From a562944023fd0de61a9751affa4ad51d7d718621 Mon Sep 17 00:00:00 2001
From: Christophe Geuzaine <cgeuzaine@ulg.ac.be>
Date: Fri, 16 Dec 2005 19:17:34 +0000
Subject: [PATCH] cleanup+add comments so that students can understand what's
going on with the projection stuff.
(still need to cleanup the zooming in handle() to use gluUnproject() instead
of the ad-hock stuff that only works for an orthographic proj)
---
Fltk/Opengl_Window.cpp | 3 +-
Graphics/CreateFile.cpp | 3 +-
Graphics/Draw.cpp | 84 ++++++++++++++++++-----------------------
Graphics/Draw.h | 10 ++---
Graphics/Mesh.cpp | 12 +++---
5 files changed, 48 insertions(+), 64 deletions(-)
diff --git a/Fltk/Opengl_Window.cpp b/Fltk/Opengl_Window.cpp
index 7287e55275..42f472117a 100644
--- a/Fltk/Opengl_Window.cpp
+++ b/Fltk/Opengl_Window.cpp
@@ -1,4 +1,4 @@
-// $Id: Opengl_Window.cpp,v 1.51 2005-12-16 17:35:33 geuzaine Exp $
+// $Id: Opengl_Window.cpp,v 1.52 2005-12-16 19:17:33 geuzaine Exp $
//
// Copyright (C) 1997-2005 C. Geuzaine, J.-F. Remacle
//
@@ -64,7 +64,6 @@ void Opengl_Window::draw()
if(!ZoomMode) {
ClearOpengl();
- Orthogonalize(0, 0);
Draw3d();
Draw2d();
}
diff --git a/Graphics/CreateFile.cpp b/Graphics/CreateFile.cpp
index e5f9fca99b..d0d28fa240 100644
--- a/Graphics/CreateFile.cpp
+++ b/Graphics/CreateFile.cpp
@@ -1,4 +1,4 @@
-// $Id: CreateFile.cpp,v 1.70 2005-12-16 17:35:33 geuzaine Exp $
+// $Id: CreateFile.cpp,v 1.71 2005-12-16 19:17:33 geuzaine Exp $
//
// Copyright (C) 1997-2005 C. Geuzaine, J.-F. Remacle
//
@@ -41,7 +41,6 @@ void FillBuffer(void)
{
SetOpenglContext();
ClearOpengl();
- Orthogonalize(0, 0);
Draw3d();
Draw2d();
}
diff --git a/Graphics/Draw.cpp b/Graphics/Draw.cpp
index 59c7d58472..da79246cfa 100644
--- a/Graphics/Draw.cpp
+++ b/Graphics/Draw.cpp
@@ -1,4 +1,4 @@
-// $Id: Draw.cpp,v 1.81 2005-12-16 17:35:33 geuzaine Exp $
+// $Id: Draw.cpp,v 1.82 2005-12-16 19:17:34 geuzaine Exp $
//
// Copyright (C) 1997-2005 C. Geuzaine, J.-F. Remacle
//
@@ -75,6 +75,8 @@ void Draw3d(void)
glDepthFunc(GL_LESS);
glEnable(GL_DEPTH_TEST);
+ InitProjection(0, 0);
+ InitPosition();
InitRenderModel();
Draw_Mesh(&M);
@@ -129,38 +131,25 @@ void ClearOpengl(void)
glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
}
-// Ortho
+// Init
-void Orthogonalize(int x, int y)
+void InitProjection(int x, int y)
{
- double Va, Wa;
