Rework postprocessor handling in GLMakie

GLMakie/src/GLAbstraction/GLAbstraction.jl

@@ -44,7 +44,7 @@ import ModernGL.glScissor
 include("GLUtils.jl")
 
 include("shaderabstraction.jl")
-include("GLTypes.jl")
+include("GLTypes.jl") # also includes GLTexture and GLBuffer
 export GLProgram                # Shader/program object
 export Texture                  # Texture object, basically a 1/2/3D OpenGL data array
 export TextureParameters
@@ -99,4 +99,12 @@ export getUniformsInfo
 export getProgramInfo
 export getAttributesInfo
 
+include("GLFrameBuffer.jl")
+export GLRenderbuffer
+export GLFramebuffer
+export attach_colorbuffer, attach_depthbuffer, attach_stencilbuffer, attach_depthstencilbuffer
+export get_attachment, get_buffer
+export set_draw_buffers
+export check_framebuffer
+
 end # module

GLMakie/src/GLAbstraction/GLFrameBuffer.jl

@@ -0,0 +1,243 @@
+# For completion sake
+
+# Doesn't implement getindex, setindex etc I think?
+mutable struct GLRenderbuffer
+    id::GLuint
+    size::NTuple{2, Int}
+    format::GLenum
+    context::GLContext
+
+    function GLRenderbuffer(size, format::GLenum)
+        renderbuffer = GLuint[0]
+        glGenRenderbuffers(1, renderbuffer)
+        glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer[1])
+        glRenderbufferStorage(GL_RENDERBUFFER, format, size...)
+
+        obj = new(renderbuffer[1], size, format, current_context())
+        finalizer(free, obj)
+
+        return obj
+    end
+end
+
+function bind(buffer::GLRenderbuffer)
+    if buffer.id == 0
+        error("Binding freed GLRenderbuffer")
+    end
+    glBindRenderbuffer(GL_RENDERBUFFER, buffer.id)
+    return
+end
+
+function unsafe_free(x::GLRenderbuffer)
+    # don't free if already freed
+    x.id == 0 && return
+    # don't free from other context
+    GLAbstraction.context_alive(x.context) || return
+    GLAbstraction.switch_context!(x.context)
+    id = Ref(x.id)
+    glDeleteRenderbuffers(1, id)
+    x.id = 0
+    return
+end
+
+
+# TODO: Add RenderBuffer, resize!() with renderbuffer (recreate?)
+mutable struct GLFramebuffer
+    id::GLuint
+    size::NTuple{2, Int}
+
+    context::GLContext
+
+    name2idx::Dict{Symbol, Int}
+    attachments::Vector{GLenum}
+    buffers::Vector{Texture}
+    counter::UInt32 # for color attachments
+
+    function GLFramebuffer(size::NTuple{2, Int})
+        # Create framebuffer
+        id = glGenFramebuffers()
+        glBindFramebuffer(GL_FRAMEBUFFER, id)
+
+        obj = new(
+            id, size, current_context(),
+            Dict{Symbol, Int}(), GLenum[], Texture[], UInt32(0)
+        )
+        finalizer(free, obj)
+
+        return obj
+    end
+end
+
+function bind(fb::GLFramebuffer, target = fb.id)
+    if fb.id == 0
+        error("Binding freed GLFramebuffer")
+    end
+    glBindFramebuffer(GL_FRAMEBUFFER, target)
+    return
+end
+
+"""
+    draw_buffers(fb::GLFrameBuffer[, N::Int])
+
+Activates the first N color buffers attached to the given GLFramebuffer. If N
+is not given all color attachments are activated.
+"""
+function set_draw_buffers(fb::GLFramebuffer, N::Integer = fb.counter)
+    bind(fb)
+    glDrawBuffers(N, fb.attachments)
+end
+function set_draw_buffers(fb::GLFramebuffer, key::Symbol)
+    bind(fb)
+    glDrawBuffer(get_attachment(fb, key))
+end
+function set_draw_buffers(fb::GLFramebuffer, keys::Symbol...)
+    bind(fb)
+    glDrawBuffer(get_attachment.(Ref(fb), keys))
+end
+
+function unsafe_free(x::GLFramebuffer)
+    # don't free if already freed
+    x.id == 0 && return
