Port frustum culling to C

src/Client/Client.vcxproj

@@ -178,6 +178,7 @@
     <ClInclude Include="Bitmap.h" />
     <ClInclude Include="Drawer.h" />
     <ClInclude Include="ErrorHandler.h" />
+    <ClInclude Include="FrustumCulling.h" />
     <ClInclude Include="TerrainAtlas1D.h" />
     <ClInclude Include="TerrainAtlas2D.h" />
     <ClInclude Include="WorldEvents.h" />
@@ -213,6 +214,7 @@
     <ClCompile Include="Drawer.c" />
     <ClCompile Include="EventHandler.c" />
     <ClCompile Include="ExtMath.c" />
+    <ClCompile Include="FrustumCulling.c" />
     <ClCompile Include="PackedCol.c" />
     <ClCompile Include="Funcs.c" />
     <ClCompile Include="GraphicsCommon.c" />

src/Client/Client.vcxproj.filters

@@ -88,6 +88,12 @@
     <Filter Include="Header Files\MeshBuilder">
       <UniqueIdentifier>{1012ed27-a9f2-4b01-a9a4-be75e2a1e2f0}</UniqueIdentifier>
     </Filter>
+    <Filter Include="Source Files\Rendering">
+      <UniqueIdentifier>{d746c4e4-411e-4e25-9e79-a2fceabe7cda}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="Header Files\Rendering">
+      <UniqueIdentifier>{2134e4ed-c57e-40b2-b329-5f5b7b71a799}</UniqueIdentifier>
+    </Filter>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="NotchyGenerator.h">
@@ -192,6 +198,9 @@
     <ClInclude Include="Drawer.h">
       <Filter>Header Files\MeshBuilder</Filter>
     </ClInclude>
+    <ClInclude Include="FrustumCulling.h">
+      <Filter>Header Files\Rendering</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="NotchyGenerator.c">
@@ -275,5 +284,8 @@
     <ClCompile Include="Drawer.c">
       <Filter>Source Files\MeshBuilder</Filter>
     </ClCompile>
+    <ClCompile Include="FrustumCulling.c">
+      <Filter>Source Files\Rendering</Filter>
+    </ClCompile>
   </ItemGroup>
 </Project>

src/Client/FrustumCulling.c

@@ -0,0 +1,81 @@
+#include "FrustumCulling.h"
+#include "ExtMath.h"
+
+Real32
+frustum00, frustum01, frustum02, frustum03,
+frustum10, frustum11, frustum12, frustum13,
+frustum20, frustum21, frustum22, frustum23,
+frustum30, frustum31, frustum32, frustum33,
+frustum40, frustum41, frustum42, frustum43;
+
+bool FrustumCulling_SphereInFrustum(Real32 x, Real32 y, Real32 z, Real32 radius) {
+	float d = frustum00 * x + frustum01 * y + frustum02 * z + frustum03;
+	if (d <= -radius) return false;
+
+	d = frustum10 * x + frustum11 * y + frustum12 * z + frustum13;
+	if (d <= -radius) return false;
+
+	d = frustum20 * x + frustum21 * y + frustum22 * z + frustum23;
+	if (d <= -radius) return false;
+
+	d = frustum30 * x + frustum31 * y + frustum32 * z + frustum33;
+	if (d <= -radius) return false;
+
+	d = frustum40 * x + frustum41 * y + frustum42 * z + frustum43;
+	if (d <= -radius) return false;
+	// Don't test NEAR plane, it's pointless
+	return true;
+}
+
+void FrustumCulling_CalcFrustumEquations(Matrix* projection, Matrix* modelView) {
+	Matrix clipMatrix;
+	Matrix_Mul(modelView, projection, &clipMatrix);
+
+	Real32* clip = (Real32*)&clipMatrix;
+	// Extract the numbers for the RIGHT plane
+	frustum00 = clip[3] - clip[0];
+	frustum01 = clip[7] - clip[4];
+	frustum02 = clip[11] - clip[8];
+	frustum03 = clip[15] - clip[12];
+	FrustumCulling_Normalise(&frustum00, &frustum01, &frustum02, &frustum03);
+
+	// Extract the numbers for the LEFT plane
+	frustum10 = clip[3] + clip[0];
+	frustum11 = clip[7] + clip[4];
+	frustum12 = clip[11] + clip[8];
+	frustum13 = clip[15] + clip[12];
+	FrustumCulling_Normalise(&frustum10, &frustum11, &frustum12, &frustum13);
+
+	// Extract the BOTTOM plane
+	frustum20 = clip[3] + clip[1];
+	frustum21 = clip[7] + clip[5];
+	frustum22 = clip[11] + clip[9];
+	frustum23 = clip[15] + clip[13];
+	FrustumCulling_Normalise(&frustum20, &frustum21, &frustum22, &frustum23);
+
+	// Extract the TOP plane
+	frustum30 = clip[3] - clip[1];
+	frustum31 = clip[7] - clip[5];
+	frustum32 = clip[11] - clip[9];
+	frustum33 = clip[15] - clip[13];
+	FrustumCulling_Normalise(&frustum30, &frustum31, &frustum32, &frustum33);
+
+	// Extract the FAR plane
+	frustum40 = clip[3] - clip[2];
+	frustum41 = clip[7] - clip[6];
+	frustum42 = clip[11] - clip[10];
+	frustum43 = clip[15] - clip[14];
+	FrustumCulling_Normalise(&frustum40, &frustum41, &frustum42, &frustum43);
+}
+
+void FrustumCulling_Normalise(Real32* plane0, Real32* plane1, Real32* plane2, Real32* plane3) {
+	Real32 val1 = *plane0;
+	Real32 val2 = *plane1;
+	Real32 val3 = *plane2;
+	Real32 t = (Real32)Math_Sqrt(val1 * val1 + val2 * val2 + val3 * val3);
+
+	*plane0 /= t;
+	*plane1 /= t;
+	*plane2 /= t;
+	*plane3 /= t;
+}

src/Client/FrustumCulling.h

@@ -0,0 +1,17 @@
+#ifndef CS_FRUSTUMCULLING_H
+#define CS_FRUSTUMCULLING_H
+#include "Matrix.h"
+#include "Typedefs.h"
+/* Implements frustum culling of bounding spheres.
+   Copyright 2014-2017 ClassicalSharp | Licensed under BSD-3
+    Sourced from http://www.crownandcutlass.com/features/technicaldetails/frustum.html
+*/
+
+/* Returns whether the given bounding sphere is in the view frustum. */
+bool FrustumCulling_SphereInFrustum(Real32 x, Real32 y, Real32 z, Real32 radius);
+
+/* Calculates the planes that constitute view frustum. */
+void FrustumCulling_CalcFrustumEquations(Matrix* projection, Matrix* modelView);
+
+static void FrustumCulling_Normalise(Real32* plane0, Real32* plane1, Real32* plane2, Real32* plane3);
+#endif