Made the wallpaper be rescaled when necessary under SDL and OpenGL.

The SDL methods to rescale the wallpaper has been optimized to permit rescaling
at load time while OpenGL draws directly rescaled. Does someone know how to smooth
the rescaled image under OpenGL?

1 files changed, 67 insertions, 0 deletions

diff --git a/src/openglgraphics.cpp b/src/openglgraphics.cpp
index b9d837ad..5c9e2049 100644
--- a/src/openglgraphics.cpp
+++ b/src/openglgraphics.cpp
@@ -140,6 +140,42 @@ static inline void drawQuad(Image *image,
     }
 }
 
+static inline void drawRescaledQuad(Image *image,
+                            int srcX, int srcY, int dstX, int dstY,
+                            int width, int height,
+                            int desiredWidth, int desiredHeight)
+{
+    if (image->getTextureType() == GL_TEXTURE_2D)
+    {
+        // Find OpenGL normalized texture coordinates.
+        float texX1 = srcX / (float) image->getTextureWidth();
+        float texY1 = srcY / (float) image->getTextureHeight();
+        float texX2 = (srcX + width) / (float) image->getTextureWidth();
+        float texY2 = (srcY + height) / (float) image->getTextureHeight();
+
+        glTexCoord2f(texX1, texY1);
+        glVertex2i(dstX, dstY);
+        glTexCoord2f(texX2, texY1);
+        glVertex2i(dstX + desiredWidth, dstY);
+        glTexCoord2f(texX2, texY2);
+        glVertex2i(dstX + desiredWidth, dstY + desiredHeight);
+        glTexCoord2f(texX1, texY2);
+        glVertex2i(dstX, dstY + desiredHeight);
+    }
+    else
+    {
+        glTexCoord2i(srcX, srcY);
+        glVertex2i(dstX, dstY);
+        glTexCoord2i(srcX + width, srcY);
+        glVertex2i(dstX + desiredWidth, dstY);
+        glTexCoord2i(srcX + width, srcY + height);
+        glVertex2i(dstX + desiredWidth, dstY + desiredHeight);
+        glTexCoord2i(srcX, srcY + height);
+        glVertex2i(dstX, dstY + desiredHeight);
+    }
+}
+
+
 bool OpenGLGraphics::drawImage(Image *image, int srcX, int srcY,
                                int dstX, int dstY,
                                int width, int height, bool useColor)
@@ -168,6 +204,37 @@ bool OpenGLGraphics::drawImage(Image *image, int srcX, int srcY,
     return true;
 }
 
+bool OpenGLGraphics::drawRescaledImage(Image *image, int srcX, int srcY,
+                               int dstX, int dstY,
+                               int width, int height,
+                               int desiredWidth, int desiredHeight,
+                               bool useColor)
+{
+    if (!image)
+        return false;
+
+    srcX += image->mBounds.x;
+    srcY += image->mBounds.y;
+
+    if (!useColor)
+        glColor4f(1.0f, 1.0f, 1.0f, image->mAlpha);
+
+    glBindTexture(Image::mTextureType, image->mGLImage);
+
+    setTexturingAndBlending(true);
+
+    // Draw a textured quad.
+    glBegin(GL_QUADS);
+    drawRescaledQuad(image, srcX, srcY, dstX, dstY, width, height,
+                     desiredWidth, desiredHeight);
+    glEnd();
+
+    if (!useColor)
+        glColor4ub(mColor.r, mColor.g, mColor.b, mColor.a);
+
+    return true;
+}
+
 /* Optimising the functions that Graphics::drawImagePattern would call,
  * so that glBegin...glEnd are outside the main loop. */
 void OpenGLGraphics::drawImagePattern(Image *image, int x, int y, int w, int h)