-
- glMatrixMode(GL_PROJECTION);
- glLoadIdentity();
-
- if(CTX.render_mode == GMSH_SELECT)
- gluPickMatrix((GLdouble) x,
- (GLdouble) (CTX.viewport[3] - y),
- 5.0, 5.0, (GLint *) CTX.viewport);
-
- Va = (GLdouble) (CTX.viewport[3] - CTX.viewport[1]) /
+ double Va =
+ (GLdouble) (CTX.viewport[3] - CTX.viewport[1]) /
(GLdouble) (CTX.viewport[2] - CTX.viewport[0]);
+ double Wa = (CTX.max[1] - CTX.min[1]) / (CTX.max[0] - CTX.min[0]);
- Wa = (CTX.max[1] - CTX.min[1]) / (CTX.max[0] - CTX.min[0]);
-
+ // compute the viewport in World coordinates (with margins)
if(Va > Wa) {
CTX.vxmin = CTX.min[0];
CTX.vxmax = CTX.max[0];
- CTX.vymin =
- 0.5 * (CTX.min[1] + CTX.max[1] - Va * (CTX.max[0] - CTX.min[0]));
- CTX.vymax =
- 0.5 * (CTX.min[1] + CTX.max[1] + Va * (CTX.max[0] - CTX.min[0]));
+ CTX.vymin = 0.5 * (CTX.min[1] + CTX.max[1] - Va * (CTX.max[0] - CTX.min[0]));
+ CTX.vymax = 0.5 * (CTX.min[1] + CTX.max[1] + Va * (CTX.max[0] - CTX.min[0]));
}
else {
- CTX.vxmin =
- 0.5 * (CTX.min[0] + CTX.max[0] - (CTX.max[1] - CTX.min[1]) / Va);
- CTX.vxmax =
- 0.5 * (CTX.min[0] + CTX.max[0] + (CTX.max[1] - CTX.min[1]) / Va);
+ CTX.vxmin = 0.5 * (CTX.min[0] + CTX.max[0] - (CTX.max[1] - CTX.min[1]) / Va);
+ CTX.vxmax = 0.5 * (CTX.min[0] + CTX.max[0] + (CTX.max[1] - CTX.min[1]) / Va);
CTX.vymin = CTX.min[1];
CTX.vymax = CTX.max[1];
}
@@ -169,21 +158,24 @@ void Orthogonalize(int x, int y)
CTX.vymin -= (CTX.vymax - CTX.vymin) / 3.;
CTX.vymax += 0.25 * (CTX.vymax - CTX.vymin);
- CTX.pixel_equiv_x =
- (CTX.vxmax - CTX.vxmin) / (CTX.viewport[2] - CTX.viewport[0]);
- CTX.pixel_equiv_y =
- (CTX.vymax - CTX.vymin) / (CTX.viewport[3] - CTX.viewport[1]);
+ // store what one pixel represents in world coordinates
+ CTX.pixel_equiv_x = (CTX.vxmax - CTX.vxmin) / (CTX.viewport[2] - CTX.viewport[0]);
+ CTX.pixel_equiv_y = (CTX.vymax - CTX.vymin) / (CTX.viewport[3] - CTX.viewport[1]);
- // We should have a look at how the scaling is done in "real" opengl
- // applications (I guess they normalize the scene to fit in a 1x1x1
- // box or something...). Here, we set up a large box around the
- // object, so that if we zoom a lot the resolution of the depth
- // buffer might become insufficient (at least with the "software"
- // Mesa on Linux; with hardware acceleration or on Windows
- // everyhting seems to be fine).
