From 14b5ae08fd2fd24d9235ffaf94a29f5a193ae2ee Mon Sep 17 00:00:00 2001
From: turanszkij <turanszkij@gmail.com>
Date: Tue, 15 Nov 2016 18:07:52 +0100
Subject: [PATCH] particle system GPU culling refactor

---
 WickedEngine/cullingShaderHF.hlsli | 15 +++++++++++++
 WickedEngine/grassGS.hlsl          |  3 ++-
 WickedEngine/grassHF_GS.hlsli      | 34 ------------------------------
 WickedEngine/pointspriteGS.hlsl    | 12 +++++++++--
 WickedEngine/qgrassGS.hlsl         |  3 ++-
 5 files changed, 29 insertions(+), 38 deletions(-)

diff --git a/WickedEngine/cullingShaderHF.hlsli b/WickedEngine/cullingShaderHF.hlsli
index 15ad7b5e6..8862acfed 100644
--- a/WickedEngine/cullingShaderHF.hlsli
+++ b/WickedEngine/cullingShaderHF.hlsli
@@ -154,4 +154,19 @@ bool ConeInsideFrustum(Cone cone, Frustum frustum, float zNear, float zFar)
 	return result;
 }
 
+
+
+static const float4 frustumCorners[4] = {
+	float4(-1, -1, 1, 1),
+	float4(1, -1, 1, 1),
+	float4(-1, 1, 1, 1),
+	float4(1, 1, 1, 1)
+};
+static const Frustum frustum = {
+	ComputePlane(float3(0,0,0), frustumCorners[2].xyz, frustumCorners[0].xyz),
+	ComputePlane(float3(0,0,0), frustumCorners[1].xyz, frustumCorners[3].xyz),
+	ComputePlane(float3(0,0,0), frustumCorners[0].xyz, frustumCorners[1].xyz),
+	ComputePlane(float3(0,0,0), frustumCorners[3].xyz, frustumCorners[2].xyz)
+};
+
 #endif // _CULLING_SHADER_HF_
diff --git a/WickedEngine/grassGS.hlsl b/WickedEngine/grassGS.hlsl
index 7a57549df..2a79d33c1 100644
--- a/WickedEngine/grassGS.hlsl
+++ b/WickedEngine/grassGS.hlsl
@@ -9,7 +9,8 @@ void main(
 	float grassLength = input[0].nor.w;
 	float3 root = mul(float4(input[0].pos.xyz, 1), xWorld).xyz;
 
-	if (!IsVisible(root, grassLength))
+	Sphere sphere = { mul(float4(root,1), g_xCamera_View).xyz, grassLength };
+	if (!SphereInsideFrustum(sphere, frustum, 1, LOD2))
 	{
 		return;
 	}
diff --git a/WickedEngine/grassHF_GS.hlsli b/WickedEngine/grassHF_GS.hlsli
index ff9a247ce..c402d7fbc 100644
--- a/WickedEngine/grassHF_GS.hlsli
+++ b/WickedEngine/grassHF_GS.hlsli
@@ -41,40 +41,6 @@ struct QGS_OUT
 	float4 pos2D : SCREENPOSITION;
 };
 
-inline bool IsVisible(in float3 root, in float length)
-{
-	// culling:
-	// View space eye position is always at the origin.
-	const float3 eyePos = float3(0, 0, 0);
-
-	// Compute 4 points on the far clipping plane to use as the 
-	// frustum vertices.
-	float4 corners[4];
-	// Top left point
-	corners[0] = float4(-1, -1, 1, 1);
-	// Top right point
-	corners[1] = float4(1, -1, 1, 1);
-	// Bottom left point
-	corners[2] = float4(-1, 1, 1, 1);
-	// Bottom right point
-	corners[3] = float4(1, 1, 1, 1);
-
-	// Now build the frustum planes from the view space points
-	Frustum frustum;
-
-	// Left plane
-	frustum.planes[0] = ComputePlane(eyePos, corners[2].xyz, corners[0].xyz);
-	// Right plane
-	frustum.planes[1] = ComputePlane(eyePos, corners[1].xyz, corners[3].xyz);
-	// Top plane
-	frustum.planes[2] = ComputePlane(eyePos, corners[0].xyz, corners[1].xyz);
-	// Bottom plane
-	frustum.planes[3] = ComputePlane(eyePos, corners[3].xyz, corners[2].xyz);
-
-	Sphere sphere = { mul(float4(root,1), g_xCamera_View).xyz, length };
-	return SphereInsideFrustum(sphere, frustum, 1, LOD2);
-}
-
 static const float3 MOD[] = {
 	float3(-0.010735935, 0.01647018, 0.0062425877),
 	float3(-0.06533369, 0.3647007, -0.13746321),
diff --git a/WickedEngine/pointspriteGS.hlsl b/WickedEngine/pointspriteGS.hlsl
index 66a8d12b2..1239f18b8 100644
--- a/WickedEngine/pointspriteGS.hlsl
+++ b/WickedEngine/pointspriteGS.hlsl
@@ -1,4 +1,5 @@
 #include "globals.hlsli"
+#include "cullingShaderHF.hlsli"
 
 CBUFFER(EmittedParticleCB, CBSLOT_OTHER_EMITTEDPARTICLE)
 {
@@ -25,8 +26,16 @@ struct VertextoPixel
 };
 
 [maxvertexcount(4)]
-void main(point GS_INPUT p[1], inout TriangleStream<VertextoPixel> triStream)
+void main(point GS_INPUT p[1], inout TriangleStream<VertextoPixel> triStream, uint vid : SV_PrimitiveID)
 {
+	float quadLength = p[0].inSizOpMir.x*0.5f;
+
+	Sphere sphere = { mul(float4(p[0].pos.xyz,1), g_xCamera_View).xyz, quadLength };
+	if (!SphereInsideFrustum(sphere, frustum, 1, g_xFrame_MainCamera_ZFarP))
+	{
+		return;
+	}
+
 	VertextoPixel p1 = (VertextoPixel)0;
 	float2x2 rot = float2x2(
 		cos(p[0].rot),-sin(p[0].rot),
@@ -49,7 +58,6 @@ void main(point GS_INPUT p[1], inout TriangleStream<VertextoPixel> triStream)
 	p[0].vel				= mul(p[0].vel, (float3x3)g_xCamera_View);
 
 
-	float quadLength = p[0].inSizOpMir.x*0.5f;
 
 	//p1.col = p[0].color;
 	p1.opaAddDarkSiz = float4(saturate(p[0].inSizOpMir.y),xAdd.x,xAdd.y,p[0].inSizOpMir.x);
diff --git a/WickedEngine/qgrassGS.hlsl b/WickedEngine/qgrassGS.hlsl
index 48551a49b..94a68fa49 100644
--- a/WickedEngine/qgrassGS.hlsl
+++ b/WickedEngine/qgrassGS.hlsl
@@ -9,7 +9,8 @@ void main(
 	float grassLength = input[0].nor.w;
 	float3 root = mul(float4(input[0].pos.xyz,1), xWorld).xyz;
 
-	if (!IsVisible(root, grassLength))
+	Sphere sphere = { mul(float4(root,1), g_xCamera_View).xyz, grassLength };
+	if (!SphereInsideFrustum(sphere, frustum, 1, LOD2))
 	{
 		return;
 	}