From 90a4f1d49fbc3b96b85931812ba2deabeead94a7 Mon Sep 17 00:00:00 2001
From: hyzboy <hyzboy@gmail.com>
Date: Tue, 18 Jun 2024 13:08:59 +0800
Subject: [PATCH] finished BillboardFixedSize. next step is use ShaderVariable

---
 example/Basic/BillboardTest.cpp           |  8 +++++---
 src/ShaderGen/3d/M_BillboardFixedSize.cpp | 20 +++++++++++++++++++-
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/example/Basic/BillboardTest.cpp b/example/Basic/BillboardTest.cpp
index 7f2e82df..b69b3215 100644
--- a/example/Basic/BillboardTest.cpp
+++ b/example/Basic/BillboardTest.cpp
@@ -28,8 +28,6 @@ class TestApp:public SceneAppFramework
 {
     Color4f color;
 
-    DeviceBuffer *ubo_color=nullptr;
-
 private:
 
     Material *          mtl_plane_grid      =nullptr;
@@ -73,7 +71,7 @@ private:
         mtl::BillboardMaterialCreateConfig cfg(device->GetDeviceAttribute(),"Billboard2D",Prim::Billboard);
 
         {
-            cfg.fixed_size=false;
+            cfg.fixed_size=true;
 
             AutoDelete<mtl::MaterialCreateInfo> mci=mtl::CreateBillboard2D(&cfg);
        
@@ -100,6 +98,10 @@ private:
                                                             sampler))                           ///<采样器
             return(false);
 
+        Vector2u texture_size(texture->GetWidth(),texture->GetHeight());
+
+        mi_billboard->WriteMIData(texture_size);
+
         return(true);
     }
     
diff --git a/src/ShaderGen/3d/M_BillboardFixedSize.cpp b/src/ShaderGen/3d/M_BillboardFixedSize.cpp
index c0742c55..ec43ebed 100644
--- a/src/ShaderGen/3d/M_BillboardFixedSize.cpp
+++ b/src/ShaderGen/3d/M_BillboardFixedSize.cpp
@@ -4,9 +4,16 @@
 STD_MTL_NAMESPACE_BEGIN
 namespace
 {
+    constexpr const char mi_codes[]="uvec2 BillboardSize;";         //材质实例代码
+    constexpr const uint32_t mi_bytes=sizeof(Vector2u);             //材质实例数据大小
+
     constexpr const char vs_main[]=R"(
 void main()
 {
+    MaterialInstance mi=GetMI();
+
+    Output.BillboardSize=mi.BillboardSize/viewport.canvas_resolution;
+
     gl_Position=GetPosition3D();
     gl_Position/=gl_Position.w;
 })";
@@ -25,7 +32,7 @@ void main()
     for(int i=0;i<4;i++)
     {
         gl_Position=gl_in[0].gl_Position;
-        gl_Position.xy+=BillboardVertex[i];
+        gl_Position.xy+=BillboardVertex[i]*Input[0].BillboardSize;
 
         Output.TexCoord=BillboardVertex[i]+vec2(0.5);
 
@@ -52,6 +59,8 @@ void main()
             if(!Std3DMaterial::CustomVertexShader(vsc))
                 return(false);
 
+            vsc->AddOutput(VAT_VEC2,"BillboardSize");
+
             vsc->SetMain(vs_main);
             return(true);
         }
@@ -75,6 +84,15 @@ void main()
             fsc->SetMain(fs_main);
             return(true);
         }
+
+        bool EndCustomShader() override
+        {
+            mci->SetMaterialInstance(   mi_codes,                       //材质实例glsl代码
+                                        mi_bytes,                       //材质实例数据大小
+                                        VK_SHADER_STAGE_VERTEX_BIT);    //只在Vertex Shader中使用材质实例最终数据
+
+            return(true);
+        }
     };//class MaterialBillboard2DFixedSize:public Std3DMaterial
 }//namespace