nkeynes@352: /**
nkeynes@561:  * $Id$
nkeynes@352:  *
nkeynes@352:  * GL framebuffer-based driver shell. This requires the EXT_framebuffer_object
nkeynes@352:  * extension, but is much nicer/faster/etc than pbuffers when it's available.
nkeynes@352:  * This is (optionally) used indirectly by the top-level GLX driver.
nkeynes@352:  *
nkeynes@352:  * Strategy-wise, we maintain 2 framebuffers with up to 4 target colour
nkeynes@352:  * buffers a piece. Effectively this reserves one fb for display output,
nkeynes@352:  * and the other for texture output (each fb has a single size).
nkeynes@352:  *
nkeynes@352:  * Copyright (c) 2005 Nathan Keynes.
nkeynes@352:  *
nkeynes@352:  * This program is free software; you can redistribute it and/or modify
nkeynes@352:  * it under the terms of the GNU General Public License as published by
nkeynes@352:  * the Free Software Foundation; either version 2 of the License, or
nkeynes@352:  * (at your option) any later version.
nkeynes@352:  *
nkeynes@352:  * This program is distributed in the hope that it will be useful,
nkeynes@352:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
nkeynes@352:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nkeynes@352:  * GNU General Public License for more details.
nkeynes@352:  */
nkeynes@352: 
nkeynes@424: #define GL_GLEXT_PROTOTYPES 1
nkeynes@424: 
nkeynes@477: #include <stdlib.h>
nkeynes@477: #include "lxdream.h"
nkeynes@352: #include "display.h"
nkeynes@635: #include "drivers/video_gl.h"
nkeynes@635: #include "pvr2/glutil.h"
nkeynes@352: 
nkeynes@1210: #if defined(HAVE_OPENGL_FBO) || defined(HAVE_OPENGL_FBO_EXT)
nkeynes@656: 
nkeynes@352: #define MAX_FRAMEBUFFERS 2
nkeynes@798: #define MAX_TEXTURES_PER_FB 16
nkeynes@352: 
nkeynes@805: static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height, GLuint tex_id );
nkeynes@352: static void gl_fbo_destroy_render_buffer( render_buffer_t buffer );
nkeynes@352: static gboolean gl_fbo_set_render_target( render_buffer_t buffer );
nkeynes@805: static void gl_fbo_finish_render( render_buffer_t buffer );
nkeynes@669: static void gl_fbo_display_render_buffer( render_buffer_t buffer );
nkeynes@477: static void gl_fbo_load_frame_buffer( frame_buffer_t frame, render_buffer_t buffer );
nkeynes@669: static void gl_fbo_display_blank( uint32_t colour );
nkeynes@1166: static gboolean gl_fbo_test_framebuffer( );
nkeynes@477: static gboolean gl_fbo_read_render_buffer( unsigned char *target, render_buffer_t buffer, int rowstride, int format );
nkeynes@352: 
nkeynes@352: extern uint32_t video_width, video_height;
nkeynes@352: 
nkeynes@352: /**
nkeynes@352:  * Framebuffer info structure
nkeynes@352:  */
nkeynes@352: struct gl_fbo_info {
nkeynes@352:     GLuint fb_id;
nkeynes@352:     GLuint depth_id;
nkeynes@352:     GLuint stencil_id;
nkeynes@352:     GLuint tex_ids[MAX_TEXTURES_PER_FB];
nkeynes@352:     int width, height;
nkeynes@352: };
nkeynes@352: 
nkeynes@798: static GLint gl_fbo_max_attachments = 0;
nkeynes@1251: static GLint gl_fbo_depth_component;
nkeynes@863: static gboolean gl_fbo_have_packed_stencil = FALSE;
nkeynes@352: static struct gl_fbo_info fbo[MAX_FRAMEBUFFERS];
nkeynes@798: 
nkeynes@1210: #define ATTACHMENT_POINT(n) (GL_COLOR_ATTACHMENT0+(n))
nkeynes@352: static int last_used_fbo;
nkeynes@352: 
nkeynes@352: gboolean gl_fbo_is_supported()
nkeynes@352: {
nkeynes@1245:     return isGLExtensionSupported("GL_EXT_framebuffer_object") || isOpenGLES2();
nkeynes@352: }
nkeynes@352: 
nkeynes@352: /**
nkeynes@352:  * Construct the initial frame buffers and allocate ids for everything.
