From 3d2160056e409ad2508a8bff4288944d37e32f85 Mon Sep 17 00:00:00 2001
From: Laszlo Agocs <laszlo.agocs@digia.com>
Date: Wed, 12 Mar 2014 13:38:24 +0100
Subject: Resurrect QGLWidget::renderText()
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The variant taking x, y, z has been broken in all Qt 5.x releases.
This is now corrected by making the GL2 paint engine capable of applying
a Z translation.

Task-number: QTBUG-31156
Change-Id: I119566e9e9577f6cdf7e8bae56cac1e34995e622
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
---
 src/opengl/gl2paintengineex/qglengineshadermanager.cpp |  3 ++-
 src/opengl/gl2paintengineex/qglengineshadermanager_p.h |  1 +
 src/opengl/gl2paintengineex/qglengineshadersource_p.h  |  5 ++++-
 src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp | 17 +++++++++++++++++
 src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h |  9 ++++++++-
 5 files changed, 32 insertions(+), 3 deletions(-)

(limited to 'src/opengl/gl2paintengineex')

diff --git a/src/opengl/gl2paintengineex/qglengineshadermanager.cpp b/src/opengl/gl2paintengineex/qglengineshadermanager.cpp
index 56f3f5ad0a..f266318ba6 100644
--- a/src/opengl/gl2paintengineex/qglengineshadermanager.cpp
+++ b/src/opengl/gl2paintengineex/qglengineshadermanager.cpp
@@ -534,7 +534,8 @@ GLuint QGLEngineShaderManager::getUniformLocation(Uniform id)
         "invertedTextureSize",
         "brushTransform",
         "brushTexture",
-        "matrix"
+        "matrix",
+        "translateZ"
     };
 
     if (uniformLocations.at(id) == GLuint(-1))
diff --git a/src/opengl/gl2paintengineex/qglengineshadermanager_p.h b/src/opengl/gl2paintengineex/qglengineshadermanager_p.h
index bbd9d86773..166d9a0593 100644
--- a/src/opengl/gl2paintengineex/qglengineshadermanager_p.h
+++ b/src/opengl/gl2paintengineex/qglengineshadermanager_p.h
@@ -444,6 +444,7 @@ public:
         BrushTransform,
         BrushTexture,
         Matrix,
+        TranslateZ,
         NumUniforms
     };
 
diff --git a/src/opengl/gl2paintengineex/qglengineshadersource_p.h b/src/opengl/gl2paintengineex/qglengineshadersource_p.h
index 90bd7edf54..aad2c1f7db 100644
--- a/src/opengl/gl2paintengineex/qglengineshadersource_p.h
+++ b/src/opengl/gl2paintengineex/qglengineshadersource_p.h
@@ -106,10 +106,13 @@ static const char* const qglslPositionOnlyVertexShader = "\n\
 
 static const char* const qglslComplexGeometryPositionOnlyVertexShader = "\n\
     uniform highp mat3 matrix; \n\
+    uniform highp float translateZ; \n\
     attribute highp vec2 vertexCoordsArray; \n\
     void setPosition(void) \n\
     { \n\
-      gl_Position = vec4(matrix * vec3(vertexCoordsArray, 1), 1);\n\
+      vec3 v = matrix * vec3(vertexCoordsArray, 1.0); \n\
+      vec4 vz = mat4(1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, translateZ, 1) * vec4(v, 1.0); \n\
+      gl_Position = vec4(vz.xyz, 1.0);\n\
     } \n";
 
 static const char* const qglslUntransformedPositionVertexShader = "\n\
diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index fd64a4a71f..2b49e4d2d1 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -1158,6 +1158,7 @@ bool QGL2PaintEngineExPrivate::prepareForDraw(bool srcPixelsAreOpaque)
         brushUniformsDirty = true;
         opacityUniformDirty = true;
         matrixUniformDirty = true;
+        translateZUniformDirty = true;
     }
 
     if (brushUniformsDirty && mode != ImageDrawingMode && mode != ImageArrayDrawingMode)
@@ -1174,6 +1175,12 @@ bool QGL2PaintEngineExPrivate::prepareForDraw(bool srcPixelsAreOpaque)
         matrixUniformDirty = false;
     }
 
+    if (translateZUniformDirty && shaderManager->hasComplexGeometry()) {
+        shaderManager->currentProgram()->setUniformValue(location(QGLEngineShaderManager::TranslateZ),
+                                                         translateZ);
+        translateZUniformDirty = false;
+    }
+
     return changed;
 }
 
@@ -2011,6 +2018,7 @@ bool QGL2PaintEngineEx::begin(QPaintDevice *pdev)
     d->matrixDirty = true;
     d->compositionModeDirty = true;
     d->opacityUniformDirty = true;
+    d->translateZUniformDirty = true;
     d->needsSync = true;
     d->useSystemClip = !systemClip().isEmpty();
     d->currentBrush = QBrush();
@@ -2375,6 +2383,15 @@ void QGL2PaintEngineExPrivate::systemStateChanged()
     }
 }
 
+void QGL2PaintEngineEx::setTranslateZ(GLfloat z)
+{
+    Q_D(QGL2PaintEngineEx);
+    if (d->translateZ != z) {
+        d->translateZ = z;
+        d->translateZUniformDirty = true;
+    }
+}
+
 void QGL2PaintEngineEx::setState(QPainterState *new_state)
 {
     //     qDebug("QGL2PaintEngineEx::setState()");
diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h b/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h
index 33a8869ecf..15ed5bc57d 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h
@@ -158,6 +158,9 @@ public:
     bool isNativePaintingActive() const;
     bool requiresPretransformedGlyphPositions(QFontEngine *, const QTransform &) const { return false; }
     bool shouldDrawCachedGlyphs(QFontEngine *, const QTransform &) const;
+
+    void setTranslateZ(GLfloat z);
+
 private:
     Q_DISABLE_COPY(QGL2PaintEngineEx)
 };
@@ -183,7 +186,8 @@ public:
             snapToPixelGrid(false),
             nativePaintingActive(false),
             inverseScale(1),
-            lastMaskTextureUsed(0)
+            lastMaskTextureUsed(0),
+            translateZ(0)
     { }
 
     ~QGL2PaintEngineExPrivate();
@@ -266,6 +270,7 @@ public:
     bool brushUniformsDirty;
     bool opacityUniformDirty;
     bool matrixUniformDirty;
+    bool translateZUniformDirty;
 
     bool stencilClean; // Has the stencil not been used for clipping so far?
     bool useSystemClip;
@@ -309,6 +314,8 @@ public:
     QVector<GLuint> unusedIBOSToClean;
 
     const GLfloat *vertexAttribPointers[3];
+
+    GLfloat translateZ;
 };
 
 
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