Implement a special case, simplified vertex shader for complex geometry

When drawing text, the vertex count will most likely be so high that
using a uniform-based, simpler vertex shader is faster. We implement
the ability to inform the shader manager that the geometry is considered
complex, so that it can choose the simpler vertex shader in these cases.

Task-number: QT-2887
Reviewed-by: tom

1 files changed, 12 insertions, 1 deletions

diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index d68a268..b90f0c2 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -395,6 +395,7 @@ void QGL2PaintEngineExPrivate::updateMatrix()
                         qreal(0.0001));
 
     matrixDirty = false;
+    matrixUniformDirty = true;
 
     // Set the PMV matrix attribute. As we use an attributes rather than uniforms, we only
     // need to do this once for every matrix change and persists across all shader programs.
@@ -594,6 +595,9 @@ void QGL2PaintEngineExPrivate::transferMode(EngineMode newMode)
     if (newMode == TextDrawingMode) {
         setVertexAttributePointer(QT_VERTEX_COORDS_ATTR, (GLfloat*)vertexCoordinateArray.data());
         setVertexAttributePointer(QT_TEXTURE_COORDS_ATTR, (GLfloat*)textureCoordinateArray.data());
+        shaderManager->setHasComplexGeometry(true);
+    } else {
+        shaderManager->setHasComplexGeometry(false);
     }
 
     if (newMode == ImageDrawingMode) {
@@ -1045,6 +1049,7 @@ bool QGL2PaintEngineExPrivate::prepareForDraw(bool srcPixelsAreOpaque)
         // The shader program has changed so mark all uniforms as dirty:
         brushUniformsDirty = true;
         opacityUniformDirty = true;
+        matrixUniformDirty = true;
     }
 
     if (brushUniformsDirty && mode != ImageDrawingMode && mode != ImageArrayDrawingMode)
@@ -1055,6 +1060,12 @@ bool QGL2PaintEngineExPrivate::prepareForDraw(bool srcPixelsAreOpaque)
         opacityUniformDirty = false;
     }
 
+    if (matrixUniformDirty && shaderManager->hasComplexGeometry()) {
+        shaderManager->currentProgram()->setUniformValue(location(QGLEngineShaderManager::Matrix),
+                                                         pmvMatrix);
+        matrixUniformDirty = false;
+    }
+
     return changed;
 }
 
@@ -1631,7 +1642,6 @@ void QGL2PaintEngineExPrivate::drawCachedGlyphs(QFontEngineGlyphCache::Type glyp
         lastMaskTextureUsed = cache->texture();
     }
     updateTextureFilter(GL_TEXTURE_2D, GL_REPEAT, false);
-
     shaderManager->currentProgram()->setUniformValue(location(QGLEngineShaderManager::MaskTexture), QT_MASK_TEXTURE_UNIT);
 
 #if defined(QT_OPENGL_DRAWCACHEDGLYPHS_INDEX_ARRAY_VBO)
@@ -1776,6 +1786,7 @@ bool QGL2PaintEngineEx::begin(QPaintDevice *pdev)
     d->mode = BrushDrawingMode;
     d->brushTextureDirty = true;
     d->brushUniformsDirty = true;
+    d->matrixUniformDirty = true;
     d->matrixDirty = true;
     d->compositionModeDirty = true;
     d->opacityUniformDirty = true;