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Cocos2d-x讲解之绘图API

关键词:Cocos2d绘图API  阅读(6196) 赞(12)

[摘要]本文是对Cocos2d-x讲解之绘图API的讲解,对学习C++编程技术有所帮助,与大家分享。

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));


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