Using render border with real-time viewport Blender Internal rendering and DrawPixels Images Draw Method results in the wrong area being rendered #49429

New Issue

Forest Katsch · 2016-09-22T18:53:56+02:00

Forest Katsch commented

2016-09-22 18:53:56 +02:00

Blender version 2.78rc2, but this is in 2.77 as well as a week-old git master.
OS: Arch Linux.

The same bug is present on an nVidia card with the proprietary 340 driver (it's a GTX 285, and nVidia's 340xx driver is the latest supported driver for the card) as well as Intel integrated graphics. I'm 90% sure this is a Blender bug, anyway.

When using border render in conjunction with real-time viewport rendering and DrawPixels (as opposed to 2D texture or GLSL), the x-y offset of the render border is at the lower left corner of the 3D view.

To reproduce:

(You need to have Images Draw Method in settings set to DrawPixels.)

Set Blender Internal as the renderer.
Make sure there's something visible in your scene; having a non-transparent world background is enough.
Set a render border with Ctrl-B; make sure it doesn't reach the lower-left corner.
Press Shift-Z to enable render preview.

I've also attached a test case file; all you have to do is open it and press Shift-Z.

testcase.blend

Blender version 2.78rc2, but this is in 2.77 as well as a week-old git master. OS: Arch Linux. The same bug is present on an nVidia card with the proprietary 340 driver (it's a GTX 285, and nVidia's 340xx driver is the latest supported driver for the card) as well as Intel integrated graphics. I'm 90% sure this is a Blender bug, anyway. When using border render in conjunction with real-time viewport rendering and DrawPixels (as opposed to 2D texture or GLSL), the x-y offset of the render border is at the lower left corner of the 3D view. To reproduce: (You need to have Images Draw Method in settings set to DrawPixels.) 1. Set Blender Internal as the renderer. 2. Make sure there's something visible in your scene; having a non-transparent world background is enough. 3. Set a render border with Ctrl-B; make sure it doesn't reach the lower-left corner. 4. Press Shift-Z to enable render preview. I've also attached a test case file; all you have to do is open it and press Shift-Z. [testcase.blend](https://archive.blender.org/developer/F366306/testcase.blend) ![screenshot.png](https://archive.blender.org/developer/F366304/screenshot.png)

Forest Katsch commented

2016-09-22 18:53:56 +02:00

Changed status to: 'Open'

Forest Katsch commented

2016-09-22 18:53:56 +02:00

Added subscriber: @forestkatsch

Ton Roosendaal commented

2016-09-22 20:18:40 +02:00

Added subscriber: @Ton

Ton Roosendaal commented

2016-09-22 20:18:40 +02:00

No error for me (2.77a release)

Forest Katsch changed title from ~~Using Blender Internal render border with real-time rendering results in the wrong area being rendered~~ to Using render border with real-time viewport Blender Internal rendering and DrawPixels Images Draw Method results in the wrong area being rendered

2016-09-22 20:24:22 +02:00

YAFU commented

2016-09-22 20:57:47 +02:00

Added subscriber: @YAFU

YAFU commented

2016-09-22 20:57:47 +02:00

I can reproduce the problem if 'File > User Preferences > System > Images Draw Method > DrawPixels' is selected, in Blender 2.77a ( abf6f08 ) and blender from buildbot 2.78 ( 21e9db9 ).
Kubuntu Linux 14.04 64 bits, GTX 960 (370.28)

I can reproduce the problem if 'File > User Preferences > System > Images Draw Method > DrawPixels' is selected, in Blender 2.77a ( abf6f08 ) and blender from buildbot 2.78 ( 21e9db9 ). Kubuntu Linux 14.04 64 bits, GTX 960 (370.28)

Julian Eisel commented

2016-09-22 23:20:48 +02:00

Added subscriber: @JulianEisel

Julian Eisel commented

2016-09-22 23:20:48 +02:00

This seems to do the trick:

diff --git a/source/blender/editors/screen/glutil.c b/source/blender/editors/screen/glutil.c
index 93bac3f..79e9e3d 100644
--- a/source/blender/editors/screen/glutil.c
+++ b/source/blender/editors/screen/glutil.c
@@ -582,11 +582,10 @@ void glaDrawPixelsSafe(float x, float y, int img_w, int img_h, int row_w, int fo
         * covers the entire screen).
         */
        glGetFloatv(GL_SCISSOR_BOX, scissor);
-       draw_w = min_ii(img_w - off_x, ceil((scissor[2] - rast_x) / xzoom));
-       draw_h = min_ii(img_h - off_y, ceil((scissor[3] - rast_y) / yzoom));
+       draw_w = min_ii(img_w - off_x, ceil(scissor[2] / xzoom) + 1.0f);
+       draw_h = min_ii(img_h - off_y, ceil(scissor[3] / yzoom) + 1.0f);
 
        if (draw_w > 0 && draw_h > 0) {
-
                int bound_options;
                GPU_BASIC_SHADER_DISABLE_AND_STORE(bound_options);

