增加大气渲染范例

example/Vulkan/Atomsphere.cpp

@@ -0,0 +1,160 @@
+// 8.大气渲染
+//  画一个球，纯粹使用shader计算出颜色
+
+#include"VulkanAppFramework.h"
+#include<hgl/filesystem/FileSystem.h>
+#include<hgl/graph/InlineGeometry.h>
+#include<hgl/graph/SceneDB.h>
+#include<hgl/graph/RenderableInstance.h>
+#include<hgl/graph/RenderList.h>
+
+using namespace hgl;
+using namespace hgl::graph;
+
+constexpr uint32_t SCREEN_WIDTH=128;
+constexpr uint32_t SCREEN_HEIGHT=128;
+
+struct AtomsphereData
+{
+    alignas(16) Vector3f position;
+    float intensity;
+    float scattering_direction;
+};//
+
+class TestApp:public CameraAppFramework
+{
+private:
+
+    SceneNode   render_root;
+    RenderList  render_list;
+
+    vulkan::Material *          material            =nullptr;
+    vulkan::DescriptorSets *    descriptor_sets     =nullptr;
+
+    vulkan::Renderable          *ro_sphere;
+
+    vulkan::Pipeline            *pipeline_solid     =nullptr;
+    
+    vulkan::Buffer *            ubo_atomsphere      =nullptr;
+    AtomsphereData              atomsphere_data;
+
+private:
+
+    bool InitMaterial()
+    {
+        material=shader_manage->CreateMaterial(OS_TEXT("Atomsphere.vert.spv"),
+                                               OS_TEXT("Atomsphere.frag.spv"));
+        if(!material)
+            return(false);
+
+        descriptor_sets=material->CreateDescriptorSets();
+
+        db->Add(material);
+        db->Add(descriptor_sets);
+        return(true);
+    }
+
+    void CreateRenderObject()
+    {
+        ro_sphere=CreateRenderableSphere(db,material,16);
+    }
+    
+    bool InitAtomsphereUBO(vulkan::DescriptorSets *desc_set,uint bindpoint)
+    {
+        atomsphere_data.position.Set(0,0.1f,-1.0f);
+        atomsphere_data.intensity=22.0f;
+        atomsphere_data.scattering_direction=0.758f;
+
+        ubo_atomsphere=db->CreateUBO(sizeof(AtomsphereData),&atomsphere_data);
+
+        if(!ubo_atomsphere)
+            return(false);
+
+        return desc_set->BindUBO(bindpoint,*ubo_atomsphere);
+    }
+
+    bool InitUBO()
+    {
+        if(!InitCameraUBO(descriptor_sets,material->GetUBO("world")))
+            return(false);
+
+        if(!InitAtomsphereUBO(descriptor_sets,material->GetUBO("sun")))
+            return(false);
+
+        descriptor_sets->Update();
+        return(true);
+    }
+
+    bool InitPipeline()
+    {
+        vulkan::PipelineCreater *pipeline_creater=new vulkan::PipelineCreater(device,material,device->GetRenderPass(),device->GetExtent());
+        pipeline_creater->SetDepthTest(true);
+        pipeline_creater->SetDepthWrite(true);
+        pipeline_creater->SetCullMode(VK_CULL_MODE_NONE);
+        pipeline_creater->Set(PRIM_TRIANGLES);
+        pipeline_solid=pipeline_creater->Create();
+        
+        if(!pipeline_solid)
+            return(false);
+
+        db->Add(pipeline_solid);
+
+        delete pipeline_creater;
+        return(true);
+    }
+
+    bool InitScene()
+    {
+        render_root.Add(db->CreateRenderableInstance(pipeline_solid,descriptor_sets,ro_sphere),scale(1000));
+
+        render_root.RefreshMatrix();
+        render_root.ExpendToList(&render_list);
+
+        return(true);
+    }
+
+public:
+
+    bool Init()
+    {
+        if(!CameraAppFramework::Init(SCREEN_WIDTH,SCREEN_HEIGHT))
+            return(false);
+
+        if(!InitMaterial())
+            return(false);
+
+        CreateRenderObject();
+
+        if(!InitUBO())
+            return(false);
+
+        if(!InitPipeline())
+            return(false);
+
+        if(!InitScene())
+            return(false);
+
+        return(true);
+    }
+    
+    void BuildCommandBuffer(uint32_t index) override
+    {
+        render_root.RefreshMatrix();
+        render_list.Clear();
+        render_root.ExpendToList(&render_list);
+        
+        VulkanApplicationFramework::BuildCommandBuffer(index,&render_list);
+    }
+};//class TestApp:public CameraAppFramework
+
+int main(int,char **)
+{
+    TestApp app;
+
+    if(!app.Init())
+        return(-1);
+
+    while(app.Run());
+
+    return 0;
+}

