source/framebuffer.h

   1 /* $Id$
   2
   3 This file is part of libmspgl
   4 Copyright © 2007  Mikko Rasa, Mikkosoft Productions
   5 Distributed under the LGPL
   6 */
   7
   8 #ifndef MSP_GL_FRAMEBUFFER_H_
   9 #define MSP_GL_FRAMEBUFFER_H_
  10
  11 #include <vector>
  12 #include "gl.h"
  13 #include "types.h"
  14
  15 namespace Msp {
  16 namespace GL {
  17
  18 class Renderbuffer;
  19 class Texture;
  20 class Texture2D;
  21
  22 enum FramebufferAttachment
  23 {
  24         COLOR_ATTACHMENT0  = GL_COLOR_ATTACHMENT0_EXT,
  25         COLOR_ATTACHMENT1  = GL_COLOR_ATTACHMENT1_EXT,
  26         COLOR_ATTACHMENT2  = GL_COLOR_ATTACHMENT2_EXT,
  27         COLOR_ATTACHMENT3  = GL_COLOR_ATTACHMENT3_EXT,
  28         DEPTH_ATTACHMENT   = GL_DEPTH_ATTACHMENT_EXT,
  29         STENCIL_ATTACHMENT = GL_STENCIL_ATTACHMENT_EXT
  30 };
  31
  32 enum FramebufferStatus
  33 {
  34         FRAMEBUFFER_INCOMPLETE_ATTACHMENT         = GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_EXT,
  35         FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT = GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT_EXT,
  36         FRAMEBUFFER_INCOMPLETE_DIMENSIONS         = GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT,
  37         FRAMEBUFFER_INCOMPLETE_FORMATS            = GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT,
  38         FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER        = GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT,
  39         FRAMEBUFFER_INCOMPLETE_READ_BUFFER        = GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT,
  40         FRAMEBUFFER_UNSUPPORTED                   = GL_FRAMEBUFFER_UNSUPPORTED_EXT,
  41         FRAMEBUFFER_COMPLETE                      = GL_FRAMEBUFFER_COMPLETE_EXT
  42 };
  43
  44 enum BufferBits
  45 {
  46         COLOR_BUFFER_BIT   = GL_COLOR_BUFFER_BIT,
  47         DEPTH_BUFFER_BIT   = GL_DEPTH_BUFFER_BIT,
  48         STENCIL_BUFFER_BIT = GL_STENCIL_BUFFER_BIT,
  49         ACCUM_BUFFER_BIT   = GL_ACCUM_BUFFER_BIT
  50 };
  51
  52 enum RWBuffer
  53 {
  54         NO_BUFFER      = GL_NONE,
  55         FRONT_LEFT     = GL_FRONT_LEFT,
  56         FRONT_RIGHT    = GL_FRONT_RIGHT,
  57         BACK_LEFT      = GL_BACK_LEFT,
  58         BACK_RIGHT     = GL_BACK_RIGHT,
  59         FRONT          = GL_FRONT,
  60         BACK           = GL_BACK,
  61         LEFT           = GL_LEFT,
  62         RIGHT          = GL_RIGHT,
  63         FRONT_AND_BACK = GL_FRONT_AND_BACK
  64 };
  65
  66 /**
  67 Framebuffer objects can be used to perform offscreen rendering.  The most
  68 common application is rendering to a texture, which can then be used for
  69 fullscreen shader effects.
  70
  71 A framebuffer consist of a number of logical buffers, such as color and depth
  72 buffers.  Renderbuffers and Textures can be attached to the logical buffers.  At
  73 least one image must be attached for the framebuffer to be usable.
  74
  75 Requires the GL_EXT_framebuffer_object extension.
  76 */
  77 class Framebuffer
  78 {
  79 private:
  80         struct Attachment
  81         {
  82                 FramebufferAttachment attachment;
  83                 GLenum type;
  84                 union
  85                 {
  86                         Renderbuffer *rbuf;
  87                         Texture *tex;
  88                 };
  89
  90                 Attachment(FramebufferAttachment);
  91                 Attachment &operator=(Renderbuffer &);
  92                 Attachment &operator=(Texture &);
  93         };
  94
  95         uint id;
  96         std::vector<Attachment> attachments;
  97         unsigned width;
  98         unsigned height;
  99
 100         static const Framebuffer *cur_fbo;
 101         static int sys_viewport[4];
 102
 103 public:
 104         Framebuffer();
 105         ~Framebuffer();
 106
 107         void bind() const;
 108
 109         void attach(FramebufferAttachment attch, Renderbuffer &rbuf);
 110         void attach(FramebufferAttachment attch, Texture2D &tex, int level);
 111         void detach(FramebufferAttachment attch);
 112
 113         /**
 114         Checks the completeness status of the framebuffer.  Returns
 115         FRAMEBUFFER_COMPLETE if the framebuffer is complate and can be rendered to,
 116         or one of the error status codes otherwise.
 117         */
 118         FramebufferStatus check_status() const;
 119
 120         static const Framebuffer *current();
 121         static void unbind();
 122 private:
 123         void maybe_bind() const;
 124         Attachment &get_or_create_attachment(FramebufferAttachment);
 125         void check_size();
 126 };
 127
 128 inline BufferBits operator|(BufferBits a, BufferBits b)
 129 { return static_cast<BufferBits>(static_cast<int>(a)|static_cast<int>(b)); }
 130
 131 void viewport(int, int, unsigned, unsigned);
 132 void clear(BufferBits);
 133 void draw_buffer(RWBuffer);
 134 void read_buffer(RWBuffer);
 135
 136 } // namespace GL
 137 } // namespace Msp
 138
 139 #endif