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_gl.h"
31 #include "pvr2/glutil.h"
33 #if defined(HAVE_OPENGL_FBO) || defined(HAVE_OPENGL_FBO_EXT)
35 #define MAX_FRAMEBUFFERS 2
36 #define MAX_TEXTURES_PER_FB 16
38 static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height, GLuint tex_id );
39 static void gl_fbo_destroy_render_buffer( render_buffer_t buffer );
40 static gboolean gl_fbo_set_render_target( render_buffer_t buffer );
41 static void gl_fbo_finish_render( render_buffer_t buffer );
42 static void gl_fbo_display_render_buffer( render_buffer_t buffer );
43 static void gl_fbo_load_frame_buffer( frame_buffer_t frame, render_buffer_t buffer );
44 static void gl_fbo_display_blank( uint32_t colour );
45 static gboolean gl_fbo_test_framebuffer( );
46 static gboolean gl_fbo_read_render_buffer( unsigned char *target, render_buffer_t buffer, int rowstride, int format );
48 extern uint32_t video_width, video_height;
51 * Framebuffer info structure
57 GLuint tex_ids[MAX_TEXTURES_PER_FB];
61 static GLint gl_fbo_max_attachments = 0;
62 static gboolean gl_fbo_have_packed_stencil = FALSE;
63 static struct gl_fbo_info fbo[MAX_FRAMEBUFFERS];
65 #define ATTACHMENT_POINT(n) (GL_COLOR_ATTACHMENT0+(n))
66 static int last_used_fbo;
68 gboolean gl_fbo_is_supported()
70 return isGLExtensionSupported("GL_EXT_framebuffer_object") || isOpenGLES2();
74 * Construct the initial frame buffers and allocate ids for everything.
75 * The render handling driver methods are set to the fbo versions.
77 void gl_fbo_init( display_driver_t driver )
80 GLuint fbids[MAX_FRAMEBUFFERS];
81 GLuint rbids[MAX_FRAMEBUFFERS*2]; /* depth buffer, stencil buffer per fb */
83 gl_fbo_max_attachments = glGetMaxColourAttachments();
84 glGenFramebuffers( MAX_FRAMEBUFFERS, &fbids[0] );
85 glGenRenderbuffers( MAX_FRAMEBUFFERS*2, &rbids[0] );
86 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
87 fbo[i].fb_id = fbids[i];
88 fbo[i].depth_id = rbids[i*2];
89 fbo[i].stencil_id = rbids[i*2+1];
92 for( j=0; j<MAX_TEXTURES_PER_FB; j++ ) {
93 fbo[i].tex_ids[j] = -1;
98 if( isGLExtensionSupported("GL_EXT_packed_depth_stencil" ) ) {
99 driver->capabilities.stencil_bits = 8;
100 gl_fbo_have_packed_stencil = TRUE;
102 driver->capabilities.stencil_bits = 0;
103 gl_fbo_have_packed_stencil = FALSE;
104 WARN( "Packed depth stencil not available - disabling shadow volumes" );
107 driver->create_render_buffer = gl_fbo_create_render_buffer;
108 driver->destroy_render_buffer = gl_fbo_destroy_render_buffer;
109 driver->set_render_target = gl_fbo_set_render_target;
110 driver->finish_render = gl_fbo_finish_render;
111 driver->display_render_buffer = gl_fbo_display_render_buffer;
112 driver->load_frame_buffer = gl_fbo_load_frame_buffer;
113 driver->display_blank = gl_fbo_display_blank;
114 driver->read_render_buffer = gl_fbo_read_render_buffer;
116 gl_fbo_test_framebuffer();
117 glBindFramebuffer(GL_FRAMEBUFFER, 0);
120 void gl_fbo_shutdown()
123 glBindFramebuffer( GL_FRAMEBUFFER, 0 );
124 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
125 glDeleteFramebuffers( 1, &fbo[i].fb_id );
126 glDeleteRenderbuffers( 2, &fbo[i].depth_id );
130 static void gl_fbo_setup_framebuffer( int bufno, int width, int height )
133 glBindFramebuffer(GL_FRAMEBUFFER, fbo[bufno].fb_id);
135 /* Clear out any existing texture attachments */
136 for( i=0; i<gl_fbo_max_attachments; i++ ) {
137 if( fbo[bufno].tex_ids[i] != -1 ) {
138 glFramebufferTexture2D(GL_FRAMEBUFFER, ATTACHMENT_POINT(i),
139 GL_TEXTURE_2D, 0, 0);
140 fbo[bufno].tex_ids[i] = -1;
144 /* Setup the renderbuffers */
145 if( gl_fbo_have_packed_stencil ) {
146 glBindRenderbuffer(GL_RENDERBUFFER, fbo[bufno].depth_id);
147 glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
148 glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
149 GL_RENDERBUFFER, fbo[bufno].depth_id);
150 glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
151 GL_RENDERBUFFER, fbo[bufno].depth_id);
153 glBindRenderbuffer(GL_RENDERBUFFER, fbo[bufno].depth_id);
154 glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, width, height);
155 glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
156 GL_RENDERBUFFER, fbo[bufno].depth_id);
157 /* In theory you could attach a separate stencil buffer. In practice this
158 * isn't actually supported by any hardware I've had access to, so we're
162 fbo[bufno].width = width;
163 fbo[bufno].height = height;
166 static int gl_fbo_get_framebuffer( int width, int height )
169 /* find a compatible framebuffer context */
170 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
171 if( fbo[i].width == -1 && bufno == -1 ) {
173 } else if( fbo[i].width == width && fbo[i].height == height ) {
179 bufno = last_used_fbo + 1;
180 if( bufno >= MAX_FRAMEBUFFERS ) {
183 last_used_fbo = bufno;
185 if( fbo[bufno].width == width && fbo[bufno].height == height ) {
186 glBindFramebuffer( GL_FRAMEBUFFER, fbo[bufno].fb_id );
188 gl_fbo_setup_framebuffer( bufno, width, height );
194 * Attach a texture to the framebuffer. The texture must already be initialized
195 * to the correct dimensions etc.
