From 6b954fd7af7cbf7996efb2e35806d16acc7a2d5e Mon Sep 17 00:00:00 2001
From: Hleb Valoshka <375gnu@gmail.com>
Date: Wed, 20 Nov 2019 19:21:05 +0300
Subject: [PATCH] Replace gluProject with own implementation

---
 src/celengine/render.cpp | 34 +++++++++++++---------------------
 src/celengine/render.h   |  4 ++--
 src/celmath/geomutil.h   | 25 +++++++++++++++++++++++++
 3 files changed, 40 insertions(+), 23 deletions(-)

diff --git a/src/celengine/render.cpp b/src/celengine/render.cpp
index 5e38d579..ce04b611 100644
--- a/src/celengine/render.cpp
+++ b/src/celengine/render.cpp
@@ -1298,30 +1298,22 @@ void Renderer::addAnnotation(vector<Annotation>& annotations,
                              float size,
                              bool special)
 {
-    double winX, winY, winZ;
     GLint view[4] = { 0, 0, windowWidth, windowHeight };
-    float depth = (float) (pos.x() * modelMatrix[2] +
-                           pos.y() * modelMatrix[6] +
-                           pos.z() * modelMatrix[10]);
-    if (gluProject(pos.x(), pos.y(), pos.z(),
-                   modelMatrix,
-                   projMatrix,
-                   view,
-                   &winX, &winY, &winZ) != GL_FALSE)
+    Vector3d win;
+    Vector3d posd = pos.cast<double>();
+    if (Project(posd, modelMatrix, projMatrix, view, win))
     {
+        double depth = pos.x() * modelMatrix(2, 0) +
+                       pos.y() * modelMatrix(2, 1) +
+                       pos.z() * modelMatrix(2, 2);
+        win.z() = -depth;
+
         Annotation a;
-        if (special)
-        {
-            if (markerRep == nullptr)
-                a.labelText = labelText;
-        }
-        else
-        {
-            a.labelText = labelText;
-        }
+        if (!special || markerRep == nullptr)
+             a.labelText = labelText;
         a.markerRep = markerRep;
         a.color = color;
-        a.position = Vector3f((float) winX, (float) winY, -depth);
+        a.position = win.cast<float>();
         a.halign = halign;
         a.valign = valign;
         a.size = size;
@@ -2522,8 +2514,8 @@ void Renderer::draw(const Observer& observer,
 
     // Get the model matrix *before* translation.  We'll use this for
     // positioning star and planet labels.
-    glGetDoublev(GL_MODELVIEW_MATRIX, modelMatrix);
-    glGetDoublev(GL_PROJECTION_MATRIX, projMatrix);
+    glGetDoublev(GL_MODELVIEW_MATRIX, modelMatrix.data());
+    glGetDoublev(GL_PROJECTION_MATRIX, projMatrix.data());
 
     clearSortedAnnotations();
 
diff --git a/src/celengine/render.h b/src/celengine/render.h
index a637cda7..41464341 100644
--- a/src/celengine/render.h
+++ b/src/celengine/render.h
@@ -719,8 +719,8 @@ class Renderer
 
     std::vector<LightSource> lightSourceList;
 
-    double modelMatrix[16];
-    double projMatrix[16];
+    Eigen::Matrix4d modelMatrix;
+    Eigen::Matrix4d projMatrix;
 
     bool useCompressedTextures{ false };
     unsigned int textureResolution;
diff --git a/src/celmath/geomutil.h b/src/celmath/geomutil.h
index 2e0fa6a8..0aa51936 100644
--- a/src/celmath/geomutil.h
+++ b/src/celmath/geomutil.h
@@ -62,6 +62,31 @@ LookAt(const Eigen::Matrix<T, 3, 1>& from, const Eigen::Matrix<T, 3, 1>& to, con
     return Eigen::Quaternion<T>(m).conjugate();
 }
 
+/*! Project to screen space
+ */
+template<class T> bool
+Project(const Eigen::Matrix<T, 3, 1>& from,
+        const Eigen::Matrix<T, 4, 4>& modelViewMatrix,
+        const Eigen::Matrix<T, 4, 4>& projMatrix,
+        const int viewport[4],
+        Eigen::Matrix<T, 3, 1>& to)
+{
+    Eigen::Matrix<T, 4, 1> in(from.x(), from.y(), from.z(), T(1.0));
+    Eigen::Matrix<T, 4, 1> out = projMatrix * modelViewMatrix * in;
+    if (out.w() == T(0.0))
+        return false;
+
+    out = out.array() / out.w();
+    // Map x, y and z to range 0-1
+    out = T(0.5) + out.array() * T(0.5);
+    // Map x,y to viewport
+    out.x() = viewport[0] + out.x() * viewport[2];
+    out.y() = viewport[1] + out.y() * viewport[3];
+
+    to = { out.x(), out.y(), out.z() };
+    return true;
+}
+
 }; // namespace celmath
 
 #endif // _CELMATH_GEOMUTIL_H_