cocos2d-x 中box2d 绘制线条帮助类

/*
 * Copyright (c) 2006-2007 Erin Catto http://www.gphysics.com
 *
 * iPhone port by Simon Oliver - http://www.simonoliver.com - http://www.handcircus.com
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 * 1. The origin of this software must not be misrepresented; you must not
 * claim that you wrote the original software. If you use this software
 * in a product, an acknowledgment in the product documentation would be
 * appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 * misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */

//
// File modified for cocos2d integration
// http://www.cocos2d-iphone.org
//

#ifndef GLES_RENDER_H
#define GLES_RENDER_H


#include "Box2D/Box2D.h"
#include "cocos2d.h"

struct b2AABB;

// This class implements debug drawing callbacks that are invoked
// inside b2World::Step.
class GLESDebugDraw : public b2Draw
{
	float32 mRatio;
	cocos2d::GLProgram *mShaderProgram;
	GLint		mColorLocation;
    
	void initShader( void );
public:
	GLESDebugDraw();
    
	GLESDebugDraw( float32 ratio );
    
	void DrawPolygon(const b2Vec2* vertices, int32 vertexCount, const b2Color& color);
    
	void DrawSolidPolygon(const b2Vec2* vertices, int32 vertexCount, const b2Color& color);
    
	void DrawCircle(const b2Vec2& center, float32 radius, const b2Color& color);
    
	void DrawSolidCircle(const b2Vec2& center, float32 radius, const b2Vec2& axis, const b2Color& color);
    
	void DrawSegment(const b2Vec2& p1, const b2Vec2& p2, const b2Color& color);
    
	void DrawTransform(const b2Transform& xf);
    
    void DrawPoint(const b2Vec2& p, float32 size, const b2Color& color);
    
    void DrawString(int x, int y, const char* string, ...);
    
    void DrawAABB(b2AABB* aabb, const b2Color& color);
};


#endif // GLES_RENDER_H

#include "cocos2d.h"


#include <cstdio>
#include <cstdarg>

#include <cstring>

USING_NS_CC;

GLESDebugDraw::GLESDebugDraw()
: mRatio( 1.0f )
{
	this->initShader();
}

GLESDebugDraw::GLESDebugDraw( float32 ratio )
: mRatio( ratio )
{
	this->initShader();
}

void GLESDebugDraw::initShader( void )
{
	mShaderProgram = ShaderCache::getInstance()->getProgram(GLProgram::SHADER_NAME_POSITION_U_COLOR);

	mColorLocation = glGetUniformLocation( mShaderProgram->getProgram(), "u_color");
}

void GLESDebugDraw::DrawPolygon(const b2Vec2* old_vertices, int32 vertexCount, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	b2Vec2* vertices = new b2Vec2[vertexCount];
	for( int i=0;i<vertexCount;i++) 
	{
		vertices[i] = old_vertices[i];
		vertices[i] *= mRatio;
	}

	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);

	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, vertices);
	glDrawArrays(GL_LINE_LOOP, 0, vertexCount);

	CC_INCREMENT_GL_DRAWS(1);

	CHECK_GL_ERROR_DEBUG();

	delete[] vertices;
}

void GLESDebugDraw::DrawSolidPolygon(const b2Vec2* old_vertices, int32 vertexCount, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	b2Vec2* vertices = new b2Vec2[vertexCount];
	for( int i=0;i<vertexCount;i++) {
		vertices[i] = old_vertices[i];
		vertices[i] *= mRatio;
	}

	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r*0.5f, color.g*0.5f, color.b*0.5f, 0.5f);

	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, vertices);

	glDrawArrays(GL_TRIANGLE_FAN, 0, vertexCount);

	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);
	glDrawArrays(GL_LINE_LOOP, 0, vertexCount);

	CC_INCREMENT_GL_DRAWS(2);

	CHECK_GL_ERROR_DEBUG();

	delete[] vertices;
}

void GLESDebugDraw::DrawCircle(const b2Vec2& center, float32 radius, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	const float32 k_segments = 16.0f;
	int vertexCount=16;
	const float32 k_increment = 2.0f * b2_pi / k_segments;
	float32 theta = 0.0f;

