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Include/ZRenderer/ZSampler.hpp

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+/*
+	ZSampler.hpp
+	Author: James Russell <jcrussell@762studios.com>
+	Created: 7/1/2012
+
+	Purpose: 
+
+	Samplers act as a view onto a texture object, encapsulating all the filtering, mipmapping,
+	and addressing settings for shaders to access a texture.
+
+	TODO - A writeup here on the various settings and how they interact, or at least a link to
+	some place that does
+
+	License:
+
+	TODO
+
+*/
+
+#pragma once
+
+#ifndef _ZSAMPLER_HPP
+#define _ZSAMPLER_HPP
+
+#include <ZRenderer/ZRendererBuild.hpp>
+#include <ZRenderer/ZRendererResource.hpp>
+
+//This should be ~log2 of ZT_MAX_TEXTURE_DIMENSION
+#ifndef ZS_DEFAULT_MAX_LOD
+#define ZS_DEFAULT_MAX_LOD (13.0f)
+#endif
+
+//Enumeration of sampler wrapping modes
+enum ZSamplerWrapMode
+{
+	ZSWM_CLAMP_EDGE,		//Sampling beyond the edge results in the last pixel value
+	ZSWM_CLAMP_BORDER,		//Sampling beyond the edge results in the specified border value
+	ZSWM_MIRROR_REPEAT,		//Sampling beyond the edge wraps back in on itself
+	ZSWM_REPEAT,			//Sampling beyond the edge wraps around to the other side
+	ZSWM_SIZE
+};
+
+//Enumeration of magnification sampler filtering modes
+enum ZSamplerMagFilter
+{
+	ZSMAGF_NEAREST,			//Nearest mode filter
+	ZSMAGF_LINEAR,			//Linear mode filter
+	ZSMAGF_SIZE
+};
+
+//Enumeration of minification sampler filtering modes
+enum ZSamplerMinFilter
+{
+	ZSMINF_NEAREST,				//Nearest-neighbor pixel, no mip levels
+	ZSMINF_NEAREST_MIP_NEAREST,	//Nearest-neighbor sampling on nearest mip level
+	ZSMINF_NEAREST_MIP_LINEAR,	//Nearest-neighbor sampling on lerped mip level
+	ZSMINF_LINEAR,				//Linear interpolation, no mip levels
+	ZSMINF_LINEAR_MIP_NEAREST,	//Lerped sampling on nearest mip level
+	ZSMINF_LINEAR_MIP_LINEAR,	//Lerped sampling on lerped mip level
+	ZSMINF_SIZE
+};
+
+//Enumeration of sampler comparison modes
+enum ZSamplerCompareMode
+{
+	ZSCM_COMPARE_REF_TO_TEXTURE,	//Compares reference to texture
+	ZSCM_NONE,						//No comparison
+	ZSCM_SIZE
+};
+
+//Enumeration of sampler comparison functions
+enum ZSamplerCompareFunc
+{
+	ZSCF_LESS_EQUAL,				//Less than or equal
+	ZSCF_GREATER_EQUAL,				//Greater than or equal
+	ZSCF_LESS,						//Less than
+	ZSCF_GREATER,					//Greater than
+	ZSCF_EQUAL,						//Equal
+	ZSCF_NOT_EQUAL,					//Not Equal
+	ZSCF_ALWAYS,					//Always
+	ZSCF_NEVER,						//Never
+	ZSCF_SIZE
+};
+
+//Struct that encapsulates the sampler state
+struct ZSamplerState
+{
+	ZSamplerWrapMode SWrapMode;			//Wrapping mode for S
+	ZSamplerWrapMode TWrapMode;			//Wrapping mode for T (unused for 1D)
+	ZSamplerWrapMode RWrapMode;			//Wrapping mode for R (unused for 1D, 2D)
+	
+	ZSamplerMinFilter MinFilter;		//Minification Filter
+	ZSamplerMagFilter MagFilter;		//Magnification Filter
+
+	float MaxAnisotropy;				//Maximum Anisotropy (< 2.0 has no effect)
+	float MinLOD;						//Minimum LOD
+	float MaxLOD;						//Maximum LOD
+	float LODBias;						//LOD Bias
+
+	float BorderColor[4];				//RGBA Border Color
+
+	ZSamplerCompareMode CompareMode;	//Sampler Comparison Mode
+	ZSamplerCompareFunc CompareFunc;	//Sampler Comparison Function
+
+	//Default Configuration
+	ZSamplerState() 
+		: SWrapMode(ZSWM_REPEAT), TWrapMode(ZSWM_REPEAT), RWrapMode(ZSWM_REPEAT),
+		  MinFilter(ZSMINF_LINEAR), MagFilter(ZSMAGF_LINEAR),
+		  MaxAnisotropy(1.0), MinLOD(0), MaxLOD(ZS_DEFAULT_MAX_LOD), LODBias(0),
+		  CompareMode(ZSCM_NONE), CompareFunc(ZSCF_ALWAYS) 
+	{ }
+};
+
+/*
+Sampler interface class.
