nkeynes@352: /**
nkeynes@443:  * $Id: gl_fbo.c,v 1.5 2007-10-13 04:01:02 nkeynes Exp $
nkeynes@352:  *
nkeynes@352:  * GL framebuffer-based driver shell. This requires the EXT_framebuffer_object
nkeynes@352:  * extension, but is much nicer/faster/etc than pbuffers when it's available.
nkeynes@352:  * This is (optionally) used indirectly by the top-level GLX driver.
nkeynes@352:  *
nkeynes@352:  * Strategy-wise, we maintain 2 framebuffers with up to 4 target colour
nkeynes@352:  * buffers a piece. Effectively this reserves one fb for display output,
nkeynes@352:  * and the other for texture output (each fb has a single size).
nkeynes@352:  *
nkeynes@352:  * Copyright (c) 2005 Nathan Keynes.
nkeynes@352:  *
nkeynes@352:  * This program is free software; you can redistribute it and/or modify
nkeynes@352:  * it under the terms of the GNU General Public License as published by
nkeynes@352:  * the Free Software Foundation; either version 2 of the License, or
nkeynes@352:  * (at your option) any later version.
nkeynes@352:  *
nkeynes@352:  * This program is distributed in the hope that it will be useful,
nkeynes@352:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
nkeynes@352:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nkeynes@352:  * GNU General Public License for more details.
nkeynes@352:  */
nkeynes@352: 
nkeynes@424: #define GL_GLEXT_PROTOTYPES 1
nkeynes@424: 
nkeynes@352: #include <GL/gl.h>
nkeynes@424: #include <GL/glext.h>
nkeynes@352: #include "display.h"
nkeynes@424: #include "drivers/video_x11.h"
nkeynes@424: #include "drivers/gl_common.h"
nkeynes@352: 
nkeynes@352: #define MAX_FRAMEBUFFERS 2
nkeynes@352: #define MAX_TEXTURES_PER_FB 4
nkeynes@352: 
nkeynes@352: static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height );
nkeynes@352: static void gl_fbo_destroy_render_buffer( render_buffer_t buffer );
nkeynes@352: static gboolean gl_fbo_set_render_target( render_buffer_t buffer );
nkeynes@352: static gboolean gl_fbo_display_render_buffer( render_buffer_t buffer );
nkeynes@352: static gboolean gl_fbo_display_frame_buffer( frame_buffer_t buffer );
nkeynes@352: static gboolean gl_fbo_display_blank( uint32_t colour );
nkeynes@429: static gboolean gl_fbo_read_render_buffer( render_buffer_t buffer, unsigned char *target );
nkeynes@352: 
nkeynes@352: extern uint32_t video_width, video_height;
nkeynes@352: 
nkeynes@352: /**
nkeynes@352:  * Framebuffer info structure
nkeynes@352:  */
nkeynes@352: struct gl_fbo_info {
nkeynes@352:     GLuint fb_id;
nkeynes@352:     GLuint depth_id;
nkeynes@352:     GLuint stencil_id;
nkeynes@352:     GLuint tex_ids[MAX_TEXTURES_PER_FB];
nkeynes@352:     int width, height;
nkeynes@352: };
nkeynes@352: 
nkeynes@352: static struct gl_fbo_info fbo[MAX_FRAMEBUFFERS];
nkeynes@352: const static int ATTACHMENT_POINTS[MAX_TEXTURES_PER_FB] = {
nkeynes@352:     GL_COLOR_ATTACHMENT0_EXT, GL_COLOR_ATTACHMENT1_EXT, 
nkeynes@352:     GL_COLOR_ATTACHMENT2_EXT, GL_COLOR_ATTACHMENT3_EXT };
nkeynes@352: static int last_used_fbo;
nkeynes@352: 
nkeynes@352: gboolean gl_fbo_is_supported()
nkeynes@352: {
nkeynes@352:     return isGLExtensionSupported("GL_EXT_framebuffer_object");
nkeynes@352: }
nkeynes@352: 
nkeynes@352: /**
nkeynes@352:  * Construct the initial frame buffers and allocate ids for everything.
nkeynes@352:  * The render handling driver methods are set to the fbo versions.
