src/scene-terrain.cpp - people/jessebarker/glmark2 - Git at Google

 /*
  * 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 "scene.h"
 #include "mat.h"
 #include "stack.h"
 #include "vec.h"
 #include "log.h"
 #include "mesh.h"
 #include "util.h"
 #include "texture.h"
 #include "shader-source.h"
 #include "renderer.h"

 using LibMatrix::vec2;
 using LibMatrix::vec3;
 using LibMatrix::vec4;
 using LibMatrix::mat4;

 class SceneTerrainPrivate
 {
 public:
     SceneTerrainPrivate(Canvas &canvas, const LibMatrix::vec2 &repeat_overlay,
                         bool use_bloom, bool use_tilt_shift) :
         canvas(canvas), repeat_overlay(repeat_overlay),
         use_bloom(use_bloom), use_tilt_shift(use_tilt_shift),
         terrain_renderer(0), bloom_v_renderer(0), bloom_h_renderer(0),
         overlay_renderer(0), tilt_v_renderer(0), tilt_h_renderer(0),
         copy_renderer(0), height_map_renderer(0), normal_map_renderer(0),
         specular_map_renderer(0),
         height_normal_chain(0), bloom_chain(0), tilt_chain(0), terrain_chain(0)
     {
         init_renderers();
     }

     ~SceneTerrainPrivate()
     {
         release_renderers();
     }

     void init_renderers()
     {
         /* Create and set up renderers */
         const vec2 map_res(256.0f, 256.0f);
         const vec2 screen_res(canvas.width(), canvas.height());
         const vec2 bloom_res(256.0f, 256.0f);
         const vec2 grass_res(512.0f, 512.0f);

         height_map_renderer = new SimplexNoiseRenderer(map_res);
         height_map_renderer->setup(height_map_renderer->size(), false, false);

         normal_map_renderer = new NormalFromHeightRenderer(map_res);
         normal_map_renderer->setup(normal_map_renderer->size(), false, false);

         specular_map_renderer = new LuminanceRenderer(grass_res);
         specular_map_renderer->setup_texture(GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR,
                                              GL_REPEAT, GL_REPEAT);
         specular_map_renderer->setup(specular_map_renderer->size(), false, false);

         terrain_renderer = new TerrainRenderer(screen_res, repeat_overlay);
         terrain_renderer->setup(terrain_renderer->size(),
                                 !use_bloom && !use_tilt_shift,
                                 true);
         terrain_renderer->setup_texture(GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR,
                                         GL_CLAMP_TO_EDGE, GL_CLAMP_TO_EDGE);

         /* Bloom */
         if (use_bloom) {
             bloom_h_renderer = new BlurRenderer(bloom_res, 2, 4.0,
                                                 BlurRenderer::BlurDirectionHorizontal,
                                                 vec2(1.0, 1.0) / screen_res,
                                                 0.0);
             bloom_h_renderer->setup_texture(GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR,
                                             GL_CLAMP_TO_EDGE, GL_CLAMP_TO_EDGE);
             bloom_h_renderer->setup(bloom_h_renderer->size(), false, false);

             bloom_v_renderer = new BlurRenderer(bloom_res, 2, 4.0,
                                                 BlurRenderer::BlurDirectionVertical,
                                                 vec2(1.0, 1.0) / bloom_res,
                                                 0.0);
             bloom_v_renderer->setup_texture(GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR,
                                             GL_CLAMP_TO_EDGE, GL_CLAMP_TO_EDGE);
             bloom_v_renderer->setup(bloom_v_renderer->size(), false, false);
             overlay_renderer = new OverlayRenderer(*terrain_renderer, 0.6);
         }