Don't see why rast_x/y should be subtracted from scissor values, to me this would only make sense if scissor- [x]/- [x] were the max coords, but they are width/height. Added the + 1.0f to fix flickering in zoomed in images (with DrawPixels, open image in clip editor, zoom in really close).
Couldn't find any breakage but would still prefer a second pair of eyes to confirm before committing.

This seems to do the trick: ``` diff --git a/source/blender/editors/screen/glutil.c b/source/blender/editors/screen/glutil.c index 93bac3f..79e9e3d 100644 --- a/source/blender/editors/screen/glutil.c +++ b/source/blender/editors/screen/glutil.c @@ -582,11 +582,10 @@ void glaDrawPixelsSafe(float x, float y, int img_w, int img_h, int row_w, int fo * covers the entire screen). */ glGetFloatv(GL_SCISSOR_BOX, scissor); - draw_w = min_ii(img_w - off_x, ceil((scissor[2] - rast_x) / xzoom)); - draw_h = min_ii(img_h - off_y, ceil((scissor[3] - rast_y) / yzoom)); + draw_w = min_ii(img_w - off_x, ceil(scissor[2] / xzoom) + 1.0f); + draw_h = min_ii(img_h - off_y, ceil(scissor[3] / yzoom) + 1.0f); if (draw_w > 0 && draw_h > 0) { - int bound_options; GPU_BASIC_SHADER_DISABLE_AND_STORE(bound_options); ``` Don't see why rast_x/y should be subtracted from scissor values, to me this would only make sense if scissor- [x]/- [x] were the max coords, but they are width/height. Added the `+ 1.0f` to fix flickering in zoomed in images (with DrawPixels, open image in clip editor, zoom in really close). Couldn't find any breakage but would still prefer a second pair of eyes to confirm before committing.

Brecht Van Lommel commented

2016-09-23 01:14:37 +02:00

Added subscriber: @brecht

Brecht Van Lommel commented

2016-09-23 01:14:37 +02:00

Subtracting rast_x/y make sense if you want to clip away the right/top part of the image that's outside the scissor box. Since the purpose of this code is to clamp the width/height to some reasonable value to work around a driver bug, the proposed fix should work fine even it we loose that exact clipping.

I think the mistake in the original code is assuming that rast_x/y are relative to GL_SCISSOR_BOX coordinates, while they are actually relative to GL_VIEWPORT coordinates. In other cases where this function is used (image editor) these coordinates are always the same, but here with border render the scissor box is a subset of the viewport. So an alternative fix would be to use GL_VIEWPORT coordinates instead of GL_SCISSOR_BOX.

Subtracting rast_x/y make sense if you want to clip away the right/top part of the image that's outside the scissor box. Since the purpose of this code is to clamp the width/height to some reasonable value to work around a driver bug, the proposed fix should work fine even it we loose that exact clipping. I think the mistake in the original code is assuming that rast_x/y are relative to `GL_SCISSOR_BOX` coordinates, while they are actually relative to `GL_VIEWPORT` coordinates. In other cases where this function is used (image editor) these coordinates are always the same, but here with border render the scissor box is a subset of the viewport. So an alternative fix would be to use `GL_VIEWPORT` coordinates instead of `GL_SCISSOR_BOX`.

Forest Katsch commented

2017-04-10 04:05:31 +02:00

I can confirm that @JulianEisel's fix works properly for me.

blender-admin commented

2017-04-14 16:26:10 +02:00

This issue was referenced by 6fc7521ade

This issue was referenced by 6fc7521adeec11fa9e68f77a30924d5ff05819a4

Brecht Van Lommel commented

2017-04-14 16:39:02 +02:00

Changed status from 'Open' to: 'Resolved'

Brecht Van Lommel closed this issue

2017-04-14 16:39:02 +02:00

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Using render border with real-time viewport Blender Internal rendering and DrawPixels Images Draw Method results in the wrong area being rendered #49429