lxdream 0.9.1| filename | src/drivers/gl_fbo.c |
| changeset | 352:f0df7a6d4703 |
| next | 424:421d68e78c46 |
| author | nkeynes |
| date | Sun Feb 11 10:09:32 2007 +0000 (16 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. |
| view | annotate | diff | log | raw |
1 /**
2 * $Id: gl_fbo.c,v 1.1 2007-02-11 10:09:32 nkeynes Exp $
3 *
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.
7 *
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).
11 *
12 * Copyright (c) 2005 Nathan Keynes.
13 *
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.
18 *
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.
23 */
25 #include <GL/gl.h>
26 #include "display.h"
28 #define MAX_FRAMEBUFFERS 2
29 #define MAX_TEXTURES_PER_FB 4
31 static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height );
32 static void gl_fbo_destroy_render_buffer( render_buffer_t buffer );
33 static gboolean gl_fbo_set_render_target( render_buffer_t buffer );
34 static gboolean gl_fbo_display_render_buffer( render_buffer_t buffer );
35 static gboolean gl_fbo_display_frame_buffer( frame_buffer_t buffer );
36 static gboolean gl_fbo_display_blank( uint32_t colour );
37 static gboolean gl_fbo_read_render_buffer( render_buffer_t buffer, char *target );
39 extern uint32_t video_width, video_height;
41 /**
42 * Framebuffer info structure
43 */
44 struct gl_fbo_info {
45 GLuint fb_id;
46 GLuint depth_id;
47 GLuint stencil_id;
48 GLuint tex_ids[MAX_TEXTURES_PER_FB];
49 int width, height;
50 };
52 static struct gl_fbo_info fbo[MAX_FRAMEBUFFERS];
53 const static int ATTACHMENT_POINTS[MAX_TEXTURES_PER_FB] = {
54 GL_COLOR_ATTACHMENT0_EXT, GL_COLOR_ATTACHMENT1_EXT,
55 GL_COLOR_ATTACHMENT2_EXT, GL_COLOR_ATTACHMENT3_EXT };
56 static int last_used_fbo;
58 gboolean gl_fbo_is_supported()
59 {
60 return isGLExtensionSupported("GL_EXT_framebuffer_object");
61 }
63 /**
64 * Construct the initial frame buffers and allocate ids for everything.
65 * The render handling driver methods are set to the fbo versions.
66 */
67 void gl_fbo_init( display_driver_t driver )
68 {
69 int i,j;
70 int fbids[MAX_FRAMEBUFFERS];
71 int rbids[MAX_FRAMEBUFFERS*2]; /* depth buffer, stencil buffer per fb */
73 glGenFramebuffersEXT( MAX_FRAMEBUFFERS, &fbids );
74 glGenRenderbuffersEXT( MAX_FRAMEBUFFERS*2, &rbids );
75 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
76 fbo[i].fb_id = fbids[i];
77 fbo[i].depth_id = rbids[i*2];
78 fbo[i].stencil_id = rbids[i*2+1];
79 fbo[i].width = -1;
80 fbo[i].height = -1;
81 for( j=0; j<MAX_TEXTURES_PER_FB; j++ ) {
82 fbo[i].tex_ids[j] = -1;
83 }
84 }
85 last_used_fbo = 0;
87 driver->create_render_buffer = gl_fbo_create_render_buffer;
88 driver->destroy_render_buffer = gl_fbo_destroy_render_buffer;
89 driver->set_render_target = gl_fbo_set_render_target;
90 driver->display_render_buffer = gl_fbo_display_render_buffer;
91 driver->display_frame_buffer = gl_fbo_display_frame_buffer;
92 driver->display_blank = gl_fbo_display_blank;
93 driver->read_render_buffer = gl_fbo_read_render_buffer;
94 }
96 void gl_fbo_shutdown()
97 {
98 int i;
99 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
100 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
101 glDeleteFramebuffersEXT( 1, &fbo[i].fb_id );
102 glDeleteRenderbuffersEXT( 2, &fbo[i].depth_id );
103 }
104 }
106 void gl_fbo_setup_framebuffer( int bufno, int width, int height )
107 {
108 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id);
109 glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
110 glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height);
111 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
112 GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
113 /* Stencil doesn't work on ATI, and we're not using it at the moment anyway, so...
114 glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);
115 glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_STENCIL_INDEX, width, height);
116 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,
117 GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);
118 */
119 fbo[bufno].width = width;
120 fbo[bufno].height = height;
121 }
123 int gl_fbo_get_framebuffer( int width, int height )
124 {
125 int bufno = -1, i;
126 /* find a compatible framebuffer context */
127 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
128 if( fbo[i].width == -1 && bufno == -1 ) {
129 bufno = i;
130 } else if( fbo[i].width == width && fbo[i].height == height ) {
131 bufno = i;
132 break;
133 }
134 }
135 if( bufno == -1 ) {
136 bufno = last_used_fbo + 1;
137 if( bufno > MAX_FRAMEBUFFERS ) {
138 bufno = 0;
139 }
140 last_used_fbo = bufno;
141 }
142 if( fbo[bufno].width == width && fbo[bufno].height == height ) {
143 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id );
144 } else {
145 gl_fbo_setup_framebuffer( bufno, width, height );
146 }
147 return bufno;
148 }
150 /**
151 * Attach a texture to the framebuffer. The texture must already be initialized
152 * to the correct dimensions etc.
