec2(o,o), Vec2(o+w,o-h), Vec2(o+w*2, o), // lower spike
Vec2(o + w*2 + h, o+w ), Vec2(o + w*2, o+w*2), // right spike
Vec2(o +w, o+w*2+h), Vec2(o,o+w*2), // top spike
Vec2(o -h, o+w), // left spike
};
draw->drawPolygon(star, sizeof(star)/sizeof(star[0]), Color4F(1,0,0,0.5), 1, Color4F(0,0,1,1));
}// 画片段
draw->drawSegment(Vec2(20,s.height), Vec2(20,s.height/2), 10, Color4F(0, 1, 0, 1));
draw->drawSegment(Vec2(10,s.height/2), Vec2(s.width/2, s.height/2), 40, Color4F(1, 0, 1, 0.5));// 三角形
draw->drawTriangle(Vec2(10, 10), Vec2(70, 30), Vec2(100, 140), Color4F(CCRANDOM_0_1(), CCRANDOM_0_1(), CCRANDOM_0_1(), 0.5));// 二次方贝赛尔曲线
draw->drawQuadraticBezier(Vec2(s.width - 150, s.height - 150), Vec2(s.width - 70, s.height - 10), Vec2(s.width - 10, s.height - 10), 10, Color4F(CCRANDOM_0_1(), CCRANDOM_0_1(), CCRANDOM_0_1(), 0.5));draw->drawCubicBezier(Vec2(s.width - 250, 40), Vec2(s.width - 70, 100), Vec2(s.width - 30, 250), Vec2(s.width - 10, s.height - 50), 10, Color4F(CCRANDOM_0_1(), CCRANDOM_0_1(), CCRANDOM_0_1(), 0.5));
}
上面的代码画出来的多图形如下:
二、继承Layer，在onDraw/draw方法中绘制图形
void DrawPrimitivesTest::draw(Renderer *renderer, const Mat4 &transform, bool transformUpdated)
{
_customCommand.init(_globalZOrder); // _customCommand为DrawPrimitivesTest的一个字段(CustomCommand)；
_customCommand.func = CC_CALLBACK_0(DrawPrimitivesTest::onDraw, this, transform, transformUpdated);
renderer->addCommand(&_customCommand);
}void DrawPrimitivesTest::onDraw(const Mat4 &transform, bool transformUpdated)
{
Director* director = Director::getInstance();
CCASSERT(nullptr != director, "Director is null when seting matrix stack");
director->pushMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW);
director->loadMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW, transform);//draw
CHECK_GL_ERROR_DEBUG();// 画线，默认宽度1,白色，
DrawPrimitives::drawLine( VisibleRect::leftBottom(), VisibleRect::rightTop() );CHECK_GL_ERROR_DEBUG();
// 画线: 指定颜色和宽度，当宽度大于1时，GL_LINE_SMOOTH无效果// GL_SMOOTH_LINE_WIDTH_RANGE = (1,1) on iPhone
// glDisable(GL_LINE_SMOOTH);
glLineWidth( 5.0f );
DrawPrimitives::setDrawColor4B(255,0,0,255);
DrawPrimitives::drawLine( VisibleRect::leftTop(), VisibleRect::rightBottom() );CHECK_GL_ERROR_DEBUG();
// 画点
DrawPrimitives::setPointSize(64);
DrawPrimitives::setDrawColor4B(0,0,255,128);
DrawPrimitives::drawPoint( VisibleRect::center() );CHECK_GL_ERROR_DEBUG();
// draw 4 small points
Vec2 points[] = { Vec2(60,60), Vec2(70,70), Vec2(60,70), Vec2(70,60) };
DrawPrimitives::setPointSize(4);
DrawPrimitives::setDrawColor4B(0,255,255,255);
DrawPrimitives::drawPoints( points, 4);CHECK_GL_ERROR_DEBUG();
// draw a green circle with 10 segments
glLineWidth(16);
DrawPrimitives::setDrawColor4B(0, 255, 0, 255);
DrawPrimitives::drawCircle( VisibleRect::center(), 100, 0, 10, false);CHECK_GL_ERROR_DEBUG();