nkeynes@352:  * The render handling driver methods are set to the fbo versions.
nkeynes@352:  */
nkeynes@352: void gl_fbo_init( display_driver_t driver ) 
nkeynes@352: {
nkeynes@352:     int i,j;
nkeynes@424:     GLuint fbids[MAX_FRAMEBUFFERS];
nkeynes@424:     GLuint rbids[MAX_FRAMEBUFFERS*2]; /* depth buffer, stencil buffer per fb */
nkeynes@736: 
nkeynes@1223:     gl_fbo_max_attachments = glGetMaxColourAttachments();
nkeynes@1210:     glGenFramebuffers( MAX_FRAMEBUFFERS, &fbids[0] );
nkeynes@1210:     glGenRenderbuffers( MAX_FRAMEBUFFERS*2, &rbids[0] );
nkeynes@352:     for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
nkeynes@736:         fbo[i].fb_id = fbids[i];
nkeynes@736:         fbo[i].depth_id = rbids[i*2];
nkeynes@736:         fbo[i].stencil_id = rbids[i*2+1];
nkeynes@736:         fbo[i].width = -1;
nkeynes@736:         fbo[i].height = -1;
nkeynes@736:         for( j=0; j<MAX_TEXTURES_PER_FB; j++ ) {
nkeynes@736:             fbo[i].tex_ids[j] = -1;
nkeynes@736:         }
nkeynes@352:     }
nkeynes@352:     last_used_fbo = 0;
nkeynes@352: 
nkeynes@863:     if( isGLExtensionSupported("GL_EXT_packed_depth_stencil" ) ) {
nkeynes@863:         driver->capabilities.stencil_bits = 8;
nkeynes@863:         gl_fbo_have_packed_stencil = TRUE;
nkeynes@863:     } else {
nkeynes@863:         driver->capabilities.stencil_bits = 0;
nkeynes@863:         gl_fbo_have_packed_stencil = FALSE;
nkeynes@863:         WARN( "Packed depth stencil not available - disabling shadow volumes" );
nkeynes@863:     }
nkeynes@1251:     if( driver->capabilities.depth_bits >= 24 ) {
nkeynes@1251:         gl_fbo_depth_component = GL_DEPTH_COMPONENT24;
nkeynes@1251:     } else {
nkeynes@1251:         gl_fbo_depth_component = GL_DEPTH_COMPONENT16;
nkeynes@1251:     }
nkeynes@863: 
nkeynes@352:     driver->create_render_buffer = gl_fbo_create_render_buffer;
nkeynes@352:     driver->destroy_render_buffer = gl_fbo_destroy_render_buffer;
nkeynes@352:     driver->set_render_target = gl_fbo_set_render_target;
nkeynes@805:     driver->finish_render = gl_fbo_finish_render;
nkeynes@352:     driver->display_render_buffer = gl_fbo_display_render_buffer;
nkeynes@477:     driver->load_frame_buffer = gl_fbo_load_frame_buffer;
nkeynes@352:     driver->display_blank = gl_fbo_display_blank;
nkeynes@352:     driver->read_render_buffer = gl_fbo_read_render_buffer;
nkeynes@445: 
nkeynes@1166:     gl_fbo_test_framebuffer();
nkeynes@1210:     glBindFramebuffer(GL_FRAMEBUFFER, 0);
nkeynes@352: }
nkeynes@352: 
nkeynes@352: void gl_fbo_shutdown()
nkeynes@352: {
nkeynes@352:     int i;
nkeynes@1210:     glBindFramebuffer( GL_FRAMEBUFFER, 0 );
nkeynes@352:     for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
nkeynes@1210:         glDeleteFramebuffers( 1, &fbo[i].fb_id );
nkeynes@1210:         glDeleteRenderbuffers( 2, &fbo[i].depth_id );
nkeynes@352:     }
nkeynes@352: }
nkeynes@352: 
nkeynes@863: static void gl_fbo_setup_framebuffer( int bufno, int width, int height )
nkeynes@352: {
nkeynes@877:     int i;
nkeynes@1210:     glBindFramebuffer(GL_FRAMEBUFFER, fbo[bufno].fb_id);
nkeynes@877: 
