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+// BEGIN_COPYRIGHT
+//
+// Copyright (C) 1999 Allen Akin All Rights Reserved.
+//
+// Permission is hereby granted, free of charge, to any person
+// obtaining a copy of this software and associated documentation
+// files (the "Software"), to deal in the Software without
+// restriction, including without limitation the rights to use,
+// copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following
+// conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the
+// Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+// KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+// WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL ALLEN AKIN BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+// AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
+// OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+//
+// END_COPYRIGHT
+
+
+
+
+// Data unpacking utilities. Note that these map component values per
+// the usual OpenGL conventions.
+
+// XXX The construction of SCALE and BIAS is clumsy, and the need to
+// test bias is really unfortunate, but egcs 1.1.2 won't propagate
+// floating-point constant expressions from equivalent const
+// declarations.
+
+#include "image.h"
+
+namespace {
+
+#define SCALE (static_cast<double>(num) / static_cast<double>(denom))
+#define BIAS (static_cast<double>(bias) / static_cast<double>(denom))
+
+// See comments in pack.cpp concerning this workaround for a VC6 problem.
+
+template<class component, int num, unsigned int denom, int bias>
+class Unpack
+{
+public :
+ // unpack_l
+ static void unpack_l(GLsizei n, double* rgba, char* src)
+ {
+ component* in = reinterpret_cast<component*>(src);
+ // XXX It seems to me that static_cast should be sufficient,
+ // but egcs 1.1.2 thinks otherwise.
+
+ double* end = rgba + 4 * n;
+ for (; rgba != end; rgba += 4) {
+ if (bias)
+ rgba[0] = SCALE * in[0] + BIAS;
+ else
+ rgba[0] = SCALE * in[0];
+ rgba[1] = rgba[2] = rgba[3] = 0.0;
+ in += 1;
+ }
+ }
+
+ // unpack_la
+ static void unpack_la(GLsizei n, double* rgba, char* src)
+ {
+ component* in = reinterpret_cast<component*>(src);
+ double* end = rgba + 4 * n;
+ for (; rgba != end; rgba += 4) {
+ if (bias) {
+ rgba[0] = SCALE * in[0] + BIAS;
+ rgba[3] = SCALE * in[1] + BIAS;
+ } else {
+ rgba[0] = SCALE * in[0];
+ rgba[3] = SCALE * in[1];
+ }
+ rgba[1] = rgba[2] = 0.0;
+ in += 2;
+ }
+ }
+
+ // unpack_rgb
+ static void unpack_rgb(GLsizei n, double* rgba, char* src)
+ {
+ component* in = reinterpret_cast<component*>(src);
+ double* end = rgba + 4 * n;
+ for (; rgba != end; rgba += 4) {
+ if (bias) {
+ rgba[0] = SCALE * in[0] + BIAS;
+ rgba[1] = SCALE * in[1] + BIAS;
+ rgba[2] = SCALE * in[2] + BIAS;
+ } else {
+ rgba[0] = SCALE * in[0];
+ rgba[1] = SCALE * in[1];
+ rgba[2] = SCALE * in[2];
+ }
+ rgba[3] = 0.0;
+ in += 3;
+ }
+ }
+
+ // unpack_rgba
+ static void unpack_rgba(GLsizei n, double* rgba, char* src)
+ {
+ component* in = reinterpret_cast<component*>(src);
+ double* end = rgba + 4 * n;
+ for (; rgba != end; rgba += 4) {
+ if (bias) {
+ rgba[0] = SCALE * in[0] + BIAS;
+ rgba[1] = SCALE * in[1] + BIAS;
+ rgba[2] = SCALE * in[2] + BIAS;
+ rgba[3] = SCALE * in[3] + BIAS;
+ } else {
+ rgba[0] = SCALE * in[0];
+ rgba[1] = SCALE * in[1];
+ rgba[2] = SCALE * in[2];
+ rgba[3] = SCALE * in[3];
+ }
+ in += 4;
+ }
+ }
+
+}; // class Unpack
+
+#undef SCALE
+#undef BIAS
+
+}; // anonymous namespace
+
+
+namespace GLEAN {
+
