void GpGpuApp::draw()
{
// We're going to draw new data onto the "ping" FBO,
// using the "pong" FBO's textures as input
size_t pong = ( mFboIndex + 1 ) % 2;
// Set up OpenGL for data
gl::disableDepthRead();
gl::disableDepthWrite();
gl::setViewport( mFbo[ mFboIndex ].getBounds() );
gl::color( ColorAf::white() );
// Draw any new input onto the acceleration texture
mFbo[ pong ].bindFramebuffer();
glDrawBuffer( GL_COLOR_ATTACHMENT2 );
if ( mMouseDown ) {
Vec2f fboSize = Vec2f( mFbo[ mFboIndex ].getSize() );
Vec2f winSize = Vec2f( app::getWindowSize() );
gl::setMatricesWindow( fboSize, true );
Vec2f brushSize = Vec2f::one() * mBrushSize * fboSize;
Vec2f pos = ( mMouse / winSize );
pos.y = 1.0f - pos.y;
pos *= fboSize;
mGlslProgGpGpu0->bind();
mGlslProgGpGpu0->uniform( "color", ColorAf( mMouseVelocity.x, 0.0f, 1.0f - mMouseVelocity.y, 1.0f ) );
mGlslProgGpGpu0->uniform( "tex", 0 );
gl::enable( GL_TEXTURE_2D );
mTextureBrush->bind();
gl::drawSolidRect( Rectf( pos - brushSize, pos + brushSize ) );
mTextureBrush->unbind();
gl::disable( GL_TEXTURE_2D );
mGlslProgGpGpu0->unbind();
}
mFbo[ pong ].unbindFramebuffer();
// Now let's do an update pass in GLSL
mFbo[ mFboIndex ].bindFramebuffer();
gl::setMatricesWindow( mFbo[ mFboIndex ].getSize(), false );
// Bind the "pong" textures to use as input data
for ( int32_t i = 0; i < 3; ++i ) {
mFbo[ pong ].bindTexture( i, i );
}
// Set up shader to read data textures
mGlslProgGpGpu1->bind();
mGlslProgGpGpu1->uniform( "offsets", 0 );
mGlslProgGpGpu1->uniform( "velocities", 1 );
mGlslProgGpGpu1->uniform( "acceleration", 2 );
// Draw a rect to process data
glDrawBuffers( 3, kColorAttachments );
gl::drawSolidRect( mFbo[ pong ].getBounds() );
// Unbind everything
mFbo[ pong ].unbindTexture();
mGlslProgGpGpu1->unbind();
mFbo[ mFboIndex ].unbindFramebuffer();
// Swap FBOs
mFboIndex = pong;
/////////////////////////////////
// Make sure we have data to work with before we draw geometry
if ( mFbo[ mFboIndex ] &&
mFbo[ mFboIndex ].getTexture( 0 ) &&
mFbo[ mFboIndex ].getTexture( 1 ) ) {
// Set up window for 3D drawing
gl::clear( Colorf( 0.5f, 0.45f, 0.4f ) );
gl::setViewport( getWindowBounds() );
gl::setMatrices( mCamera );
gl::enableDepthRead();
gl::enableDepthWrite();
gl::multModelView( mArcball.getQuat() );
gl::color( ColorAf::black() );
// Set up shader to render scene
mGlslProgDraw->bind();
mGlslProgDraw->uniform( "Ax", mLightAmbient );
mGlslProgDraw->uniform( "Ac", mLightAttenuationConstant );
mGlslProgDraw->uniform( "Al", mLightAttenuationLinear );
mGlslProgDraw->uniform( "Aq", mLightAttenuationQuadratic );
mGlslProgDraw->uniform( "Dx", mLightDiffuse );
mGlslProgDraw->uniform( "eyePoint", mEyePoint );
mGlslProgDraw->uniform( "Ka", mMaterialAmbient );
mGlslProgDraw->uniform( "Kd", mMaterialDiffuse );
mGlslProgDraw->uniform( "Ke", mMaterialEmissive );
mGlslProgDraw->uniform( "Ks", mMaterialSpecular );
mGlslProgDraw->uniform( "lightPos", mLightPosition );
mGlslProgDraw->uniform( "n", mLightShine );
mGlslProgDraw->uniform( "offsets", 0 );
mGlslProgDraw->uniform( "projection", mCamera.getProjectionMatrix() );
mGlslProgDraw->uniform( "size", Vec2f( mSize ) );
mGlslProgDraw->uniform( "Sx", mLightSpecular );
mGlslProgDraw->uniform( "t", (float)getElapsedSeconds() );
// Bind textures to use as input data
for ( int32_t i = 0; i <= 2; ++i ) {
mFbo[ mFboIndex ].bindTexture( i, i );
}
// Draw instanced
drawInstanced( mMesh, mSize.x * mSize.y );
// Finished drawing
mFbo[ mFboIndex ].unbindTexture();
mGlslProgDraw->unbind();
// Draw textures so we can see what's going on under the hood
gl::setMatricesWindow( getWindowSize() );
gl::disableDepthRead();
gl::disableDepthWrite();
gl::color( ColorAf::white() );
gl::pushMatrices();
float x = 20.0f;
float y = 440.0f;
float width = 64.0f;
Area srcArea( Vec2i::zero(), mSize );
Rectf destRect( x, y, x + width, y + width );
gl::draw( mFbo[ 0 ].getTexture( 0 ), srcArea, destRect );
destRect.x1 += width;
destRect.x2 += width;
gl::draw( mFbo[ 1 ].getTexture( 0 ), srcArea, destRect );
destRect.y1 += width;
destRect.y2 += width;
destRect.x1 = x;
destRect.x2 = x + width;
gl::draw( mFbo[ 0 ].getTexture( 1 ), srcArea, destRect );
destRect.x1 += width;
destRect.x2 += width;
gl::draw( mFbo[ 1 ].getTexture( 1 ), srcArea, destRect );
destRect.y1 += width;
destRect.y2 += width;
destRect.x1 = x;
destRect.x2 = x + width;
gl::draw( mFbo[ 0 ].getTexture( 2 ), srcArea, destRect );
destRect.x1 += width;
destRect.x2 += width;
gl::draw( mFbo[ 1 ].getTexture( 2 ), srcArea, destRect );
gl::popMatrices();
}
// Draw parameters
if ( getElapsedFrames() > 1 ) { // This condition prevents a memory leak
mParams->draw();
}
}
