void ClippingNode::onBeforeVisit()
{
///////////////////////////////////
// INIT
// increment the current layer
s_layer++;
// mask of the current layer (ie: for layer 3: 00000100)
GLint mask_layer = 0x1 << s_layer;
// mask of all layers less than the current (ie: for layer 3: 00000011)
GLint mask_layer_l = mask_layer - 1;
// mask of all layers less than or equal to the current (ie: for layer 3: 00000111)
_mask_layer_le = mask_layer | mask_layer_l;
// manually save the stencil state
_currentStencilEnabled = glIsEnabled(GL_STENCIL_TEST);
glGetIntegerv(GL_STENCIL_WRITEMASK, (GLint *)&_currentStencilWriteMask);
glGetIntegerv(GL_STENCIL_FUNC, (GLint *)&_currentStencilFunc);
glGetIntegerv(GL_STENCIL_REF, &_currentStencilRef);
glGetIntegerv(GL_STENCIL_VALUE_MASK, (GLint *)&_currentStencilValueMask);
glGetIntegerv(GL_STENCIL_FAIL, (GLint *)&_currentStencilFail);
glGetIntegerv(GL_STENCIL_PASS_DEPTH_FAIL, (GLint *)&_currentStencilPassDepthFail);
glGetIntegerv(GL_STENCIL_PASS_DEPTH_PASS, (GLint *)&_currentStencilPassDepthPass);
// enable stencil use
glEnable(GL_STENCIL_TEST);
// check for OpenGL error while enabling stencil test
CHECK_GL_ERROR_DEBUG();
// all bits on the stencil buffer are readonly, except the current layer bit,
// this means that operation like glClear or glStencilOp will be masked with this value
glStencilMask(mask_layer);
// manually save the depth test state
glGetBooleanv(GL_DEPTH_WRITEMASK, &_currentDepthWriteMask);
// disable depth test while drawing the stencil
//glDisable(GL_DEPTH_TEST);
// disable update to the depth buffer while drawing the stencil,
// as the stencil is not meant to be rendered in the real scene,
// it should never prevent something else to be drawn,
// only disabling depth buffer update should do
glDepthMask(GL_FALSE);
///////////////////////////////////
// CLEAR STENCIL BUFFER
// manually clear the stencil buffer by drawing a fullscreen rectangle on it
// setup the stencil test func like this:
// for each pixel in the fullscreen rectangle
// never draw it into the frame buffer
// if not in inverted mode: set the current layer value to 0 in the stencil buffer
// if in inverted mode: set the current layer value to 1 in the stencil buffer
glStencilFunc(GL_NEVER, mask_layer, mask_layer);
glStencilOp(!_inverted ? GL_ZERO : GL_REPLACE, GL_KEEP, GL_KEEP);
// draw a fullscreen solid rectangle to clear the stencil buffer
//ccDrawSolidRect(Point::ZERO, ccpFromSize([[Director sharedDirector] winSize]), Color4F(1, 1, 1, 1));
drawFullScreenQuadClearStencil();
///////////////////////////////////
// DRAW CLIPPING STENCIL
// setup the stencil test func like this:
// for each pixel in the stencil node
// never draw it into the frame buffer
// if not in inverted mode: set the current layer value to 1 in the stencil buffer
// if in inverted mode: set the current layer value to 0 in the stencil buffer
glStencilFunc(GL_NEVER, mask_layer, mask_layer);
glStencilOp(!_inverted ? GL_REPLACE : GL_ZERO, GL_KEEP, GL_KEEP);
// enable alpha test only if the alpha threshold < 1,
// indeed if alpha threshold == 1, every pixel will be drawn anyways
if (_alphaThreshold < 1) {
#if (CC_TARGET_PLATFORM == CC_PLATFORM_MAC || CC_TARGET_PLATFORM == CC_PLATFORM_WINDOWS || CC_TARGET_PLATFORM == CC_PLATFORM_LINUX)
// manually save the alpha test state
_currentAlphaTestEnabled = glIsEnabled(GL_ALPHA_TEST);
glGetIntegerv(GL_ALPHA_TEST_FUNC, (GLint *)&_currentAlphaTestFunc);
glGetFloatv(GL_ALPHA_TEST_REF, &_currentAlphaTestRef);
// enable alpha testing
glEnable(GL_ALPHA_TEST);
// check for OpenGL error while enabling alpha test
CHECK_GL_ERROR_DEBUG();
// pixel will be drawn only if greater than an alpha threshold
glAlphaFunc(GL_GREATER, _alphaThreshold);
#else
#endif
}
//Draw _stencil
}
void BeginStencilCommand::execute()
{
// increment the current layer
++_layer;
++_stencilCount;
auto state = getCurrentState();
// enable stencil use
if (1 == _stencilCount)
glEnable(GL_STENCIL_TEST);
// check for OpenGL error while enabling stencil test
CHECK_GL_ERROR_DEBUG();
// all bits on the stencil buffer are readonly, except the current layer bit,
// this means that operation like glClear or glStencilOp will be masked with this value
glStencilMask(state._mask_layer);
// manually save the depth test state
glGetBooleanv(GL_DEPTH_WRITEMASK, &state._depthWriteMask);
_stencilStates.push(state);
if (_clearStencil)
{
// disable depth test while drawing the stencil
//glDisable(GL_DEPTH_TEST);
// disable update to the depth buffer while drawing the stencil,
// as the stencil is not meant to be rendered in the real scene,
// it should never prevent something else to be drawn,
// only disabling depth buffer update should do
glDepthMask(GL_FALSE);
// manually clear the stencil buffer by drawing a fullscreen rectangle on it
// setup the stencil test func like this:
// for each pixel in the fullscreen rectangle
// never draw it into the frame buffer
// if not in inverted mode: set the current layer value to 0 in the stencil buffer
// if in inverted mode: set the current layer value to 1 in the stencil buffer
glStencilFunc(GL_NEVER, state._mask_layer, state._mask_layer);
glStencilOp(!_inverted ? GL_ZERO : GL_REPLACE, GL_KEEP, GL_KEEP);
// draw a fullscreen solid rectangle to clear the stencil buffer
drawFullScreenQuadClearStencil();
}
// setup the stencil test func like this:
// for each pixel in the stencil node
// never draw it into the frame buffer
// if not in inverted mode: set the current layer value to 1 in the stencil buffer
// if in inverted mode: set the current layer value to 0 in the stencil buffer
glStencilFunc(GL_NEVER, state._mask_layer, state._mask_layer);
glStencilOp(!_inverted ? GL_REPLACE : GL_ZERO, GL_KEEP, GL_KEEP);
// enable alpha test only if the alpha threshold < 1,
// indeed if alpha threshold == 1, every pixel will be drawn anyways
if (_alphaThreshold < 1) {
#if (CC_TARGET_PLATFORM == CC_PLATFORM_MAC || CC_TARGET_PLATFORM == CC_PLATFORM_WIN32 || CC_TARGET_PLATFORM == CC_PLATFORM_LINUX)
// manually save the alpha test state
// _currentAlphaTestEnabled = glIsEnabled(GL_ALPHA_TEST);
// glGetIntegerv(GL_ALPHA_TEST_FUNC, (GLint *)&_currentAlphaTestFunc);
// glGetFloatv(GL_ALPHA_TEST_REF, &_currentAlphaTestRef);
// enable alpha testing
glEnable(GL_ALPHA_TEST);
// check for OpenGL error while enabling alpha test
CHECK_GL_ERROR_DEBUG();
// pixel will be drawn only if greater than an alpha threshold
glAlphaFunc(GL_GREATER, _alphaThreshold);
#else
#endif
}
}
