X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fcore%2Fsampler.h;h=7cf3d83a7b0915481eef1417e2fe48c0a1e8bcee;hb=190a7e11237351f6b730c28f7b16f183e8adc69c;hp=b2011d3bed3db8dc7631fc3224c37c6011d39c3f;hpb=24b24e2203c776aacd9744bb947f5cf47b03d328;p=libs%2Fgl.git

diff --git a/source/core/sampler.h b/source/core/sampler.h
index b2011d3b..7cf3d83a 100644
--- a/source/core/sampler.h
+++ b/source/core/sampler.h
@@ -4,6 +4,7 @@
 #include <msp/datafile/objectloader.h>
 #include "color.h"
 #include "predicate.h"
+#include "sampler_backend.h"
 
 namespace Msp {
 namespace GL {
@@ -47,22 +48,16 @@ enum TextureWrap
 
 
 /**
-Samplers are used to access texture data in shaders.  To use a sampler with a
-texture, bind it to the same texture unit.  Each texture has a default sampler
-which is used if no external sampler is bound.
-
-A texture is generally rendered at a size that's either smaller or larger than
-its native size, so that the texture coordinates do not exactly correspond to
-the texels of the texture.  The kind of filtering used, if any, is determined
-by the minification and magnification filter parameters.  The default is LINEAR
-for magnification and NEAREST_MIPMAP_LINEAR for minification.
-
-If texture coordinates fall outside of the principal range of the texture,
-wrapping is applied.  The default for all directions is REPEAT.
+Stores settings affecting how values are obtained from textures in a shader.
+Samplers are always used together with textures.
+
+Texture coordinates are first transformed according to the wrap mode for each
+axis.  One or more texel values are then read and combined according to the
+filtering mode.
 */
-class Sampler
+class Sampler: public SamplerBackend
 {
-	friend class PipelineState;
+	friend SamplerBackend;
 
 public:
 	class Loader: public DataFile::ObjectLoader<Sampler>
@@ -97,26 +92,26 @@ private:
 		COMPARE = 128
 	};
 
-	unsigned id;
-	TextureFilter min_filter;
-	TextureFilter mag_filter;
-	float max_anisotropy;
-	TextureWrap wrap_s;
-	TextureWrap wrap_t;
-	TextureWrap wrap_r;
-	Color border_color;
-	bool compare;
-	Predicate cmp_func;
-	mutable int dirty_params;
-
-public:
-	Sampler();
+	TextureFilter min_filter = NEAREST_MIPMAP_LINEAR;
+	TextureFilter mag_filter = LINEAR;
+	float max_anisotropy = 1.0f;
+	TextureWrap wrap_s = REPEAT;
+	TextureWrap wrap_t = REPEAT;
+	TextureWrap wrap_r = REPEAT;
+	Color border_color = { 0.0f, 0.0f, 0.0f, 0.0f };
+	bool compare = false;
+	Predicate cmp_func = LEQUAL;
+	mutable int dirty_params = 0;
 
-private:
 	void update() const;
 
 public:
+	/** Sets filter to use when the texture is drawn at a size smaller than
+	original. */
 	void set_min_filter(TextureFilter);
+
+	/** Sets filter to use when the texture is drawn at a size larger than
+	original.  Mipmapped filters can't be used. */
 	void set_mag_filter(TextureFilter);
 
 	/** Sets filter for both minification and magnification.  If a mipmapping
@@ -126,6 +121,9 @@ public:
 	TextureFilter get_min_filter() const { return min_filter; }
 	TextureFilter get_mag_filter() const { return mag_filter; }
 
+	/** Sets the maximum aspect ratio for anisotropic filtering.  If greater
+	than 1, filtering will consider more than than four samples when the texture
+	is drawn at an oblique angle. */
 	void set_max_anisotropy(float);
 	float get_max_anisotropy() const { return max_anisotropy; }
 
@@ -136,7 +134,9 @@ public:
 	void set_wrap_t(TextureWrap);
 	void set_wrap_r(TextureWrap);
 
+	/** Sets the border color for CLAMP_TO_BORDER wrap mode. */
 	void set_border_color(const Color &);
+
 	const Color &get_border_color() const { return border_color; }
 
 	/** Disables depth comparison. */
@@ -144,7 +144,7 @@ public:
 
 	/** Enables depth comparison and sets the compare function.  Only has an
 	effect when used with a depth texture.  When depth comparison is enabled,
-	the third component of the texture coordinate is compared against the texel
+	the last component of the texture coordinate is compared against the texel
 	value, and the result is returned as the texture sample.*/
 	void set_compare(Predicate);
 
@@ -153,13 +153,11 @@ public:
 
 	void refresh() const { if(dirty_params) update(); }
 
-	void set_debug_name(const std::string &);
+	using SamplerBackend::set_debug_name;
 };
 
 
 bool is_mipmapped(TextureFilter);
-unsigned get_gl_filter(TextureFilter);
-unsigned get_gl_wrap(TextureWrap);
 
 void operator>>(const LexicalConverter &, TextureFilter &);
 void operator>>(const LexicalConverter &, TextureWrap &);