         /* Tilt-shift */
         if (use_tilt_shift) {
             tilt_h_renderer = new BlurRenderer(screen_res, 4, 2.7,
                                                BlurRenderer::BlurDirectionHorizontal,
                                                vec2(1.0, 1.0) / screen_res,
                                                0.5);
             tilt_h_renderer->setup_texture(GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR,
                                            GL_CLAMP_TO_EDGE, GL_CLAMP_TO_EDGE);
             tilt_h_renderer->setup(tilt_h_renderer->size(), false, false);

             tilt_v_renderer = new BlurRenderer(screen_res, 4, 2.7,
                                                BlurRenderer::BlurDirectionVertical,
                                                vec2(1.0, 1.0) / screen_res,
                                                0.5);
         }

         /* Copy renderer */
         if (use_bloom && !use_tilt_shift)
             copy_renderer = new CopyRenderer(screen_res);

         /* Height normal chain */
         height_normal_chain = new RendererChain();
         height_normal_chain->append(*height_map_renderer);
         height_normal_chain->append(*normal_map_renderer);

         /* Bloom effect chain */
         if (use_bloom) {
             bloom_chain = new RendererChain();
             bloom_chain->append(*bloom_h_renderer);
             bloom_chain->append(*bloom_v_renderer);
             bloom_chain->append(*overlay_renderer);
         }

         /* Tilt-shift effect chain */
         if (use_tilt_shift) {
             tilt_chain = new RendererChain();
             tilt_chain->append(*tilt_h_renderer);
             tilt_chain->append(*tilt_v_renderer);
         }

         /* Terrain chain */
         terrain_chain = new RendererChain();
         terrain_chain->append(*terrain_renderer);
         if (use_bloom)
             terrain_chain->append(*bloom_chain);
         if (use_tilt_shift)
             terrain_chain->append(*tilt_chain);

         /*
          * If are just using bloom, the terrain is rendered to a texture and
          * bloom applied on that texture. We need to "copy" that texture's
          * contents to the screen to make the scene visible.
          */
         if (use_bloom && !use_tilt_shift)
             terrain_chain->append(*copy_renderer);

         /*
          * Set up renderer textures.
          */
         terrain_renderer->height_map_texture(height_map_renderer->texture());
         terrain_renderer->normal_map_texture(normal_map_renderer->texture());
         terrain_renderer->specular_map_texture(specular_map_renderer->texture());

         specular_map_renderer->input_texture(terrain_renderer->diffuse1_texture());
     }

     void release_renderers()
     {
         delete terrain_chain;
         delete bloom_chain;
         delete tilt_chain;
         delete height_normal_chain;

         delete height_map_renderer;
         delete normal_map_renderer;
         delete specular_map_renderer;
         delete terrain_renderer;
         delete bloom_v_renderer;
         delete bloom_h_renderer;
         delete overlay_renderer;
         delete tilt_v_renderer;
         delete tilt_h_renderer;
         delete copy_renderer;
     }

     Canvas &canvas;
     LibMatrix::vec2 repeat_overlay;
     bool use_bloom;
     bool use_tilt_shift;

     /* Renderers */
     TerrainRenderer *terrain_renderer;
     BlurRenderer *bloom_v_renderer;
     BlurRenderer *bloom_h_renderer;
     OverlayRenderer *overlay_renderer;
     BlurRenderer *tilt_v_renderer;
     BlurRenderer *tilt_h_renderer;
     CopyRenderer *copy_renderer;

     SimplexNoiseRenderer *height_map_renderer;
     NormalFromHeightRenderer *normal_map_renderer;
     LuminanceRenderer *specular_map_renderer;

     /* Chains */
     RendererChain *height_normal_chain;
     RendererChain *bloom_chain;
     RendererChain *tilt_chain;
     RendererChain *terrain_chain;
 };

 SceneTerrain::SceneTerrain(Canvas &pCanvas) :
     Scene(pCanvas, "terrain"), priv_(0)
 {
     options_["repeat-overlay"] = Scene::Option("repeat-overlay", "6.0",
             "How many times to repeat the terrain texture on the terrain plane (per side)");
     options_["bloom"] = Scene::Option("bloom", "true",
                                       "Use bloom post-processing effect",
                                       "false,true");
     options_["tilt-shift"] = Scene::Option("tilt-shift", "true",
                                            "Use tilt-shift post-processing effect",
                                            "false,true");
 }

