use textures in the shared context to test how this works when using multiple windows with the same context

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@45479 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/opengl/cube/cube.cpp

@@ -38,6 +38,82 @@
     #include "../../sample.xpm"
 #endif
 
+// ----------------------------------------------------------------------------
+// helper functions
+// ----------------------------------------------------------------------------
+
+static void CheckGLError()
+{
+    GLenum errLast = GL_NO_ERROR;
+
+    for ( ;; )
+    {
+        GLenum err = glGetError();
+        if ( err == GL_NO_ERROR )
+            return;
+
+        // normally the error is reset by the call to glGetError() but if
+        // glGetError() itself returns an error, we risk looping forever here
+        // so check that we get a different error than the last time
+        if ( err == errLast )
+        {
+            wxLogError(_T("OpenGL error state couldn't be reset."));
+            return;
+        }
+
+        errLast = err;
+
+        wxLogError(_T("OpenGL error %d"), err);
+    }
+}
+
+// function to draw the texture for cube faces
+static wxImage DrawDice(int size, unsigned num)
+{
+    wxASSERT_MSG( num >= 1 && num <= 6, _T("invalid dice index") );
+
+    const int dot = size/16;        // radius of a single dot
+    const int gap = 5*size/32;      // gap between dots
+
+    wxBitmap bmp(size, size);
+    wxMemoryDC dc;
+    dc.SelectObject(bmp);
+    dc.SetBackground(*wxWHITE_BRUSH);
+    dc.Clear();
+    dc.SetBrush(*wxBLACK_BRUSH);
+
+    // the upper left and lower right points
+    if ( num != 1 )
+    {
+        dc.DrawCircle(gap + dot, gap + dot, dot);
+        dc.DrawCircle(size - gap - dot, size - gap - dot, dot);
+    }
+
+    // draw the central point for odd dices
+    if ( num % 2 )
+    {
+        dc.DrawCircle(size/2, size/2, dot);
+    }
+
+    // the upper right and lower left points
+    if ( num > 3 )
+    {
+        dc.DrawCircle(size - gap - dot, gap + dot, dot);
+        dc.DrawCircle(gap + dot, size - gap - dot, dot);
+    }
+
+    // finally those 2 are only for the last dice
+    if ( num == 6 )
+    {
+        dc.DrawCircle(gap + dot, size/2, dot);
+        dc.DrawCircle(size - gap - dot, size/2, dot);
+    }
+
+    dc.SelectObject(wxNullBitmap);
+
+    return bmp.ConvertToImage();
+}
+
 // ============================================================================
 // implementation
 // ============================================================================
@@ -71,8 +147,6 @@ TestGLContext& MyApp::GetContext(wxGLCanvas *canvas)
     if ( !m_glContext )
         m_glContext = new TestGLContext(canvas);
 
-    m_glContext->SetCurrent(*canvas);
-
     return *m_glContext;
 }
 
@@ -83,62 +157,47 @@ TestGLContext& MyApp::GetContext(wxGLCanvas *canvas)
 TestGLContext::TestGLContext(wxGLCanvas *canvas)
              : wxGLContext(canvas)
 {
-    m_gllist = 0;
+    SetCurrent(*canvas);
-}
 
-void TestGLContext::Init()
+    // set up the parameters we want to use
-{
+    glEnable(GL_DEPTH_TEST);
-    if ( m_gllist )
+    glEnable(GL_LIGHTING);
-        return;
+    glEnable(GL_LIGHT0);
+    glEnable(GL_TEXTURE_2D);
 
-    /* set viewing projection */
+    // set viewing projection
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
     glFrustum(-0.5f, 0.5f, -0.5f, 0.5f, 1.0f, 3.0f);
 
-    glEnable(GL_DEPTH_TEST);
+    // create the textures to use for cube sides: they will be reused by all
-    glEnable(GL_LIGHTING);
+    // canvases (which is probably not critical in the case of simple textures
-    glEnable(GL_LIGHT0);
+    // we use here but could be really important for a real application where
+    // each texture could take many megabytes)
+    glGenTextures(WXSIZEOF(m_textures), m_textures);
 
