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filename src/drivers/gl_fbo.c
changeset 352:f0df7a6d4703
next424:421d68e78c46
author nkeynes
date Sun Feb 11 10:09:32 2007 +0000 (14 years ago)
permissions -rw-r--r--
last change Bug 27: Implement opengl framebuffer objects
Rewrite much of the final video output stage. Now uses generic "render
buffers", implemented on GL using framebuffer objects + textures.
file annotate diff log raw 
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000

     1.2 +++ b/src/drivers/gl_fbo.c	Sun Feb 11 10:09:32 2007 +0000

     1.3 @@ -0,0 +1,299 @@

     1.4 +/**

     1.5 + * $Id: gl_fbo.c,v 1.1 2007-02-11 10:09:32 nkeynes Exp $

     1.6 + *

     1.7 + * GL framebuffer-based driver shell. This requires the EXT_framebuffer_object

     1.8 + * extension, but is much nicer/faster/etc than pbuffers when it's available.

     1.9 + * This is (optionally) used indirectly by the top-level GLX driver.

    1.10 + *

    1.11 + * Strategy-wise, we maintain 2 framebuffers with up to 4 target colour

    1.12 + * buffers a piece. Effectively this reserves one fb for display output,

    1.13 + * and the other for texture output (each fb has a single size).

    1.14 + *

    1.15 + * Copyright (c) 2005 Nathan Keynes.

    1.16 + *

    1.17 + * This program is free software; you can redistribute it and/or modify

    1.18 + * it under the terms of the GNU General Public License as published by

    1.19 + * the Free Software Foundation; either version 2 of the License, or

    1.20 + * (at your option) any later version.

    1.21 + *

    1.22 + * This program is distributed in the hope that it will be useful,

    1.23 + * but WITHOUT ANY WARRANTY; without even the implied warranty of

    1.24 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    1.25 + * GNU General Public License for more details.

    1.26 + */

    1.27 +

    1.28 +#include <GL/gl.h>

    1.29 +#include "display.h"

    1.30 +

    1.31 +#define MAX_FRAMEBUFFERS 2

    1.32 +#define MAX_TEXTURES_PER_FB 4

    1.33 +

    1.34 +static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height );

    1.35 +static void gl_fbo_destroy_render_buffer( render_buffer_t buffer );

    1.36 +static gboolean gl_fbo_set_render_target( render_buffer_t buffer );

    1.37 +static gboolean gl_fbo_display_render_buffer( render_buffer_t buffer );

    1.38 +static gboolean gl_fbo_display_frame_buffer( frame_buffer_t buffer );

    1.39 +static gboolean gl_fbo_display_blank( uint32_t colour );

    1.40 +static gboolean gl_fbo_read_render_buffer( render_buffer_t buffer, char *target );

    1.41 +

    1.42 +extern uint32_t video_width, video_height;

    1.43 +

    1.44 +/**

    1.45 + * Framebuffer info structure

    1.46 + */

    1.47 +struct gl_fbo_info {

    1.48 +    GLuint fb_id;

    1.49 +    GLuint depth_id;

    1.50 +    GLuint stencil_id;

    1.51 +    GLuint tex_ids[MAX_TEXTURES_PER_FB];

    1.52 +    int width, height;

    1.53 +};

    1.54 +

    1.55 +static struct gl_fbo_info fbo[MAX_FRAMEBUFFERS];

    1.56 +const static int ATTACHMENT_POINTS[MAX_TEXTURES_PER_FB] = {

    1.57 +    GL_COLOR_ATTACHMENT0_EXT, GL_COLOR_ATTACHMENT1_EXT, 

    1.58 +    GL_COLOR_ATTACHMENT2_EXT, GL_COLOR_ATTACHMENT3_EXT };

    1.59 +static int last_used_fbo;

    1.60 +

    1.61 +gboolean gl_fbo_is_supported()

    1.62 +{

    1.63 +    return isGLExtensionSupported("GL_EXT_framebuffer_object");

    1.64 +}

    1.65 +

    1.66 +/**

    1.67 + * Construct the initial frame buffers and allocate ids for everything.

