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