example/Vulkan/CMakeLists.txt

@@ -15,4 +15,6 @@ target_link_libraries(6.LoadModel assimp)
 
 CreateProject(7.InlineGeometryScene InlineGeometryScene.cpp)
 
-CreateProject(8.RenderToColor RenderToColor.cpp TGATexture.cpp)
+CreateProject(8.Atomsphere Atomsphere.cpp)
+
+CreateProject(9.RenderToColor RenderToColor.cpp TGATexture.cpp)

res/shader/Atomsphere.frag

@@ -0,0 +1,141 @@
+#version 450 core
+
+#define PI 3.141592
+#define iSteps 16
+#define jSteps 8
+
+layout(location = 0) in vec4 FragmentVertex;
+
+layout(location = 0) out vec4 FragColor;
+
+layout(binding = 1) uniform AtomSphere
+{
+    vec3 position;
+    float intensity;
+    float scattering_direction;
+}sun;
+
+vec2 rsi(vec3 r0, vec3 rd, float sr) {
+    // ray-sphere intersection that assumes
+    // the sphere is centered at the origin.
+    // No intersection when result.x > result.y
+    float a = dot(rd, rd);
+    float b = 2.0 * dot(rd, r0);
+    float c = dot(r0, r0) - (sr * sr);
+    float d = (b*b) - 4.0*a*c;
+    if (d < 0.0) return vec2(1e5,-1e5);
+    return vec2(
+        (-b - sqrt(d))/(2.0*a),
+        (-b + sqrt(d))/(2.0*a)
+    );
+}
+
+vec3 atmosphere(vec3 r, vec3 r0, vec3 pSun, float iSun, float rPlanet, float rAtmos, vec3 kRlh, float kMie, float shRlh, float shMie, float g) 
+{
+    // Normalize the sun and view directions.
+    pSun = normalize(pSun);
+    r = normalize(r);
+
+    // Calculate the step size of the primary ray.
+    vec2 p = rsi(r0, r, rAtmos);
+    if (p.x > p.y) return vec3(0,0,0);
+    p.y = min(p.y, rsi(r0, r, rPlanet).x);
+    float iStepSize = (p.y - p.x) / float(iSteps);
+
+    // Initialize the primary ray time.
+    float iTime = 0.0;
+
+    // Initialize accumulators for Rayleigh and Mie scattering.
+    vec3 totalRlh = vec3(0,0,0);
+    vec3 totalMie = vec3(0,0,0);
+
+    // Initialize optical depth accumulators for the primary ray.
+    float iOdRlh = 0.0;
+    float iOdMie = 0.0;
+
+    // Calculate the Rayleigh and Mie phases.
+    float mu = dot(r, pSun);
+    float mumu = mu * mu;
+    float gg = g * g;
+    float pRlh = 3.0 / (16.0 * PI) * (1.0 + mumu);
+    float pMie = 3.0 / (8.0 * PI) * ((1.0 - gg) * (mumu + 1.0)) / (pow(1.0 + gg - 2.0 * mu * g, 1.5) * (2.0 + gg));
+
+    // Sample the primary ray.
+    for (int i = 0; i < iSteps; i++) {
+
+        // Calculate the primary ray sample position.
+        vec3 iPos = r0 + r * (iTime + iStepSize * 0.5);
+
+        // Calculate the height of the sample.
+        float iHeight = length(iPos) - rPlanet;
+
+        // Calculate the optical depth of the Rayleigh and Mie scattering for this step.
+        float odStepRlh = exp(-iHeight / shRlh) * iStepSize;
+        float odStepMie = exp(-iHeight / shMie) * iStepSize;
+
+        // Accumulate optical depth.
+        iOdRlh += odStepRlh;
+        iOdMie += odStepMie;
+
+        // Calculate the step size of the secondary ray.
+        float jStepSize = rsi(iPos, pSun, rAtmos).y / float(jSteps);
+
+        // Initialize the secondary ray time.
+        float jTime = 0.0;
+
+        // Initialize optical depth accumulators for the secondary ray.
+        float jOdRlh = 0.0;
+        float jOdMie = 0.0;
+
+        // Sample the secondary ray.
+        for (int j = 0; j < jSteps; j++) {
+
+            // Calculate the secondary ray sample position.
+            vec3 jPos = iPos + pSun * (jTime + jStepSize * 0.5);
+
+            // Calculate the height of the sample.
+            float jHeight = length(jPos) - rPlanet;
+
+            // Accumulate the optical depth.
+            jOdRlh += exp(-jHeight / shRlh) * jStepSize;
+            jOdMie += exp(-jHeight / shMie) * jStepSize;
+
+            // Increment the secondary ray time.
+            jTime += jStepSize;
+        }
+
+        // Calculate attenuation.
+        vec3 attn = exp(-(kMie * (iOdMie + jOdMie) + kRlh * (iOdRlh + jOdRlh)));
+
+        // Accumulate scattering.
+        totalRlh += odStepRlh * attn;
+        totalMie += odStepMie * attn;
+
+        // Increment the primary ray time.
+        iTime += iStepSize;
+    }
+
+    // Calculate and return the final color.
+    return iSun * (pRlh * kRlh * totalRlh + pMie * kMie * totalMie);
+}
+
+void main()
+{
+    vec3 nrd=vec3(.x,-FragmentVertex.y,FragmentVertex.z);       //vulkan coord to opengl(shader from opengl sample)
+
+    vec3 color=atmosphere(
+        nrd,                            // normalized ray direction
+        vec3(0,6372e3,0),               // ray origin
+        sun.position,                   // position of the sun
+        sun.intensity,                  // intensity of the sun
+        6371e3,                         // radius of the planet in meters
+        6471e3,                         // radius of the atmosphere in meters
+        vec3(5.5e-6, 13.0e-6, 22.4e-6), // Rayleigh scattering coefficient
+        21e-6,                          // Mie scattering coefficient
+        8e3,                            // Rayleigh scale height
+        1.2e3,                          // Mie scale height
+        sun.scattering_direction        // Mie preferred scattering direction
+    );
+
+    FragColor=vec4(1.0-exp(-color),1);
+}