nkeynes@877:     /* Clear out any existing texture attachments */
nkeynes@877:     for( i=0; i<gl_fbo_max_attachments; i++ ) {
nkeynes@877:         if( fbo[bufno].tex_ids[i] != -1 ) {
nkeynes@1210:             glFramebufferTexture2D(GL_FRAMEBUFFER, ATTACHMENT_POINT(i),
nkeynes@1222:                     GL_TEXTURE_2D, 0, 0);
nkeynes@877:             fbo[bufno].tex_ids[i] = -1;
nkeynes@877:         }
nkeynes@877:     }
nkeynes@877: 
nkeynes@877:     /* Setup the renderbuffers */
nkeynes@863:     if( gl_fbo_have_packed_stencil ) {
nkeynes@1210:         glBindRenderbuffer(GL_RENDERBUFFER, fbo[bufno].depth_id);
nkeynes@1222:         glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
nkeynes@1210:         glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
nkeynes@1210:                                      GL_RENDERBUFFER, fbo[bufno].depth_id);
nkeynes@1210:         glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
nkeynes@1210:                                      GL_RENDERBUFFER, fbo[bufno].depth_id);
nkeynes@863:     } else {
nkeynes@1210:         glBindRenderbuffer(GL_RENDERBUFFER, fbo[bufno].depth_id);
nkeynes@1251:         glRenderbufferStorage(GL_RENDERBUFFER, gl_fbo_depth_component, width, height);
nkeynes@1210:         glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
nkeynes@1210:                                      GL_RENDERBUFFER, fbo[bufno].depth_id);
nkeynes@863:         /* In theory you could attach a separate stencil buffer. In practice this 
nkeynes@863:          * isn't actually supported by any hardware I've had access to, so we're
nkeynes@863:          * stencil-less.
nkeynes@863:          */
nkeynes@863:     }
nkeynes@352:     fbo[bufno].width = width;
nkeynes@352:     fbo[bufno].height = height;
nkeynes@352: }
nkeynes@352: 
nkeynes@863: static int gl_fbo_get_framebuffer( int width, int height ) 
nkeynes@352: {
nkeynes@352:     int bufno = -1, i;
nkeynes@352:     /* find a compatible framebuffer context */
nkeynes@352:     for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
nkeynes@736:         if( fbo[i].width == -1 && bufno == -1 ) {
nkeynes@736:             bufno = i;
nkeynes@736:         } else if( fbo[i].width == width && fbo[i].height == height ) {
nkeynes@736:             bufno = i;
nkeynes@736:             break;
nkeynes@736:         }
nkeynes@352:     }
nkeynes@352:     if( bufno == -1 ) {
nkeynes@736:         bufno = last_used_fbo + 1;
nkeynes@877:         if( bufno >= MAX_FRAMEBUFFERS ) {
nkeynes@736:             bufno = 0;
nkeynes@736:         }
nkeynes@736:         last_used_fbo = bufno;
nkeynes@352:     }
nkeynes@352:     if( fbo[bufno].width == width && fbo[bufno].height == height ) {
nkeynes@1210:         glBindFramebuffer( GL_FRAMEBUFFER, fbo[bufno].fb_id );
nkeynes@352:     } else {
nkeynes@736:         gl_fbo_setup_framebuffer( bufno, width, height );
nkeynes@352:     } 
nkeynes@352:     return bufno;
nkeynes@352: }
nkeynes@352: 
nkeynes@352: /**
nkeynes@352:  * Attach a texture to the framebuffer. The texture must already be initialized
nkeynes@352:  * to the correct dimensions etc.
