Initial commit.

Framework/external/embree/tutorials/common/texture/texture2d.h

@@ -0,0 +1,104 @@
+// Copyright 2009-2021 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include "texture.h"
+#include "../math/vec.h"
+
+namespace embree {
+
+struct Texture2D;
+
+typedef Vec4f (*Texture2D_get)(const Texture2D *self,
+                                       const Vec2f &p);
+
+struct Texture2D {
+  Vec2i         size;
+  Vec2f         sizef;     // size, as floats; slightly smaller than 'size' to avoid range checks
+  Vec2f         halfTexel; // 0.5/size, needed for bilinear filtering and clamp-to-edge
+  Texture2D_get get;
+  void         *data;
+};
+
+// XXX won't work with MIPmapping: clean implementation with clamping on integer coords needed then 
+inline Vec2f clamp2edge(const Texture2D *self, const Vec2f p)
+{
+  return clamp(p, self->halfTexel, 1.0f - self->halfTexel);
+}
+
+/*! helper function that returns the sampled value for the first
+  channel of the given texture
+
+  Right now, this function always asks the texture for all four
+  channels, and then discards all but one; later implementations may
+  have specialized 'get1f' methods with the texture
+
+  \note self may NOT be nullptr!
+*/
+inline float get1f(const Texture2D *self,
+                   const Vec2f where)
+{
+  Vec4f ret = self->get(self, where);
+  return ret.x;
+}
+
+/*! helper function that returns the sampled value for the first three
+  channels of the given texture
+
+  Right now, this function always asks the texture for all four
+  channels, and then discards all but one; later implementations may
+  have specialized 'get3f' methods with the texture
+
+  \note self may NOT be nullptr!
+*/
+inline Vec3fa get3f(const Texture2D *self,
+                   const Vec2f where)
+{
+  Vec4f ret = self->get(self, where);
+  return Vec3fa(ret);
+}
+
+/*! helper function that returns the sampled value of the four
+  channels of the given texture.
+
+  Note that it's up to the texture to define clearly what happens if
+  we ask for four channels even if the texture has less physical
+  channels.
+
+  \note self may NOT be nullptr!
+*/
+inline Vec4f get4f(const Texture2D *self,
+                   const Vec2f where)
+{
+  return self->get(self, where);
+}
+
+/*! helper function: get1f() with a default value if the texture is nullptr */
+inline float get1f(const Texture2D *self,
+                   const Vec2f where,
+                   const float defaultValue)
+{
+  if (self == nullptr) return defaultValue;
+  else return get1f(self,where);
+}
+
+/*! helper function: get3f() with a default value if the texture is nullptr */
+inline Vec3fa get3f(const Texture2D *self,
+                   const Vec2f where,
+                   const Vec3fa& defaultValue)
+{
+  if (self == nullptr) return defaultValue;
+  else return get3f(self,where);
+}
+
+/*! helper function: get4f() with a default value if the texture is nullptr */
+inline Vec4f get4f(const Texture2D *self,
+                   const Vec2f where,
+                   const Vec4f defaultValue)
+{
+  if (self == nullptr) return defaultValue;
+  else return get4f(self,where);
+}
+
+} // namespace embree