How could I create a FBO with stencil buffer in OpenGL ES 2.0?
- by Alphones
I need stencil buffer on 3GS to render planar shadow, and polygon
offset won't work prefect, still has z-fighting problem. So I use
stencil buffer to make the shadow correct, it works on win32 gles2
emulator, but not on iPhone. After I added a post effect to the whole
scene. The stencil buffer won't work even on win32 gles2 emulator.
And I tried to attach a stencil buffer to FBO, buf the screen turns to
black. Here's my code,
glGenRenderbuffers(1, &dbo); // depth buffer
glBindRenderbuffer(GL_RENDERBUFFER, dbo);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24_OES,
widthGL, heightGL);
glGenRenderbuffers(1, &sbo); // stencil buffer
glBindRenderbuffer(GL_RENDERBUFFER, sbo);
glRenderbufferStorage(GL_RENDERBUFFER, GL_STENCIL_INDEX8, widthGL,
heightGL);
glGenFramebuffers(1, &fbo);
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
GL_TEXTURE_2D, tex, 0);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
GL_RENDERBUFFER, dbo);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
GL_RENDERBUFFER, sbo); // this make the whole screen black.
The eglContext is created with STENCIL_SIZE=8, it works without a RTT.
I tried to change the RenderbufferStorage for both depth buffer and
stencil buffer, but none of them works.
Is there anything I have missed? Does the stencil buffer pack with
depth buffer? (I cannot find things like GL_DEPTH24_STENCIL8 ...)
