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_read_render_buffer( unsigned char *target, render_buffer_t buffer, int rowstride, int format );
47 extern uint32_t video_width, video_height;
50 * Framebuffer info structure
56 GLuint tex_ids[MAX_TEXTURES_PER_FB];
60 static GLint gl_fbo_max_attachments = 0;
61 static struct gl_fbo_info fbo[MAX_FRAMEBUFFERS];
63 #define ATTACHMENT_POINT(n) (GL_COLOR_ATTACHMENT0_EXT+(n))
64 static int last_used_fbo;
66 gboolean gl_fbo_is_supported()
68 return isGLExtensionSupported("GL_EXT_framebuffer_object");
72 * Construct the initial frame buffers and allocate ids for everything.
73 * The render handling driver methods are set to the fbo versions.
75 void gl_fbo_init( display_driver_t driver )
78 GLuint fbids[MAX_FRAMEBUFFERS];
79 GLuint rbids[MAX_FRAMEBUFFERS*2]; /* depth buffer, stencil buffer per fb */
81 glGetIntegerv(GL_MAX_COLOR_ATTACHMENTS_EXT, &gl_fbo_max_attachments);
82 glGenFramebuffersEXT( MAX_FRAMEBUFFERS, &fbids[0] );
83 glGenRenderbuffersEXT( MAX_FRAMEBUFFERS*2, &rbids[0] );
84 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
85 fbo[i].fb_id = fbids[i];
86 fbo[i].depth_id = rbids[i*2];
87 fbo[i].stencil_id = rbids[i*2+1];
90 for( j=0; j<MAX_TEXTURES_PER_FB; j++ ) {
91 fbo[i].tex_ids[j] = -1;
96 driver->create_render_buffer = gl_fbo_create_render_buffer;
97 driver->destroy_render_buffer = gl_fbo_destroy_render_buffer;
98 driver->set_render_target = gl_fbo_set_render_target;
99 driver->finish_render = gl_fbo_finish_render;
100 driver->display_render_buffer = gl_fbo_display_render_buffer;
101 driver->load_frame_buffer = gl_fbo_load_frame_buffer;
102 driver->display_blank = gl_fbo_display_blank;
103 driver->read_render_buffer = gl_fbo_read_render_buffer;
105 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
106 glDrawBuffer(GL_FRONT);
107 glReadBuffer(GL_FRONT);
110 void gl_fbo_shutdown()
113 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
114 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
115 glDeleteFramebuffersEXT( 1, &fbo[i].fb_id );
116 glDeleteRenderbuffersEXT( 2, &fbo[i].depth_id );
120 void gl_fbo_setup_framebuffer( int bufno, int width, int height )
122 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id);
123 glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
124 glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height);
125 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
126 GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
127 /* Stencil doesn't work on ATI, and we're not using it at the moment anyway, so...
128 glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);
129 glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_STENCIL_INDEX, width, height);
130 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,
131 GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);
133 fbo[bufno].width = width;
134 fbo[bufno].height = height;
137 int gl_fbo_get_framebuffer( int width, int height )
140 /* find a compatible framebuffer context */
141 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
142 if( fbo[i].width == -1 && bufno == -1 ) {
144 } else if( fbo[i].width == width && fbo[i].height == height ) {
150 bufno = last_used_fbo + 1;
151 if( bufno > MAX_FRAMEBUFFERS ) {
154 last_used_fbo = bufno;
156 if( fbo[bufno].width == width && fbo[bufno].height == height ) {
157 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id );
159 gl_fbo_setup_framebuffer( bufno, width, height );
165 * Attach a texture to the framebuffer. The texture must already be initialized
166 * to the correct dimensions etc.
