2 * $Id: gl_fbo.c,v 1.3 2007-10-08 11:49:35 nkeynes Exp $
4 * GL framebuffer-based driver shell. This requires the EXT_framebuffer_object
5 * extension, but is much nicer/faster/etc than pbuffers when it's available.
6 * This is (optionally) used indirectly by the top-level GLX driver.
8 * Strategy-wise, we maintain 2 framebuffers with up to 4 target colour
9 * buffers a piece. Effectively this reserves one fb for display output,
10 * and the other for texture output (each fb has a single size).
12 * Copyright (c) 2005 Nathan Keynes.
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
25 #define GL_GLEXT_PROTOTYPES 1
30 #include "drivers/video_x11.h"
31 #include "drivers/gl_common.h"
33 #define MAX_FRAMEBUFFERS 2
34 #define MAX_TEXTURES_PER_FB 4
36 static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height );
37 static void gl_fbo_destroy_render_buffer( render_buffer_t buffer );
38 static gboolean gl_fbo_set_render_target( render_buffer_t buffer );
39 static gboolean gl_fbo_display_render_buffer( render_buffer_t buffer );
40 static gboolean gl_fbo_display_frame_buffer( frame_buffer_t buffer );
41 static gboolean gl_fbo_display_blank( uint32_t colour );
42 static gboolean gl_fbo_read_render_buffer( render_buffer_t buffer, unsigned char *target );
44 extern uint32_t video_width, video_height;
47 * Framebuffer info structure
53 GLuint tex_ids[MAX_TEXTURES_PER_FB];
57 static struct gl_fbo_info fbo[MAX_FRAMEBUFFERS];
58 const static int ATTACHMENT_POINTS[MAX_TEXTURES_PER_FB] = {
59 GL_COLOR_ATTACHMENT0_EXT, GL_COLOR_ATTACHMENT1_EXT,
60 GL_COLOR_ATTACHMENT2_EXT, GL_COLOR_ATTACHMENT3_EXT };
61 static int last_used_fbo;
63 gboolean gl_fbo_is_supported()
65 return isGLExtensionSupported("GL_EXT_framebuffer_object");
69 * Construct the initial frame buffers and allocate ids for everything.
70 * The render handling driver methods are set to the fbo versions.
72 void gl_fbo_init( display_driver_t driver )
75 GLuint fbids[MAX_FRAMEBUFFERS];
76 GLuint rbids[MAX_FRAMEBUFFERS*2]; /* depth buffer, stencil buffer per fb */
78 glGenFramebuffersEXT( MAX_FRAMEBUFFERS, &fbids[0] );
79 glGenRenderbuffersEXT( MAX_FRAMEBUFFERS*2, &rbids[0] );
80 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
81 fbo[i].fb_id = fbids[i];
82 fbo[i].depth_id = rbids[i*2];
83 fbo[i].stencil_id = rbids[i*2+1];
86 for( j=0; j<MAX_TEXTURES_PER_FB; j++ ) {
87 fbo[i].tex_ids[j] = -1;
92 driver->create_render_buffer = gl_fbo_create_render_buffer;
93 driver->destroy_render_buffer = gl_fbo_destroy_render_buffer;
94 driver->set_render_target = gl_fbo_set_render_target;
95 driver->display_render_buffer = gl_fbo_display_render_buffer;
96 driver->display_frame_buffer = gl_fbo_display_frame_buffer;
97 driver->display_blank = gl_fbo_display_blank;
98 driver->read_render_buffer = gl_fbo_read_render_buffer;
101 void gl_fbo_shutdown()
104 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
105 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
106 glDeleteFramebuffersEXT( 1, &fbo[i].fb_id );
107 glDeleteRenderbuffersEXT( 2, &fbo[i].depth_id );
111 void gl_fbo_setup_framebuffer( int bufno, int width, int height )
113 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id);
114 glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
115 glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height);
116 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
117 GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
118 /* Stencil doesn't work on ATI, and we're not using it at the moment anyway, so...
119 glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);
120 glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_STENCIL_INDEX, width, height);
121 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,
122 GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);
124 fbo[bufno].width = width;
125 fbo[bufno].height = height;
128 int gl_fbo_get_framebuffer( int width, int height )
131 /* find a compatible framebuffer context */
132 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
133 if( fbo[i].width == -1 && bufno == -1 ) {
135 } else if( fbo[i].width == width && fbo[i].height == height ) {
141 bufno = last_used_fbo + 1;
142 if( bufno > MAX_FRAMEBUFFERS ) {
145 last_used_fbo = bufno;
147 if( fbo[bufno].width == width && fbo[bufno].height == height ) {
148 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id );
150 gl_fbo_setup_framebuffer( bufno, width, height );
156 * Attach a texture to the framebuffer. The texture must already be initialized
157 * to the correct dimensions etc.