+    # don't free from other context
+    GLAbstraction.context_alive(x.context) || return
+    GLAbstraction.switch_context!(x.context)
+    id = Ref(x.id)
+    glDeleteFramebuffers(1, id)
+    x.id = 0
+    return
+end
+
+Base.size(fb::GLFramebuffer) = fb.size
+Base.haskey(fb::GLFramebuffer, key::Symbol) = haskey(fb.name2idx, key)
+
+function Base.resize!(fb::GLFramebuffer, w::Int, h::Int)
+    (w > 0 && h > 0 && (w, h) != size(fb)) || return
+    for buffer in fb.buffers
+        resize_nocopy!(buffer, (w, h))
+    end
+    fb.size = (w, h)
+    return
+end
+
+function get_next_colorbuffer_attachment(fb::GLFramebuffer)
+    if fb.counter >= 15
+        error("The framebuffer has exhausted its maximum number of color attachments.")
+    end
+    attachment = GL_COLOR_ATTACHMENT0 + fb.counter
+    fb.counter += 1
+    return (fb.counter, attachment)
+end
+
+function attach_colorbuffer(fb::GLFramebuffer, key::Symbol, buffer)
+    return attach(fb, key, buffer, get_next_colorbuffer_attachment(fb)...)
+end
+function attach_depthbuffer(fb::GLFramebuffer, key::Symbol, buffer)
+    return attach(fb, key, buffer, length(fb.attachments) + 1, GL_DEPTH_ATTACHMENT)
+end
+function attach_stencilbuffer(fb::GLFramebuffer, key::Symbol, buffer)
+    return attach(fb, key, buffer, length(fb.attachments) + 1, GL_STENCIL_ATTACHMENT)
+end
+function attach_depthstencilbuffer(fb::GLFramebuffer, key::Symbol, buffer)
+    return attach(fb, key, buffer, length(fb.attachments) + 1, GL_DEPTH_STENCIL_ATTACHMENT)
+end
+
+function attach(fb::GLFramebuffer, key::Symbol, buffer, idx::Integer, attachment::GLenum)
+    haskey(fb, key) && error("Cannot attach $key to Framebuffer because it is already set.")
+    if attachment in fb.attachments
+        if attachment == GL_DEPTH_ATTACHMENT
+            type = "depth"
+        elseif attachment == GL_STENCIL_ATTACHMENT
+            type = "stencil"
+        elseif attachment == GL_DEPTH_STENCIL_ATTACHMENT
+            type = "depth-stencil"
+        else
+            type = "color"
+        end
+        error("Cannot attach $key as a $type attachment as it is already attached.")
+    end
+
+    bind(fb)
+    gl_attach(buffer, attachment)
+    # keep depth/stenctil/depth_stencil at end so that we can directly use
+    # fb.attachments when setting drawbuffers
+    for (k, v) in fb.name2idx
+        fb.name2idx[k] = ifelse(v < idx, v, v+1)
+    end
+    fb.name2idx[key] = idx
+    insert!(fb.attachments, idx, attachment)
+    insert!(fb.buffers, idx, buffer)
+    return attachment
+end
+
+function gl_attach(t::Texture{T, 2}, attachment::GLenum) where {T}
+    glFramebufferTexture2D(GL_FRAMEBUFFER, attachment, GL_TEXTURE_2D, t.id, 0)
+end
+function gl_attach(buffer::RenderBuffer, attachment::GLenum)
+    glFramebufferRenderbuffer(GL_FRAMEBUFFER, attachment, GL_RENDERBUFFER, buffer)
+end
+
+get_attachment(fb::GLFramebuffer, key::Symbol) = fb.attachments[fb.name2idx[key]]
+get_buffer(fb::GLFramebuffer, key::Symbol) = fb.buffers[fb.name2idx[key]]
+
+function enum_to_error(s)
+    s == GL_FRAMEBUFFER_COMPLETE && return
+    s == GL_FRAMEBUFFER_UNDEFINED &&
+        error("GL_FRAMEBUFFER_UNDEFINED: The specified framebuffer is the default read or draw framebuffer, but the default framebuffer does not exist.")
+    s == GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT &&
+        error("GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT: At least one of the framebuffer attachment points is incomplete.")
