From 72e6d5bb058d8c8e6cf93e82188bf20e6385ba8c Mon Sep 17 00:00:00 2001
From: Hleb Valoshka <375gnu@gmail.com>
Date: Wed, 20 Nov 2019 20:53:50 +0300
Subject: [PATCH] Replace gluOrtho2D with own implementation

---
 src/celengine/console.cpp |  8 ++++----
 src/celengine/overlay.cpp |  6 +++---
 src/celengine/render.cpp  | 12 ++++--------
 src/celmath/geomutil.h    | 23 ++++++++++++++++++++++-
 4 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/src/celengine/console.cpp b/src/celengine/console.cpp
index 8c7eca20..008654fc 100644
--- a/src/celengine/console.cpp
+++ b/src/celengine/console.cpp
@@ -11,13 +11,14 @@
 #include <cstdarg>
 #include <cassert>
 #include <algorithm>
-#include "celutil/utf8.h"
+#include <celutil/utf8.h>
+#include <celmath/geomutil.h>
 #include <GL/glew.h>
 #include "vecgl.h"
 #include "console.h"
 
 using namespace std;
-
+using namespace celmath;
 
 static int pmod(int n, int m)
 {
@@ -74,8 +75,7 @@ void Console::begin()
 {
     glMatrixMode(GL_PROJECTION);
     glPushMatrix();
-    glLoadIdentity();
-    gluOrtho2D(0, xscale, 0, yscale);
+    glLoadMatrix(Ortho2D(0.0f, (float)xscale, 0.0f, (float)yscale));
     glMatrixMode(GL_MODELVIEW);
     glPushMatrix();
     glLoadIdentity();
diff --git a/src/celengine/overlay.cpp b/src/celengine/overlay.cpp
index 296d3fac..1da2d12d 100644
--- a/src/celengine/overlay.cpp
+++ b/src/celengine/overlay.cpp
@@ -13,6 +13,7 @@
 #include <GL/glew.h>
 #include <Eigen/Core>
 #include <celutil/debug.h>
+#include <celmath/geomutil.h>
 #include "vecgl.h"
 #include "overlay.h"
 #include "rectangle.h"
@@ -21,7 +22,7 @@
 
 using namespace std;
 using namespace Eigen;
-
+using namespace celmath;
 
 Overlay::Overlay(const Renderer& r) :
     ostream(&sbuf),
@@ -34,8 +35,7 @@ void Overlay::begin()
 {
     glMatrixMode(GL_PROJECTION);
     glPushMatrix();
-    glLoadIdentity();
-    gluOrtho2D(0, windowWidth, 0, windowHeight);
+    glLoadMatrix(Ortho2D(0.0f, (float)windowWidth, 0.0f, (float)windowHeight));
     glMatrixMode(GL_MODELVIEW);
     glPushMatrix();
     glLoadIdentity();
diff --git a/src/celengine/render.cpp b/src/celengine/render.cpp
index 49eb2caa..d815d0e6 100644
--- a/src/celengine/render.cpp
+++ b/src/celengine/render.cpp
@@ -2423,8 +2423,7 @@ void Renderer::render(const Observer& observer,
 
     glMatrixMode(GL_PROJECTION);
     glPushMatrix();
-    glLoadIdentity();
-    glOrtho( 0.0, 1.0, 0.0, 1.0, -1.0, 1.0 );
+    glLoadMatrix(Ortho2D(0.0f, 1.0f, 0.0f, 1.0f));
     glMatrixMode (GL_MODELVIEW);
     glPushMatrix();
     glLoadIdentity();
@@ -7095,8 +7094,7 @@ void Renderer::renderAnnotations(const vector<Annotation>& annotations, FontStyl
 
     glMatrixMode(GL_PROJECTION);
     glPushMatrix();
-    glLoadIdentity();
-    gluOrtho2D(0, windowWidth, 0, windowHeight);
+    glLoadMatrix(Ortho2D(0.0f, (float)windowWidth, 0.0f, (float)windowHeight));
     glMatrixMode(GL_MODELVIEW);
     glPushMatrix();
     glLoadIdentity();
@@ -7229,8 +7227,7 @@ Renderer::renderSortedAnnotations(vector<Annotation>::iterator iter,
 
     glMatrixMode(GL_PROJECTION);
     glPushMatrix();
-    glLoadIdentity();
-    gluOrtho2D(0, windowWidth, 0, windowHeight);
+    glLoadMatrix(Ortho2D(0.0f, (float)windowWidth, 0.0f, (float)windowHeight));
     glMatrixMode(GL_MODELVIEW);
     glPushMatrix();
     glLoadIdentity();
@@ -7316,8 +7313,7 @@ Renderer::renderAnnotations(vector<Annotation>::iterator startIter,
 
     glMatrixMode(GL_PROJECTION);
     glPushMatrix();
-    glLoadIdentity();
-    gluOrtho2D(0, windowWidth, 0, windowHeight);
+    glLoadMatrix(Ortho2D(0.0f, (float)windowWidth, 0.0f, (float)windowHeight));
     glMatrixMode(GL_MODELVIEW);
     glPushMatrix();
     glLoadIdentity();
diff --git a/src/celmath/geomutil.h b/src/celmath/geomutil.h
index 9ed8e720..12c4e5d0 100644
--- a/src/celmath/geomutil.h
+++ b/src/celmath/geomutil.h
@@ -115,6 +115,27 @@ Perspective(T fovy, T aspect, T nearZ, T farZ)
     return m;
 }
 
-}; // namespace celmath
+/*! Return an orthographic projection matrix
+ */
+template<class T> Eigen::Matrix<T, 4, 4>
+Ortho(T left, T right, T bottom, T top, T nearZ, T farZ)
+{
+    T rl = right - left;
+    T tb = top - bottom;
+    T fn = farZ - nearZ;
+    Eigen::Matrix<T, 4, 4> m;
+    m << 2/rl,    0,     0, - (right + left) / rl,
+            0, 2/tb,     0, - (top + bottom) / tb,
+            0,    0, -2/fn, - (farZ + nearZ) / fn,
+            0,    0,     0,                     1;
+    return m;
+}
 
+template<class T> Eigen::Matrix<T, 4, 4>
+Ortho2D(T left, T right, T bottom, T top)
+{
+    return Ortho(left, right, bottom, top, T(-1), T(1));
+}
+
+}; // namespace celmath
 #endif // _CELMATH_GEOMUTIL_H_