added alpha

include/ZE_ZImage.h

@@ -13,7 +13,7 @@
 File: ZE_ZImage.h <br>
 Description: Header file for core ZEngine Image and Texture Object. <br>
 Author(s): James Turk, Gamer Tazar <br>
-$Id: ZE_ZImage.h,v 1.10 2003/01/24 02:47:06 cozman Exp $<br>
+$Id: ZE_ZImage.h,v 1.11 2003/01/25 19:56:05 cozman Exp $<br>
 
     \file ZE_ZImage.h
     \brief Definition file for ZImage.
@@ -53,6 +53,8 @@ class ZImage : public ZObject
         unsigned int rWidth;
         //! Current draw height of Texture.
         unsigned int rHeight;
+        //! Stored alpha value for drawing texture.
+        Uint8 rAlpha;
     
     public:
 
@@ -159,7 +161,16 @@ class ZImage : public ZObject
         ////////////
 
         /*!
-            \brief Set Color Key (transparent color) of Image.
+            \brief Set alpha value (translucency) of image.
+
+            Set translucency value 0-255 (0 is transparent, 255 = opaque).
+            \since 0.8.2
+            \param alpha Number 0-255 setting translucency for image.
+        **/
+        void SetAlpha(Uint8 alpha);
+
+        /*!
+            \brief Set Color Key (transparent color) of image.
 
             Set color which will not be drawn in image.
             \param red Red component of colorkey (0-255).
@@ -256,6 +267,15 @@ class ZImage : public ZObject
             \return Image Height.
         **/
         int Height() const;
+
+        /*!
+            \brief Get Alpha component.
+
+            Get current alpha value of image.
+            \since 0.8.2
+            \return Image Alpha.
+        **/
+        Uint8 Alpha() const;
 };
 
 }

src/ZE_ZImage.cpp

@@ -13,7 +13,7 @@
 File: ZE_ZImage.cpp <br>
 Description: Implementation source file for core ZEngine Image or Texture Object. <br>
 Author(s): James Turk, Gamer Tazar <br>
-$Id: ZE_ZImage.cpp,v 1.20 2003/01/24 10:27:42 cozman Exp $<br>
+$Id: ZE_ZImage.cpp,v 1.21 2003/01/25 19:56:05 cozman Exp $<br>
 
     \file ZE_ZImage.cpp
     \brief Source file for ZImage.
@@ -29,30 +29,35 @@ namespace ZE
 ZImage::ZImage()
 {
     rImage = NULL;
+    rAlpha = 255;
     Release();
 }
 
 ZImage::ZImage(const ZImage &rhs)
 {
     rImage = NULL;
+    rAlpha = rhs.Alpha();
     OpenFromImage(rhs.Surface(),0,0,(Sint16)rhs.Width(),(Sint16)rhs.Height());
 }
 
 ZImage::ZImage(string filename)
 {
     rImage = NULL;
+    rAlpha = 255;
     Open(filename);
 }
 
 ZImage::ZImage(SDL_Surface *surface)
 {
     rImage = NULL;
+    rAlpha = 255;
     Attach(surface);
 }
 
 ZImage::ZImage(SDL_Surface *img, Sint16 x, Sint16 y, Sint16 w, Sint16 h)
 {
     rImage = NULL;
+    rAlpha = 255;
     OpenFromImage(img,x,y,w,h);
 }
 
@@ -147,6 +152,11 @@ void ZImage::Release()
     FreeImage(rImage);
 }
 
+void ZImage::SetAlpha(Uint8 alpha)
+{
+    rAlpha = alpha;
+}
+
 void ZImage::SetColorKey(Uint8 red, Uint8 green, Uint8 blue)
 {
     SDL_Surface *temp=NULL;
@@ -201,7 +211,10 @@ void ZImage::Bind() const
     if(!rTexID)
         rEngine->ReportError(ZERR_NOIMAGE,"Bind");
     else
+    {
+        glColor4ub(255,255,255,rAlpha); 
         glBindTexture(GL_TEXTURE_2D, rTexID);
+    }
 }
 
 void ZImage::Draw(float x, float y) const
@@ -213,6 +226,7 @@ void ZImage::Draw(float x, float y) const
         glTexCoord2f(rTexMinX,rTexMaxY);    glVertex2f(x,y+rHeight);
         glTexCoord2f(rTexMaxX,rTexMaxY);    glVertex2f(x+rWidth,y+rHeight);
     glEnd();
+    glColor4ub(255,255,255,255);    //return to standard color state
 }
 
 void ZImage::DrawRotated(int x, int y, float angle) const
@@ -255,4 +269,9 @@ int ZImage::Height() const
     return rHeight;
 }
 
+Uint8 ZImage::Alpha() const
+{
+    return rAlpha;
+}
+
 }

test/ZImageTest.cpp

@@ -8,7 +8,7 @@
      and the home of this Library is http://www.zengine.sourceforge.net
 *******************************************************************************/
 
-/*$Id: ZImageTest.cpp,v 1.14 2003/01/12 19:00:15 cozman Exp $*/
+/*$Id: ZImageTest.cpp,v 1.15 2003/01/25 19:59:38 cozman Exp $*/
 
 #include <ZEngine.h>
 #include <string> 
@@ -39,10 +39,11 @@ void Test()
 {
     ZEngine *engine = ZEngine::GetInstance();
     float angle=0.0f;
+    Uint8 alpha=128,alphaDelta=1;
 
     //Open and Setup all the Images//
     SDL_Surface *temp;
-    ZImage image1, image2, image3, textImage;
+    ZImage image1, image2, image3, textImage, cp;
     ZFont font("data/almontew.ttf",30);
 
     font.SetColor(0,255,0);
@@ -76,17 +77,20 @@ void Test()
             if(engine->KeyIsPressed(SDLK_s))
             {
                 //code to toggle screen//
-                engine->SetupDisplay(engine->Width(),engine->Height(),engine->BPP(),!engine->IsFullscreen());
+                engine->ToggleFullscreen();
-                engine->CreateDisplay("ZImage Test");
-                engine->SetReloadNeed(true);
             }
             if(engine->KeyIsPressed(SDLK_ESCAPE))
                 engine->RequestQuit();
 
             engine->Clear();    //clear screen
             //draw the images//
+            alpha += alphaDelta;
+            if(alpha ==255 || alpha == 0)
+                alphaDelta *= -1;
+            image1.SetAlpha(alpha);
             image1.Draw(0,0);
 
+            
             image2.DrawRotated(100,0,angle);
             if(++angle > 360)
                 angle = 0.0f;
@@ -95,6 +99,8 @@ void Test()
             textImage.Draw(0,100);
             engine->Update();    //update the screen
         }
+        else
+            engine->Delay(10);
 
     } while(!engine->QuitRequested());    //quit only when engine has encountered a quit request
 }