RenderingTarget

From SWWorkshop

Jump to: navigation, search

In default, OpenGL renders the output back color buffer in framework and every screen refresh, front and back buffer switch. So last updates displayed on screen. If we want to change rendering target. For example want to render on a texture. What you do.

OpenGL

  • glCopyTexImage2D
  • PBuffer
  • FBO(Frame Buffer Object) SWEngine uses this technique


In SWEngine
Define a Rendering Target. Switch to framebuffer -->rendering target. Render screen. Switch to rendering target -->framebuffer, Use rendering target as a texture object, Apply effects and transformation on this.

ScreenShot
Image:RenderingOnTexture.JPG

Api Docs
SwEngine, swGraphics, swRect, 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 rendOnTexApp;
swPoint elipsCenter={400,300};
swDimension elipsDim={300,100};
float rot2=0;
float rot3=0;
 
int rendTargID=-1;
int imgID=-1;
swRect rect={0,0,200,150};
swRect rect2={100,100,300,300};
swRect rect3={250,150,400,400};
 
 
 
//-------------------------------------------------------------------------------------------
void rotateSecondElips(void *obj){ //This function triggered 0,05 seconds..
	rot2+=10;  
}
 
//-------------------------------------------------------------------------------------------
void rotateThirdElips(void *obj){ //This function triggered 1 seconds
	rot3-=10;
}
 
 
//-------------------------------------------------------------------------------------------
void GameLoop(){ //This function triggered when 1 frame process end Independent Time
 
 
	//Display Scene	
	swGraphicsBeginScene();
 
		//Active Rendering Target
		swGraphicsSetRenderingTarget(rendTargID);	
		swGraphicsClearRenderingTarget();
 
		//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+rot2);
 
		swGraphicsSetColor0(0,0,1,0.5);
		swGraphicsRenderSolidElips2(&elipsCenter,&elipsDim,30,120+rot3);
 
 
		//Active FrameBuffer	
		swGraphicsSetRenderingTarget(SW_RENDERING_TARGET_DEFAULT);
		swGraphicsSetBgColor0(0.6f,0.6f,0.6f);
		swGraphicsSetColor0(1,1,1,1);
		swGraphicsRenderImg0(imgID,&rect);
		swGraphicsRenderImg0(imgID,&rect2);
		swGraphicsRenderImg0(imgID,&rect3);
 
 
 
	swGraphicsEndScene();
}
 
 
//-------------------------------------------------------------------------------------------
int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nShowCmd)
{ 
 
	//Application Settings
	rendOnTexApp.hInstance=hInstance;
	rendOnTexApp.fullScreen=false;
	rendOnTexApp.cursor=true;
	rendOnTexApp.width=800;
	rendOnTexApp.height=600;
	rendOnTexApp.title="Rendering On Texture";
	rendOnTexApp.path="resource";
	rendOnTexApp.appRun=GameLoop;
 
	//Application Execution
	//Init SWEngine
	swEngineInit(&rendOnTexApp);
 
	//Init My Application
	int secondTimer=swTimerCreate(0.05f,NULL,rotateSecondElips);
	int thirdTimer=swTimerCreate(1.0f,NULL,rotateThirdElips);
 
 
	rendTargID=swGraphicsCreateRenderingTarget(400,300,3); //Define New RenderingTarget 
	imgID=swGraphicsRenderingTargetGetImgID(rendTargID); //Get ImgID  
 
	swEngineRun();
	swEngineExit();
 
	return 0;
}
Retrieved from "http://www.skywar.org/wiki/index.php/RenderingTarget"
Personal tools