nkeynes@352:  */
nkeynes@352: void gl_fbo_init( display_driver_t driver ) 
nkeynes@352: {
nkeynes@352:     int i,j;
nkeynes@424:     GLuint fbids[MAX_FRAMEBUFFERS];
nkeynes@424:     GLuint rbids[MAX_FRAMEBUFFERS*2]; /* depth buffer, stencil buffer per fb */
nkeynes@352:     
nkeynes@424:     glGenFramebuffersEXT( MAX_FRAMEBUFFERS, &fbids[0] );
nkeynes@424:     glGenRenderbuffersEXT( MAX_FRAMEBUFFERS*2, &rbids[0] );
nkeynes@352:     for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
nkeynes@352: 	fbo[i].fb_id = fbids[i];
nkeynes@352: 	fbo[i].depth_id = rbids[i*2];
nkeynes@352: 	fbo[i].stencil_id = rbids[i*2+1];
nkeynes@352: 	fbo[i].width = -1;
nkeynes@352: 	fbo[i].height = -1;
nkeynes@352: 	for( j=0; j<MAX_TEXTURES_PER_FB; j++ ) {
nkeynes@352: 	    fbo[i].tex_ids[j] = -1;
nkeynes@352: 	}
nkeynes@352:     }
nkeynes@352:     last_used_fbo = 0;
nkeynes@352: 
nkeynes@352:     driver->create_render_buffer = gl_fbo_create_render_buffer;
nkeynes@352:     driver->destroy_render_buffer = gl_fbo_destroy_render_buffer;
nkeynes@352:     driver->set_render_target = gl_fbo_set_render_target;
nkeynes@352:     driver->display_render_buffer = gl_fbo_display_render_buffer;
nkeynes@352:     driver->display_frame_buffer = gl_fbo_display_frame_buffer;
nkeynes@352:     driver->display_blank = gl_fbo_display_blank;
nkeynes@352:     driver->read_render_buffer = gl_fbo_read_render_buffer;
nkeynes@352: }
nkeynes@352: 
nkeynes@352: void gl_fbo_shutdown()
nkeynes@352: {
nkeynes@352:     int i;
nkeynes@352:     glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
nkeynes@352:     for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
nkeynes@352: 	glDeleteFramebuffersEXT( 1, &fbo[i].fb_id );
nkeynes@352: 	glDeleteRenderbuffersEXT( 2, &fbo[i].depth_id );
nkeynes@352:     }
nkeynes@352: }
nkeynes@352: 
nkeynes@352: void gl_fbo_setup_framebuffer( int bufno, int width, int height )
nkeynes@352: {
nkeynes@352:     glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id);
nkeynes@352:     glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
nkeynes@352:     glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height);
nkeynes@352:     glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
nkeynes@352: 				 GL_RENDERBUFFER_EXT, fbo[bufno].depth_id);
nkeynes@352:     /* Stencil doesn't work on ATI, and we're not using it at the moment anyway, so...
nkeynes@352:     glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);
nkeynes@352:     glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_STENCIL_INDEX, width, height);
nkeynes@352:     glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,
nkeynes@352: 				 GL_RENDERBUFFER_EXT, fbo[bufno].stencil_id);
nkeynes@352:     */
nkeynes@352:     fbo[bufno].width = width;
nkeynes@352:     fbo[bufno].height = height;
nkeynes@352: }
nkeynes@352: 
nkeynes@352: int gl_fbo_get_framebuffer( int width, int height ) 
nkeynes@352: {
nkeynes@352:     int bufno = -1, i;
nkeynes@352:     /* find a compatible framebuffer context */
nkeynes@352:     for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
nkeynes@352: 	if( fbo[i].width == -1 && bufno == -1 ) {
nkeynes@352: 	    bufno = i;
nkeynes@352: 	} else if( fbo[i].width == width && fbo[i].height == height ) {
nkeynes@352: 	    bufno = i;
nkeynes@352: 	    break;
nkeynes@352: 	}
nkeynes@352:     }
nkeynes@352:     if( bufno == -1 ) {
nkeynes@352: 	bufno = last_used_fbo + 1;
nkeynes@352: 	if( bufno > MAX_FRAMEBUFFERS ) {
nkeynes@352: 	    bufno = 0;
nkeynes@352: 	}
nkeynes@352: 	last_used_fbo = bufno;
nkeynes@352:     }
nkeynes@352:     if( fbo[bufno].width == width && fbo[bufno].height == height ) {
nkeynes@352: 	glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, fbo[bufno].fb_id );
nkeynes@352:     } else {
nkeynes@352: 	gl_fbo_setup_framebuffer( bufno, width, height );
nkeynes@352:     } 
nkeynes@352:     return bufno;
nkeynes@352: }
nkeynes@352: 
nkeynes@352: /**
nkeynes@352:  * Attach a texture to the framebuffer. The texture must already be initialized
nkeynes@352:  * to the correct dimensions etc.
