2 * $Id: gl_fbo.c,v 1.6 2007-10-16 12:27:28 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;
100 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
101 glDrawBuffer(GL_FRONT);
102 glReadBuffer(GL_FRONT);
105 void gl_fbo_shutdown()
108 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
109 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
110 glDeleteFramebuffersEXT( 1, &fbo[i].fb_id );
111 glDeleteRenderbuffersEXT( 2, &fbo[i].depth_id );
115 void gl_fbo_setup_framebuffer( int bufno, int width, int height )
117 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id);
118 glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
119 glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height);
120 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
121 GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
122 /* Stencil doesn't work on ATI, and we're not using it at the moment anyway, so...
123 glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);
124 glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_STENCIL_INDEX, width, height);
125 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,
126 GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);
128 fbo[bufno].width = width;
129 fbo[bufno].height = height;
132 int gl_fbo_get_framebuffer( int width, int height )
135 /* find a compatible framebuffer context */
136 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
137 if( fbo[i].width == -1 && bufno == -1 ) {
139 } else if( fbo[i].width == width && fbo[i].height == height ) {
145 bufno = last_used_fbo + 1;
146 if( bufno > MAX_FRAMEBUFFERS ) {
149 last_used_fbo = bufno;
151 if( fbo[bufno].width == width && fbo[bufno].height == height ) {
152 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id );
154 gl_fbo_setup_framebuffer( bufno, width, height );
160 * Attach a texture to the framebuffer. The texture must already be initialized
161 * to the correct dimensions etc.
163 static GLint gl_fbo_attach_texture( int fbo_no, GLint tex_id ) {
165 for( i=0; i<MAX_TEXTURES_PER_FB; i++ ) {
166 if( fbo[fbo_no].tex_ids[i] == tex_id ) {
167 glDrawBuffer(ATTACHMENT_POINTS[i]);
168 glReadBuffer(ATTACHMENT_POINTS[i]);
169 return ATTACHMENT_POINTS[i]; // already attached
170 } else if( fbo[fbo_no].tex_ids[i] == -1 && attach == -1 ) {
175 /* should never happen */
178 fbo[fbo_no].tex_ids[attach] = tex_id;
179 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, 0 ); // Ensure the output texture is unbound
180 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINTS[attach],
181 GL_TEXTURE_RECTANGLE_ARB, tex_id, 0 );
182 /* Set draw/read buffers by default */
183 glDrawBuffer(ATTACHMENT_POINTS[attach]);
184 glReadBuffer(ATTACHMENT_POINTS[attach]);
187 GLint status = glGetError();
188 if( status != GL_NO_ERROR ) {
189 ERROR( "GL error setting render target (%x)!", status );
191 status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
192 if( status != GL_FRAMEBUFFER_COMPLETE_EXT ) {
193 ERROR( "Framebuffer failure: %x", status );
197 return ATTACHMENT_POINTS[attach];
200 static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height )
202 render_buffer_t buffer = calloc( sizeof(struct render_buffer), 1 );
203 buffer->width = width;
204 buffer->height = height;
205 glGenTextures( 1, &buffer->buf_id );
206 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->buf_id );
207 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP );
208 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP );
209 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
210 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
211 glTexImage2D( GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL );
215 static void gl_fbo_destroy_render_buffer( render_buffer_t buffer )
218 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
219 for( j=0; j < MAX_TEXTURES_PER_FB; j++ ) {
220 if( fbo[i].tex_ids[j] == buffer->buf_id ) {
221 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINTS[j],
222 GL_TEXTURE_RECTANGLE_ARB, GL_NONE, 0 );
223 fbo[i].tex_ids[j] = -1;
228 glDeleteTextures( 1, &buffer->buf_id );
233 static gboolean gl_fbo_set_render_target( render_buffer_t buffer )
236 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
237 gl_fbo_attach_texture( fb, buffer->buf_id );
238 /* setup the gl context */
239 glViewport( 0, 0, buffer->width, buffer->height );
245 * Render the texture holding the given buffer to the front window
248 static gboolean gl_fbo_display_render_buffer( render_buffer_t buffer )
251 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 ); // real window
252 glDrawBuffer( GL_FRONT );
253 glReadBuffer( GL_FRONT );
254 gl_display_tex_rectangle( buffer->buf_id, buffer->width, buffer->height, TRUE );
256 glViewport( 0, 0, video_width, video_height );
257 glEnable( GL_TEXTURE_RECTANGLE_ARB );
258 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->buf_id );
259 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE );
260 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
261 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
262 glDisable( GL_ALPHA_TEST );
263 glDisable( GL_DEPTH_TEST );
264 glDisable( GL_SCISSOR_TEST );
265 glDisable( GL_CULL_FACE );
267 glMatrixMode(GL_PROJECTION);
269 glOrtho( 0, buffer->width, buffer->height, 0, 0, -65535 );
270 glMatrixMode(GL_MODELVIEW);
272 glEnable( GL_BLEND );
273 glBlendFunc( GL_ONE, GL_ZERO );
274 glDisable( GL_DEPTH_TEST );
276 glTexCoord2i( 0.5, buffer->height-0.5 );
277 glVertex2f( 0.0, 0.0 );
278 glTexCoord2i( buffer->width-0.5, buffer->height-0.5 );
279 glVertex2f( buffer->width, 0.0 );
280 glTexCoord2i( buffer->width-0.5, 0 );
281 glVertex2f( buffer->width, buffer->height );
282 glTexCoord2i( 0.5, 0.5 );
283 glVertex2f( 0.0, buffer->height );
285 glDisable( GL_TEXTURE_RECTANGLE_ARB );
291 static gboolean gl_fbo_display_frame_buffer( frame_buffer_t buffer )
293 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
294 glDrawBuffer( GL_FRONT );
295 glReadBuffer( GL_FRONT );
296 return gl_display_frame_buffer( buffer );
299 static gboolean gl_fbo_display_blank( uint32_t colour )
301 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
302 glDrawBuffer( GL_FRONT );
303 glReadBuffer( GL_FRONT );
304 return gl_display_blank( colour );
307 static gboolean gl_fbo_read_render_buffer( render_buffer_t buffer, unsigned char *target )
309 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
310 gl_fbo_attach_texture( fb, buffer->buf_id );
311 return gl_read_render_buffer( buffer, target );
.