Fix: multisample viewport drawing didn't work well with selection or particle

brushes, due to issues with color coded drawing or slow/buggy reading from such
a buffer on some systems.

In case multisample is enabled now, it uses an offscreen buffer for such drawing,
which is not multisampled and so should not cause issues. This does mean there is
some extra GPU memory usage when multisample is enabled, and we could optimize
triple buffer to work together here somehow to share buffers, but it's better than
having selection not working.

1 files changed, 10 insertions, 2 deletions

diff --git a/source/blender/gpu/intern/gpu_extensions.c b/source/blender/gpu/intern/gpu_extensions.c
index f5eaa716dfa..c7a421a49fc 100644
--- a/source/blender/gpu/intern/gpu_extensions.c
+++ b/source/blender/gpu/intern/gpu_extensions.c
@@ -905,10 +905,8 @@ void GPU_framebuffer_texture_bind(GPUFrameBuffer *UNUSED(fb), GPUTexture *tex, i
 
 	glMatrixMode(GL_PROJECTION);
 	glPushMatrix();
-	glLoadIdentity();
 	glMatrixMode(GL_MODELVIEW);
 	glPushMatrix();
-	glLoadIdentity();
 }
 
 void GPU_framebuffer_texture_unbind(GPUFrameBuffer *UNUSED(fb), GPUTexture *UNUSED(tex))
@@ -1096,6 +1094,16 @@ void GPU_offscreen_read_pixels(GPUOffScreen *ofs, int type, void *pixels)
 	glReadPixels(0, 0, ofs->w, ofs->h, GL_RGBA, type, pixels);
 }
 
+int GPU_offscreen_width(GPUOffScreen *ofs)
+{
+	return ofs->w;
+}
+
+int GPU_offscreen_height(GPUOffScreen *ofs)
+{
+	return ofs->h;
+}
+
 /* GPUShader */
 
 struct GPUShader {