    1.68 + * The render handling driver methods are set to the fbo versions.

    1.69 + */

    1.70 +void gl_fbo_init( display_driver_t driver ) 

    1.71 +{

    1.72 +    int i,j;

    1.73 +    int fbids[MAX_FRAMEBUFFERS];

    1.74 +    int rbids[MAX_FRAMEBUFFERS*2]; /* depth buffer, stencil buffer per fb */

    1.75 +    

    1.76 +    glGenFramebuffersEXT( MAX_FRAMEBUFFERS, &fbids );

    1.77 +    glGenRenderbuffersEXT( MAX_FRAMEBUFFERS*2, &rbids );

    1.78 +    for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {

    1.79 +	fbo[i].fb_id = fbids[i];

    1.80 +	fbo[i].depth_id = rbids[i*2];

    1.81 +	fbo[i].stencil_id = rbids[i*2+1];

    1.82 +	fbo[i].width = -1;

    1.83 +	fbo[i].height = -1;

    1.84 +	for( j=0; j<MAX_TEXTURES_PER_FB; j++ ) {

    1.85 +	    fbo[i].tex_ids[j] = -1;

    1.86 +	}

    1.87 +    }

    1.88 +    last_used_fbo = 0;

    1.89 +

    1.90 +    driver->create_render_buffer = gl_fbo_create_render_buffer;

    1.91 +    driver->destroy_render_buffer = gl_fbo_destroy_render_buffer;

    1.92 +    driver->set_render_target = gl_fbo_set_render_target;

    1.93 +    driver->display_render_buffer = gl_fbo_display_render_buffer;

    1.94 +    driver->display_frame_buffer = gl_fbo_display_frame_buffer;

    1.95 +    driver->display_blank = gl_fbo_display_blank;

    1.96 +    driver->read_render_buffer = gl_fbo_read_render_buffer;

    1.97 +}

    1.98 +

    1.99 +void gl_fbo_shutdown()

   1.100 +{

   1.101 +    int i;

   1.102 +    glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );

   1.103 +    for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {

   1.104 +	glDeleteFramebuffersEXT( 1, &fbo[i].fb_id );

   1.105 +	glDeleteRenderbuffersEXT( 2, &fbo[i].depth_id );

   1.106 +    }

   1.107 +}

   1.108 +

   1.109 +void gl_fbo_setup_framebuffer( int bufno, int width, int height )

   1.110 +{

   1.111 +    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id);

   1.112 +    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);

   1.113 +    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height);

   1.114 +    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,

   1.115 +				 GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);

   1.116 +    /* Stencil doesn't work on ATI, and we're not using it at the moment anyway, so...

   1.117 +    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);

   1.118 +    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_STENCIL_INDEX, width, height);

   1.119 +    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,

   1.120 +				 GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);

   1.121 +    */

   1.122 +    fbo[bufno].width = width;

   1.123 +    fbo[bufno].height = height;

   1.124 +}

   1.125 +

   1.126 +int gl_fbo_get_framebuffer( int width, int height ) 

   1.127 +{

   1.128 +    int bufno = -1, i;

   1.129 +    /* find a compatible framebuffer context */

   1.130 +    for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {

   1.131 +	if( fbo[i].width == -1 && bufno == -1 ) {

   1.132 +	    bufno = i;

   1.133 +	} else if( fbo[i].width == width && fbo[i].height == height ) {

   1.134 +	    bufno = i;

   1.135 +	    break;

   1.136 +	}

   1.137 +    }

   1.138 +    if( bufno == -1 ) {

   1.139 +	bufno = last_used_fbo + 1;

   1.140 +	if( bufno > MAX_FRAMEBUFFERS ) {

   1.141 +	    bufno = 0;

   1.142 +	}

   1.143 +	last_used_fbo = bufno;

   1.144 +    }

   1.145 +    if( fbo[bufno].width == width && fbo[bufno].height == height ) {

   1.146 +	glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id );

   1.147 +    } else {

   1.148 +	gl_fbo_setup_framebuffer( bufno, width, height );

   1.149 +    } 

   1.150 +    return bufno;

   1.151 +}

   1.152 +

   1.153 +/**

   1.154 + * Attach a texture to the framebuffer. The texture must already be initialized

   1.155 + * to the correct dimensions etc.

