Transfers gpu buffer data to cpu

Added some code to retrieve the data in the gpu back to a cpu pointer
in the opengl helpers.

Added a framegraph node which specifies if any data must be downloaded
from the gpu

Added a flag in the buffer object to specify if the data from that
buffer must be downloaded.

Added a job to send the data back to the frontend.

Added a path in the renderer to download the gpu data.

Task number: QTBUG-57727

Change-Id: I315a9221e5116c7d07f818e00c654fe1901144f4
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/render/graphicshelpers/graphicshelpergl3_3.cpp b/src/render/graphicshelpers/graphicshelpergl3_3.cpp
index 023e90965..4f6e38bf4 100644
--- a/src/render/graphicshelpers/graphicshelpergl3_3.cpp
+++ b/src/render/graphicshelpers/graphicshelpergl3_3.cpp
@@ -879,6 +879,16 @@ void GraphicsHelperGL3_3::dispatchCompute(GLuint wx, GLuint wy, GLuint wz)
     qWarning() << "Compute Shaders are not supported by OpenGL 3.3 (since OpenGL 4.3)";
 }
 
+char *GraphicsHelperGL3_3::mapBuffer(GLenum target)
+{
+    return static_cast<char*>(m_funcs->glMapBuffer(target, GL_READ_WRITE));
+}
+
+GLboolean GraphicsHelperGL3_3::unmapBuffer(GLenum target)
+{
+    return m_funcs->glUnmapBuffer(target);
+}
+
 void GraphicsHelperGL3_3::glUniform1fv(GLint location, GLsizei count, const GLfloat *values)
 {
     m_funcs->glUniform1fv(location, count, values);