nkeynes@352:  */
nkeynes@352: static GLint gl_fbo_attach_texture( int fbo_no, GLint tex_id ) {
nkeynes@352:     int attach = -1, i;
nkeynes@798:     for( i=0; i<gl_fbo_max_attachments; i++ ) {
nkeynes@736:         if( fbo[fbo_no].tex_ids[i] == tex_id ) {
nkeynes@1228: #ifdef HAVE_OPENGL_DRAW_BUFFER
nkeynes@798:             glDrawBuffer(ATTACHMENT_POINT(i));
nkeynes@798:             glReadBuffer(ATTACHMENT_POINT(i)); 
nkeynes@1228: #endif
nkeynes@798:             return ATTACHMENT_POINT(i); // already attached
nkeynes@736:         } else if( fbo[fbo_no].tex_ids[i] == -1 && attach == -1 ) {
nkeynes@736:             attach = i;
nkeynes@736:         }
nkeynes@352:     }
nkeynes@352:     if( attach == -1 ) {
nkeynes@736:         attach = 0;
nkeynes@352:     }
nkeynes@352:     fbo[fbo_no].tex_ids[attach] = tex_id;
nkeynes@1222:     glBindTexture( GL_TEXTURE_2D, 0 ); // Ensure the output texture is unbound
nkeynes@1210:     glFramebufferTexture2D(GL_FRAMEBUFFER, ATTACHMENT_POINT(attach), 
nkeynes@1222:                               GL_TEXTURE_2D, tex_id, 0 );
nkeynes@352:     /* Set draw/read buffers by default */
nkeynes@1228: #ifdef HAVE_OPENGL_DRAW_BUFFER    
nkeynes@798:     glDrawBuffer(ATTACHMENT_POINT(attach));
nkeynes@798:     glReadBuffer(ATTACHMENT_POINT(attach)); 
nkeynes@1228: #endif
nkeynes@352: 
nkeynes@1166:     return ATTACHMENT_POINT(attach);
nkeynes@1166: }
nkeynes@352: 
nkeynes@1166: static gboolean gl_fbo_test_framebuffer( )
nkeynes@1166: {
nkeynes@1166:     gboolean result = TRUE;
nkeynes@1166:     glGetError(); /* Clear error state just in case */
nkeynes@1166:     render_buffer_t buffer = gl_fbo_create_render_buffer( 640, 480, 0 );
nkeynes@1166:     gl_fbo_set_render_target(buffer);
nkeynes@1166: 
nkeynes@1210:     GLint status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
nkeynes@1210:     if( status != GL_FRAMEBUFFER_COMPLETE ) {
nkeynes@736:         ERROR( "Framebuffer failure: %x", status );
nkeynes@1166:         result = FALSE;
nkeynes@1166:     }
nkeynes@1166:     if( result ) {
nkeynes@1166:         result = gl_check_error( "Setting up framebuffer" );
nkeynes@352:     }
nkeynes@352: 
nkeynes@1166:     gl_fbo_destroy_render_buffer( buffer );
nkeynes@1166:     return result;
nkeynes@352: }
nkeynes@352: 
nkeynes@805: static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height, GLuint tex_id )
nkeynes@352: {
nkeynes@352:     render_buffer_t buffer = calloc( sizeof(struct render_buffer), 1 );
nkeynes@352:     buffer->width = width;
nkeynes@352:     buffer->height = height;
nkeynes@805:     buffer->tex_id = tex_id;
nkeynes@805:     if( tex_id == 0 ) {
nkeynes@805:         GLuint tex;
nkeynes@805:         glGenTextures( 1, &tex );
nkeynes@805:         buffer->buf_id = tex;
nkeynes@805:     } else {
nkeynes@805:         buffer->buf_id = tex_id;
nkeynes@1222:         glBindTexture( GL_TEXTURE_2D, tex_id );
nkeynes@805:     }
nkeynes@1222:     glBindTexture( GL_TEXTURE_2D, buffer->buf_id );
nkeynes@1222:     glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL );
nkeynes@1223:     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
nkeynes@1223:     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
nkeynes@1222:     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
nkeynes@1222:     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
nkeynes@352:     return buffer;
nkeynes@352: }
nkeynes@352: 
nkeynes@805: /**
nkeynes@805:  * Ensure the texture in the given render buffer is not attached to a 
nkeynes@805:  * framebuffer (ie, so we can safely use it as a texture during the rendering
nkeynes@805:  * cycle, or before deletion).
nkeynes@805:  */
nkeynes@805: static void gl_fbo_detach_render_buffer( render_buffer_t buffer )
nkeynes@805: {
nkeynes@805:     int i,j;
nkeynes@805:     for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
nkeynes@805:         if( fbo[i].width == buffer->width && fbo[i].height == buffer->height ) {
nkeynes@805:             for( j=0; j<gl_fbo_max_attachments; j++ ) {
nkeynes@805:                 if( fbo[i].tex_ids[j] == buffer->buf_id ) {
nkeynes@1210:                     glBindFramebuffer(GL_FRAMEBUFFER, fbo[i].fb_id);
nkeynes@1210:                     glFramebufferTexture2D(GL_FRAMEBUFFER, ATTACHMENT_POINT(j), 
nkeynes@1222:                                               GL_TEXTURE_2D, GL_NONE, 0 );
nkeynes@805:                     fbo[i].tex_ids[j] = -1;
nkeynes@805:                     return;
nkeynes@805:                 }                    
nkeynes@805:             }
nkeynes@805:             break;
nkeynes@805:         }
nkeynes@805:     }
nkeynes@805: }
nkeynes@805: 
nkeynes@352: static void gl_fbo_destroy_render_buffer( render_buffer_t buffer )
nkeynes@352: {
nkeynes@805:     gl_fbo_detach_render_buffer( buffer );
nkeynes@805: 
nkeynes@805:     if( buffer->buf_id != buffer->tex_id ) {
nkeynes@805:         // If tex_id was set at buffer creation, we don't own the texture.