res/shader/Atomsphere.vert

@@ -0,0 +1,24 @@
+#version 450 core
+
+layout(location = 0) in vec3 Vertex;
+
+layout(binding = 0) uniform WorldMatrix
+{
+    mat4 two_dim;
+    mat4 projection;
+    mat4 modelview;
+    mat4 mvp;
+    mat3 normal;
+} world;
+
+layout(push_constant) uniform Consts {
+    mat4 local_to_world;
+} pc;
+
+layout(location = 0) out vec4 FragmentVertex;
+
+void main()
+{
+    FragmentVertex=vec4(Vertex,1.0)*pc.local_to_world*world.mvp;
+    gl_Position=FragmentVertex;
+}

res/shader/shader_compile.sh

@@ -10,4 +10,7 @@ glslangValidator -V -o PositionColor3D.vert.spv PositionColor3D.vert
 glslangValidator -V -o OnlyPosition3D.vert.spv OnlyPosition3D.vert
 
 glslangValidator -V -o c_gbuffer.vert.spv c_gbuffer.vert
-glslangValidator -V -o c_gbuffer.frag.spv c_gbuffer.frag
+glslangValidator -V -o c_gbuffer.frag.spv c_gbuffer.frag
+
+glslangValidator -V -o Atomsphere.vert.spv Atomsphere.vert
+glslangValidator -V -o Atomsphere.frag.spv Atomsphere.frag