cocos2d-x 2.0 版本的 GLES-Render

GLES-Render 是用来做 Box2D 的 debug draw 功能的，比较重要。

在 cocos2d-x 2.0 模板工程里面没有看到这个东西的影子，

而且我又有需要，便拿 cocos2d-iphone 2.0 的改了一个来用。

注意的一个地方是 shader 成员可以从  cocos2d shader 缓存里面拿，不用自己创建一个。

因为这里我是探索，所以就自己创建了一个玩玩儿。

代码如下：

GLES-Render.h

/*
* 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

#import "cocos2d.h"

#ifdef __CC_PLATFORM_IOS
#import <OpenGLES/EAGL.h>
#elif defined(__CC_PLATFORM_MAC)
#import <OpenGL/OpenGL.h>
#endif

#include "Box2D.h"
#include "ccShaders.h"

USING_NS_CC;

struct b2AABB;

// This class implements debug drawing callbacks that are invoked
// inside b2World::Step.
class GLESDebugDraw : public b2Draw {
	float32 mRatio;
	CCGLProgram* 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

GLES-Render.cpp

/*
 * 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
//

#import "cocos2d.h"
#include "GLES-Render.h"


#include <cstdio>
#include <cstdarg>

#include <string>

using namespace std;

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

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

void GLESDebugDraw::initShader( void ) {
	mShaderProgram = new CCGLProgram();
    
    /**
     * 0.CCString 方法存在问题~
     */
//    mShaderProgram->initWithVertexShaderFilename("Position_uColor.vsh", "Position_uColor.fsh");
    
    /**
     * 1.报 shader 文件编译错误~
     */
//    string t_oStr0("#ifdef GL_ES\nprecision lowp float;\n#endif\nvarying vec4 v_fragmentColor;\nvoid main() {\ngl_FragColor = v_fragmentColor;\n}");
//    string t_oStr1("attribute vec4 a_position;\nuniform	mat4 u_MVPMatrix;\nuniform	vec4 u_color;\nuniform float u_pointSize;\n#ifdef GL_ES\nvarying lowp vec4 v_fragmentColor;\n#else\nvarying vec4 v_fragmentColor;\n#endif\nvoid main()\n{\ngl_Position = u_MVPMatrix * a_position;\ngl_PointSize = u_pointSize;\nv_fragmentColor = u_color;\n}");
//    mShaderProgram->initWithVertexShaderByteArray(t_oStr0.c_str(), t_oStr1.c_str());
    
    /**
     * 2.终于成功了~
     */
    mShaderProgram->initWithVertexShaderByteArray(ccPosition_uColor_vert, ccPosition_uColor_frag);
    
    mShaderProgram->addAttribute("aVertex", kCCVertexAttrib_Position);
    mShaderProgram->link();
    mShaderProgram->updateUniforms();

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

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

	ccVertex2F vertices[vertexCount];

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

	glUniform4f( mColorLocation, color.r, color.g, color.b, 1);

	glVertexAttribPointer(kCCVertexAttrib_Position, 2, GL_FLOAT, GL_FALSE, 0, vertices);
	glDrawArrays(GL_LINE_LOOP, 0, vertexCount);

	CHECK_GL_ERROR_DEBUG();
}

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

	ccVertex2F vertices[vertexCount];

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

	glUniform4f( mColorLocation, color.r*0.5f, color.g*0.5f, color.b*0.5f,0.5f);
	glVertexAttribPointer(kCCVertexAttrib_Position, 2, GL_FLOAT, GL_FALSE, 0, vertices);

	glDrawArrays(GL_TRIANGLE_FAN, 0, vertexCount);

	glUniform4f( mColorLocation, color.r, color.g, color.b,1);
	glDrawArrays(GL_LINE_LOOP, 0, vertexCount);

	CHECK_GL_ERROR_DEBUG();
}

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


	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[vertexCount*2];
	for (int32 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;
	}

	glUniform4f( mColorLocation, color.r, color.g, color.b,1);
	glVertexAttribPointer(kCCVertexAttrib_Position, 2, GL_FLOAT, GL_FALSE, 0, glVertices);

	glDrawArrays(GL_LINE_LOOP, 0, vertexCount);

	CHECK_GL_ERROR_DEBUG();
}

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

	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[vertexCount*2];
	for (int32 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;
	}


	glUniform4f( mColorLocation, color.r *0.5f, color.g*0.5f, color.b*0.5f,0.5f );
	glVertexAttribPointer(kCCVertexAttrib_Position, 2, GL_FLOAT, GL_FALSE, 0, glVertices);
	glDrawArrays(GL_TRIANGLE_FAN, 0, vertexCount);


	glUniform4f( mColorLocation, color.r, color.g, color.b,1);
	glDrawArrays(GL_LINE_LOOP, 0, vertexCount);

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

	CHECK_GL_ERROR_DEBUG();
}

void GLESDebugDraw::DrawSegment(const b2Vec2& p1, const b2Vec2& p2, const b2Color& color)
{
	ccGLUseProgram(mShaderProgram->getProgram());
	mShaderProgram->setUniformForModelViewProjectionMatrix();

	glUniform4f( mColorLocation, color.r, color.g, color.b,1);

	GLfloat				glVertices[] = {
		p1.x * mRatio, p1.y * mRatio,
		p2.x * mRatio, p2.y * mRatio
	};

	glVertexAttribPointer(kCCVertexAttrib_Position, 2, GL_FLOAT, GL_FALSE, 0, glVertices);

	glDrawArrays(GL_LINES, 0, 2);

	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)
{
	ccGLUseProgram(mShaderProgram->getProgram());
	mShaderProgram->setUniformForModelViewProjectionMatrix();

	glUniform4f( mColorLocation, color.r, color.g, color.b,1);

//	glPointSize(size);

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

	glVertexAttribPointer(kCCVertexAttrib_Position, 2, GL_FLOAT, GL_FALSE, 0, glVertices);

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

	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& c)
{
	ccGLUseProgram(mShaderProgram->getProgram());
	mShaderProgram->setUniformForModelViewProjectionMatrix();

	glUniform4f( mColorLocation, c.r, c.g, c.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(kCCVertexAttrib_Position, 2, GL_FLOAT, GL_FALSE, 0, glVertices);
	glDrawArrays(GL_LINE_LOOP, 0, 8);

	CHECK_GL_ERROR_DEBUG();
}