Transparency

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We succeed primitive drawing with color. Now we expand drawing capability and draw transparent objects. Transparent objects can be drawn using OpenGL blending function( glBlendFunc(SRC_FACTOR , DST_FACTOR) ). SRC_FACTOR and DST_FACTOR are predefined OpenGL constants used for blending operation. These can be constants like GL_ONE , GL_SRC_ALPHA etc.. look for your opengl guide for the complete list of this constants and their meanings. SWEngine graphics api provides an abstraction layer on OpenGL. So you don't need to learn OpenGL Blending functions. 

swGraphicsSetBlendingMode(SW_BLENDING_MODE_ADDITIVE); //Enable Apha Channel For Blending
swGraphicsSetColor0(0,1,0,'''0.5'''); //Set transparency ratio

ScreenShot
Image:Transparency.jpg

Api Docs
SwEngine, swGraphics, swPoint, swDimension, swApplication


Source Code 

#include "../../include/SWEngine.h"
 
#pragma comment (lib,"../../lib/SWUtil.lib")    
#pragma comment (lib,"../../lib/SWTypes.lib")    
#pragma comment (lib,"../../lib/SWCore.lib")    
#pragma comment (lib,"../../lib/SWEngine.lib")    
 
 
swApplication transparencyApp;
swPoint elipsCenter={400,300};
swDimension elipsDim={300,100};
 
 
//-------------------------------------------------------------------------------------------
void GameLoop(){ 
 
	swGraphicsBeginScene();
 
	//Background
	swGraphicsSetBgColor0(0.6f,0.6f,0.6f);
 
	//BlendingMode
	swGraphicsSetBlendingMode(SW_BLENDING_MODE_ADDITIVE);
 
	//Draw Elips
	swGraphicsSetColor0(0,1,0,0.5);
	swGraphicsRenderSolidElips2(&elipsCenter,&elipsDim,30,0);
 
	swGraphicsSetColor0(1,0,0,0.5);
	swGraphicsRenderSolidElips2(&elipsCenter,&elipsDim,30,60);
 
	swGraphicsSetColor0(0,0,1,0.5);
	swGraphicsRenderSolidElips2(&elipsCenter,&elipsDim,30,120);
 
	swGraphicsEndScene();
 
}
 
 
 
 
 
//-------------------------------------------------------------------------------------------
int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nShowCmd)
{ 
 
 
	//Application Settings
	transparencyApp.hInstance=hInstance;
	transparencyApp.fullScreen=false;
	transparencyApp.cursor=true;
	transparencyApp.width=800;
	transparencyApp.height=600;
	transparencyApp.title="Transparency";
	transparencyApp.path="resource";
	transparencyApp.appRun=GameLoop;
 
	//Application Execution
	swEngineInit(&transparencyApp);
	swEngineRun();
	swEngineExit();
 
	return 0;
}
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