src/graphics/framebuffer.c

   1 /************************************************************************
   2 * framebuffer.c
   3 * voxelands - 3d voxel world sandbox game
   4 * Copyright (C) Lisa 'darkrose' Milne 2016 <lisa@ltmnet.com>
   5 *
   6 * This program is free software: you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation, either version 3 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful, but
  12 * WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  14 * See the GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program.  If not, see <http://www.gnu.org/licenses/>
  18 ************************************************************************/
  19
  20 #include "common.h"
  21 #include "graphics.h"
  22 #include "list.h"
  23
  24 static struct {
  25         framebuffer_t *buffers;
  26         int ids;
  27 } fbo_data = {
  28         NULL,
  29         0
  30 };
  31
  32 /* create a texture attachment for a fbo */
  33 static int fbo_create_texture(int w, int h, fbo_buffer_t *b, uint8_t d)
  34 {
  35         texture_t *t;
  36
  37         t = tex_create();
  38
  39         glGenTextures(1,&t->glid);
  40         glBindTexture(GL_TEXTURE_2D, t->glid);
  41         if (d) {
  42                 glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT32, w, h, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
  43         }else{
  44                 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
  45         }
  46
  47         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  48         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  49
  50         if (d) {
  51                 glFramebufferTexture(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, t->glid, 0);
  52         }else{
  53                 glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, t->glid, 0);
  54         }
  55
  56         t->state = 1;
  57
  58         b->texture = t;
  59
  60         return 0;
  61 }
  62
  63 /* create a buffer attachment for a fbo */
  64 static int fbo_create_buffer(int w, int h, fbo_buffer_t *b)
  65 {
  66         glGenRenderbuffers(1,&b->glid);
  67
  68         glBindRenderbuffer(GL_RENDERBUFFER, b->glid);
  69         glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, w, h);
  70         glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, b->glid);
  71
  72         return 0;
  73 }
  74
  75 /* create a frame buffer object of width and height, with colour and depth buffers optionally bound to textures */
  76 framebuffer_t *fbo_create(int w, int h, uint8_t c_texture, uint8_t d_texture)
  77 {
  78         framebuffer_t *f;
  79
  80         f = malloc(sizeof(framebuffer_t));
  81         if (!f)
  82                 return NULL;
  83
  84         f->depth.glid = 0;
  85         f->colour.glid = 0;
  86         f->id = ++fbo_data.ids;
  87         f->w = w;
  88         f->h = h;
  89
  90         glGenFramebuffers(1,&f->glid);
  91
  92         glBindFramebuffer(GL_FRAMEBUFFER, f->glid);
  93
  94         if (c_texture) {
  95                 glDrawBuffer(GL_COLOR_ATTACHMENT0);
  96                 fbo_create_texture(w,h,&f->colour,0);
  97         }else{
  98                 glDrawBuffer(GL_NONE);
  99         }
 100
 101         if (d_texture) {
 102                 fbo_create_texture(w,h,&f->depth,1);
 103         }else{
 104                 fbo_create_buffer(w,h,&f->depth);
 105         }
 106
 107         glBindFramebuffer(GL_FRAMEBUFFER, 0);
 108
 109         fbo_data.buffers = list_append(&fbo_data.buffers,f);
 110
 111         return f;
 112 }
 113
 114 /* free a framebuffer */
 115 void fbo_free(framebuffer_t *f)
 116 {
 117         /* TODO: this */
 118 }
 119
 120 /* get a framebuffer by id */
 121 framebuffer_t *fbo_get(int id)
 122 {
 123         framebuffer_t *f = fbo_data.buffers;
 124
 125         while (f) {
 126                 if (f->id == id)
 127                         return f;
 128                 f = f->next;
 129         }
 130
 131         return NULL;
 132 }
 133
 134 /* use/bind a framebuffer */
 135 void fbo_use(framebuffer_t *f)
 136 {
 137         glBindTexture(GL_TEXTURE_2D, 0);
 138         glBindFramebuffer(GL_FRAMEBUFFER, f->glid);
 139         glViewport(0, 0, f->w, f->h);
 140         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 141         glEnable(GL_DEPTH_TEST);
 142 }
 143
 144 /* unbind framebuffers */
 145 void fbo_unbind_all()
 146 {
 147         glBindFramebuffer(GL_FRAMEBUFFER, 0);
 148         glViewport(0, 0, wm_data.size.width, wm_data.size.height);
 149 }