   1.156 + */

   1.157 +static GLint gl_fbo_attach_texture( int fbo_no, GLint tex_id ) {

   1.158 +    int attach = -1, i;

   1.159 +    for( i=0; i<MAX_TEXTURES_PER_FB; i++ ) {

   1.160 +	if( fbo[fbo_no].tex_ids[i] == tex_id ) {

   1.161 +	    glDrawBuffer(ATTACHMENT_POINTS[i]);

   1.162 +	    glReadBuffer(ATTACHMENT_POINTS[i]); 

   1.163 +	    return ATTACHMENT_POINTS[i]; // already attached

   1.164 +	} else if( fbo[fbo_no].tex_ids[i] == -1 && attach == -1 ) {

   1.165 +	    attach = i;

   1.166 +	}

   1.167 +    }

   1.168 +    if( attach == -1 ) {

   1.169 +	/* should never happen */

   1.170 +	attach = 0;

   1.171 +    }

   1.172 +    fbo[fbo_no].tex_ids[attach] = tex_id;

   1.173 +    glBindTexture( GL_TEXTURE_RECTANGLE_ARB, 0 ); // Ensure the output texture is unbound

   1.174 +    glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINTS[attach], 

   1.175 +			      GL_TEXTURE_RECTANGLE_ARB, tex_id, 0 );

   1.176 +    /* Set draw/read buffers by default */

   1.177 +    glDrawBuffer(ATTACHMENT_POINTS[attach]);

   1.178 +    glReadBuffer(ATTACHMENT_POINTS[attach]); 

   1.179 +

   1.180 +

   1.181 +    GLint status = glGetError();

   1.182 +    if( status != GL_NO_ERROR ) {

   1.183 +	ERROR( "GL error setting render target (%x)!", status );

   1.184 +    }

   1.185 +    status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);

   1.186 +    if( status != GL_FRAMEBUFFER_COMPLETE_EXT ) {

   1.187 +	ERROR( "Framebuffer failure: %x", status );

   1.188 +	exit(1);

   1.189 +    }

   1.190 +

   1.191 +    return ATTACHMENT_POINTS[attach];

   1.192 +}

   1.193 +

   1.194 +static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height )

   1.195 +{

   1.196 +    render_buffer_t buffer = calloc( sizeof(struct render_buffer), 1 );

   1.197 +    buffer->width = width;

   1.198 +    buffer->height = height;

   1.199 +    glGenTextures( 1, &buffer->buf_id );

   1.200 +    glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->buf_id );

   1.201 +    glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP );

   1.202 +    glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP );

   1.203 +    glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_NEAREST );

   1.204 +    glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_NEAREST );

   1.205 +    glTexImage2D( GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL );

   1.206 +    return buffer;

   1.207 +}

   1.208 +

   1.209 +static void gl_fbo_destroy_render_buffer( render_buffer_t buffer )

   1.210 +{

   1.211 +    int i,j;

   1.212 +    for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {

   1.213 +	for( j=0; j < MAX_TEXTURES_PER_FB; j++ ) {

   1.214 +	    if( fbo[i].tex_ids[j] == buffer->buf_id ) {

   1.215 +		glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINTS[j], 

   1.216 +					  GL_TEXTURE_RECTANGLE_ARB, GL_NONE, 0 );

   1.217 +		fbo[i].tex_ids[j] = -1;

   1.218 +	    }

   1.219 +	}

   1.220 +    }

   1.221 +    

   1.222 +    glDeleteTextures( 1, &buffer->buf_id );