-    // create the list of commands to draw the cube: then we can just (quickly)
+    for ( unsigned i = 0; i < WXSIZEOF(m_textures); i++ )
-    // execute it in DrawRotatedCube() later
+    {
-    m_gllist = glGenLists(1);
+        glBindTexture(GL_TEXTURE_2D, m_textures[i]);
-    glNewList(m_gllist, GL_COMPILE);
 
-    /* draw six faces of a cube */
+        glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
-    glBegin(GL_QUADS);
+        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
-    glNormal3f( 0.0f, 0.0f, 1.0f);
+        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
-    glVertex3f( 0.5f, 0.5f, 0.5f); glVertex3f(-0.5f, 0.5f, 0.5f);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
-    glVertex3f(-0.5f,-0.5f, 0.5f); glVertex3f( 0.5f,-0.5f, 0.5f);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 
-    glNormal3f( 0.0f, 0.0f,-1.0f);
+        const wxImage img(DrawDice(256, i + 1));
-    glVertex3f(-0.5f,-0.5f,-0.5f); glVertex3f(-0.5f, 0.5f,-0.5f);
-    glVertex3f( 0.5f, 0.5f,-0.5f); glVertex3f( 0.5f,-0.5f,-0.5f);
 
-    glNormal3f( 0.0f, 1.0f, 0.0f);
+        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
-    glVertex3f( 0.5f, 0.5f, 0.5f); glVertex3f( 0.5f, 0.5f,-0.5f);
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, img.GetWidth(), img.GetHeight(), 
-    glVertex3f(-0.5f, 0.5f,-0.5f); glVertex3f(-0.5f, 0.5f, 0.5f);
+                     0, GL_RGB, GL_UNSIGNED_BYTE, img.GetData());
+    }
 
-    glNormal3f( 0.0f,-1.0f, 0.0f);
+    CheckGLError();
-    glVertex3f(-0.5f,-0.5f,-0.5f); glVertex3f( 0.5f,-0.5f,-0.5f);
-    glVertex3f( 0.5f,-0.5f, 0.5f); glVertex3f(-0.5f,-0.5f, 0.5f);
-
-    glNormal3f( 1.0f, 0.0f, 0.0f);
-    glVertex3f( 0.5f, 0.5f, 0.5f); glVertex3f( 0.5f,-0.5f, 0.5f);
-    glVertex3f( 0.5f,-0.5f,-0.5f); glVertex3f( 0.5f, 0.5f,-0.5f);
-
-    glNormal3f(-1.0f, 0.0f, 0.0f);
-    glVertex3f(-0.5f,-0.5f,-0.5f); glVertex3f(-0.5f,-0.5f, 0.5f);
-    glVertex3f(-0.5f, 0.5f, 0.5f); glVertex3f(-0.5f, 0.5f,-0.5f);
-    glEnd();
-
-    glEndList();
 }
 
 void TestGLContext::DrawRotatedCube(float xangle, float yangle)
 {
-    Init();
-
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
     glMatrixMode(GL_MODELVIEW);
@@ -147,9 +206,64 @@ void TestGLContext::DrawRotatedCube(float xangle, float yangle)
     glRotatef(xangle, 1.0f, 0.0f, 0.0f);
     glRotatef(yangle, 0.0f, 1.0f, 0.0f);
 