168 static GLint gl_fbo_attach_texture( int fbo_no, GLint tex_id ) {
170 for( i=0; i<gl_fbo_max_attachments; i++ ) {
171 if( fbo[fbo_no].tex_ids[i] == tex_id ) {
172 glDrawBuffer(ATTACHMENT_POINT(i));
173 glReadBuffer(ATTACHMENT_POINT(i));
174 return ATTACHMENT_POINT(i); // already attached
175 } else if( fbo[fbo_no].tex_ids[i] == -1 && attach == -1 ) {
182 fbo[fbo_no].tex_ids[attach] = tex_id;
183 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, 0 ); // Ensure the output texture is unbound
184 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINT(attach),
185 GL_TEXTURE_RECTANGLE_ARB, tex_id, 0 );
186 /* Set draw/read buffers by default */
187 glDrawBuffer(ATTACHMENT_POINT(attach));
188 glReadBuffer(ATTACHMENT_POINT(attach));
191 GLint status = glGetError();
192 if( status != GL_NO_ERROR ) {
193 ERROR( "GL error setting render target (%x)!", status );
195 status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
196 if( status != GL_FRAMEBUFFER_COMPLETE_EXT ) {
197 ERROR( "Framebuffer failure: %x", status );
201 return ATTACHMENT_POINT(attach);
204 static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height, GLuint tex_id )
206 render_buffer_t buffer = calloc( sizeof(struct render_buffer), 1 );
207 buffer->width = width;
208 buffer->height = height;
209 buffer->tex_id = tex_id;
212 glGenTextures( 1, &tex );
213 buffer->buf_id = tex;
214 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, tex );
215 glTexImage2D( GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL );
217 buffer->buf_id = tex_id;
218 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, tex_id );
220 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP );
221 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP );
222 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
223 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
228 * Ensure the texture in the given render buffer is not attached to a
229 * framebuffer (ie, so we can safely use it as a texture during the rendering
230 * cycle, or before deletion).
232 static void gl_fbo_detach_render_buffer( render_buffer_t buffer )
235 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
236 if( fbo[i].width == buffer->width && fbo[i].height == buffer->height ) {
237 for( j=0; j<gl_fbo_max_attachments; j++ ) {
238 if( fbo[i].tex_ids[j] == buffer->buf_id ) {
239 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo[i].fb_id);
240 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINT(j),
241 GL_TEXTURE_RECTANGLE_ARB, GL_NONE, 0 );
242 fbo[i].tex_ids[j] = -1;
251 static void gl_fbo_destroy_render_buffer( render_buffer_t buffer )
255 gl_fbo_detach_render_buffer( buffer );
257 if( buffer->buf_id != buffer->tex_id ) {
258 // If tex_id was set at buffer creation, we don't own the texture.
259 // Otherwise, delete it now.
260 GLuint tex = buffer->buf_id;
261 glDeleteTextures( 1, &tex );
268 static gboolean gl_fbo_set_render_target( render_buffer_t buffer )
272 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
273 gl_fbo_attach_texture( fb, buffer->buf_id );
274 /* setup the gl context */
275 glViewport( 0, 0, buffer->width, buffer->height );
280 static void gl_fbo_finish_render( render_buffer_t buffer )
284 gl_fbo_detach_render_buffer(buffer);
288 * Render the texture holding the given buffer to the front window
291 static void gl_fbo_display_render_buffer( render_buffer_t buffer )
295 gl_display_render_buffer( buffer );
298 static void gl_fbo_load_frame_buffer( frame_buffer_t frame, render_buffer_t buffer )
302 gl_load_frame_buffer( frame, buffer->buf_id );
305 static void gl_fbo_display_blank( uint32_t colour )
309 gl_display_blank( colour );
314 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
315 glDrawBuffer( GL_FRONT );
316 glReadBuffer( GL_FRONT );
319 static gboolean gl_fbo_read_render_buffer( unsigned char *target, render_buffer_t buffer,
320 int rowstride, int format )
322 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
323 gl_fbo_attach_texture( fb, buffer->buf_id );
324 return gl_read_render_buffer( target, buffer, rowstride, format );
328 gboolean gl_fbo_is_supported()
333 void gl_fbo_init( display_driver_t driver )
.