153 */
154 static GLint gl_fbo_attach_texture( int fbo_no, GLint tex_id ) {
155 int attach = -1, i;
156 for( i=0; i<MAX_TEXTURES_PER_FB; i++ ) {
157 if( fbo[fbo_no].tex_ids[i] == tex_id ) {
158 glDrawBuffer(ATTACHMENT_POINTS[i]);
159 glReadBuffer(ATTACHMENT_POINTS[i]);
160 return ATTACHMENT_POINTS[i]; // already attached
161 } else if( fbo[fbo_no].tex_ids[i] == -1 && attach == -1 ) {
162 attach = i;
163 }
164 }
165 if( attach == -1 ) {
166 /* should never happen */
167 attach = 0;
168 }
169 fbo[fbo_no].tex_ids[attach] = tex_id;
170 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, 0 ); // Ensure the output texture is unbound
171 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINTS[attach],
172 GL_TEXTURE_RECTANGLE_ARB, tex_id, 0 );
173 /* Set draw/read buffers by default */
174 glDrawBuffer(ATTACHMENT_POINTS[attach]);
175 glReadBuffer(ATTACHMENT_POINTS[attach]);
178 GLint status = glGetError();
179 if( status != GL_NO_ERROR ) {
180 ERROR( "GL error setting render target (%x)!", status );
181 }
182 status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
183 if( status != GL_FRAMEBUFFER_COMPLETE_EXT ) {
184 ERROR( "Framebuffer failure: %x", status );
185 exit(1);
186 }
188 return ATTACHMENT_POINTS[attach];
189 }
191 static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height )
192 {
193 render_buffer_t buffer = calloc( sizeof(struct render_buffer), 1 );
194 buffer->width = width;
195 buffer->height = height;
196 glGenTextures( 1, &buffer->buf_id );
197 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->buf_id );
198 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP );
199 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP );
200 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
201 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
202 glTexImage2D( GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL );
203 return buffer;
204 }
206 static void gl_fbo_destroy_render_buffer( render_buffer_t buffer )
207 {
208 int i,j;
209 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
210 for( j=0; j < MAX_TEXTURES_PER_FB; j++ ) {
211 if( fbo[i].tex_ids[j] == buffer->buf_id ) {
212 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINTS[j],
213 GL_TEXTURE_RECTANGLE_ARB, GL_NONE, 0 );
214 fbo[i].tex_ids[j] = -1;
215 }
216 }
217 }
219 glDeleteTextures( 1, &buffer->buf_id );
220 buffer->buf_id = 0;
221 free( buffer );
222 }
224 static gboolean gl_fbo_set_render_target( render_buffer_t buffer )
225 {
226 glGetError();
227 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
228 GLint attach = gl_fbo_attach_texture( fb, buffer->buf_id );
229 /* setup the gl context */
230 glViewport( 0, 0, buffer->width, buffer->height );
232 return TRUE;
233 }
235 /**
236 * Render the texture holding the given buffer to the front window
237 * buffer.
238 */
239 static gboolean gl_fbo_display_render_buffer( render_buffer_t buffer )
240 {
241 glFinish();
242 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 ); // real window
243 glViewport( 0, 0, video_width, video_height );
244 glEnable( GL_TEXTURE_RECTANGLE_ARB );
245 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->buf_id );
246 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE );
247 glDrawBuffer( GL_FRONT );
248 glReadBuffer( GL_FRONT );
249 glDisable( GL_ALPHA_TEST );
250 glDisable( GL_DEPTH_TEST );
251 glDisable( GL_SCISSOR_TEST );
252 glDisable( GL_CULL_FACE );
254 glMatrixMode(GL_PROJECTION);
255 glLoadIdentity();
256 glOrtho( 0, buffer->width, buffer->height, 0, 0, -65535 );
257 glMatrixMode(GL_MODELVIEW);
258 glLoadIdentity();
259 glEnable( GL_BLEND );
260 glBlendFunc( GL_ONE, GL_ZERO );
261 glDisable( GL_DEPTH_TEST );
262 glBegin( GL_QUADS );
263 glTexCoord2i( 0, buffer->height );
264 glVertex2f( 0.0, 0.0 );
265 glTexCoord2i( buffer->width, buffer->height );
266 glVertex2f( buffer->width, 0.0 );
267 glTexCoord2i( buffer->width, 0 );
268 glVertex2f( buffer->width, buffer->height );
269 glTexCoord2i( 0, 0 );
270 glVertex2f( 0.0, buffer->height );
271 glEnd();
272 glDisable( GL_TEXTURE_RECTANGLE_ARB );
273 glFlush();
274 return TRUE;
275 }
277 static gboolean gl_fbo_display_frame_buffer( frame_buffer_t buffer )
278 {
279 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
280 glDrawBuffer( GL_FRONT );
281 glReadBuffer( GL_FRONT );
282 return gl_display_frame_buffer( buffer );
283 }
285 static gboolean gl_fbo_display_blank( uint32_t colour )
286 {
287 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
288 glDrawBuffer( GL_FRONT );
289 glReadBuffer( GL_FRONT );
290 return gl_display_blank( colour );
291 }
293 static gboolean gl_fbo_read_render_buffer( render_buffer_t buffer, char *target )
294 {
295 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
296 GLint attach = gl_fbo_attach_texture( fb, buffer->buf_id );
297 return gl_read_render_buffer( buffer, target );
298 }
.