Add clipping to distance field fonts

Removes fallback to the old text renderer and adds the clipping feature
to the distance field font renderer.

Task-number: QT3DS-3329
Change-Id: Ie41b93c9a9ed791297349007c7e2b3bf10c982b1
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: Tomi Korpipää <tomi.korpipaa@qt.io>

2 files changed, 88 insertions, 38 deletions

diff --git a/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldRenderer.cpp b/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldRenderer.cpp
index 64e5a737..2562ea79 100644
--- a/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldRenderer.cpp
+++ b/src/Runtime/Source/runtimerender/Qt3DSDistanceFieldRenderer.cpp
@@ -115,6 +115,9 @@ Q3DSDistanceFieldRenderer::buildGlyphsPerTexture(const SText &textInfo)
         return QHash<Q3DSDistanceFieldGlyphCache::TextureInfo *, GlyphInfo>();
 
     QVector2D boundingBox = QVector2D(textInfo.m_BoundingBox.x, textInfo.m_BoundingBox.y);
+    const float halfWidth = boundingBox.x() / 2.0f;
+    const float halfHeight = boundingBox.y() / 2.0f;
+    bool hasValidBoundingBox = boundingBox.x() > 0 || boundingBox.y() > 0;
 
     QRawFont font = m_fontDatabase.findFont(textInfo.m_Font.c_str());
     font.setPixelSize(qreal(textInfo.m_FontSize));
@@ -391,6 +394,43 @@ Q3DSDistanceFieldRenderer::buildGlyphsPerTexture(const SText &textInfo)
                         cy2 += float(shadowOffsetY * fontScale);
                 }
 
+                float x1Clip = 1.0f;
+                float x2Clip = 1.0f;
+                float y1Clip = 1.0f;
+                float y2Clip = 1.0f;
+
+                if (hasValidBoundingBox) {
+                    if ((cx1 < -halfWidth && cx2 < -halfWidth)
+                            || (cx1 > halfWidth && cx2 > halfWidth)
+                            || (cy1 < -halfHeight && cy2 < -halfHeight)
+                            || (cy1 > halfHeight && cy2 > halfHeight)) {
+                        continue;
+                    }
+
+                    float xDiff = qAbs(cx1 - cx2);
+                    float yDiff = qAbs(cy1 - cy2);
+
+                    if (cx1 < -halfWidth) {
+                        x1Clip = 1.0f - qAbs(cx1 - (-halfWidth)) / xDiff;
+                        cx1 = -halfWidth;
+                    }
+
+                    if (cx2 > halfWidth) {
+                        x2Clip = 1.0f - qAbs(cx2 - halfWidth) / xDiff;
+                        cx2 = halfWidth;
+                    }
+
+                    if (cy1 < -halfHeight) {
+                        y1Clip = 1.0f - qAbs(cy1 - (-halfHeight)) / yDiff;
+                        cy1 = -halfHeight;
+                    }
+
+                    if (cy2 > halfHeight) {
+                        y2Clip = 1.0f - qAbs(cy2 - halfHeight) / yDiff;
+                        cy2 = halfHeight;
+                    }
+                }
+
                 cy1 = -cy1;
                 cy2 = -cy2;
 
@@ -414,9 +454,7 @@ Q3DSDistanceFieldRenderer::buildGlyphsPerTexture(const SText &textInfo)
                 else if (cy2 > maximum.y)
                     maximum.y = cy2;
 
-                if (boundingBox.x() > 0 || boundingBox.y() > 0) {
-                    const float halfWidth = boundingBox.x() / 2.0f;
-                    const float halfHeight = boundingBox.y() / 2.0f;
+                if (hasValidBoundingBox) {
                     if (maximum.x < halfWidth)
                         maximum.x = halfWidth;
                     if (minimum.x > -halfWidth)
@@ -450,6 +488,21 @@ Q3DSDistanceFieldRenderer::buildGlyphsPerTexture(const SText &textInfo)
                         ty2 += float(c.height * shadowOffsetY * fontScale) / float(metrics.height);
                 }
 
+                if (hasValidBoundingBox) {
+                    float tx1Orig = tx1;
+                    float tx2Orig = tx2;
+                    float ty1Orig = ty1;
+                    float ty2Orig = ty2;
+
+                    float xDiff = qAbs(tx1 - tx2);
+                    tx1 = tx2Orig - xDiff * x1Clip;
+                    tx2 = tx1Orig + xDiff * x2Clip;
+
+                    float yDiff = qAbs(ty1 - ty2);
+                    ty1 = ty2Orig - yDiff * y1Clip;
+                    ty2 = ty1Orig + yDiff * y2Clip;
+                }
+
                 const QSGDistanceFieldGlyphCache::Texture *texture
                         = cache->glyphTexture(glyphIndex);
                 if (texture->textureId == 0) {
diff --git a/src/Runtime/Source/runtimerender/rendererimpl/Qt3DSRendererImplLayerRenderPreparationData.cpp b/src/Runtime/Source/runtimerender/rendererimpl/Qt3DSRendererImplLayerRenderPreparationData.cpp
index 2940f088..e1086304 100644
--- a/src/Runtime/Source/runtimerender/rendererimpl/Qt3DSRendererImplLayerRenderPreparationData.cpp
+++ b/src/Runtime/Source/runtimerender/rendererimpl/Qt3DSRendererImplLayerRenderPreparationData.cpp
@@ -383,44 +383,41 @@ namespace render {
             inText.CalculateMVPAndNormalMatrix(inViewProjection, theMVP, theNormalMatrix);
 