nkeynes@805:         // Otherwise, delete it now.
nkeynes@805:         GLuint tex = buffer->buf_id; 
nkeynes@805:         glDeleteTextures( 1, &tex );
nkeynes@352:     }
nkeynes@352:     buffer->buf_id = 0;
nkeynes@805:     buffer->tex_id = 0;
nkeynes@352:     free( buffer );
nkeynes@352: }
nkeynes@352: 
nkeynes@352: static gboolean gl_fbo_set_render_target( render_buffer_t buffer )
nkeynes@352: {
nkeynes@352:     int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
nkeynes@424:     gl_fbo_attach_texture( fb, buffer->buf_id );
nkeynes@352:     /* setup the gl context */
nkeynes@352:     glViewport( 0, 0, buffer->width, buffer->height );
nkeynes@736: 
nkeynes@352:     return TRUE;
nkeynes@352: }
nkeynes@352: 
nkeynes@805: static void gl_fbo_finish_render( render_buffer_t buffer )
nkeynes@805: {
nkeynes@805:     glFinish();
nkeynes@805:     gl_fbo_detach_render_buffer(buffer);
nkeynes@805: }
nkeynes@805: 
nkeynes@352: /**
nkeynes@352:  * Render the texture holding the given buffer to the front window
nkeynes@352:  * buffer.
nkeynes@352:  */
nkeynes@669: static void gl_fbo_display_render_buffer( render_buffer_t buffer )
nkeynes@352: {
nkeynes@477:     gl_fbo_detach();
nkeynes@477:     gl_display_render_buffer( buffer );
nkeynes@1251:     if( display_driver->swap_buffers )
nkeynes@1251:         display_driver->swap_buffers();
nkeynes@352: }
nkeynes@352: 
nkeynes@477: static void gl_fbo_load_frame_buffer( frame_buffer_t frame, render_buffer_t buffer )
nkeynes@477: {
nkeynes@477:     gl_fbo_detach();
nkeynes@1298:     gl_frame_buffer_to_tex( frame, buffer->buf_id );
nkeynes@477: }
nkeynes@477: 
nkeynes@669: static void gl_fbo_display_blank( uint32_t colour )
nkeynes@477: {
nkeynes@477:     gl_fbo_detach();
nkeynes@669:     gl_display_blank( colour );
nkeynes@1251:     if( display_driver->swap_buffers )
nkeynes@1251:         display_driver->swap_buffers();
nkeynes@477: }
nkeynes@477: 
nkeynes@477: void gl_fbo_detach()
nkeynes@352: {
nkeynes@1210:     glBindFramebuffer( GL_FRAMEBUFFER, 0 );
nkeynes@1076:     /* Make sure texture attachment is not a current draw/read buffer */
nkeynes@1228: #ifdef HAVE_OPENGL_DRAW_BUFFER
nkeynes@352:     glDrawBuffer( GL_FRONT );
nkeynes@352:     glReadBuffer( GL_FRONT );
nkeynes@1228: #endif
nkeynes@477: }    
nkeynes@352: 
nkeynes@477: static gboolean gl_fbo_read_render_buffer( unsigned char *target, render_buffer_t buffer, 
nkeynes@736:                                            int rowstride, int format )
nkeynes@352: {
nkeynes@352:     int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
nkeynes@424:     gl_fbo_attach_texture( fb, buffer->buf_id );
nkeynes@477:     return gl_read_render_buffer( target, buffer, rowstride, format );
nkeynes@352: }
nkeynes@352: 
nkeynes@656: #else
nkeynes@656: gboolean gl_fbo_is_supported()
nkeynes@656: {
nkeynes@656:     return FALSE;
nkeynes@656: }
nkeynes@656: 
nkeynes@656: void gl_fbo_init( display_driver_t driver ) 
nkeynes@656: {
nkeynes@656: }
nkeynes@656: 
nkeynes@656: #endif