From 777f5f37f2d89ef2a787a77d74372b643968740e Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Thu, 16 Aug 2012 22:19:28 +0300
Subject: [PATCH] Add TexGen wrapper class

---
 source/texgen.cpp  | 62 ++++++++++++++++++++++++++++++++++++++++++++++
 source/texgen.h    | 49 ++++++++++++++++++++++++++++++++++++
 source/texunit.cpp | 20 ++++++++++++++-
 source/texunit.h   |  4 +++
 4 files changed, 134 insertions(+), 1 deletion(-)
 create mode 100644 source/texgen.cpp
 create mode 100644 source/texgen.h

diff --git a/source/texgen.cpp b/source/texgen.cpp
new file mode 100644
index 00000000..e9a75d7a
--- /dev/null
+++ b/source/texgen.cpp
@@ -0,0 +1,62 @@
+#include <stdexcept>
+#include "misc.h"
+#include "texgen.h"
+#include "texunit.h"
+
+using namespace std;
+
+namespace Msp {
+namespace GL {
+
+TexGen::TexGen():
+	mode(EYE_LINEAR)
+{ }
+
+void TexGen::set_mode(TexGenMode m)
+{
+	mode = m;
+}
+
+void TexGen::set_plane(const Vector4 &p)
+{
+	plane = p;
+}
+
+void TexGen::bind_to(TexCoordComponent c) const
+{
+	if(TexUnit::current().set_texgen(coord_index(c), this))
+	{
+		glTexGeni(c, GL_TEXTURE_GEN_MODE, mode);
+		if(mode==EYE_LINEAR)
+			glTexGenfv(c, GL_EYE_PLANE, &plane.x);
+		else if(mode==OBJECT_LINEAR)
+			glTexGenfv(c, GL_OBJECT_PLANE, &plane.x);
+		enable(GL_TEXTURE_GEN_S+coord_index(c));
+	}
+}
+
+const TexGen *TexGen::current(TexCoordComponent c)
+{
+	return TexUnit::current().get_texgen(coord_index(c));
+}
+
+void TexGen::unbind_from(TexCoordComponent c)
+{
+	if(TexUnit::current().set_texgen(coord_index(c), 0))
+		disable(GL_TEXTURE_GEN_S+coord_index(c));
+}
+
+unsigned TexGen::coord_index(TexCoordComponent c)
+{
+	switch(c)
+	{
+	case SCOORD: return 0;
+	case TCOORD: return 1;
+	case RCOORD: return 2;
+	case QCOORD: return 3;
+	default: throw invalid_argument("TexGen::coord_index");
+	}
+}
+
+} // namespace GL
+} // namespace Msp
diff --git a/source/texgen.h b/source/texgen.h
new file mode 100644
index 00000000..bb076c62
--- /dev/null
+++ b/source/texgen.h
@@ -0,0 +1,49 @@
+#ifndef MSP_GL_TEXGEN_H_
+#define MSP_GL_TEXGEN_H_
+
+#include "gl.h"
+#include "vector.h"
+
+namespace Msp {
+namespace GL {
+
+enum TexCoordComponent
+{
+	SCOORD = GL_S,
+	TCOORD = GL_T,
+	RCOORD = GL_R,
+	QCOORD = GL_Q
+};
+
+enum TexGenMode
+{
+	EYE_LINEAR = GL_EYE_LINEAR,
+	OBJECT_LINEAR = GL_OBJECT_LINEAR,
+	REFLECTION_MAP = GL_REFLECTION_MAP,
+	NORMAL_MAP = GL_NORMAL_MAP
+};
+
+class TexGen
+{
+private:
+	TexGenMode mode;
+	Vector4 plane;
+
+public:
+	TexGen();
+
+	void set_mode(TexGenMode);
+	void set_plane(const Vector4 &);
+
+	void bind_to(TexCoordComponent) const;
+
+	static const TexGen *current(TexCoordComponent);
+	static void unbind_from(TexCoordComponent);
+private:
+	static unsigned coord_index(TexCoordComponent);
+};
+
+} // namespace GL
+} // namespace Msp
+
+#endif
diff --git a/source/texunit.cpp b/source/texunit.cpp
index 4d71e3b9..d581598a 100644
--- a/source/texunit.cpp
+++ b/source/texunit.cpp
@@ -15,7 +15,9 @@ TexUnit *TexUnit::cur_unit = 0;
 TexUnit::TexUnit():
 	texture(0),
 	texenv(0)
-{ }
+{
+	fill(texgen, texgen+4, static_cast<const TexGen *>(0));
+}
 
 bool TexUnit::set_texture(const Texture *tex)
 {
@@ -31,6 +33,22 @@ bool TexUnit::set_texenv(const TexEnv *env)
 	return result;
 }
 
+bool TexUnit::set_texgen(unsigned i, const TexGen *gen)
+{
+	if(i>=4)
+		throw invalid_argument("TexUnit::set_texgen");
+	bool result = (texgen[i]!=gen);
+	texgen[i] = gen;
+	return result;
+}
+
+const TexGen *TexUnit::get_texgen(unsigned i)
+{
+	if(i>=4)
+		throw invalid_argument("TexUnit::get_texgen");
+	return texgen[i];
+}
+
 unsigned TexUnit::get_n_units()
 {
 	static int count = -1;
diff --git a/source/texunit.h b/source/texunit.h
index 8f0af01f..82c4b579 100644
--- a/source/texunit.h
+++ b/source/texunit.h
@@ -7,6 +7,7 @@ namespace Msp {
 namespace GL {
 
 class TexEnv;
+class TexGen;
 class Texture;
 
 class TexUnit
@@ -14,6 +15,7 @@ class TexUnit
 private:
 	const Texture *texture;
 	const TexEnv *texenv;
+	const TexGen *texgen[4];
 
 	static std::vector<TexUnit> units;
 	static TexUnit *cur_unit;
@@ -25,6 +27,8 @@ public:
 	const Texture *get_texture() const { return texture; }
 	bool set_texenv(const TexEnv *);
 	const TexEnv *get_texenv() const { return texenv; }
+	bool set_texgen(unsigned, const TexGen *);
+	const TexGen *get_texgen(unsigned);
 
 	static unsigned get_n_units();
 	static TexUnit &activate(unsigned);
-- 
2.43.0