Initialization for depth texture

Precaution for using depth texture before nothing has been drawn.

Task-number: QTRD-2570
Change-Id: I47ece387542acbd1ffed8d650a70ecc471efb30e
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@digia.com>

2 files changed, 19 insertions, 1 deletions

diff --git a/src/datavisualization/utils/texturehelper.cpp b/src/datavisualization/utils/texturehelper.cpp
index cb18fcc2..41c5b452 100644
--- a/src/datavisualization/utils/texturehelper.cpp
+++ b/src/datavisualization/utils/texturehelper.cpp
@@ -182,7 +182,7 @@ GLuint TextureHelper::createDepthTexture(const QSize &size, GLuint textureSize)
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE_ARB, GL_COMPARE_R_TO_TEXTURE_ARB);
     glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, size.width() * textureSize,
-                 size.height() * textureSize, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, NULL);
+                 size.height() * textureSize, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
     glBindTexture(GL_TEXTURE_2D, 0);
 
     return depthtextureid;
@@ -219,6 +219,23 @@ GLuint TextureHelper::createDepthTextureFrameBuffer(const QSize &size, GLuint &f
 }
 #endif
 
+#if !defined(QT_OPENGL_ES_2)
+void TextureHelper::fillDepthTexture(GLuint texture,const QSize &size, GLuint textureSize, GLfloat value)
+{
+    int nItems = size.width() * textureSize * size.height() * textureSize;
+    GLfloat *bits = new GLfloat[nItems];
+    for (int i = 0; i < nItems; i++)
+        bits[i] = value;
+
+    glBindTexture(GL_TEXTURE_2D, texture);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, size.width() * textureSize,
+                 size.height() * textureSize, 0, GL_DEPTH_COMPONENT, GL_FLOAT, bits);
+    glBindTexture(GL_TEXTURE_2D, 0);
+
+    delete[] bits;
+}
+#endif
+
 void TextureHelper::deleteTexture(const GLuint *texture)
 {
     glDeleteTextures(1, texture);
diff --git a/src/datavisualization/utils/texturehelper_p.h b/src/datavisualization/utils/texturehelper_p.h
index 84570a13..11022495 100644
--- a/src/datavisualization/utils/texturehelper_p.h
+++ b/src/datavisualization/utils/texturehelper_p.h
@@ -53,6 +53,7 @@ class TextureHelper : protected QOpenGLFunctions
     GLuint createDepthTexture(const QSize &size, GLuint textureSize);
     // Returns depth texture and inserts generated framebuffer to parameter
     GLuint createDepthTextureFrameBuffer(const QSize &size, GLuint &frameBuffer, GLuint textureSize);
+    void fillDepthTexture(GLuint texture, const QSize &size, GLuint textureSize, GLfloat value);
 #endif
     void deleteTexture(const GLuint *texture);