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 "bindable.h"
  13 #include "gl.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: public Bindable<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         unsigned id;
  96         std::vector<Attachment> attachments;
  97         unsigned width;
  98         unsigned height;
  99
 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 void unbind();
 120 private:
 121         void maybe_bind() const;
 122         Attachment &get_or_create_attachment(FramebufferAttachment);
 123         void check_size();
 124 };
 125
 126 inline BufferBits operator|(BufferBits a, BufferBits b)
 127 { return static_cast<BufferBits>(static_cast<int>(a)|static_cast<int>(b)); }
 128
 129 void viewport(int, int, unsigned, unsigned);
 130 void clear(BufferBits);
 131 void draw_buffer(RWBuffer);
 132 void read_buffer(RWBuffer);
 133
 134 } // namespace GL
 135 } // namespace Msp
 136
 137 #endif