197 static GLint gl_fbo_attach_texture( int fbo_no, GLint tex_id ) {
199 for( i=0; i<gl_fbo_max_attachments; i++ ) {
200 if( fbo[fbo_no].tex_ids[i] == tex_id ) {
201 #ifdef HAVE_OPENGL_DRAW_BUFFER
202 glDrawBuffer(ATTACHMENT_POINT(i));
203 glReadBuffer(ATTACHMENT_POINT(i));
205 return ATTACHMENT_POINT(i); // already attached
206 } else if( fbo[fbo_no].tex_ids[i] == -1 && attach == -1 ) {
213 fbo[fbo_no].tex_ids[attach] = tex_id;
214 glBindTexture( GL_TEXTURE_2D, 0 ); // Ensure the output texture is unbound
215 glFramebufferTexture2D(GL_FRAMEBUFFER, ATTACHMENT_POINT(attach),
216 GL_TEXTURE_2D, tex_id, 0 );
217 /* Set draw/read buffers by default */
218 #ifdef HAVE_OPENGL_DRAW_BUFFER
219 glDrawBuffer(ATTACHMENT_POINT(attach));
220 glReadBuffer(ATTACHMENT_POINT(attach));
223 return ATTACHMENT_POINT(attach);
226 static gboolean gl_fbo_test_framebuffer( )
228 gboolean result = TRUE;
229 glGetError(); /* Clear error state just in case */
230 render_buffer_t buffer = gl_fbo_create_render_buffer( 640, 480, 0 );
231 gl_fbo_set_render_target(buffer);
233 GLint status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
234 if( status != GL_FRAMEBUFFER_COMPLETE ) {
235 ERROR( "Framebuffer failure: %x", status );
239 result = gl_check_error( "Setting up framebuffer" );
242 gl_fbo_destroy_render_buffer( buffer );
246 static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height, GLuint tex_id )
248 render_buffer_t buffer = calloc( sizeof(struct render_buffer), 1 );
249 buffer->width = width;
250 buffer->height = height;
251 buffer->tex_id = tex_id;
254 glGenTextures( 1, &tex );
255 buffer->buf_id = tex;
257 buffer->buf_id = tex_id;
258 glBindTexture( GL_TEXTURE_2D, tex_id );
260 glBindTexture( GL_TEXTURE_2D, buffer->buf_id );
261 glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL );
262 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
263 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
264 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
265 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
270 * Ensure the texture in the given render buffer is not attached to a
271 * framebuffer (ie, so we can safely use it as a texture during the rendering
272 * cycle, or before deletion).
274 static void gl_fbo_detach_render_buffer( render_buffer_t buffer )
277 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
278 if( fbo[i].width == buffer->width && fbo[i].height == buffer->height ) {
279 for( j=0; j<gl_fbo_max_attachments; j++ ) {
280 if( fbo[i].tex_ids[j] == buffer->buf_id ) {
281 glBindFramebuffer(GL_FRAMEBUFFER, fbo[i].fb_id);
282 glFramebufferTexture2D(GL_FRAMEBUFFER, ATTACHMENT_POINT(j),
283 GL_TEXTURE_2D, GL_NONE, 0 );
284 fbo[i].tex_ids[j] = -1;
293 static void gl_fbo_destroy_render_buffer( render_buffer_t buffer )
297 gl_fbo_detach_render_buffer( buffer );
299 if( buffer->buf_id != buffer->tex_id ) {
300 // If tex_id was set at buffer creation, we don't own the texture.
301 // Otherwise, delete it now.
302 GLuint tex = buffer->buf_id;
303 glDeleteTextures( 1, &tex );
310 static gboolean gl_fbo_set_render_target( render_buffer_t buffer )
312 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
313 gl_fbo_attach_texture( fb, buffer->buf_id );
314 /* setup the gl context */
315 glViewport( 0, 0, buffer->width, buffer->height );
320 static void gl_fbo_finish_render( render_buffer_t buffer )
323 gl_fbo_detach_render_buffer(buffer);
327 * Render the texture holding the given buffer to the front window
330 static void gl_fbo_display_render_buffer( render_buffer_t buffer )
333 gl_display_render_buffer( buffer );
336 static void gl_fbo_load_frame_buffer( frame_buffer_t frame, render_buffer_t buffer )
339 gl_load_frame_buffer( frame, buffer->buf_id );
342 static void gl_fbo_display_blank( uint32_t colour )
345 gl_display_blank( colour );
350 glBindFramebuffer( GL_FRAMEBUFFER, 0 );
351 /* Make sure texture attachment is not a current draw/read buffer */
352 #ifdef HAVE_OPENGL_DRAW_BUFFER
353 glDrawBuffer( GL_FRONT );
354 glReadBuffer( GL_FRONT );
356 if( display_driver->swap_buffers )
357 display_driver->swap_buffers();
360 static gboolean gl_fbo_read_render_buffer( unsigned char *target, render_buffer_t buffer,
361 int rowstride, int format )
363 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
364 gl_fbo_attach_texture( fb, buffer->buf_id );
365 return gl_read_render_buffer( target, buffer, rowstride, format );
369 gboolean gl_fbo_is_supported()
374 void gl_fbo_init( display_driver_t driver )
.