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 #ifdef HAVE_OPENGL_FBO
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_EXT+(n))
66 static int last_used_fbo;
68 gboolean gl_fbo_is_supported()
70 return isGLExtensionSupported("GL_EXT_framebuffer_object");
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 glGetIntegerv(GL_MAX_COLOR_ATTACHMENTS_EXT, &gl_fbo_max_attachments);
84 glGenFramebuffersEXT( MAX_FRAMEBUFFERS, &fbids[0] );
85 glGenRenderbuffersEXT( 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 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
120 void gl_fbo_shutdown()
123 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
124 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
125 glDeleteFramebuffersEXT( 1, &fbo[i].fb_id );
126 glDeleteRenderbuffersEXT( 2, &fbo[i].depth_id );
130 static void gl_fbo_setup_framebuffer( int bufno, int width, int height )
133 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 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 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINT(i),
139 GL_TEXTURE_RECTANGLE_ARB, 0, 0);
140 fbo[bufno].tex_ids[i] = -1;
144 /* Setup the renderbuffers */
145 if( gl_fbo_have_packed_stencil ) {
146 glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
147 glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH24_STENCIL8_EXT, width, height);
148 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
149 GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
150 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,
151 GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
153 glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
154 glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height);
155 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
156 GL_RENDERBUFFER_EXT, 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 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 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 glDrawBuffer(ATTACHMENT_POINT(i));
202 glReadBuffer(ATTACHMENT_POINT(i));
203 return ATTACHMENT_POINT(i); // already attached
204 } else if( fbo[fbo_no].tex_ids[i] == -1 && attach == -1 ) {
211 fbo[fbo_no].tex_ids[attach] = tex_id;
212 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, 0 ); // Ensure the output texture is unbound
213 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINT(attach),
214 GL_TEXTURE_RECTANGLE_ARB, tex_id, 0 );
215 /* Set draw/read buffers by default */
216 glDrawBuffer(ATTACHMENT_POINT(attach));
217 glReadBuffer(ATTACHMENT_POINT(attach));
219 return ATTACHMENT_POINT(attach);
222 static gboolean gl_fbo_test_framebuffer( )
224 gboolean result = TRUE;
225 glGetError(); /* Clear error state just in case */
226 render_buffer_t buffer = gl_fbo_create_render_buffer( 640, 480, 0 );
227 gl_fbo_set_render_target(buffer);
229 GLint status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
230 if( status != GL_FRAMEBUFFER_COMPLETE_EXT ) {
231 ERROR( "Framebuffer failure: %x", status );
235 result = gl_check_error( "Setting up framebuffer" );
238 gl_fbo_destroy_render_buffer( buffer );
242 static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height, GLuint tex_id )
244 render_buffer_t buffer = calloc( sizeof(struct render_buffer), 1 );
245 buffer->width = width;
246 buffer->height = height;
247 buffer->tex_id = tex_id;
250 glGenTextures( 1, &tex );
251 buffer->buf_id = tex;
253 buffer->buf_id = tex_id;
254 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, tex_id );
256 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->buf_id );
257 glTexImage2D( GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL );
258 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP );
259 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP );
260 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
261 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
266 * Ensure the texture in the given render buffer is not attached to a
267 * framebuffer (ie, so we can safely use it as a texture during the rendering
268 * cycle, or before deletion).
270 static void gl_fbo_detach_render_buffer( render_buffer_t buffer )
273 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
274 if( fbo[i].width == buffer->width && fbo[i].height == buffer->height ) {
275 for( j=0; j<gl_fbo_max_attachments; j++ ) {
276 if( fbo[i].tex_ids[j] == buffer->buf_id ) {
277 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo[i].fb_id);
278 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINT(j),
279 GL_TEXTURE_RECTANGLE_ARB, GL_NONE, 0 );
280 fbo[i].tex_ids[j] = -1;
289 static void gl_fbo_destroy_render_buffer( render_buffer_t buffer )
293 gl_fbo_detach_render_buffer( buffer );
295 if( buffer->buf_id != buffer->tex_id ) {
296 // If tex_id was set at buffer creation, we don't own the texture.
297 // Otherwise, delete it now.
298 GLuint tex = buffer->buf_id;
299 glDeleteTextures( 1, &tex );
306 static gboolean gl_fbo_set_render_target( render_buffer_t buffer )
308 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
309 gl_fbo_attach_texture( fb, buffer->buf_id );
310 /* setup the gl context */
311 glViewport( 0, 0, buffer->width, buffer->height );
316 static void gl_fbo_finish_render( render_buffer_t buffer )
319 gl_fbo_detach_render_buffer(buffer);
323 * Render the texture holding the given buffer to the front window
326 static void gl_fbo_display_render_buffer( render_buffer_t buffer )
329 gl_display_render_buffer( buffer );
332 static void gl_fbo_load_frame_buffer( frame_buffer_t frame, render_buffer_t buffer )
335 gl_load_frame_buffer( frame, buffer->buf_id );
338 static void gl_fbo_display_blank( uint32_t colour )
341 gl_display_blank( colour );
346 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
347 /* Make sure texture attachment is not a current draw/read buffer */
348 glDrawBuffer( GL_FRONT );
349 glReadBuffer( GL_FRONT );
350 display_driver->swap_buffers();
353 static gboolean gl_fbo_read_render_buffer( unsigned char *target, render_buffer_t buffer,
354 int rowstride, int format )
356 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
357 gl_fbo_attach_texture( fb, buffer->buf_id );
358 return gl_read_render_buffer( target, buffer, rowstride, format );
362 gboolean gl_fbo_is_supported()
367 void gl_fbo_init( display_driver_t driver )
.