+*/
+class ZSampler : public ZRendererResource
+{
+public:
+	//Virtual Destructor
+	virtual ~ZSampler() { }
+
+	/*
+	ZSampler::Get*
+
+	The following methods are getters for the various ZSampler settings 
+	that can be set on a given sampler.  For a greater explanation of each
+	setting and what it does, see above.
+	*/
+
+	//Getters for the S, T, and R Wrap Mode set on this sampler
+	virtual ZSamplerWrapMode GetSWrapMode() = 0;	
+	virtual ZSamplerWrapMode GetTWrapMode() = 0;
+	virtual ZSamplerWrapMode GetRWrapMode() = 0;
+
+	//Getters for the minification filter and magnification filter
+	virtual ZSamplerMagFilter GetMagFilter() = 0;
+	virtual ZSamplerMinFilter GetMinFilter() = 0;
+
+	//Getters for the maximum anisotropy, minimum LOD, maximum LOD, and LOD bias
+	virtual float GetMaxAnisotropy() = 0;
+	virtual float GetMinLOD() = 0;
+	virtual float GetMaxLOD() = 0;
+	virtual float GetLODBias() = 0;
+
+	//Getter for the border color setting (four-element array, RGBA)
+	virtual const float* GetBorderColor() = 0;
+
+	//Getter for the comparison mode and comparison function
+	virtual ZSamplerCompareMode GetCompareMode() = 0;
+	virtual ZSamplerCompareFunc GetCompareFunc() = 0;
+
+	//Getter for the entire sampler state
+	virtual const ZSamplerState& GetSamplerState() = 0;
+
+	/*
+	ZSampler::Set*
+
+	The following methods are setters for the various ZSampler settings than
+	can be set on a given sampler.  For a greater explanation of each setting and what it 
+	does, see above.
+
+	If any of the setters returns false, it is because the resource is contended.
+	*/
+
+	//Setters for the S, T, and R wrapping modes
+	virtual bool SetSWrapMode(ZSamplerWrapMode _mode) = 0;
+	virtual bool SetTWrapMode(ZSamplerWrapMode _mode) = 0;
+	virtual bool SetRWrapMode(ZSamplerWrapMode _mode) = 0;
+
+	//Setters for the minification and magnification filter
+	virtual bool SetMagFilter(ZSamplerMagFilter _filter) = 0;
+	virtual bool SetMinFilter(ZSamplerMinFilter _filter) = 0;
+
+	//Setters for maximum anisotropy, minimum LOD, maximum LOD, and LOD bias
+	virtual bool SetMaxAnisotropy(float _max) = 0;
+	virtual bool SetMinLOD(float _min) = 0;
+	virtual bool SetMaxLOD(float _max) = 0;
+	virtual bool SetLODBias(float _bias) = 0;
+
+	//Setter for border color 
+	virtual bool SetBorderColor(float _r, float _g, float _b, float _a) = 0;
+
+	//Setter for comparison mode and comparison function
+	virtual bool SetCompareMode(ZSamplerCompareMode _mode) = 0;
+	virtual bool SetCompareFunc(ZSamplerCompareFunc _func) = 0;
+
+	//Setter for entire sampler state
+	virtual bool SetSamplerState(const ZSamplerState& _state) = 0;
+};
+
+#endif