nkeynes@352:  */
nkeynes@352: static GLint gl_fbo_attach_texture( int fbo_no, GLint tex_id ) {
nkeynes@352:     int attach = -1, i;
nkeynes@352:     for( i=0; i<MAX_TEXTURES_PER_FB; i++ ) {
nkeynes@352: 	if( fbo[fbo_no].tex_ids[i] == tex_id ) {
nkeynes@352: 	    glDrawBuffer(ATTACHMENT_POINTS[i]);
nkeynes@352: 	    glReadBuffer(ATTACHMENT_POINTS[i]); 
nkeynes@352: 	    return ATTACHMENT_POINTS[i]; // already attached
nkeynes@352: 	} else if( fbo[fbo_no].tex_ids[i] == -1 && attach == -1 ) {
nkeynes@352: 	    attach = i;
nkeynes@352: 	}
nkeynes@352:     }
nkeynes@352:     if( attach == -1 ) {
nkeynes@352: 	/* should never happen */
nkeynes@352: 	attach = 0;
nkeynes@352:     }
nkeynes@352:     fbo[fbo_no].tex_ids[attach] = tex_id;
nkeynes@352:     glBindTexture( GL_TEXTURE_RECTANGLE_ARB, 0 ); // Ensure the output texture is unbound
nkeynes@352:     glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINTS[attach], 
nkeynes@352: 			      GL_TEXTURE_RECTANGLE_ARB, tex_id, 0 );
nkeynes@352:     /* Set draw/read buffers by default */
nkeynes@352:     glDrawBuffer(ATTACHMENT_POINTS[attach]);
nkeynes@352:     glReadBuffer(ATTACHMENT_POINTS[attach]); 
nkeynes@352: 
nkeynes@352: 
nkeynes@352:     GLint status = glGetError();
nkeynes@352:     if( status != GL_NO_ERROR ) {
nkeynes@352: 	ERROR( "GL error setting render target (%x)!", status );
nkeynes@352:     }
nkeynes@352:     status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
nkeynes@352:     if( status != GL_FRAMEBUFFER_COMPLETE_EXT ) {
nkeynes@352: 	ERROR( "Framebuffer failure: %x", status );
nkeynes@352: 	exit(1);
nkeynes@352:     }
nkeynes@352: 
nkeynes@352:     return ATTACHMENT_POINTS[attach];
nkeynes@352: }
nkeynes@352: 
nkeynes@352: static render_buffer_t gl_fbo_create_render_buffer( uint32_t width, uint32_t height )
nkeynes@352: {
nkeynes@352:     render_buffer_t buffer = calloc( sizeof(struct render_buffer), 1 );
nkeynes@352:     buffer->width = width;
nkeynes@352:     buffer->height = height;
nkeynes@352:     glGenTextures( 1, &buffer->buf_id );
nkeynes@352:     glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->buf_id );
nkeynes@352:     glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP );
nkeynes@352:     glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP );
nkeynes@352:     glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
nkeynes@352:     glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
nkeynes@352:     glTexImage2D( GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL );
nkeynes@352:     return buffer;
nkeynes@352: }
nkeynes@352: 
nkeynes@352: static void gl_fbo_destroy_render_buffer( render_buffer_t buffer )
nkeynes@352: {
nkeynes@352:     int i,j;
nkeynes@352:     for( i=0; i<MAX_FRAMEBUFFERS; i++ ) {
nkeynes@352: 	for( j=0; j < MAX_TEXTURES_PER_FB; j++ ) {
nkeynes@352: 	    if( fbo[i].tex_ids[j] == buffer->buf_id ) {
nkeynes@352: 		glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, ATTACHMENT_POINTS[j], 
nkeynes@352: 					  GL_TEXTURE_RECTANGLE_ARB, GL_NONE, 0 );
nkeynes@352: 		fbo[i].tex_ids[j] = -1;
nkeynes@352: 	    }
nkeynes@352: 	}
nkeynes@352:     }
nkeynes@352:     
nkeynes@352:     glDeleteTextures( 1, &buffer->buf_id );
nkeynes@352:     buffer->buf_id = 0;
nkeynes@352:     free( buffer );
nkeynes@352: }
nkeynes@352: 
nkeynes@352: static gboolean gl_fbo_set_render_target( render_buffer_t buffer )
nkeynes@352: {
nkeynes@352:     glGetError();
nkeynes@352:     int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
nkeynes@424:     gl_fbo_attach_texture( fb, buffer->buf_id );
nkeynes@352:     /* setup the gl context */
nkeynes@352:     glViewport( 0, 0, buffer->width, buffer->height );
nkeynes@352:     
nkeynes@352:     return TRUE;
nkeynes@352: }
nkeynes@352: 
nkeynes@352: /**
nkeynes@352:  * Render the texture holding the given buffer to the front window
nkeynes@352:  * buffer.
