source/buffer.h

   1 #ifndef MSP_GL_BUFFER_H_
   2 #define MSP_GL_BUFFER_H_
   3
   4 #include <stdexcept>
   5 #include <string>
   6 #include <vector>
   7 #include "gl.h"
   8 #include <msp/gl/extensions/arb_pixel_buffer_object.h>
   9 #include <msp/gl/extensions/arb_vertex_buffer_object.h>
  10 #include <msp/gl/extensions/arb_uniform_buffer_object.h>
  11 #include <msp/gl/extensions/oes_mapbuffer.h>
  12
  13 namespace Msp {
  14 namespace GL {
  15
  16 class buffer_too_small: public std::logic_error
  17 {
  18 public:
  19         buffer_too_small(const std::string &w): std::logic_error(w) { }
  20         virtual ~buffer_too_small() throw() { }
  21 };
  22
  23 enum BufferType
  24 {
  25         ARRAY_BUFFER         = GL_ARRAY_BUFFER,
  26         ELEMENT_ARRAY_BUFFER = GL_ELEMENT_ARRAY_BUFFER,
  27         PIXEL_PACK_BUFFER    = GL_PIXEL_PACK_BUFFER,
  28         PIXEL_UNPACK_BUFFER  = GL_PIXEL_UNPACK_BUFFER,
  29         UNIFORM_BUFFER       = GL_UNIFORM_BUFFER
  30 };
  31
  32 enum BufferUsage
  33 {
  34         STREAM_DRAW  = GL_STREAM_DRAW,
  35         STREAM_READ  = GL_STREAM_READ,
  36         STREAM_COPY  = GL_STREAM_COPY,
  37         STATIC_DRAW  = GL_STATIC_DRAW,
  38         STATIC_READ  = GL_STATIC_READ,
  39         STATIC_COPY  = GL_STATIC_COPY,
  40         DYNAMIC_DRAW = GL_DYNAMIC_DRAW,
  41         DYNAMIC_READ = GL_DYNAMIC_READ,
  42         DYNAMIC_COPY = GL_DYNAMIC_COPY
  43 };
  44
  45 enum BufferAccess
  46 {
  47         READ_ONLY = GL_READ_ONLY,
  48         WRITE_ONLY = GL_WRITE_ONLY,
  49         READ_WRITE = GL_READ_WRITE
  50 };
  51
  52 class BufferRange;
  53
  54 /**
  55 A buffer for storing data in GL memory.  Putting vertex and index data in
  56 buffers can improve rendering performance.  The VertexArray, Mesh and
  57 UniformBlock classes contain built-in support for buffers.
  58 */
  59 class Buffer
  60 {
  61         friend class BufferRange;
  62
  63 private:
  64         BufferType type;
  65         BufferUsage usage;
  66         unsigned id;
  67         unsigned size;
  68
  69         static const Buffer *bound[5];
  70
  71 public:
  72         Buffer(BufferType);
  73         ~Buffer();
  74
  75 private:
  76         static void require_buffer_type(BufferType);
  77
  78 public:
  79         /** Returns the OpenGL ID of the buffer.  For internal use only. */
  80         unsigned get_id() const { return id; }
  81
  82         /** Returns the default binding type for the buffer. */
  83         BufferType get_type() const { return type; }
  84
  85         /** Sets the usage hint of the buffer.  It will take effect the next time
  86         the buffer's contents are defined. */
  87         void set_usage(BufferUsage);
  88
  89         /** Uploads data into the buffer, completely replacing any previous
  90         contents. */
  91         void data(unsigned, const void *);
  92
  93         /** Overwrites part of the buffer data with new data.  The buffer size can
  94         not be changed with this call. */
  95         void sub_data(unsigned, unsigned, const void *);
  96
  97         unsigned get_size() const { return size; }
  98
  99         void require_size(unsigned) const;
 100
 101         BufferRange *create_range(unsigned, unsigned);
 102
 103         void *map(BufferAccess);
 104         bool unmap();
 105
 106         /** Binds the buffer in its default slot. */
 107         void bind() const { bind_to(type); }
 108
 109         /** Binds the buffer in an alternate slot. */
 110         void bind_to(BufferType) const;
 111
 112         /** Unbinds the buffer from its default slot. */
 113         void unbind() const { unbind_from(type); }
 114
 115         static const Buffer *current(BufferType);
 116         static void unbind_from(BufferType);
 117 private:
 118         static const Buffer *&binding(BufferType);
 119         static bool set_current(BufferType, const Buffer *);
 120 };
 121
 122
 123 /**
 124 A proxy for a subset of a buffer.  Can be bound for use with uniform blocks.
 125 */
 126 class BufferRange
 127 {
 128 private:
 129         Buffer &buffer;
 130         unsigned offset;
 131         unsigned size;
 132
 133         static std::vector<const BufferRange *> bound_uniform;
 134
 135 public:
 136         BufferRange(Buffer &, unsigned, unsigned);
 137         ~BufferRange();
 138
 139         void data(const void *);
 140
 141         void bind_to(BufferType, unsigned);
 142
 143         static const BufferRange *current(BufferType t, unsigned i) { return binding(t, i); }
 144         static void unbind_from(BufferType, unsigned);
 145 private:
 146         static const BufferRange *&binding(BufferType, unsigned);
 147         static bool set_current(BufferType, unsigned, const BufferRange *);
 148
 149 public:
 150         static unsigned get_n_uniform_buffer_bindings();
 151         static unsigned get_uniform_buffer_alignment();
 152 };
 153
 154 } // namespace GL
 155 } // namespace Msp
 156
 157 #endif