 SceneTerrain::~SceneTerrain()
 {
     delete priv_;
 }

 bool
 SceneTerrain::supported(bool show_errors)
 {
     GLint vertex_textures;
     glGetIntegerv(GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS, &vertex_textures);

     if (show_errors && vertex_textures <= 0) {
         Log::error("SceneTerrain requires Vertex Texture Fetch support, "
                    "but GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS is %d\n",
                    vertex_textures);
     }

     return vertex_textures > 0;
 }

 bool
 SceneTerrain::load()
 {
     Scene::load();

     running_ = false;

     return true;
 }

 void
 SceneTerrain::unload()
 {
     Scene::unload();
 }

 bool
 SceneTerrain::setup()
 {
     if (!Scene::setup())
         return false;

     /* Parse options */
     float repeat = Util::fromString<double>(options_["repeat-overlay"].value);
     LibMatrix::vec2 repeat_overlay(repeat, repeat);
     bool use_bloom = options_["bloom"].value == "true";
     bool use_tilt_shift = options_["tilt-shift"].value == "true";

     priv_ = new SceneTerrainPrivate(canvas_, repeat_overlay,
                                     use_bloom, use_tilt_shift);

     /* Set up terrain rendering program */
     LibMatrix::Stack4 model;
     LibMatrix::Stack4 camera;
     LibMatrix::mat4 projection = LibMatrix::Mat4::perspective(
             40.0, canvas_.width() / static_cast<float>(canvas_.height()),
             2.0, 4000.0);

     /* Place camera */
     camera.lookAt(-1200.0f, 800.0f, 1200.0f,
                   0.0, 0.0, 0.0,
                   0.0, 1.0, 0.0);

     /* Move and rotate plane */
     model.translate(0.0f, -125.0f, 0.0f);
     model.rotate(-90.0, 1.0f, 0.0f, 0.0f);

     LibMatrix::mat4 view_matrix(camera.getCurrent());
     LibMatrix::mat4 model_matrix(model.getCurrent());

     LibMatrix::mat4 model_view_matrix(view_matrix * model_matrix);

     LibMatrix::mat4 normal_matrix(model_view_matrix);
     normal_matrix.inverse().transpose();

     /* Set up terrain renderer program */
     priv_->terrain_renderer->program().start();
     priv_->terrain_renderer->program()["viewMatrix"] = view_matrix;
     priv_->terrain_renderer->program()["modelViewMatrix"] = model_view_matrix;
     priv_->terrain_renderer->program()["normalMatrix"] = normal_matrix;
     priv_->terrain_renderer->program()["projectionMatrix"] = projection;

     /* Create the specular map */
     priv_->specular_map_renderer->render();

     glBindFramebuffer(GL_FRAMEBUFFER, 0);
     glViewport(0, 0, canvas_.width(), canvas_.height());

     currentFrame_ = 0;
     startTime_ = Util::get_timestamp_us() / 1000000.0;
     running_ = true;

     return true;
 }

 void
 SceneTerrain::teardown()
 {
     delete priv_;
     priv_ = 0;
     Scene::teardown();
 }

 void
 SceneTerrain::update()
 {
     Scene::update();

     double now = Util::get_timestamp_us() / 1000000.0;
     float diff = now - startTime_;
     float scale = priv_->terrain_renderer->repeat_overlay().x() /
                   priv_->height_map_renderer->uv_scale().x();

     /* Update height map */
     priv_->height_map_renderer->program().start();
     priv_->height_map_renderer->program()["uvOffset"] = vec2(diff * 0.05f, 0.0f);
     priv_->terrain_renderer->program().start();
     priv_->terrain_renderer->program()["uOffset"] = vec2(scale * diff * 0.05f, 0.0f);
 }

 void
 SceneTerrain::draw()
 {
     /* Render the height and normal maps used by the terrain */
     priv_->height_normal_chain->render();

     /* Render the terrain plus any post-processing effects */
     priv_->terrain_chain->render();
 }

 Scene::ValidationResult
 SceneTerrain::validate()
 {
     return Scene::ValidationUnknown;
 }
	/*
	* 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 "scene.h"
	#include "mat.h"
	#include "stack.h"
	#include "vec.h"
	#include "log.h"
	#include "mesh.h"
	#include "util.h"
	#include "texture.h"
	#include "shader-source.h"
	#include "renderer.h"

	using LibMatrix::vec2;
	using LibMatrix::vec3;
	using LibMatrix::vec4;
	using LibMatrix::mat4;

	class SceneTerrainPrivate
	{
	public:
	SceneTerrainPrivate(Canvas &canvas, const LibMatrix::vec2 &repeat_overlay,
	bool use_bloom, bool use_tilt_shift) :
	canvas(canvas), repeat_overlay(repeat_overlay),
	use_bloom(use_bloom), use_tilt_shift(use_tilt_shift),
	terrain_renderer(0), bloom_v_renderer(0), bloom_h_renderer(0),
	overlay_renderer(0), tilt_v_renderer(0), tilt_h_renderer(0),
	copy_renderer(0), height_map_renderer(0), normal_map_renderer(0),
	specular_map_renderer(0),
	height_normal_chain(0), bloom_chain(0), tilt_chain(0), terrain_chain(0)
	{
	init_renderers();
	}

	~SceneTerrainPrivate()
	{
	release_renderers();
	}

	void init_renderers()
	{
	/* Create and set up renderers */
	const vec2 map_res(256.0f, 256.0f);
	const vec2 screen_res(canvas.width(), canvas.height());
	const vec2 bloom_res(256.0f, 256.0f);
	const vec2 grass_res(512.0f, 512.0f);

	height_map_renderer = new SimplexNoiseRenderer(map_res);
	height_map_renderer->setup(height_map_renderer->size(), false, false);

	normal_map_renderer = new NormalFromHeightRenderer(map_res);
	normal_map_renderer->setup(normal_map_renderer->size(), false, false);

	specular_map_renderer = new LuminanceRenderer(grass_res);
	specular_map_renderer->setup_texture(GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR,
	GL_REPEAT, GL_REPEAT);
	specular_map_renderer->setup(specular_map_renderer->size(), false, false);

	terrain_renderer = new TerrainRenderer(screen_res, repeat_overlay);
	terrain_renderer->setup(terrain_renderer->size(),
	!use_bloom && !use_tilt_shift,
	true);
	terrain_renderer->setup_texture(GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR,
	GL_CLAMP_TO_EDGE, GL_CLAMP_TO_EDGE);

	/* Bloom */
	if (use_bloom) {
	bloom_h_renderer = new BlurRenderer(bloom_res, 2, 4.0,
	BlurRenderer::BlurDirectionHorizontal,
	vec2(1.0, 1.0) / screen_res,
	0.0);
	bloom_h_renderer->setup_texture(GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR,
	GL_CLAMP_TO_EDGE, GL_CLAMP_TO_EDGE);
	bloom_h_renderer->setup(bloom_h_renderer->size(), false, false);

	bloom_v_renderer = new BlurRenderer(bloom_res, 2, 4.0,
	BlurRenderer::BlurDirectionVertical,
	vec2(1.0, 1.0) / bloom_res,
	0.0);
	bloom_v_renderer->setup_texture(GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR,
	GL_CLAMP_TO_EDGE, GL_CLAMP_TO_EDGE);
	bloom_v_renderer->setup(bloom_v_renderer->size(), false, false);
	overlay_renderer = new OverlayRenderer(*terrain_renderer, 0.6);
	}

	/* Tilt-shift */
	if (use_tilt_shift) {
	tilt_h_renderer = new BlurRenderer(screen_res, 4, 2.7,
	BlurRenderer::BlurDirectionHorizontal,
	vec2(1.0, 1.0) / screen_res,
	0.5);
	tilt_h_renderer->setup_texture(GL_LINEAR_MIPMAP_LINEAR, GL_LINEAR,
	GL_CLAMP_TO_EDGE, GL_CLAMP_TO_EDGE);
	tilt_h_renderer->setup(tilt_h_renderer->size(), false, false);

	tilt_v_renderer = new BlurRenderer(screen_res, 4, 2.7,
	BlurRenderer::BlurDirectionVertical,
	vec2(1.0, 1.0) / screen_res,
	0.5);
	}

	/* Copy renderer */
	if (use_bloom && !use_tilt_shift)
	copy_renderer = new CopyRenderer(screen_res);

	/* Height normal chain */
	height_normal_chain = new RendererChain();
	height_normal_chain->append(*height_map_renderer);
	height_normal_chain->append(*normal_map_renderer);

	/* Bloom effect chain */
	if (use_bloom) {
	bloom_chain = new RendererChain();
	bloom_chain->append(*bloom_h_renderer);
	bloom_chain->append(*bloom_v_renderer);
	bloom_chain->append(*overlay_renderer);
	}

	/* Tilt-shift effect chain */
	if (use_tilt_shift) {
	tilt_chain = new RendererChain();
	tilt_chain->append(*tilt_h_renderer);
	tilt_chain->append(*tilt_v_renderer);
	}

	/* Terrain chain */
	terrain_chain = new RendererChain();
	terrain_chain->append(*terrain_renderer);
	if (use_bloom)
	terrain_chain->append(*bloom_chain);
	if (use_tilt_shift)
	terrain_chain->append(*tilt_chain);

	/*
	* If are just using bloom, the terrain is rendered to a texture and
	* bloom applied on that texture. We need to "copy" that texture's
	* contents to the screen to make the scene visible.
	*/
	if (use_bloom && !use_tilt_shift)
	terrain_chain->append(*copy_renderer);

	/*
	* Set up renderer textures.
	*/
	terrain_renderer->height_map_texture(height_map_renderer->texture());
	terrain_renderer->normal_map_texture(normal_map_renderer->texture());
	terrain_renderer->specular_map_texture(specular_map_renderer->texture());

	specular_map_renderer->input_texture(terrain_renderer->diffuse1_texture());
	}

	void release_renderers()
	{
	delete terrain_chain;
	delete bloom_chain;
	delete tilt_chain;
	delete height_normal_chain;

	delete height_map_renderer;
	delete normal_map_renderer;
	delete specular_map_renderer;
	delete terrain_renderer;
	delete bloom_v_renderer;
	delete bloom_h_renderer;
	delete overlay_renderer;
	delete tilt_v_renderer;
	delete tilt_h_renderer;
	delete copy_renderer;
	}

	Canvas &canvas;
	LibMatrix::vec2 repeat_overlay;
	bool use_bloom;
	bool use_tilt_shift;

	/* Renderers */
	TerrainRenderer *terrain_renderer;
	BlurRenderer *bloom_v_renderer;
	BlurRenderer *bloom_h_renderer;
	OverlayRenderer *overlay_renderer;
	BlurRenderer *tilt_v_renderer;
	BlurRenderer *tilt_h_renderer;
	CopyRenderer *copy_renderer;

	SimplexNoiseRenderer *height_map_renderer;
	NormalFromHeightRenderer *normal_map_renderer;
	LuminanceRenderer *specular_map_renderer;

	/* Chains */
	RendererChain *height_normal_chain;
	RendererChain *bloom_chain;
	RendererChain *tilt_chain;
	RendererChain *terrain_chain;
	};

	SceneTerrain::SceneTerrain(Canvas &pCanvas) :
	Scene(pCanvas, "terrain"), priv_(0)
	{
	options_["repeat-overlay"] = Scene::Option("repeat-overlay", "6.0",
	"How many times to repeat the terrain texture on the terrain plane (per side)");
	options_["bloom"] = Scene::Option("bloom", "true",
	"Use bloom post-processing effect",
	"false,true");
	options_["tilt-shift"] = Scene::Option("tilt-shift", "true",
	"Use tilt-shift post-processing effect",
	"false,true");
	}

	SceneTerrain::~SceneTerrain()
	{
	delete priv_;
	}

	bool
	SceneTerrain::supported(bool show_errors)
	{
	GLint vertex_textures;
	glGetIntegerv(GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS, &vertex_textures);

	if (show_errors && vertex_textures <= 0) {
	Log::error("SceneTerrain requires Vertex Texture Fetch support, "
	"but GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS is %d\n",
	vertex_textures);
	}

	return vertex_textures > 0;
	}

	bool
	SceneTerrain::load()
	{
	Scene::load();

	running_ = false;

	return true;
	}

	void
	SceneTerrain::unload()
	{
	Scene::unload();
	}

	bool
	SceneTerrain::setup()
	{
	if (!Scene::setup())
	return false;

	/* Parse options */
	float repeat = Util::fromString<double>(options_["repeat-overlay"].value);
	LibMatrix::vec2 repeat_overlay(repeat, repeat);
	bool use_bloom = options_["bloom"].value == "true";
	bool use_tilt_shift = options_["tilt-shift"].value == "true";

	priv_ = new SceneTerrainPrivate(canvas_, repeat_overlay,
	use_bloom, use_tilt_shift);

	/* Set up terrain rendering program */
	LibMatrix::Stack4 model;
	LibMatrix::Stack4 camera;
	LibMatrix::mat4 projection = LibMatrix::Mat4::perspective(
	40.0, canvas_.width() / static_cast<float>(canvas_.height()),
	2.0, 4000.0);

	/* Place camera */
	camera.lookAt(-1200.0f, 800.0f, 1200.0f,
	0.0, 0.0, 0.0,
	0.0, 1.0, 0.0);

	/* Move and rotate plane */
	model.translate(0.0f, -125.0f, 0.0f);
	model.rotate(-90.0, 1.0f, 0.0f, 0.0f);

	LibMatrix::mat4 view_matrix(camera.getCurrent());
	LibMatrix::mat4 model_matrix(model.getCurrent());

	LibMatrix::mat4 model_view_matrix(view_matrix * model_matrix);

	LibMatrix::mat4 normal_matrix(model_view_matrix);
	normal_matrix.inverse().transpose();

	/* Set up terrain renderer program */
	priv_->terrain_renderer->program().start();
	priv_->terrain_renderer->program()["viewMatrix"] = view_matrix;
	priv_->terrain_renderer->program()["modelViewMatrix"] = model_view_matrix;
	priv_->terrain_renderer->program()["normalMatrix"] = normal_matrix;
	priv_->terrain_renderer->program()["projectionMatrix"] = projection;

	/* Create the specular map */
	priv_->specular_map_renderer->render();

	glBindFramebuffer(GL_FRAMEBUFFER, 0);
	glViewport(0, 0, canvas_.width(), canvas_.height());

	currentFrame_ = 0;
	startTime_ = Util::get_timestamp_us() / 1000000.0;
	running_ = true;

	return true;
	}

	void
	SceneTerrain::teardown()
	{
	delete priv_;
	priv_ = 0;
	Scene::teardown();
	}

	void
	SceneTerrain::update()
	{
	Scene::update();

	double now = Util::get_timestamp_us() / 1000000.0;
	float diff = now - startTime_;
	float scale = priv_->terrain_renderer->repeat_overlay().x() /
	priv_->height_map_renderer->uv_scale().x();

	/* Update height map */
	priv_->height_map_renderer->program().start();
	priv_->height_map_renderer->program()["uvOffset"] = vec2(diff * 0.05f, 0.0f);
	priv_->terrain_renderer->program().start();
	priv_->terrain_renderer->program()["uOffset"] = vec2(scale * diff * 0.05f, 0.0f);
	}

	void
	SceneTerrain::draw()
	{
	/* Render the height and normal maps used by the terrain */
	priv_->height_normal_chain->render();

	/* Render the terrain plus any post-processing effects */
	priv_->terrain_chain->render();
	}

	Scene::ValidationResult
	SceneTerrain::validate()
	{
	return Scene::ValidationUnknown;
	}