             SRenderableObject *theRenderable = nullptr;
+
 #if QT_VERSION >= QT_VERSION_CHECK(5,12,2)
-            // TODO: Implement clipping for the distance field renderer
-            if (inText.m_WordWrap != TextWordWrap::Clip || (inText.m_BoundingBox.x == 0.0f
-                                                            && inText.m_BoundingBox.y == 0.0f)) {
-                QT3DSMat44 modelView = (inProjection.getInverse() * inViewProjection)
-                        * inText.m_GlobalTransform;
-                Q3DSDistanceFieldRenderer *distanceFieldText
-                        = static_cast<Q3DSDistanceFieldRenderer *>(
-                            m_Renderer.GetQt3DSContext().getDistanceFieldRenderer());
-                theRenderable = RENDER_FRAME_NEW(SDistanceFieldRenderable)(
-                    theFlags, inText.GetGlobalPos(), inText, inText.m_Bounds, theMVP,
-                    modelView, *distanceFieldText);
-            } else
+            QT3DSMat44 modelView = (inProjection.getInverse() * inViewProjection)
+                    * inText.m_GlobalTransform;
+            Q3DSDistanceFieldRenderer *distanceFieldText
+                    = static_cast<Q3DSDistanceFieldRenderer *>(
+                        m_Renderer.GetQt3DSContext().getDistanceFieldRenderer());
+            theRenderable = RENDER_FRAME_NEW(SDistanceFieldRenderable)(
+                        theFlags, inText.GetGlobalPos(), inText, inText.m_Bounds, theMVP,
+                        modelView, *distanceFieldText);
+#else
+            TTPathObjectAndTexture theResult
+                    = theTextRenderer->RenderText(inText, inTextScaleFactor);
+            inText.m_TextTexture = theResult.second.second.mPtr;
+            inText.m_TextTextureDetails = theResult.second.first;
+            inText.m_PathFontItem = theResult.first.second;
+            inText.m_PathFontDetails = theResult.first.first;
+            STextScaleAndOffset theScaleAndOffset(*inText.m_TextTexture,
+                                                  inText.m_TextTextureDetails, inText);
+            QT3DSVec2 theTextScale(theScaleAndOffset.m_TextScale);
+            QT3DSVec2 theTextOffset(theScaleAndOffset.m_TextOffset);
+            QT3DSVec3 minimum(theTextOffset[0] - theTextScale[0],
+                    theTextOffset[1] - theTextScale[1], 0);
+            QT3DSVec3 maximum(theTextOffset[0] + theTextScale[0],
+                    theTextOffset[1] + theTextScale[1], 0);
+            inText.m_Bounds = NVBounds3(minimum, maximum);
+
+            if (inText.m_PathFontDetails)
+                ioFlags.SetRequiresStencilBuffer(true);
+
+            theRenderable = RENDER_FRAME_NEW(STextRenderable)(
+                theFlags, inText.GetGlobalPos(), m_Renderer, inText, inText.m_Bounds, theMVP,
+                inViewProjection, *inText.m_TextTexture, theTextOffset, theTextScale);
 #endif
-            {
-                TTPathObjectAndTexture theResult
-                        = theTextRenderer->RenderText(inText, inTextScaleFactor);
-                inText.m_TextTexture = theResult.second.second.mPtr;
-                inText.m_TextTextureDetails = theResult.second.first;
-                inText.m_PathFontItem = theResult.first.second;
-                inText.m_PathFontDetails = theResult.first.first;
-                STextScaleAndOffset theScaleAndOffset(*inText.m_TextTexture,
-                                                      inText.m_TextTextureDetails, inText);
-                QT3DSVec2 theTextScale(theScaleAndOffset.m_TextScale);
-                QT3DSVec2 theTextOffset(theScaleAndOffset.m_TextOffset);
-                QT3DSVec3 minimum(theTextOffset[0] - theTextScale[0],
-                        theTextOffset[1] - theTextScale[1], 0);
-                QT3DSVec3 maximum(theTextOffset[0] + theTextScale[0],
-                        theTextOffset[1] + theTextScale[1], 0);
-                inText.m_Bounds = NVBounds3(minimum, maximum);
-
-                if (inText.m_PathFontDetails)
-                    ioFlags.SetRequiresStencilBuffer(true);
 
-                theRenderable = RENDER_FRAME_NEW(STextRenderable)(
-                    theFlags, inText.GetGlobalPos(), m_Renderer, inText, inText.m_Bounds, theMVP,
-                    inViewProjection, *inText.m_TextTexture, theTextOffset, theTextScale);
-            }
             m_TransparentObjects.push_back(theRenderable);
         }
         return retval;