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 4
38 static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height );
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_display_render_buffer( render_buffer_t buffer );
42 static void gl_fbo_load_frame_buffer( frame_buffer_t frame, render_buffer_t buffer );
43 static void gl_fbo_display_blank( uint32_t colour );
44 static gboolean gl_fbo_read_render_buffer( unsigned char *target, render_buffer_t buffer, int rowstride, int format );
46 extern uint32_t video_width, video_height;
49 * Framebuffer info structure
55 GLuint tex_ids[MAX_TEXTURES_PER_FB];
59 static struct gl_fbo_info fbo[MAX_FRAMEBUFFERS];
60 const static int ATTACHMENT_POINTS[MAX_TEXTURES_PER_FB] = {
61 GL_COLOR_ATTACHMENT0_EXT, GL_COLOR_ATTACHMENT1_EXT,
62 GL_COLOR_ATTACHMENT2_EXT, GL_COLOR_ATTACHMENT3_EXT };
63 static int last_used_fbo;
65 gboolean gl_fbo_is_supported()
67 return isGLExtensionSupported("GL_EXT_framebuffer_object");
71 * Construct the initial frame buffers and allocate ids for everything.
72 * The render handling driver methods are set to the fbo versions.
74 void gl_fbo_init( display_driver_t driver )
77 GLuint fbids[MAX_FRAMEBUFFERS];
78 GLuint rbids[MAX_FRAMEBUFFERS*2]; /* depth buffer, stencil buffer per fb */
80 glGenFramebuffersEXT( MAX_FRAMEBUFFERS, &fbids[0] );
81 glGenRenderbuffersEXT( MAX_FRAMEBUFFERS*2, &rbids[0] );
82 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
83 fbo[i].fb_id = fbids[i];
84 fbo[i].depth_id = rbids[i*2];
85 fbo[i].stencil_id = rbids[i*2+1];
88 for( j=0; j<MAX_TEXTURES_PER_FB; j++ ) {
89 fbo[i].tex_ids[j] = -1;
94 driver->create_render_buffer = gl_fbo_create_render_buffer;
95 driver->destroy_render_buffer = gl_fbo_destroy_render_buffer;
96 driver->set_render_target = gl_fbo_set_render_target;
97 driver->display_render_buffer = gl_fbo_display_render_buffer;
98 driver->load_frame_buffer = gl_fbo_load_frame_buffer;
99 driver->display_blank = gl_fbo_display_blank;
100 driver->read_render_buffer = gl_fbo_read_render_buffer;
102 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
103 glDrawBuffer(GL_FRONT);
104 glReadBuffer(GL_FRONT);
107 void gl_fbo_shutdown()
110 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
111 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
112 glDeleteFramebuffersEXT( 1, &fbo[i].fb_id );
113 glDeleteRenderbuffersEXT( 2, &fbo[i].depth_id );
117 void gl_fbo_setup_framebuffer( int bufno, int width, int height )
119 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id);
120 glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
121 glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height);
122 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
123 GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
124 /* Stencil doesn't work on ATI, and we're not using it at the moment anyway, so...
125 glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);
126 glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_STENCIL_INDEX, width, height);
127 glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,
128 GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);
130 fbo[bufno].width = width;
131 fbo[bufno].height = height;
134 int gl_fbo_get_framebuffer( int width, int height )
137 /* find a compatible framebuffer context */
138 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
139 if( fbo[i].width == -1 && bufno == -1 ) {
141 } else if( fbo[i].width == width && fbo[i].height == height ) {
147 bufno = last_used_fbo + 1;
148 if( bufno > MAX_FRAMEBUFFERS ) {
151 last_used_fbo = bufno;
153 if( fbo[bufno].width == width && fbo[bufno].height == height ) {
154 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id );
156 gl_fbo_setup_framebuffer( bufno, width, height );
162 * Attach a texture to the framebuffer. The texture must already be initialized
163 * to the correct dimensions etc.
165 static GLint gl_fbo_attach_texture( int fbo_no, GLint tex_id ) {
167 for( i=0; i<MAX_TEXTURES_PER_FB; i++ ) {
168 if( fbo[fbo_no].tex_ids[i] == tex_id ) {
169 glDrawBuffer(ATTACHMENT_POINTS[i]);
170 glReadBuffer(ATTACHMENT_POINTS[i]);
171 return ATTACHMENT_POINTS[i]; // already attached
172 } else if( fbo[fbo_no].tex_ids[i] == -1 && attach == -1 ) {
177 /* should never happen */
180 fbo[fbo_no].tex_ids[attach] = tex_id;
181 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, 0 ); // Ensure the output texture is unbound
182 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINTS[attach],
183 GL_TEXTURE_RECTANGLE_ARB, tex_id, 0 );
184 /* Set draw/read buffers by default */
185 glDrawBuffer(ATTACHMENT_POINTS[attach]);
186 glReadBuffer(ATTACHMENT_POINTS[attach]);
189 GLint status = glGetError();
190 if( status != GL_NO_ERROR ) {
191 ERROR( "GL error setting render target (%x)!", status );
193 status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
194 if( status != GL_FRAMEBUFFER_COMPLETE_EXT ) {
195 ERROR( "Framebuffer failure: %x", status );
199 return ATTACHMENT_POINTS[attach];
202 static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height )
204 render_buffer_t buffer = calloc( sizeof(struct render_buffer), 1 );
205 buffer->width = width;
206 buffer->height = height;
207 glGenTextures( 1, &buffer->buf_id );
208 glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->buf_id );
209 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP );
210 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP );
211 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
212 glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
213 glTexImage2D( GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL );
217 static void gl_fbo_destroy_render_buffer( render_buffer_t buffer )
220 for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
221 for( j=0; j < MAX_TEXTURES_PER_FB; j++ ) {
222 if( fbo[i].tex_ids[j] == buffer->buf_id ) {
223 glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo[i].fb_id);
224 glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINTS[j],
225 GL_TEXTURE_RECTANGLE_ARB, GL_NONE, 0 );
226 fbo[i].tex_ids[j] = -1;
231 glDeleteTextures( 1, &buffer->buf_id );
236 static gboolean gl_fbo_set_render_target( render_buffer_t buffer )
240 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
241 gl_fbo_attach_texture( fb, buffer->buf_id );
242 /* setup the gl context */
243 glViewport( 0, 0, buffer->width, buffer->height );
249 * Render the texture holding the given buffer to the front window
252 static void gl_fbo_display_render_buffer( render_buffer_t buffer )
256 gl_display_render_buffer( buffer );
259 static void gl_fbo_load_frame_buffer( frame_buffer_t frame, render_buffer_t buffer )
263 gl_load_frame_buffer( frame, buffer->buf_id );
266 static void gl_fbo_display_blank( uint32_t colour )
270 gl_display_blank( colour );
275 glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
276 glDrawBuffer( GL_FRONT );
277 glReadBuffer( GL_FRONT );
280 static gboolean gl_fbo_read_render_buffer( unsigned char *target, render_buffer_t buffer,
281 int rowstride, int format )
283 int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
284 gl_fbo_attach_texture( fb, buffer->buf_id );
285 return gl_read_render_buffer( target, buffer, rowstride, format );
289 gboolean gl_fbo_is_supported()
294 void gl_fbo_init( display_driver_t driver )
.