+ // setup ortho or perspective projection matrix
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+
+ if(CTX.render_mode == GMSH_SELECT)
+ gluPickMatrix((GLdouble) x, (GLdouble) (CTX.viewport[3] - y),
+ 5.0, 5.0, (GLint *) CTX.viewport);
double gradient_zdist, gradient_xyfact;
if(CTX.ortho) {
+ // setting up the near and far clipping planes so that the box is
+ // large enough to manipulate the model and zoom, but not too big
+ // (the z-buffer resolution, e.g., on software Mesa can become
+ // insufficient)
double maxz = MAX(fabs(CTX.min[2]), fabs(CTX.max[2]));
if(maxz < CTX.lc) maxz = CTX.lc;
double clip = maxz * CTX.s[2] * CTX.clip_factor;
@@ -196,18 +188,15 @@ void Orthogonalize(int x, int y)
else {
double near = 0.75 * CTX.clip_factor * CTX.lc;
double far = 75. * CTX.clip_factor * CTX.lc;
-
// recenter the model such that the perspective is always at the
// center of the screen. FIXME: this screws up the zoom, so let's
// leave it out for now
- /*
- double w = (CTX.max[0] - CTX.min[0]) / 2.;
- double h = (CTX.max[1] - CTX.min[1]) / 2.;
- CTX.vxmin -= w;
- CTX.vxmax -= w;
- CTX.vymin -= h;
- CTX.vymax -= h;
- */
+ //double w = (CTX.max[0] - CTX.min[0]) / 2.;
+ //double h = (CTX.max[1] - CTX.min[1]) / 2.;
+ //CTX.vxmin -= w;
+ //CTX.vxmax -= w;
+ //CTX.vymin -= h;
+ //CTX.vymax -= h;
double w = 0.;
double h = 0.;
glFrustum(CTX.vxmin, CTX.vxmax, CTX.vymin, CTX.vymax, near, far);
@@ -220,7 +209,7 @@ void Orthogonalize(int x, int y)
}
// draw background gradient
- if(CTX.bg_gradient){
+ if(CTX.render_mode != GMSH_SELECT && CTX.bg_gradient){
glPushMatrix();
glLoadIdentity();
glTranslated(0., 0., -gradient_zdist);
@@ -247,8 +236,6 @@ void Orthogonalize(int x, int y)
}
}
-// Init
-
void InitRenderModel(void)
{
GLfloat r, g, b;
@@ -355,7 +342,8 @@ void Process_SelectionBuffer(int x, int y, int *n, hit *hits)
// an entity is drawn
glPushMatrix();
- Orthogonalize(x, y);
+ InitProjection(x, y);
+ InitPosition();
Draw_Mesh(&M);
glPopMatrix();
diff --git a/Graphics/Draw.h b/Graphics/Draw.h
index 0c8804e5e1..66f9052a25 100644
--- a/Graphics/Draw.h
+++ b/Graphics/Draw.h
@@ -30,12 +30,12 @@
#define SELECTION_BUFFER_SIZE 1024
-void InitRenderModel(void);
-void InitPosition(void);
-
-void Orthogonalize(int x, int y);
-void ClearOpengl(void);
void SetOpenglContext(void);
+void ClearOpengl(void);
+
+void InitProjection(int x, int y);
+void InitPosition(void);
+void InitRenderModel(void);
typedef struct{
unsigned int type, ient, depth;
diff --git a/Graphics/Mesh.cpp b/Graphics/Mesh.cpp
index 7359b5f97a..77e8e2400a 100644
--- a/Graphics/Mesh.cpp
+++ b/Graphics/Mesh.cpp
@@ -1,4 +1,4 @@
-// $Id: Mesh.cpp,v 1.144 2005-12-16 17:35:33 geuzaine Exp $
+// $Id: Mesh.cpp,v 1.145 2005-12-16 19:17:34 geuzaine Exp $
//
// Copyright (C) 1997-2005 C. Geuzaine, J.-F. Remacle
//
@@ -56,18 +56,18 @@ static int stepLabelsDisplayed = 1;
void draw_polygon_2d(double r, double g, double b, int n,
double *x, double *y, double *z)
{
- int i;
-
+ // this routine is only used to display the interactive construction
+ // of the 2D aniso mesh
CalculateMinMax(THEM->Points, NULL);
SetOpenglContext();
- Orthogonalize(0, 0);
+ InitProjection(0, 0);
InitPosition();
glDisable(GL_DEPTH_TEST);
glDrawBuffer(GL_FRONT);
glColor3f(r, g, b);
glBegin(GL_LINE_STRIP);
- for(i = 0; i < n; i++)
+ for(int i = 0; i < n; i++)
if(z)
glVertex3d(x[i], y[i], z[i]);
else
@@ -141,8 +141,6 @@ int getPartition(int index)
void Draw_Mesh(Mesh * M)
{
- InitPosition();
-
for(int i = 0; i < 6; i++)
glClipPlane((GLenum)(GL_CLIP_PLANE0 + i), CTX.clip_plane[i]);
--
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