nkeynes@352:  */
nkeynes@352: static gboolean gl_fbo_display_render_buffer( render_buffer_t buffer )
nkeynes@352: {
nkeynes@352:     glFinish();
nkeynes@352:     glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 ); // real window
nkeynes@443:     glDrawBuffer( GL_FRONT );
nkeynes@443:     glReadBuffer( GL_FRONT );
nkeynes@443:     gl_display_tex_rectangle( buffer->buf_id, buffer->width, buffer->height, TRUE );
nkeynes@443:     /*
nkeynes@352:     glViewport( 0, 0, video_width, video_height );
nkeynes@352:     glEnable( GL_TEXTURE_RECTANGLE_ARB );
nkeynes@352:     glBindTexture( GL_TEXTURE_RECTANGLE_ARB, buffer->buf_id );
nkeynes@352:     glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE );
nkeynes@438:     glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
nkeynes@438:     glTexParameteri( GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
nkeynes@352:     glDisable( GL_ALPHA_TEST );
nkeynes@352:     glDisable( GL_DEPTH_TEST );
nkeynes@352:     glDisable( GL_SCISSOR_TEST );
nkeynes@352:     glDisable( GL_CULL_FACE );
nkeynes@352: 
nkeynes@352:     glMatrixMode(GL_PROJECTION);
nkeynes@352:     glLoadIdentity();
nkeynes@352:     glOrtho( 0, buffer->width, buffer->height, 0, 0, -65535 );
nkeynes@352:     glMatrixMode(GL_MODELVIEW);
nkeynes@352:     glLoadIdentity();
nkeynes@352:     glEnable( GL_BLEND );
nkeynes@352:     glBlendFunc( GL_ONE, GL_ZERO );
nkeynes@352:     glDisable( GL_DEPTH_TEST );
nkeynes@352:     glBegin( GL_QUADS );
nkeynes@438:     glTexCoord2i( 0.5, buffer->height-0.5 );
nkeynes@352:     glVertex2f( 0.0, 0.0 );
nkeynes@438:     glTexCoord2i( buffer->width-0.5, buffer->height-0.5 );
nkeynes@352:     glVertex2f( buffer->width, 0.0 );
nkeynes@438:     glTexCoord2i( buffer->width-0.5, 0 );
nkeynes@352:     glVertex2f( buffer->width, buffer->height );
nkeynes@438:     glTexCoord2i( 0.5, 0.5 );
nkeynes@352:     glVertex2f( 0.0, buffer->height );
nkeynes@352:     glEnd();
nkeynes@352:     glDisable( GL_TEXTURE_RECTANGLE_ARB );
nkeynes@352:     glFlush();
nkeynes@443:     */
nkeynes@352:     return TRUE;
nkeynes@352: }
nkeynes@352: 
nkeynes@352: static gboolean gl_fbo_display_frame_buffer( frame_buffer_t buffer )
nkeynes@352: {
nkeynes@352:     glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
nkeynes@352:     glDrawBuffer( GL_FRONT );
nkeynes@352:     glReadBuffer( GL_FRONT );
nkeynes@352:     return gl_display_frame_buffer( buffer );
nkeynes@352: }
nkeynes@352: 
nkeynes@352: static gboolean gl_fbo_display_blank( uint32_t colour )
nkeynes@352: {
nkeynes@352:     glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
nkeynes@352:     glDrawBuffer( GL_FRONT );
nkeynes@352:     glReadBuffer( GL_FRONT );
nkeynes@352:     return gl_display_blank( colour );
nkeynes@352: }
nkeynes@352: 
nkeynes@429: static gboolean gl_fbo_read_render_buffer( render_buffer_t buffer, unsigned char *target )
nkeynes@352: {
nkeynes@352:     int fb = gl_fbo_get_framebuffer( buffer->width, buffer->height );
nkeynes@424:     gl_fbo_attach_texture( fb, buffer->buf_id );
nkeynes@352:     return gl_read_render_buffer( buffer, target );
nkeynes@352: }
nkeynes@352: