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+/*
+ * Copyright 2017 Stanislav Pidhorskyi. All rights reserved.
+ * License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
+ */
+
+/*
+ * This example demonstrates:
+ * - Usage of Perez sky model [1] to render a dynamic sky.
+ * - Rendering a mesh with a lightmap, shading of which is driven by the same parameters as the sky.
+ *
+ * Typically, the sky is rendered using cubemaps or other environment maps.
+ * This approach can provide a high-quality sky, but the downside is that the
+ * image is static. To achieve daytime changes in sky appearance, there is a need
+ * in a dynamic model.
+ *
+ * Perez "An All-Weather Model for Sky Luminance Distribution" is a simple,
+ * but good enough model which is, in essence, a function that
+ * interpolates a sky color. As input, it requires several turbidity
+ * coefficients, a color at zenith and direction to the sun.
+ * Turbidity coefficients are taken from [2], which are computed using more
+ * complex physically based models. Color at zenith depends on daytime and can
+ * vary depending on many factors.
+ *
+ * In the code below, there are two tables that contain sky and sun luminance
+ * which were computed using code from [3]. Luminance in those tables
+ * represents actual scale of light energy that comes from sun compared to
+ * the sky.
+ *
+ * The sky is driven by luminance of the sky, while the material of the
+ * landscape is driven by both, the luminance of the sky and the sun. The
+ * lightening model is very simple and consists of two parts: directional
+ * light and hemisphere light. The first is used for the sun while the second
+ * is used for the sky. Additionally, the second part is modulated by a
+ * lightmap to achieve ambient occlusion effect.
+ *
+ * References
+ * ==========
+ *
+ * [1] R. Perez, R. Seals, and J. Michalsky."An All-Weather Model for Sky Luminance Distribution".
+ * Solar Energy, Volume 50, Number 3 (March 1993), pp. 235–245.
+ *
+ * [2] A. J. Preetham, Peter Shirley, and Brian Smits. "A Practical Analytic Model for Daylight",
+ * Proceedings of the 26th Annual Conference on Computer Graphics and Interactive Techniques,
+ * 1999, pp. 91–100.
+ * https://www.cs.utah.edu/~shirley/papers/sunsky/sunsky.pdf
+ *
+ * [3] E. Lengyel, Game Engine Gems, Volume One. Jones & Bartlett Learning, 2010. pp. 219 - 234
+ *
+ */
+
+#include "common.h"
+#include "bgfx_utils.h"
+#include "imgui/imgui.h"
+#include "camera.h"
+#include "bounds.h"
+
+#include <map>
+
+namespace
+{
+ // Represents color. Color-space depends on context.
+ // In the code below, used to represent color in XYZ, and RGB color-space
+ union Color
+ {
+ struct {
+ float X;
+ float Y;
+ float Z;
+ };
+ struct {
+ float r;
+ float g;
+ float b;
+ };
+
+ float data[3];
+ };
+
+
+ // HDTV rec. 709 matrix.
+ static float M_XYZ2RGB[] =
+ {
+ 3.240479f, -0.969256f, 0.055648f,
+ -1.53715f, 1.875991f, -0.204043f,
+ -0.49853f, 0.041556f, 1.057311f
+ };
+
+
+ // Converts color repesentation from CIE XYZ to RGB color-space.
+ Color XYZToRGB(const Color& xyz)
+ {
+ Color rgb;
+ rgb.r = M_XYZ2RGB[0] * xyz.X + M_XYZ2RGB[3] * xyz.Y + M_XYZ2RGB[6] * xyz.Z;
+ rgb.g = M_XYZ2RGB[1] * xyz.X + M_XYZ2RGB[4] * xyz.Y + M_XYZ2RGB[7] * xyz.Z;
+ rgb.b = M_XYZ2RGB[2] * xyz.X + M_XYZ2RGB[5] * xyz.Y + M_XYZ2RGB[8] * xyz.Z;
+ return rgb;
+ };
+
+
+ // Precomputed luminance of sunlight in XYZ colorspace.
+ // Computed using code from Game Engine Gems, Volume One, chapter 15. Implementation based on Dr. Richard Bird model.
+ // This table is used for piecewise linear interpolation. Transitions from and to 0.0 at sunset and sunrise are highly inaccurate
+ static std::map<float, Color> sunLuminanceXYZTable = {
+ { 5.0f, {{ 0.000000f, 0.000000f, 0.000000f }} },
+ { 7.0f, {{ 12.703322f, 12.989393f, 9.100411f }} },
+ { 8.0f, {{ 13.202644f, 13.597814f, 11.524929f }} },
+ { 9.0f, {{ 13.192974f, 13.597458f, 12.264488f }} },
+ { 10.0f, {{ 13.132943f, 13.535914f, 12.560032f }} },
+ { 11.0f, {{ 13.088722f, 13.489535f, 12.692996f }} },
+ { 12.0f, {{ 13.067827f, 13.467483f, 12.745179f }} },
+ { 13.0f, {{ 13.069653f, 13.469413f, 12.740822f }} },
+ { 14.0f, {{ 13.094319f, 13.495428f, 12.678066f }} },
+ { 15.0f, {{ 13.142133f, 13.545483f, 12.526785f }} },
+ { 16.0f, {{ 13.201734f, 13.606017f, 12.188001f }} },
+ { 17.0f, {{ 13.182774f, 13.572725f, 11.311157f }} },
+ { 18.0f, {{ 12.448635f, 12.672520f, 8.267771f }} },
+ { 20.0f, {{ 0.000000f, 0.000000f, 0.000000f }} }
+ };
+
+
+ // Precomputed luminance of sky in the zenith point in XYZ colorspace.
+ // Computed using code from Game Engine Gems, Volume One, chapter 15. Implementation based on Dr. Richard Bird model.
+ // This table is used for piecewise linear interpolation. Day/night transitions are highly inaccurate.
+ // The scale of luminance change in Day/night transitions is not preserved.
+ // Luminance at night was increased to eliminate need the of HDR render.
+ static std::map<float, Color> skyLuminanceXYZTable = {
+ { 0.0f, {{ 0.308f, 0.308f, 0.411f }} },
+ { 1.0f, {{ 0.308f, 0.308f, 0.410f }} },
+ { 2.0f, {{ 0.301f, 0.301f, 0.402f }} },
+ { 3.0f, {{ 0.287f, 0.287f, 0.382f }} },
+ { 4.0f, {{ 0.258f, 0.258f, 0.344f }} },
+ { 5.0f, {{ 0.258f, 0.258f, 0.344f }} },
+ { 7.0f, {{ 0.962851f, 1.000000f, 1.747835f }} },
+ { 8.0f, {{ 0.967787f, 1.000000f, 1.776762f }} },
+ { 9.0f, {{ 0.970173f, 1.000000f, 1.788413f }} },
+ { 10.0f, {{ 0.971431f, 1.000000f, 1.794102f }} },
+ { 11.0f, {{ 0.972099f, 1.000000f, 1.797096f }} },
+ { 12.0f, {{ 0.972385f, 1.000000f, 1.798389f }} },
+ { 13.0f, {{ 0.972361f, 1.000000f, 1.798278f }} },
+ { 14.0f, {{ 0.972020f, 1.000000f, 1.796740f }} },
+ { 15.0f, {{ 0.971275f, 1.000000f, 1.793407f }} },
+ { 16.0f, {{ 0.969885f, 1.000000f, 1.787078f }} },
+ { 17.0f, {{ 0.967216f, 1.000000f, 1.773758f }} },
+ { 18.0f, {{ 0.961668f, 1.000000f, 1.739891f }} },
+ { 20.0f, {{ 0.264f, 0.264f, 0.352f }} },
+ { 21.0f, {{ 0.264f, 0.264f, 0.352f }} },
+ { 22.0f, {{ 0.290f, 0.290f, 0.386f }} },
+ { 23.0f, {{ 0.303f, 0.303f, 0.404f }} }
+ };
+
+
+ // Turbidity tables. Taken from:
+ // A. J. Preetham, P. Shirley, and B. Smits. A Practical Analytic Model for Daylight. SIGGRAPH ’99
+ // Coefficients correspond to xyY colorspace.
+ static Color ABCDE[] =
+ {
+ {{ -0.2592f, -0.2608f, -1.4630f }},
+ {{ 0.0008f, 0.0092f, 0.4275f }},
+ {{ 0.2125f, 0.2102f, 5.3251f }},
+ {{ -0.8989f, -1.6537f, -2.5771f }},
+ {{ 0.0452f, 0.0529f, 0.3703f }}
+ };
+ static Color ABCDE_t[] =
+ {
+ {{ -0.0193f, -0.0167f, 0.1787f }},
+ {{ -0.0665f, -0.0950f, -0.3554f }},
+ {{ -0.0004f, -0.0079f, -0.0227f }},
+ {{ -0.0641f, -0.0441f, 0.1206f }},
+ {{ -0.0033f, -0.0109f, -0.0670f }}
+ };
+
+
+ // Performs piecewise linear interpolation of a Color parameter.
+ class DynamicValueController
+ {
+ typedef Color ValueType;
+ typedef std::map<float, ValueType> KeyMap;
+ public:
+ DynamicValueController() {};
+ ~DynamicValueController() {};
+
+ void SetMap(const KeyMap& keymap)
+ {
+ m_keyMap = keymap;
+ }
+
+ ValueType GetValue(float time) const
+ {
+ typename KeyMap::const_iterator itUpper = m_keyMap.upper_bound(time + 1e-6f);
+ typename KeyMap::const_iterator itLower = itUpper;
+ --itLower;
+ if (itLower == m_keyMap.end())
+ {
+ return itUpper->second;
+ }
+ if (itUpper == m_keyMap.end())
+ {
+ return itLower->second;
+ }
+ float lowerTime = itLower->first;
+ const ValueType& lowerVal = itLower->second;
+ float upperTime = itUpper->first;
+ const ValueType& upperVal = itUpper->second;
+ if (lowerTime == upperTime)
+ {
+ return lowerVal;
+ }
+ return interpolate(lowerTime, lowerVal, upperTime, upperVal, time);
+ };
+
+ void Clear()
+ {
+ m_keyMap.clear();
+ };
+
+ private:
+ const ValueType interpolate(float lowerTime, const ValueType& lowerVal, float upperTime, const ValueType& upperVal, float time) const
+ {
+ float x = (time - lowerTime) / (upperTime - lowerTime);
+ ValueType result;
+ bx::vec3Lerp(result.data, lowerVal.data, upperVal.data, x);
+ return result;
+ };
+
+ KeyMap m_keyMap;
+ };
+
+
+ // Controls sun position according to time, month, and observer's latitude.
+ // Sun position computation based on Earth's orbital elements: https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html
+ class SunController
+ {
+ public:
+ enum Month : int
+ {
+ January = 0,
+ February,
+ March,
+ April,
+ May,
+ June,
+ July,
+ August,
+ September,
+ October,
+ November,
+ December
+ };
+
+ SunController():
+ m_latitude(50.0f),
+ m_month(June),
+ m_eclipticObliquity(bx::toRad(23.4f)),
+ m_delta(0.0f)
+ {
+ m_northDirection[0] = 1.0;
+ m_northDirection[1] = 0.0;
+ m_northDirection[2] = 0.0;
+ m_upvector[0] = 0.0f;
+ m_upvector[1] = 1.0f;
+ m_upvector[2] = 0.0f;
+ }
+
+ void Update(float time)
+ {
+ CalculateSunOrbit();
+ UpdateSunPosition(time - 12.0f);
+ }
+
+ float m_northDirection[3];
+ float m_sunDirection[4];
+ float m_upvector[3];
+ float m_latitude;
+ Month m_month;
+
+ private:
+ void CalculateSunOrbit()
+ {
+ float day = 30.0f * m_month + 15.0f;
+ float lambda = 280.46f + 0.9856474f * day;
+ lambda = bx::toRad(lambda);
+ m_delta = bx::fasin(bx::fsin(m_eclipticObliquity) * bx::fsin(lambda));
+ }
+
+ void UpdateSunPosition(float hour)
+ {
+ float latitude = bx::toRad(m_latitude);
+ float h = hour * bx::kPi / 12.0f;
+ float azimuth = bx::fatan2(
+ bx::fsin(h),
+ bx::fcos(h) * bx::fsin(latitude) - bx::ftan(m_delta) * bx::fcos(latitude)
+ );
+
+ float altitude = bx::fasin(
+ bx::fsin(latitude) * bx::fsin(m_delta) + bx::fcos(latitude) * bx::fcos(m_delta) * bx::fcos(h)
+ );
+ float rotation[4];
+ bx::quatRotateAxis(rotation, m_upvector, -azimuth);
+ float direction[3];
+ bx::vec3MulQuat(direction, m_northDirection, rotation);
+ float v[3];
+ bx::vec3Cross(v, m_upvector, direction);
+ bx::quatRotateAxis(rotation, v, altitude);
+ bx::vec3MulQuat(m_sunDirection, direction, rotation);
+ }
+
+ float m_eclipticObliquity;
+ float m_delta;
+ };
+
+ struct ScreenPosVertex
+ {
+ float m_x;
+ float m_y;
+
+ static void init()
+ {
+ ms_decl
+ .begin()
+ .add(bgfx::Attrib::Position, 2, bgfx::AttribType::Float)
+ .end();
+ }
+
+ static bgfx::VertexDecl ms_decl;
+ };
+
+ bgfx::VertexDecl ScreenPosVertex::ms_decl;
+
+ // Renders a screen-space grid of triangles.
+ // Because of performance reasons, and because sky color is smooth, sky color is computed in vertex shader.
+ // 32x32 is a reasonable size for the grid to have smooth enough colors.
+ struct ProceduralSky
+ {
+ void init(int verticalCount, int horizontalCount)
+ {
+ // Create vertex stream declaration.
+ ScreenPosVertex::init();
+
+ m_skyProgram = loadProgram("vs_sky", "fs_sky");
+ m_skyProgram_colorBandingFix = loadProgram("vs_sky", "fs_sky_color_banding_fix");
+
+ m_preventBanding = true;
+
+ bx::AllocatorI* allocator = entry::getAllocator();
+
+ ScreenPosVertex* vertices = (ScreenPosVertex*)BX_ALLOC(allocator
+ , verticalCount * horizontalCount * sizeof(ScreenPosVertex)
+ );
+
+ for (int i = 0; i < verticalCount; i++)
+ {
+ for (int j = 0; j < horizontalCount; j++)
+ {
+ ScreenPosVertex& v = vertices[i * verticalCount + j];
+ v.m_x = float(j) / (horizontalCount - 1) * 2.0f - 1.0f;
+ v.m_y = float(i) / (verticalCount - 1) * 2.0f - 1.0f;
+ }
+ }
+
+ uint16_t* indices = (uint16_t*)BX_ALLOC(allocator
+ , (verticalCount - 1) * (horizontalCount - 1) * 6 * sizeof(uint16_t)
+ );
+
+ int k = 0;
+ for (int i = 0; i < verticalCount - 1; i++)
+ {
+ for (int j = 0; j < horizontalCount - 1; j++)
+ {
+ indices[k++] = (uint16_t)(j + 0 + horizontalCount * (i + 0));
+ indices[k++] = (uint16_t)(j + 1 + horizontalCount * (i + 0));
+ indices[k++] = (uint16_t)(j + 0 + horizontalCount * (i + 1));
+
+ indices[k++] = (uint16_t)(j + 1 + horizontalCount * (i + 0));
+ indices[k++] = (uint16_t)(j + 1 + horizontalCount * (i + 1));
+ indices[k++] = (uint16_t)(j + 0 + horizontalCount * (i + 1));
+ }
+ }
+
+ m_vbh = bgfx::createVertexBuffer(bgfx::copy(vertices, sizeof(ScreenPosVertex) * verticalCount * horizontalCount), ScreenPosVertex::ms_decl);
+ m_ibh = bgfx::createIndexBuffer(bgfx::copy(indices, sizeof(uint16_t) * k));
+
+ BX_FREE(allocator, indices);
+ BX_FREE(allocator, vertices);
+ }
+
+ void shutdown()
+ {
+ bgfx::destroy(m_ibh);
+ bgfx::destroy(m_vbh);
+ bgfx::destroy(m_skyProgram);
+ bgfx::destroy(m_skyProgram_colorBandingFix);
+ }
+
+ void draw()
+ {
+ bgfx::setState(BGFX_STATE_RGB_WRITE | BGFX_STATE_DEPTH_TEST_EQUAL);
+ bgfx::setIndexBuffer(m_ibh);
+ bgfx::setVertexBuffer(0, m_vbh);
+ bgfx::submit(0, m_preventBanding ? m_skyProgram_colorBandingFix : m_skyProgram);
+ }
+
+ bgfx::VertexBufferHandle m_vbh;
+ bgfx::IndexBufferHandle m_ibh;
+
+ bgfx::ProgramHandle m_skyProgram;
+ bgfx::ProgramHandle m_skyProgram_colorBandingFix;
+
+ bool m_preventBanding;
+ };
+
+ class ExampleProceduralSky : public entry::AppI
+ {
+ public:
+ ExampleProceduralSky(const char* _name, const char* _description): entry::AppI(_name, _description)
+ {}
+
+ void init(int32_t _argc, const char* const* _argv, uint32_t _width, uint32_t _height) override
+ {
+ Args args(_argc, _argv);
+
+ m_width = _width;
+ m_height = _height;
+ m_debug = BGFX_DEBUG_NONE;
+ m_reset = BGFX_RESET_VSYNC;
+
+ bgfx::init(args.m_type, args.m_pciId);
+ bgfx::reset(m_width, m_height, m_reset);
+
+ // Enable m_debug text.
+ bgfx::setDebug(m_debug);
+
+ // Set view 0 clear state.
+ bgfx::setViewClear(0
+ , BGFX_CLEAR_COLOR | BGFX_CLEAR_DEPTH
+ , 0x000000ff
+ , 1.0f
+ , 0
+ );
+
+ m_sunLuminanceXYZ.SetMap(sunLuminanceXYZTable);
+ m_skyLuminanceXYZ.SetMap(skyLuminanceXYZTable);
+
+ m_mesh = meshLoad("meshes/test_scene.bin");
+
+ m_lightmapTexture = loadTexture("textures/lightmap.ktx");
+
+ // Imgui.
+ imguiCreate();
+
+ m_timeOffset = bx::getHPCounter();
+ m_time = 0.0f;
+ m_timeScale = 1.0f;
+
+ s_texLightmap = bgfx::createUniform("s_texLightmap", bgfx::UniformType::Int1);
+ u_sunLuminance = bgfx::createUniform("u_sunLuminance", bgfx::UniformType::Vec4);
+ u_skyLuminanceXYZ = bgfx::createUniform("u_skyLuminanceXYZ", bgfx::UniformType::Vec4);
+ u_skyLuminance = bgfx::createUniform("u_skyLuminance", bgfx::UniformType::Vec4);
+ u_sunDirection = bgfx::createUniform("u_sunDirection", bgfx::UniformType::Vec4);
+ u_parameters = bgfx::createUniform("u_parameters", bgfx::UniformType::Vec4);
+ u_perezCoeff = bgfx::createUniform("u_perezCoeff", bgfx::UniformType::Vec4, 5);
+
+ m_landscapeProgram = loadProgram("vs_sky_landscape", "fs_sky_landscape");
+
+ m_sky.init(32, 32);
+
+ m_sun.Update(0);
+
+ cameraCreate();
+
+ const float initialPos[3] = { 5.0f, 3.0, 0.0f };
+ cameraSetPosition(initialPos);
+ cameraSetVerticalAngle(bx::kPi / 8.0f);
+ cameraSetHorizontalAngle(-bx::kPi / 3.0f);
+
+ m_turbidity = 2.15f;
+ }
+
+ virtual int shutdown() override
+ {
+ // Cleanup.
+ cameraDestroy();
+ imguiDestroy();
+
+ meshUnload(m_mesh);
+
+ m_sky.shutdown();
+
+ bgfx::destroy(s_texLightmap);
+ bgfx::destroy(u_sunLuminance);
+ bgfx::destroy(u_skyLuminanceXYZ);
+ bgfx::destroy(u_skyLuminance);
+ bgfx::destroy(u_sunDirection);
+ bgfx::destroy(u_parameters);
+ bgfx::destroy(u_perezCoeff);
+
+ bgfx::destroy(m_lightmapTexture);
+ bgfx::destroy(m_landscapeProgram);
+
+ bgfx::frame();
+
+ // Shutdown bgfx.
+ bgfx::shutdown();
+
+ return 0;
+ }
+
+ void imgui(float _width)
+ {
+ ImGui::Begin("ProceduralSky");
+ ImGui::SetWindowSize(ImVec2(_width, 200.0f) );
+ ImGui::SliderFloat("Time scale", &m_timeScale, 0.0f, 1.0f);
+ ImGui::SliderFloat("Time", &m_time, 0.0f, 24.0f);
+ ImGui::SliderFloat("Latitude", &m_sun.m_latitude, -90.0f, 90.0f);
+ ImGui::SliderFloat("Turbidity", &m_turbidity, 1.9f, 10.0f);
+ ImGui::Checkbox("Prevent color banding", &m_sky.m_preventBanding);
+
+ const char* items[] = {
+ "January",
+ "February",
+ "March",
+ "April",
+ "May",
+ "June",
+ "July",
+ "August",
+ "September",
+ "October",
+ "November",
+ "December"
+ };
+ ImGui::Combo("Month", (int*)&m_sun.m_month, items, 12);
+
+ ImGui::End();
+ }
+
+ bool update() override
+ {
+ if (!entry::processEvents(m_width, m_height, m_debug, m_reset, &m_mouseState))
+ {
+ int64_t now = bx::getHPCounter();
+ static int64_t last = now;
+ const int64_t frameTime = now - last;
+ last = now;
+ const double freq = double(bx::getHPFrequency());
+ const float deltaTime = float(frameTime / freq);
+ m_time += m_timeScale * deltaTime;
+ m_time = bx::fmod(m_time, 24.0f);
+ m_sun.Update(m_time);
+
+ imguiBeginFrame(m_mouseState.m_mx
+ , m_mouseState.m_my
+ , (m_mouseState.m_buttons[entry::MouseButton::Left] ? IMGUI_MBUT_LEFT : 0)
+ | (m_mouseState.m_buttons[entry::MouseButton::Right] ? IMGUI_MBUT_RIGHT : 0)
+ | (m_mouseState.m_buttons[entry::MouseButton::Middle] ? IMGUI_MBUT_MIDDLE : 0)
+ , m_mouseState.m_mz
+ , uint16_t(m_width)
+ , uint16_t(m_height)
+ );
+
+ showExampleDialog(this);
+
+ ImGui::SetNextWindowPos(
+ ImVec2(m_width - m_width / 5.0f - 10.0f, 10.0f)
+ , ImGuiSetCond_FirstUseEver
+ );
+
+ imgui(m_width / 5.0f - 10.0f);
+
+ imguiEndFrame();
+
+ if (!ImGui::MouseOverArea())
+ {
+ // Update camera.
+ cameraUpdate(deltaTime, m_mouseState);
+ }
+
+ // Set view 0 default viewport.
+ bgfx::setViewRect(0, 0, 0, uint16_t(m_width), uint16_t(m_height));
+
+ float view[16];
+ cameraGetViewMtx(view);
+
+ float proj[16];
+ bx::mtxProj(proj, 60.0f, float(m_width) / float(m_height), 0.1f, 2000.0f, bgfx::getCaps()->homogeneousDepth);
+
+ bgfx::setViewTransform(0, view, proj);
+
+ Color sunLuminanceXYZ = m_sunLuminanceXYZ.GetValue(m_time);
+ Color sunLuminanceRGB = XYZToRGB(sunLuminanceXYZ);
+
+ Color skyLuminanceXYZ = m_skyLuminanceXYZ.GetValue(m_time);
+ Color skyLuminanceRGB = XYZToRGB(skyLuminanceXYZ);
+
+ bgfx::setUniform(u_sunLuminance, sunLuminanceRGB.data);
+ bgfx::setUniform(u_skyLuminanceXYZ, skyLuminanceXYZ.data);
+ bgfx::setUniform(u_skyLuminance, skyLuminanceRGB.data);
+
+ bgfx::setUniform(u_sunDirection, m_sun.m_sunDirection);
+
+ float exposition[4] = { 0.02f, 3.0f, 0.1f, m_time };
+ bgfx::setUniform(u_parameters, exposition);
+
+ float perezCoeff[4 * 5];
+ computePerezCoeff(m_turbidity, perezCoeff);
+ bgfx::setUniform(u_perezCoeff, perezCoeff, 5);
+
+ bgfx::setTexture(0, s_texLightmap, m_lightmapTexture);
+ meshSubmit(m_mesh, 0, m_landscapeProgram, NULL);
+
+ m_sky.draw();
+
+ bgfx::frame();
+
+ return true;
+ }
+
+ return false;
+ }
+
+ void computePerezCoeff(float turbidity, float* perezCoeff)
+ {
+ for (int i = 0; i < 5; ++i)
+ {
+ Color tmp;
+ bx::vec3Mul(tmp.data, ABCDE_t[i].data, turbidity);
+ bx::vec3Add(perezCoeff + 4 * i, tmp.data, ABCDE[i].data);
+ perezCoeff[4 * i + 3] = 0.0f;
+ }
+ }
+
+ bgfx::ProgramHandle m_landscapeProgram;
+ bgfx::UniformHandle s_texLightmap;
+ bgfx::TextureHandle m_lightmapTexture;
+
+ bgfx::UniformHandle u_sunLuminance;
+ bgfx::UniformHandle u_skyLuminanceXYZ;
+ bgfx::UniformHandle u_skyLuminance;
+ bgfx::UniformHandle u_sunDirection;
+ bgfx::UniformHandle u_parameters;
+ bgfx::UniformHandle u_perezCoeff;
+
+ ProceduralSky m_sky;
+ SunController m_sun;
+
+ DynamicValueController m_sunLuminanceXYZ;
+ DynamicValueController m_skyLuminanceXYZ;
+
+ uint32_t m_width;
+ uint32_t m_height;
+ uint32_t m_debug;
+ uint32_t m_reset;
+
+ Mesh* m_mesh;
+
+ entry::MouseState m_mouseState;
+
+ float m_time;
+ float m_timeScale;
+ int64_t m_timeOffset;
+
+ float m_turbidity;
+ };
+
+} // namespace
+
+ENTRY_IMPLEMENT_MAIN(ExampleProceduralSky, "36-sky", "Perez dynamic sky model.");