   1.223 +    buffer->buf_id = 0;

   1.224 +    free( buffer );

   1.225 +}

   1.226 +

   1.227 +static gboolean gl_fbo_set_render_target( render_buffer_t buffer )

   1.228 +{

   1.229 +    glGetError();

   1.230 +    int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );

   1.231 +    GLint attach = gl_fbo_attach_texture( fb, buffer->buf_id );

   1.232 +    /* setup the gl context */

   1.233 +    glViewport( 0, 0, buffer->width, buffer->height );

   1.234 +    

   1.235 +    return TRUE;

   1.236 +}

   1.237 +

   1.238 +/**

   1.239 + * Render the texture holding the given buffer to the front window

   1.240 + * buffer.

   1.241 + */

   1.242 +static gboolean gl_fbo_display_render_buffer( render_buffer_t buffer )

   1.243 +{

   1.244 +    glFinish();

   1.245 +    glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 ); // real window

   1.246 +    glViewport( 0, 0, video_width, video_height );

   1.247 +    glEnable( GL_TEXTURE_RECTANGLE_ARB );

   1.248 +    glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->buf_id );

   1.249 +    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE );

   1.250 +    glDrawBuffer( GL_FRONT );

   1.251 +    glReadBuffer( GL_FRONT );

   1.252 +    glDisable( GL_ALPHA_TEST );

   1.253 +    glDisable( GL_DEPTH_TEST );

   1.254 +    glDisable( GL_SCISSOR_TEST );

   1.255 +    glDisable( GL_CULL_FACE );

   1.256 +

   1.257 +    glMatrixMode(GL_PROJECTION);

   1.258 +    glLoadIdentity();

   1.259 +    glOrtho( 0, buffer->width, buffer->height, 0, 0, -65535 );

   1.260 +    glMatrixMode(GL_MODELVIEW);

   1.261 +    glLoadIdentity();

   1.262 +    glEnable( GL_BLEND );

   1.263 +    glBlendFunc( GL_ONE, GL_ZERO );

   1.264 +    glDisable( GL_DEPTH_TEST );

   1.265 +    glBegin( GL_QUADS );

   1.266 +    glTexCoord2i( 0, buffer->height );

   1.267 +    glVertex2f( 0.0, 0.0 );

   1.268 +    glTexCoord2i( buffer->width, buffer->height );

   1.269 +    glVertex2f( buffer->width, 0.0 );

   1.270 +    glTexCoord2i( buffer->width, 0 );

   1.271 +    glVertex2f( buffer->width, buffer->height );

   1.272 +    glTexCoord2i( 0, 0 );

   1.273 +    glVertex2f( 0.0, buffer->height );

   1.274 +    glEnd();

   1.275 +    glDisable( GL_TEXTURE_RECTANGLE_ARB );

   1.276 +    glFlush();

   1.277 +    return TRUE;

   1.278 +}

   1.279 +

   1.280 +static gboolean gl_fbo_display_frame_buffer( frame_buffer_t buffer )

   1.281 +{

   1.282 +    glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );

   1.283 +    glDrawBuffer( GL_FRONT );

   1.284 +    glReadBuffer( GL_FRONT );

   1.285 +    return gl_display_frame_buffer( buffer );

   1.286 +}

   1.287 +

   1.288 +static gboolean gl_fbo_display_blank( uint32_t colour )

   1.289 +{

   1.290 +    glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );

   1.291 +    glDrawBuffer( GL_FRONT );

   1.292 +    glReadBuffer( GL_FRONT );

   1.293 +    return gl_display_blank( colour );

   1.294 +}

   1.295 +

   1.296 +static gboolean gl_fbo_read_render_buffer( render_buffer_t buffer, char *target )

   1.297 +{

   1.298 +    int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );

   1.299 +    GLint attach = gl_fbo_attach_texture( fb, buffer->buf_id );

   1.300 +    return gl_read_render_buffer( buffer, target );

   1.301 +}

   1.302 +
.