Add the uniform buffer type

diff --git a/source/buffer.cpp b/source/buffer.cpp
index 1762b20482eaa45944d94529b7c044aa25c898b5..f09268741fc7705e69432c6ee18e5f03edb069ec 100644 (file)
--- a/source/buffer.cpp
+++ b/source/buffer.cpp
@@ -1,14 +1,16 @@
 #include <stdexcept>
+#include "arb_uniform_buffer_object.h"
 #include "arb_vertex_buffer_object.h"
-#include "extension.h"
 #include "buffer.h"
+#include "extension.h"
+#include "misc.h"
 
 using namespace std;
 
 namespace Msp {
 namespace GL {
 
-const Buffer *Buffer::bound[4] = { 0, 0, 0, 0 };
+const Buffer *Buffer::bound[5] = { 0, 0, 0, 0, 0 };
 
 Buffer::Buffer(BufferType t):
        type(t),
@@ -30,6 +32,8 @@ void Buffer::require_buffer_type(BufferType type)
        static RequireExtension _req_vbo("GL_ARB_vertex_buffer_object");
        if(type==PIXEL_PACK_BUFFER || type==PIXEL_UNPACK_BUFFER)
                static RequireExtension _req_pbo("GL_ARB_pixel_buffer_object");
+       else if(type==UNIFORM_BUFFER)
+               static RequireExtension _req_ubo("GL_ARB_uniform_buffer_object");
 }
 
 void Buffer::set_usage(BufferUsage u)
@@ -54,6 +58,11 @@ void Buffer::sub_data(unsigned off, unsigned sz, const void *d)
        restore(old, type);
 }
 
+BufferRange *Buffer::create_range(unsigned s, unsigned o)
+{
+       return new BufferRange(*this, s, o);
+}
+
 void Buffer::bind_to(BufferType t) const
 {
        if(t!=type)
@@ -76,6 +85,7 @@ const Buffer *&Buffer::binding(BufferType type)
        case ELEMENT_ARRAY_BUFFER: return bound[1];
        case PIXEL_PACK_BUFFER:    return bound[2];
        case PIXEL_UNPACK_BUFFER:  return bound[3];
+       case UNIFORM_BUFFER:       return bound[4];
        default: throw invalid_argument("Buffer::binding");
        }
 }
@@ -101,5 +111,70 @@ void Buffer::restore(const Buffer *buf, BufferType type)
        }
 }
 
+
+vector<const BufferRange *> BufferRange::bound_uniform;
+
+BufferRange::BufferRange(Buffer &b, unsigned o, unsigned s):
+       buffer(b),
+       offset(o),
+       size(s)
+{
+       if(o>buffer.get_size() || o+s>buffer.get_size())
+               throw out_of_range("BufferRange::BufferRange");
+}
+
+void BufferRange::data(const void *d)
+{
+       buffer.sub_data(offset, size, d);
+}
+
+void BufferRange::bind_to(BufferType t, unsigned i)
+{
+       if(t!=buffer.type)
+               Buffer::require_buffer_type(t);
+       // Intentionally using bitwise | to avoid short-circuiting
+       if(Buffer::set_current(t, &buffer) | set_current(t, i, this))
+               glBindBufferRange(t, i, buffer.id, offset, size);
+}
+
+void BufferRange::unbind_from(BufferType t, unsigned i)
+{
+       if(set_current(t, i, 0))
+       {
+               Buffer::set_current(t, 0);
+               glBindBufferBase(t, i, 0);
+       }
+}
+
+const BufferRange *&BufferRange::binding(BufferType type, unsigned index)
+{
+       if(type==UNIFORM_BUFFER)
+       {
+               if(index>=get_n_uniform_buffer_bindings())
+                       throw out_of_range("Buffer::binding");
+               if(bound_uniform.size()<=index)
+                       bound_uniform.resize(index+1);
+               return bound_uniform[index];
+       }
+       else
+               throw invalid_argument("Buffer::binding");
+}
+
+bool BufferRange::set_current(BufferType type, unsigned index, const BufferRange *buf)
+{
+       const BufferRange *&ptr = binding(type, index);
+       if(ptr==buf)
+               return false;
+
+       ptr = buf;
+       return true;
+}
+
+unsigned BufferRange::get_n_uniform_buffer_bindings()
+{
+       static unsigned count = get_i(GL_MAX_UNIFORM_BUFFER_BINDINGS);
+       return count;
+}
+
 } // namespace GL
 } // namespace Msp

