handle upwards y axis

Author: codeanticode

core/src/processing/opengl/PGL.java

@@ -544,7 +544,7 @@ protected Texture wrapBackTexture(Texture texture) {
                    glColorTex.get(backTex), TEXTURE_2D, RGBA,
                    fboWidth, fboHeight, NEAREST, NEAREST,
                    CLAMP_TO_EDGE, CLAMP_TO_EDGE);
-      texture.invertedY(true);
+      texture.invertedY(PGraphicsOpenGL.Y_AXIS_DOWN);
       texture.colorBuffer(true);
       graphics.setCache(graphics, texture);
     } else {
@@ -561,7 +561,7 @@ protected Texture wrapFrontTexture(Texture texture)  {
                    glColorTex.get(frontTex), TEXTURE_2D, RGBA,
                    fboWidth, fboHeight, NEAREST, NEAREST,
                    CLAMP_TO_EDGE, CLAMP_TO_EDGE);
-      texture.invertedY(true);
+      texture.invertedY(PGraphicsOpenGL.Y_AXIS_DOWN);
       texture.colorBuffer(true);
     } else {
       texture.glName = glColorTex.get(frontTex);

core/src/processing/opengl/PGraphicsOpenGL.java

@@ -105,6 +105,9 @@ public void dispose() {
   /** Current flush mode. */
   protected int flushMode = FLUSH_WHEN_FULL;
 
+  /** Orientation of Y axis. */
+  static protected boolean Y_AXIS_DOWN = true;
+
   // ........................................................
 
   // VBOs for immediate rendering:
@@ -3577,10 +3580,14 @@ protected void textCharImpl(char ch, float x, float y) {
         float lextent = glyph.leftExtent / (float) textFont.getSize();
         float textent = glyph.topExtent  / (float) textFont.getSize();
 
+        // The default text setting assumes an Y axis pointing down, so
+        // inverting in the the case Y points up
+        int sign = Y_AXIS_DOWN ? +1 : -1;
+
         float x1 = x + lextent * textSize;
-        float y1 = y - textent * textSize;
+        float y1 = y - sign * textent * textSize;
         float x2 = x1 + bwidth * textSize;
-        float y2 = y1 + high * textSize;
+        float y2 = y1 + sign * high * textSize;
 
         textCharModelImpl(tinfo, x1, y1, x2, y2);
       } else if (textMode == SHAPE) {
@@ -5875,7 +5882,7 @@ protected void loadTextureImpl(int sampling, boolean mipmap) {
       Texture.Parameters params = new Texture.Parameters(ARGB,
                                                          sampling, mipmap);
       texture = new Texture(this, pixelWidth, pixelHeight, params);
-      texture.invertedY(true);
+      texture.invertedY(Y_AXIS_DOWN);
       texture.colorBuffer(true);
       setCache(this, texture);
     }
@@ -5886,7 +5893,7 @@ protected void createPTexture() {
     updatePixelSize();
     if (texture != null) {
       ptexture = new Texture(this, pixelWidth, pixelHeight, texture.getParameters());
-      ptexture.invertedY(true);
+      ptexture.invertedY(Y_AXIS_DOWN);
       ptexture.colorBuffer(true);
     }
   }
@@ -6026,7 +6033,7 @@ public void filter(PShader shader) {
     if (filterTexture == null || filterTexture.contextIsOutdated()) {
       filterTexture = new Texture(this, texture.width, texture.height,
                                   texture.getParameters());
-      filterTexture.invertedY(true);
+      filterTexture.invertedY(Y_AXIS_DOWN);
       filterImage = wrapTexture(filterTexture);
     }
     filterTexture.set(texture);
@@ -6096,7 +6103,7 @@ public void copy(int sx, int sy, int sw, int sh,
     loadTexture();
     if (filterTexture == null || filterTexture.contextIsOutdated()) {
       filterTexture = new Texture(this, texture.width, texture.height, texture.getParameters());
-      filterTexture.invertedY(true);
+      filterTexture.invertedY(Y_AXIS_DOWN);
       filterImage = wrapTexture(filterTexture);
     }
     filterTexture.put(texture, sx, height - (sy + sh), sw, height - sy);
@@ -6416,6 +6423,7 @@ protected Texture addTexture(PImage img, Texture.Parameters params) {
       img.parent = parent;
     }
     Texture tex = new Texture(this, img.pixelWidth, img.pixelHeight, params);
+    tex.invertedY(!Y_AXIS_DOWN); // Pixels are read upside down
     setCache(img, tex);
     return tex;
   }

libraries/vr/src/processing/vr/PGraphicsVR.java

@@ -52,6 +52,10 @@ public class PGraphicsVR extends PGraphics3D {
   private float[] eyePerspective;
   private PMatrix3D eyeMatrix;
 
+  static {
+    Y_AXIS_DOWN = false;
+  }
+
   @Override
   protected PGL createPGL(PGraphicsOpenGL pg) {
     return new PGLES(pg);