	GLfloat*    glVertices = new GLfloat[vertexCount*2];
	for (int i = 0; i < k_segments; ++i)
	{
		b2Vec2 v = center + radius * b2Vec2(cosf(theta), sinf(theta));
		glVertices[i*2]=v.x * mRatio;
		glVertices[i*2+1]=v.y * mRatio;
		theta += k_increment;
	}

	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);
	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, glVertices);

	glDrawArrays(GL_LINE_LOOP, 0, vertexCount);

	CC_INCREMENT_GL_DRAWS(1);

	CHECK_GL_ERROR_DEBUG();

	delete[] glVertices;
}

void GLESDebugDraw::DrawSolidCircle(const b2Vec2& center, float32 radius, const b2Vec2& axis, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	const float32 k_segments = 16.0f;
	int vertexCount=16;
	const float32 k_increment = 2.0f * b2_pi / k_segments;
	float32 theta = 0.0f;

	GLfloat*    glVertices = new GLfloat[vertexCount*2];
	for (int i = 0; i < k_segments; ++i)
	{
		b2Vec2 v = center + radius * b2Vec2(cosf(theta), sinf(theta));
		glVertices[i*2]=v.x * mRatio;
		glVertices[i*2+1]=v.y * mRatio;
		theta += k_increment;
	}

	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r*0.5f, color.g*0.5f, color.b*0.5f, 0.5f);
	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, glVertices);
	glDrawArrays(GL_TRIANGLE_FAN, 0, vertexCount);


	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);
	glDrawArrays(GL_LINE_LOOP, 0, vertexCount);

	// Draw the axis line
	DrawSegment(center,center+radius*axis,color);

	CC_INCREMENT_GL_DRAWS(2);

	CHECK_GL_ERROR_DEBUG();

	delete[] glVertices;
}

void GLESDebugDraw::DrawSegment(const b2Vec2& p1, const b2Vec2& p2, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);

	GLfloat    glVertices[] = 
	{
		p1.x * mRatio, p1.y * mRatio,
		p2.x * mRatio, p2.y * mRatio
	};
	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, glVertices);

	glDrawArrays(GL_LINES, 0, 2);

	CC_INCREMENT_GL_DRAWS(1);

	CHECK_GL_ERROR_DEBUG();
}

void GLESDebugDraw::DrawTransform(const b2Transform& xf)
{
	b2Vec2 p1 = xf.p, p2;
	const float32 k_axisScale = 0.4f;
	p2 = p1 + k_axisScale * xf.q.GetXAxis();
	DrawSegment(p1, p2, b2Color(1,0,0));
    
	p2 = p1 + k_axisScale * xf.q.GetYAxis();
	DrawSegment(p1,p2,b2Color(0,1,0));
}

void GLESDebugDraw::DrawPoint(const b2Vec2& p, float32 size, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);

	//    glPointSize(size);

	GLfloat                glVertices[] = {
		p.x * mRatio, p.y * mRatio
	};

	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, glVertices);

	glDrawArrays(GL_POINTS, 0, 1);
	//    glPointSize(1.0f);

	CC_INCREMENT_GL_DRAWS(1);

	CHECK_GL_ERROR_DEBUG();
}

void GLESDebugDraw::DrawString(int x, int y, const char *string, ...)
{
	//	NSLog(@"DrawString: unsupported: %s", string);
	//printf(string);
	/* Unsupported as yet. Could replace with bitmap font renderer at a later date */
}

void GLESDebugDraw::DrawAABB(b2AABB* aabb, const b2Color& color)
{
	mShaderProgram->use();
	mShaderProgram->setUniformsForBuiltins();

	mShaderProgram->setUniformLocationWith4f(mColorLocation, color.r, color.g, color.b, 1);

	GLfloat                glVertices[] = {
		aabb->lowerBound.x * mRatio, aabb->lowerBound.y * mRatio,
		aabb->upperBound.x * mRatio, aabb->lowerBound.y * mRatio,
		aabb->upperBound.x * mRatio, aabb->upperBound.y * mRatio,
		aabb->lowerBound.x * mRatio, aabb->upperBound.y * mRatio
	};

	glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, 0, glVertices);
	glDrawArrays(GL_LINE_LOOP, 0, 8);

	CC_INCREMENT_GL_DRAWS(1);

	CHECK_GL_ERROR_DEBUG();
}