graphics: Added depth clamp enable APIs for opengl and metal

Author: Pikachuxxxx

src/modules/graphics/Graphics.cpp

@@ -847,6 +847,7 @@ void Graphics::restoreState(const DisplayState &s)
 
 	setStencilState(s.stencil);
 	setDepthMode(s.depthTest, s.depthWrite);
+	setDepthClamp(s.depthClampEnable);
 
 	setColorMask(s.colorMask);
 	setWireframe(s.wireframe);
@@ -926,6 +927,9 @@ void Graphics::restoreStateChecked(const DisplayState &s)
 	if (s.depthTest != cur.depthTest || s.depthWrite != cur.depthWrite)
 		setDepthMode(s.depthTest, s.depthWrite);
 
+	if(s.depthClampEnable != cur.depthClampEnable)
+		setDepthClamp(s.depthClampEnable);
+
 	if (s.colorMask != cur.colorMask)
 		setColorMask(s.colorMask);
 

src/modules/graphics/Graphics.h

@@ -621,6 +621,12 @@ class Graphics : public Module
 	void setDepthMode();
 	void getDepthMode(CompareMode &compare, bool &write) const;
 
+	/**
+	 * Clamps the depth valies to [0, 1] range instead of clipping geomentry
+	 * away at near and far planes
+	 */
+	virtual void setDepthClamp(bool enable) = 0;
+
 	void setMeshCullMode(CullMode cull);
 	CullMode getMeshCullMode() const;
 
@@ -948,6 +954,7 @@ class Graphics : public Module
 
 		CompareMode depthTest = COMPARE_ALWAYS;
 		bool depthWrite = false;
+		bool depthClampEnable = false;
 
 		CullMode meshCullMode = CULL_NONE;
 		Winding winding = WINDING_CCW;

src/modules/graphics/metal/Graphics.h

@@ -96,6 +96,8 @@ class Graphics final : public love::graphics::Graphics
 
 	void setDepthMode(CompareMode compare, bool write) override;
 
+	void setDepthClamp(bool enable) override;
+
 	void setFrontFaceWinding(Winding winding) override;
 
 	void setColorMask(ColorChannelMask mask) override;

src/modules/graphics/metal/Graphics.mm

@@ -1036,6 +1036,9 @@ static bool isClampOne(SamplerState::WrapMode w)
 		id<MTLDepthStencilState> mtlstate = getCachedDepthStencilState(depth, state.stencil);
 
 		[encoder setDepthStencilState:mtlstate];
+
+		// Also set the depth clamping (depth state change is tirggered for both deptstate and clamp state changes)
+		[encoder setDepthClipMode: state.depthClampEnable == false ?  MTLDepthClipModeClip : MTLDepthClipModeClamp];
 	}
 
 	if (dirtyState & STATEBIT_STENCIL)
@@ -1842,6 +1845,18 @@ static inline void advanceVertexOffsets(const VertexAttributes &attributes, Buff
 	}
 }
 
+void Graphics::setDepthClamp(bool enable)
+{
+	DisplayState &state = states.back();
+
+	if(state.depthClampEnable != enable)
+	{
+		flushBatchedDraws();
+		state.depthClampEnable = enable;
+		dirtyRenderState |= STATEBIT_DEPTH;
+	}
+}
+
 void Graphics::setFrontFaceWinding(Winding winding)
 {
 	if (states.back().winding != winding)

src/modules/graphics/opengl/Graphics.cpp

@@ -1453,6 +1453,17 @@ void Graphics::setDepthMode(CompareMode compare, bool write)
 	}
 }
 
+void Graphics::setDepthClamp(bool enable)
+{
+	DisplayState &state = states.back();
+
+	if(state.depthClampEnable != enable)
+		flushBatchedDraws();
+
+	gl.setEnableState(OpenGL::ENABLE_DEPTH_CLAMP, enable);
+	state.depthClampEnable = enable;
+}
+
 void Graphics::setFrontFaceWinding(Winding winding)
 {
 	DisplayState &state = states.back();

src/modules/graphics/opengl/Graphics.h

@@ -92,6 +92,8 @@ class Graphics final : public love::graphics::Graphics
 
 	void setDepthMode(CompareMode compare, bool write) override;
 
+	void setDepthClamp(bool enable) override;
+
 	void setFrontFaceWinding(Winding winding) override;
 
 	void setColorMask(ColorChannelMask mask) override;

src/modules/graphics/opengl/OpenGL.cpp

@@ -830,6 +830,9 @@ void OpenGL::setEnableState(EnableState enablestate, bool enable)
 	case ENABLE_FRAMEBUFFER_SRGB:
 		glstate = GL_FRAMEBUFFER_SRGB;
 		break;
+	case ENABLE_DEPTH_CLAMP:
+		glstate = GL_DEPTH_CLAMP;
+		break;
 	case ENABLE_MAX_ENUM:
 		break;
 	}

src/modules/graphics/opengl/OpenGL.h

@@ -100,6 +100,7 @@ class OpenGL
 		ENABLE_SCISSOR_TEST,
 		ENABLE_FACE_CULL,
 		ENABLE_FRAMEBUFFER_SRGB,
+		ENABLE_DEPTH_CLAMP,
 		ENABLE_MAX_ENUM
 	};
 

src/modules/graphics/wrap_Graphics.cpp

@@ -2891,6 +2891,12 @@ int w_getDepthMode(lua_State *L)
 	return 2;
 }
 
+int w_setDepthClampEnable(lua_State *L)
+{
+	instance()->setDepthClamp(luax_checkboolean(L, 1));
+	return 0;
+}
+
 int w_setMeshCullMode(lua_State *L)
 {
 	const char *str = luaL_checkstring(L, 1);
@@ -4081,6 +4087,7 @@ static const luaL_Reg functions[] =
 	{ "getPointSize", w_getPointSize },
 	{ "setDepthMode", w_setDepthMode },
 	{ "getDepthMode", w_getDepthMode },
+	{ "setDepthClampEnable", w_setDepthClampEnable },
 	{ "setMeshCullMode", w_setMeshCullMode },
 	{ "getMeshCullMode", w_getMeshCullMode },
 	{ "setFrontFaceWinding", w_setFrontFaceWinding },