// draw a green circle with 50 segments with line to center
glLineWidth(2);
DrawPrimitives::setDrawColor4B(0, 255, 255, 255);
DrawPrimitives::drawCircle( VisibleRect::center(), 50, CC_DEGREES_TO_RADIANS(90), 50, true);CHECK_GL_ERROR_DEBUG();
// 画一个填充的圆，
glLineWidth(2);
DrawPrimitives::setDrawColor4B(255, 0, 255, 255);
DrawPrimitives::drawSolidCircle( VisibleRect::center() + Vec2(140,0), 40, CC_DEGREES_TO_RADIANS(90), 50, 1.0f, 1.0f);CHECK_GL_ERROR_DEBUG();
// 未关闭的多边形(画出来的效果其实就是一条折线)
DrawPrimitives::setDrawColor4B(255, 255, 0, 255);
glLineWidth(10);
Vec2 vertices[] = { Vec2(0,0), Vec2(50,50), Vec2(100,50), Vec2(100,100), Vec2(50,100) };
DrawPrimitives::drawPoly( vertices, 5, false);CHECK_GL_ERROR_DEBUG();
// 填充的多边形
glLineWidth(1);
Vec2 filledVertices[] = { Vec2(0,120), Vec2(50,120), Vec2(50,170), Vec2(25,200), Vec2(0,170) };
DrawPrimitives::drawSolidPoly(filledVertices, 5, Color4F(0.5f, 0.5f, 1, 1 ) );// closed purble poly
DrawPrimitives::setDrawColor4B(255, 0, 255, 255);
glLineWidth(2);
Vec2 vertices2[] = { Vec2(30,130), Vec2(30,230), Vec2(50,200) };
DrawPrimitives::drawPoly( vertices2, 3, true);CHECK_GL_ERROR_DEBUG();
// draw quad bezier path
DrawPrimitives::drawQuadBezier(VisibleRect::leftTop(), VisibleRect::center(), VisibleRect::rightTop(), 50);CHECK_GL_ERROR_DEBUG();
// draw cubic bezier path
DrawPrimitives::drawCubicBezier(VisibleRect::center(), Vec2(VisibleRect::center().x+30,VisibleRect::center().y+50), Vec2(VisibleRect::center().x+60,VisibleRect::center().y-50),VisibleRect::right(),100);CHECK_GL_ERROR_DEBUG();
//draw a solid polygon
Vec2 vertices3[] = {Vec2(60,160), Vec2(70,190), Vec2(100,190), Vec2(90,160)};
DrawPrimitives::drawSolidPoly( vertices3, 4, Color4F(1,1,0,1) );// 还原画笔为原始状态
glLineWidth(1);
DrawPrimitives::setDrawColor4B(255,255,255,255);
DrawPrimitives::setPointSize(1);CHECK_GL_ERROR_DEBUG();
//end draw
director->popMatrix(MATRIX_STACK_TYPE::MATRIX_STACK_MODELVIEW);
}
上述代码所画出的效果为
注:上面的一些画图形的方法未对部分参数注释，下边做一个简单禅述；
// 矩形
DrawPrimitives::setDrawCooolor4B(255, 0, 0, 255);
DrawPrimitives::drawRect(Point(0, 0), Point(100, 100));
// 填充的矩形
DrawPrimitives::drawSolidRect(Point(0, 0), Point(100, 100), Color4F(0, 0, 1, 1));
// 圆形，5个参数分别是圆心，半径，角度，切割片段(实际上计算机无法画圆，圆实际是点的组合，这里把圆分为50个点)，
DrawPrimitives::drawCircle(Point(0, 0), 50, M_PI * 2, 50, true);
// 填充圆形，5个参数分别是圆心，半径，角度，切割片段，
DrawPrimitives::drawSolidCircle(Point(0, 0), 50, M_PI * 2, 50);Point ps[3];
ps[0] = Point(0, 0);
ps[1] = Point(100, 0);
ps[2] = Point(0, 50);
// 多边形；第二个参数表示顶点个数
DrawPrimitives::drawPoly(ps, 3, true);
// 填充多边形
DrawPrimitives::drawSolidPoly(ps, 3, Color4F(0, 0, 1, 1));
// 线
DrawPrimitives::drawLine(Point(0, 0), Point(50, 50));
// 点
DrawPrimitives::drawPoint(Point(0, 0));
完：本人Cocos2d-x新手，如有错误，还请指教！
Cocos2d-x 系列八之绘图API,布布扣,bubuko.com