-    glCallList(m_gllist);
+    // draw six faces of a cube of size 1 centered at (0, 0, 0)
+    glBindTexture(GL_TEXTURE_2D, m_textures[0]);
+    glBegin(GL_QUADS);
+        glNormal3f( 0.0f, 0.0f, 1.0f);
+        glTexCoord2f(0, 0); glVertex3f( 0.5f, 0.5f, 0.5f);
+        glTexCoord2f(1, 0); glVertex3f(-0.5f, 0.5f, 0.5f);
+        glTexCoord2f(1, 1); glVertex3f(-0.5f,-0.5f, 0.5f);
+        glTexCoord2f(0, 1); glVertex3f( 0.5f,-0.5f, 0.5f);
+    glEnd();
+
+    glBindTexture(GL_TEXTURE_2D, m_textures[1]);
+    glBegin(GL_QUADS);
+        glNormal3f( 0.0f, 0.0f,-1.0f);
+        glTexCoord2f(0, 0); glVertex3f(-0.5f,-0.5f,-0.5f);
+        glTexCoord2f(1, 0); glVertex3f(-0.5f, 0.5f,-0.5f);
+        glTexCoord2f(1, 1); glVertex3f( 0.5f, 0.5f,-0.5f);
+        glTexCoord2f(0, 1); glVertex3f( 0.5f,-0.5f,-0.5f);
+    glEnd();
+
+    glBindTexture(GL_TEXTURE_2D, m_textures[2]);
+    glBegin(GL_QUADS);
+        glNormal3f( 0.0f, 1.0f, 0.0f);
+        glTexCoord2f(0, 0); glVertex3f( 0.5f, 0.5f, 0.5f);
+        glTexCoord2f(1, 0); glVertex3f( 0.5f, 0.5f,-0.5f);
+        glTexCoord2f(1, 1); glVertex3f(-0.5f, 0.5f,-0.5f);
+        glTexCoord2f(0, 1); glVertex3f(-0.5f, 0.5f, 0.5f);
+    glEnd();
+
+    glBindTexture(GL_TEXTURE_2D, m_textures[3]);
+    glBegin(GL_QUADS);
+        glNormal3f( 0.0f,-1.0f, 0.0f);
+        glTexCoord2f(0, 0); glVertex3f(-0.5f,-0.5f,-0.5f);
+        glTexCoord2f(1, 0); glVertex3f( 0.5f,-0.5f,-0.5f);
+        glTexCoord2f(1, 1); glVertex3f( 0.5f,-0.5f, 0.5f);
+        glTexCoord2f(0, 1); glVertex3f(-0.5f,-0.5f, 0.5f);
+    glEnd();
+
+    glBindTexture(GL_TEXTURE_2D, m_textures[4]);
+    glBegin(GL_QUADS);
+        glNormal3f( 1.0f, 0.0f, 0.0f);
+        glTexCoord2f(0, 0); glVertex3f( 0.5f, 0.5f, 0.5f);
+        glTexCoord2f(1, 0); glVertex3f( 0.5f,-0.5f, 0.5f);
+        glTexCoord2f(1, 1); glVertex3f( 0.5f,-0.5f,-0.5f);
+        glTexCoord2f(0, 1); glVertex3f( 0.5f, 0.5f,-0.5f);
+    glEnd();
+
+    glBindTexture(GL_TEXTURE_2D, m_textures[5]);
+    glBegin(GL_QUADS);
+        glNormal3f(-1.0f, 0.0f, 0.0f);
+        glTexCoord2f(0, 0); glVertex3f(-0.5f,-0.5f,-0.5f);
+        glTexCoord2f(1, 0); glVertex3f(-0.5f,-0.5f, 0.5f);
+        glTexCoord2f(1, 1); glVertex3f(-0.5f, 0.5f, 0.5f);
+        glTexCoord2f(0, 1); glVertex3f(-0.5f, 0.5f,-0.5f);
+    glEnd();
 
     glFlush();
+
+    CheckGLError();
 }
 
 // ----------------------------------------------------------------------------

samples/opengl/cube/cube.h

@@ -24,12 +24,8 @@ public:
     void DrawRotatedCube(float xangle, float yangle);
 
 private:
-    // one-time OpenGL initialization, safe to call many times
+    // textures for the cube faces
-    void Init();
+    GLuint m_textures[6];
-
-
-    // the list of commands to draw the cube
-    GLuint m_gllist;
 };
 
 // Define a new application type