+    s == GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT &&
+        error("GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT: The framebuffer does not have at least one image attached to it.")
+    s == GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER &&
+        error("GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER: The value of GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is GL_NONE for any color attachment point(s) specified by GL_DRAW_BUFFERi.")
+    s == GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER &&
+        error("GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER: GL_READ_BUFFER is not GL_NONE and the value of GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE is GL_NONE for the color attachment point specified by GL_READ_BUFFER.")
+    s == GL_FRAMEBUFFER_UNSUPPORTED &&
+        error("GL_FRAMEBUFFER_UNSUPPORTED: The combination of internal formats of the attached images violates a driver implementation-dependent set of restrictions. Check your OpenGL driver!")
+    s == GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE &&
+        error("GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE: The value of GL_RENDERBUFFER_SAMPLES is not the same for all attached renderbuffers;
+if the value of GL_TEXTURE_SAMPLES is not the same for all attached textures; or, if the attached images consist of a mix of renderbuffers and textures,
+    the value of GL_RENDERBUFFER_SAMPLES does not match the value of GL_TEXTURE_SAMPLES.
+    GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE is also returned if the value of GL_TEXTURE_FIXED_SAMPLE_LOCATIONS is not consistent across all attached textures;
+        or, if the attached images include a mix of renderbuffers and textures, the value of GL_TEXTURE_FIXED_SAMPLE_LOCATIONS is not set to GL_TRUE for all attached textures.")
+    s == GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS &&
+        error("GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS: Any framebuffer attachment is layered, and any populated attachment is not layered, or if all populated color attachments are not from textures of the same target.")
+    return error("Unknown framebuffer completion error code: $s")
+end
+
+function check_framebuffer()
+    status = glCheckFramebufferStatus(GL_FRAMEBUFFER)
+    return enum_to_error(status)
+end
+
+function Base.show(io::IO, fb::GLFramebuffer)
+    X, Y = fb.size
+    print(io, "$X×$Y GLFrameBuffer(:")
+    join(io, string.(keys(fb.name2idx)), ", :")
+    print(io, ") with id ", fb.id)
+end
+
+function attachment_enum_to_string(x::GLenum)
+    x == GL_DEPTH_ATTACHMENT && return "GL_DEPTH_ATTACHMENT"
+    x == GL_STENCIL_ATTACHMENT && return "GL_STENCIL_ATTACHMENT"
+    i = Int(x - GL_COLOR_ATTACHMENT0)
+    return "GL_COLOR_ATTACHMENT$i"
+end
+
+function Base.show(io::IO, ::MIME"text/plain", fb::GLFramebuffer)
+    X, Y = fb.size
+    print(io, "$X×$Y GLFrameBuffer() with id ", fb.id)
+
+    ks = collect(keys(fb.name2idx))
+    sort!(ks, by = k -> fb.name2idx[k])
+    key_strings = [":$k" for k in ks]
+    key_pad = mapreduce(length, max, key_strings)
+    key_strings = rpad.(key_strings, key_pad)
+
+    attachments = attachment_enum_to_string(fb.attachments)
+    attachment_pad = mapreduce(length, max, attachments)
+    attachments = rpad.(attachments, attachment_pad)
+
+    for (key, attachment, buffer) in zip(key_strings, attachments, fb.buffers)
+        print(io, "\n  ", key, " => ", attachment, " ::", typeof(buffer))
+    end
+end