src/scene-terrain/base-renderer.cpp

/*
 * Copyright © 2012 Linaro Limited
 *
 * This file is part of the glmark2 OpenGL (ES) 2.0 benchmark.
 *
 * glmark2 is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 *
 * glmark2 is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * glmark2.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Authors:
 *  Alexandros Frantzis
 */
#include "renderer.h"

BaseRenderer::BaseRenderer(const LibMatrix::vec2 &size) :
    texture_(0), input_texture_(0), fbo_(0), depth_renderbuffer_(0),
    min_filter_(GL_LINEAR), mag_filter_(GL_LINEAR),
    wrap_s_(GL_CLAMP_TO_EDGE), wrap_t_(GL_CLAMP_TO_EDGE)
{
    setup(size, true, true);
}

BaseRenderer::~BaseRenderer()
{
    glDeleteTextures(1, &texture_);
    glDeleteRenderbuffers(1, &depth_renderbuffer_);
    glDeleteFramebuffers(1, &fbo_);
}

void
BaseRenderer::setup(const LibMatrix::vec2 &size, bool onscreen, bool has_depth)
{
    size_ = size;
    recreate(onscreen, has_depth);
}

void
BaseRenderer::setup_texture(GLint min_filter, GLint mag_filter,
                            GLint wrap_s, GLint wrap_t)
{
    min_filter_ = min_filter;
    mag_filter_ = mag_filter;
    wrap_s_ = wrap_s;
    wrap_t_ = wrap_t;
    update_texture_parameters();
}

void
BaseRenderer::make_current()
{
    glBindFramebuffer(GL_FRAMEBUFFER, fbo_);
    glViewport(0, 0, size_.x(), size_.y());
    if (!fbo_ || depth_renderbuffer_) {
        glEnable(GL_DEPTH_TEST);
        glDepthMask(GL_TRUE);
    }
    else {
        glDisable(GL_DEPTH_TEST);
        glDepthMask(GL_FALSE);
    }
}

void
BaseRenderer::update_mipmap()
{
    if (texture_ && min_filter_ != GL_NEAREST && min_filter_ != GL_LINEAR) {
        glBindTexture(GL_TEXTURE_2D, texture_);
        glGenerateMipmap(GL_TEXTURE_2D);
    }
}

void
BaseRenderer::recreate(bool onscreen, bool has_depth)
{
    if (texture_) {
        glDeleteTextures(1, &texture_);
        texture_ = 0;
    }
    if (fbo_) {
        glDeleteRenderbuffers(1, &depth_renderbuffer_);
        depth_renderbuffer_ = 0;
        glDeleteFramebuffers(1, &fbo_);
        fbo_ = 0;
    }
    if (!onscreen) {
        create_texture();
        create_fbo(has_depth);
    }
}

void
BaseRenderer::create_texture()
{
    glGenTextures(1, &texture_);
    glBindTexture(GL_TEXTURE_2D, texture_);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, size_.x(), size_.y(), 0,
            GL_RGBA, GL_UNSIGNED_BYTE, 0);
    update_texture_parameters();
}

void
BaseRenderer::update_texture_parameters()
{
    if (texture_) {
        glBindTexture(GL_TEXTURE_2D, texture_);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, min_filter_);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, mag_filter_);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, wrap_s_);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, wrap_t_);
    }
    update_mipmap();
}

void
BaseRenderer::create_fbo(bool has_depth)
{
    if (has_depth) {
        /* Create a renderbuffer for depth storage */
        glGenRenderbuffers(1, &depth_renderbuffer_);
        glBindRenderbuffer(GL_RENDERBUFFER, depth_renderbuffer_);
        glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16,
                size_.x(), size_.y());
    }

    /* Create the FBO and attach the texture and the renderebuffer */
    glGenFramebuffers(1, &fbo_);
    glBindFramebuffer(GL_FRAMEBUFFER, fbo_);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
            GL_TEXTURE_2D, texture_, 0);
    if (has_depth) {
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
                GL_RENDERBUFFER, depth_renderbuffer_);
    }
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
}