159 static GLint gl_fbo_attach_texture( int fbo_no, GLint tex_id ) {
161 for( i=0; i<MAX_TEXTURES_PER_FB; i++ ) {
162 if( fbo[fbo_no].tex_ids[i] == tex_id ) {
163 glDrawBuffer(ATTACHMENT_POINTS[i]);
164 glReadBuffer(ATTACHMENT_POINTS[i]);
165 return ATTACHMENT_POINTS[i]; // already attached
166 } else if( fbo[fbo_no].tex_ids[i] == -1 && attach == -1 ) {
171 /* should never happen */
174 fbo[fbo_no].tex_ids[attach] = tex_id;
175 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, 0 ); // Ensure the output texture is unbound
176 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINTS[attach],
177 GL_TEXTURE_RECTANGLE_ARB, tex_id, 0 );
178 /* Set draw/read buffers by default */
179 glDrawBuffer(ATTACHMENT_POINTS[attach]);
180 glReadBuffer(ATTACHMENT_POINTS[attach]);
183 GLint status = glGetError();
184 if( status != GL_NO_ERROR ) {
185 ERROR( "GL error setting render target (%x)!", status );
187 status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
188 if( status != GL_FRAMEBUFFER_COMPLETE_EXT ) {
189 ERROR( "Framebuffer failure: %x", status );
193 return ATTACHMENT_POINTS[attach];
196 static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height )
198 render_buffer_t buffer = calloc( sizeof(struct render_buffer), 1 );
199 buffer->width = width;
200 buffer->height = height;
201 glGenTextures( 1, &buffer->buf_id );
202 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->buf_id );
203 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP );
204 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP );
205 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
206 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
207 glTexImage2D( GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL );
211 static void gl_fbo_destroy_render_buffer( render_buffer_t buffer )
214 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
215 for( j=0; j < MAX_TEXTURES_PER_FB; j++ ) {
216 if( fbo[i].tex_ids[j] == buffer->buf_id ) {
217 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINTS[j],
218 GL_TEXTURE_RECTANGLE_ARB, GL_NONE, 0 );
219 fbo[i].tex_ids[j] = -1;
224 glDeleteTextures( 1, &buffer->buf_id );
229 static gboolean gl_fbo_set_render_target( render_buffer_t buffer )
232 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
233 gl_fbo_attach_texture( fb, buffer->buf_id );
234 /* setup the gl context */
235 glViewport( 0, 0, buffer->width, buffer->height );
241 * Render the texture holding the given buffer to the front window
244 static gboolean gl_fbo_display_render_buffer( render_buffer_t buffer )
247 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 ); // real window
248 glViewport( 0, 0, video_width, video_height );
249 glEnable( GL_TEXTURE_RECTANGLE_ARB );
250 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->buf_id );
251 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE );
252 glDrawBuffer( GL_FRONT );
253 glReadBuffer( GL_FRONT );
254 glDisable( GL_ALPHA_TEST );
255 glDisable( GL_DEPTH_TEST );
256 glDisable( GL_SCISSOR_TEST );
257 glDisable( GL_CULL_FACE );
259 glMatrixMode(GL_PROJECTION);
261 glOrtho( 0, buffer->width, buffer->height, 0, 0, -65535 );
262 glMatrixMode(GL_MODELVIEW);
264 glEnable( GL_BLEND );
265 glBlendFunc( GL_ONE, GL_ZERO );
266 glDisable( GL_DEPTH_TEST );
268 glTexCoord2i( 0, buffer->height );
269 glVertex2f( 0.0, 0.0 );
270 glTexCoord2i( buffer->width, buffer->height );
271 glVertex2f( buffer->width, 0.0 );
272 glTexCoord2i( buffer->width, 0 );
273 glVertex2f( buffer->width, buffer->height );
274 glTexCoord2i( 0, 0 );
275 glVertex2f( 0.0, buffer->height );
277 glDisable( GL_TEXTURE_RECTANGLE_ARB );
282 static gboolean gl_fbo_display_frame_buffer( frame_buffer_t buffer )
284 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
285 glDrawBuffer( GL_FRONT );
286 glReadBuffer( GL_FRONT );
287 return gl_display_frame_buffer( buffer );
290 static gboolean gl_fbo_display_blank( uint32_t colour )
292 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
293 glDrawBuffer( GL_FRONT );
294 glReadBuffer( GL_FRONT );
295 return gl_display_blank( colour );
298 static gboolean gl_fbo_read_render_buffer( render_buffer_t buffer, unsigned char *target )
300 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
301 gl_fbo_attach_texture( fb, buffer->buf_id );
302 return gl_read_render_buffer( buffer, target );
.