+///////////////////////////////////////////////////////////////////////////////
+// Public interface
+///////////////////////////////////////////////////////////////////////////////
+void
+Image::unpack(GLsizei n, double* rgba, char* nextPixel) {
+ (*(valid(vbUnpacker)? _unpacker: validateUnpacker()))
+ (n, rgba, nextPixel);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// validateUnpacker - select appropriate pixel-unpacking utility
+///////////////////////////////////////////////////////////////////////////////
+Image::Unpacker*
+Image::validateUnpacker() {
+ switch (format()) {
+ case GL_LUMINANCE:
+ switch (type()) {
+ case GL_BYTE:
+ _unpacker = Unpack<GLbyte, 2, 255, 1>::unpack_l;
+ break;
+ case GL_UNSIGNED_BYTE:
+ _unpacker = Unpack<GLubyte, 1, 255, 0>::unpack_l;
+ break;
+ case GL_SHORT:
+ _unpacker = Unpack<GLshort, 2, 65535, 1>::unpack_l;
+ break;
+ case GL_UNSIGNED_SHORT:
+ _unpacker = Unpack<GLushort, 1, 65535, 0>::unpack_l;
+ break;
+ case GL_INT:
+ _unpacker = Unpack<GLint, 2, 4294967295U, 1>::unpack_l;
+ break;
+ case GL_UNSIGNED_INT:
+ _unpacker = Unpack<GLuint, 1, 4294967295U, 0>::unpack_l;
+ break;
+ case GL_FLOAT:
+ _unpacker = Unpack<GLfloat, 1, 1, 0>::unpack_l;
+ break;
+ default:
+ throw BadType(type());
+ }
+ break;
+ case GL_LUMINANCE_ALPHA:
+ switch (type()) {
+ case GL_BYTE:
+ _unpacker = Unpack<GLbyte, 2, 255, 1>::unpack_la;
+ break;
+ case GL_UNSIGNED_BYTE:
+ _unpacker = Unpack<GLubyte, 1, 255, 0>::unpack_la;
+ break;
+ case GL_SHORT:
+ _unpacker = Unpack<GLshort, 2, 65535, 1>::unpack_la;
+ break;
+ case GL_UNSIGNED_SHORT:
+ _unpacker = Unpack<GLushort, 1, 65535, 0>::unpack_la;
+ break;
+ case GL_INT:
+ _unpacker = Unpack<GLint, 2, 4294967295U, 1>::unpack_la;
+ break;
+ case GL_UNSIGNED_INT:
+ _unpacker = Unpack<GLuint, 2, 4294967295U, 0>::unpack_la;
+ break;
+ case GL_FLOAT:
+ _unpacker = Unpack<GLfloat, 1, 1, 0>::unpack_la;
+ break;
+ default:
+ throw BadType(type());
+ }
+ break;
+ case GL_RGB:
+ switch (type()) {
+ case GL_BYTE:
+ _unpacker = Unpack<GLbyte, 2, 255, 1>::unpack_rgb;
+ break;
+ case GL_UNSIGNED_BYTE:
+ _unpacker = Unpack<GLubyte, 1, 255, 0>::unpack_rgb;
+ break;
+ case GL_SHORT:
+ _unpacker = Unpack<GLshort, 2, 65535, 1>::unpack_rgb;
+ break;
+ case GL_UNSIGNED_SHORT:
+ _unpacker = Unpack<GLushort, 1, 65535, 0>::unpack_rgb;
+ break;
+ case GL_INT:
+ _unpacker = Unpack<GLint, 2, 4294967295U, 1>::unpack_rgb;
+ break;
+ case GL_UNSIGNED_INT:
+ _unpacker = Unpack<GLuint, 1, 4294967295U, 0>::unpack_rgb;
+ break;
+ case GL_FLOAT:
+ _unpacker = Unpack<GLfloat, 1, 1, 0>::unpack_rgb;
+ break;
+ default:
+ throw BadType(type());
+ }
+ break;
+ case GL_RGBA:
+ switch (type()) {
+ case GL_BYTE:
+ _unpacker = Unpack<GLbyte, 2, 255, 1>::unpack_rgba;
+ break;
+ case GL_UNSIGNED_BYTE:
+ _unpacker = Unpack<GLubyte, 1, 255, 0>::unpack_rgba;
+ break;
+ case GL_SHORT:
+ _unpacker = Unpack<GLshort, 2, 65535, 1>::unpack_rgba;
+ break;
+ case GL_UNSIGNED_SHORT:
+ _unpacker = Unpack<GLushort, 1, 65535, 0>::unpack_rgba;
+ break;
+ case GL_INT:
+ _unpacker = Unpack<GLint, 2, 4294967295U, 1>::unpack_rgba;
+ break;
+ case GL_UNSIGNED_INT:
+ _unpacker = Unpack<GLuint, 1, 4294967295U, 0>::unpack_rgba;
+ break;
+ case GL_FLOAT:
+ _unpacker = Unpack<GLfloat, 1, 1, 0>::unpack_rgba;
+ break;
+ default:
+ throw BadType(type());
+ }
+ break;
+ default:
+ throw BadFormat(format());
+ }
+
+ validate(vbUnpacker);
+ return _unpacker;
+}
+
+}; // namespace GLEAN
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