ofxTinyEXR

EXR reader and writer for openFrameworks

Based on TinyEXR library by syoyo https://github.com/syoyo/tinyexr

EXR is a file format for saving HDR/floating point images.

Loading EXR files

``c++ ofxTinyEXR exrIO; ofFloatImage floatImg; bool loaded = exrIO.loadImage(floatImg, “MyHDRImage.exr");

Saving EXR files

c++ int w = 512; int h = 512; int nPix = w h 3; ofImageType imgType = OF_IMAGE_COLOR; float * pix = new float[nPix]; for(int i=0; i<nPix; i++){ pix[i] = ofRandomuf(); }

ofFloatImage floatImg; floatImg.allocate(w, h, imgType); floatImg.getPixels().setFromPixels(pix, w, h, imgType); floatImg.update(); ofxTinyEXR exrIO; bool saved = exrIO.saveImage(floatImg, "Export.exr"); if( !saved ) ofLogWarning() << "Failed to save EXR image";

Writing Float FBO to files

c++ // allocate ofFbo floatFbo; floatFbo.allocate(512, 512, GL_RGB16, 0);

// draw into FBO floatFbo.begin(); ofClear(0); ofSetColor(255.0); ofDrawEllipse(512/2, 512/2, 512, 512); floatFbo.end();

// read to pixels ofFloatPixels pix; pix.allocate( 512, 512, OF_IMAGE_COLOR ); floatFbo.readToPixels(pix); // copy to float image floatImg.getPixels().setFromPixels(pix.getData(), 512, 512, OF_IMAGE_COLOR); floatImg.update(); // save file ofxTinyEXR exrIO; bool saved = exrIO.saveImage(floatImg, "Frame.exr"); if( !saved ) ofLogWarning() << "Failed to save EXR image"; ``

Viewing EXR files in Photoshop

When importing EXR files into Adobe Photoshop, you will see a large discrepancy in the contrast & saturation of your image.

This discrepancy be resolved by changing the “Proof Condition”:

View -> Proof setup -> Custom

Select “HDTV (Rec. 709)” and enable “Preserve RGB Numbers”.

Note: I recommend using EXR-IO for importing EXR files.