diff --git a/source/buffer.h b/source/buffer.h
index 117f4ea6a1f5d0a699192ebdaffae808e400c68e..bd3a999eeab0d19da7aea2f94b90abae390f4a74 100644 (file)
--- a/source/buffer.h
+++ b/source/buffer.h
@@ -1,6 +1,7 @@
 #ifndef MSP_GL_BUFFER_H_
 #define MSP_GL_BUFFER_H_
 
+#include <vector>
 #include "gl.h"
 
 namespace Msp {
@@ -11,7 +12,8 @@ enum BufferType
        ARRAY_BUFFER         = GL_ARRAY_BUFFER_ARB,
        ELEMENT_ARRAY_BUFFER = GL_ELEMENT_ARRAY_BUFFER_ARB,
        PIXEL_PACK_BUFFER    = GL_PIXEL_PACK_BUFFER_ARB,
-       PIXEL_UNPACK_BUFFER  = GL_PIXEL_UNPACK_BUFFER_ARB
+       PIXEL_UNPACK_BUFFER  = GL_PIXEL_UNPACK_BUFFER_ARB,
+       UNIFORM_BUFFER       = GL_UNIFORM_BUFFER
 };
 
 enum BufferUsage
@@ -27,6 +29,8 @@ enum BufferUsage
        DYNAMIC_COPY = GL_DYNAMIC_COPY_ARB
 };
 
+class BufferRange;
+
 /**
 A buffer for storing data in GL memory.  Putting vertex and index data in
 buffers can improve rendering performance.  The VertexArray and Mesh classes
@@ -34,13 +38,15 @@ contain built-in support for buffers.
 */
 class Buffer
 {
+       friend class BufferRange;
+
 private:
        BufferType type;
        BufferUsage usage;
        unsigned id;
        unsigned size;
 
-       static const Buffer *bound[4];
+       static const Buffer *bound[5];
 
 public:
        Buffer(BufferType);
@@ -64,6 +70,8 @@ public:
 
        unsigned get_size() const { return size; }
 
+       BufferRange *create_range(unsigned, unsigned);
+
        /** Binds the buffer in its default slot. */
        void bind() const { bind_to(type); }
 
@@ -81,6 +89,7 @@ private:
        static void restore(const Buffer *, BufferType);
 };
 
+
 /**
 An adaptor for Buffer to make it compatible with Bind.
 */
@@ -98,6 +107,36 @@ public:
        static void unbind() { Buffer::unbind_from(T); }
 };
 
+
+/**
+A proxy for a subset of a buffer.  Can be bound for use with uniform blocks.
+*/
+class BufferRange
+{
+private:
+       Buffer &buffer;
+       unsigned offset;
+       unsigned size;
+
+       static std::vector<const BufferRange *> bound_uniform;
+
+public:
+       BufferRange(Buffer &, unsigned, unsigned);
+
+       void data(const void *);
+
+       void bind_to(BufferType, unsigned);
+
+       static const BufferRange *current(BufferType t, unsigned i) { return binding(t, i); }
+       static void unbind_from(BufferType, unsigned);
+private:
+       static const BufferRange *&binding(BufferType, unsigned);
+       static bool set_current(BufferType, unsigned, const BufferRange *);
+
+public:
+       static unsigned get_n_uniform_buffer_bindings();
+};
+
 } // namespace GL
 } // namespace Msp