Difference between revisions of "Rendering to texture (RTT) in CEGUI"

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Line 6: Line 6:
  
 
<source lang="cpp">
 
<source lang="cpp">
CEGUI::System& ceSystem = CEGUI::System::getSingleton();
+
CEGUI::System& ceguiSystem = CEGUI::System::getSingleton();
 +
 
 
//Taking some random values as example for a GUIContext size.
 
//Taking some random values as example for a GUIContext size.
 
int width = 1024;
 
int width = 1024;
Line 13: Line 14:
  
 
// We create a CEGUI texture target and create a GUIContext that will use it.
 
// We create a CEGUI texture target and create a GUIContext that will use it.
CEGUI::TextureTarget* renderTextureTarget = ceSystem.getRenderer()->createTextureTarget();
+
CEGUI::TextureTarget* renderTextureTarget = ceguiSystem.getRenderer()->createTextureTarget();
CEGUI::GUIContext* renderGuiContext = ceSystem.createGUIContext(static_cast<CEGUI::RenderTarget&>(*renderTextureTarget) );
+
CEGUI::GUIContext& renderGuiContext = ceguiSystem.createGUIContext(static_cast<CEGUI::RenderTarget&>(*renderTextureTarget) );
 
renderTextureTarget->declareRenderSize(size);
 
renderTextureTarget->declareRenderSize(size);
  
 
// We create a BasicImage and set the Texture
 
// We create a BasicImage and set the Texture
textureTargetImage = static_cast<CEGUI::BitmapImage*>(&CEGUI::ImageManager::getSingleton().create("BitmapImage", "SomeGroup/MyTexturesName"));
+
CEGUI::BasicImage* textureTargetImage = static_cast<CEGUI::BasicImage*>(&CEGUI::ImageManager::getSingleton().create("BasicImage", "MyTextureGroup/MyTextureName"));
 
textureTargetImage->setTexture(&renderTextureTarget->getTexture());
 
textureTargetImage->setTexture(&renderTextureTarget->getTexture());
  
 
// We size the image using a function
 
// We size the image using a function
setTextureTargetImageArea(static_cast<float>(height), static_cast<float>(width));
+
setTextureTargetImageArea(textureTargetImage, static_cast<float>(width). static_cast<float>(height));
 
</source>
 
</source>
  
Line 29: Line 30:
  
 
<source lang="cpp">
 
<source lang="cpp">
void setTextureTargetImageArea(float height, float width)
+
void setTextureTargetImageArea(CEGUI::BasicImage* textureTargetImage, float width, float height)
 
{
 
{
     if(d_textureTarget)
+
     //Flipping is necessary due to differences between renderers regarding top or bottom being the origin
     {
+
     bool isTextureTargetVerticallyFlipped = renderTextureTarget->isRenderingInverted();
        bool isTextureTargetVerticallyFlipped = renderTextureTarget->isRenderingInverted();
+
    CEGUI::Rectf renderArea;
        CEGUI::Rectf renderArea;
+
        if (isTextureTargetVerticallyFlipped)
+
            renderArea = CEGUI::Rectf(0.0f, height, width, 0.0f);
+
        else
+
            renderArea = CEGUI::Rectf(0.0f, 0.0f, width, height);
+
  
 +
    if (isTextureTargetVerticallyFlipped)
 +
        renderArea = CEGUI::Rectf(0.0f, height, width, 0.0f);
 +
    else
 +
        renderArea = CEGUI::Rectf(0.0f, 0.0f, width, height);
  
        if(textureTargetImage)
+
    textureTargetImage->setImageArea(renderArea);
            textureTargetImage->setImageArea(renderArea);
+
    }
+
 
}
 
}
 
</source>
 
</source>

Revision as of 19:05, 4 March 2014

Written for CEGUI 0.8


Works with versions 0.8.x (stable)

Works with latest CEGUI stable!

Since version 0.8 the new GUIContext class allows it to render your CEGUI interface into a texture instead of rendering it normally into your main buffer.


CEGUI::System& ceguiSystem = CEGUI::System::getSingleton();
 
//Taking some random values as example for a GUIContext size.
int width = 1024;
int height = 800;
CEGUI::Sizef size(static_cast<float>(width), static_cast<float>(height));
 
// We create a CEGUI texture target and create a GUIContext that will use it.
CEGUI::TextureTarget* renderTextureTarget = ceguiSystem.getRenderer()->createTextureTarget();
CEGUI::GUIContext& renderGuiContext = ceguiSystem.createGUIContext(static_cast<CEGUI::RenderTarget&>(*renderTextureTarget) );
renderTextureTarget->declareRenderSize(size);
 
// We create a BasicImage and set the Texture
CEGUI::BasicImage* textureTargetImage = static_cast<CEGUI::BasicImage*>(&CEGUI::ImageManager::getSingleton().create("BasicImage", "MyTextureGroup/MyTextureName"));
textureTargetImage->setTexture(&renderTextureTarget->getTexture());
 
// We size the image using a function
setTextureTargetImageArea(textureTargetImage, static_cast<float>(width). static_cast<float>(height));

Here is the function for sizing the BasicImage:


void setTextureTargetImageArea(CEGUI::BasicImage* textureTargetImage, float width, float height)
{
    //Flipping is necessary due to differences between renderers regarding top or bottom being the origin
    bool isTextureTargetVerticallyFlipped = renderTextureTarget->isRenderingInverted();
    CEGUI::Rectf renderArea;
 
    if (isTextureTargetVerticallyFlipped)
        renderArea = CEGUI::Rectf(0.0f, height, width, 0.0f);
    else
        renderArea = CEGUI::Rectf(0.0f, 0.0f, width, height);
 
    textureTargetImage->setImageArea(renderArea);
}


If you want to retrieve the renderer-specific texture from a CEGUI texture you will need to cast it:

For example for OpenGL:

CEGUI::OpenGLTexture& glTexture = static_cast<CEGUI::OpenGLTexture&>(d_textureTarget->getTexture());

After that you can use the member function to receive whatever render-specific traits you need, such as the textureID in Opengl as an unsigned integer, etc.