[Bf-blender-cvs] [d5cb425b874] master: Possible fix for T62999: Crash when select in edit mode.

[mano-wii]

Commit: d5cb425b874561816ee52826d71c6f5e2229aa4d
Author: mano-wii
Date:   Thu Mar 28 14:17:00 2019 -0300
Branches: master
https://developer.blender.org/rBd5cb425b874561816ee52826d71c6f5e2229aa4d

Possible fix for T62999: Crash when select in edit mode.

Apparently some drivers don't allow `glReadPixel` read out pixels of texture boundaries.
Intersect `rect` to avoid such cases.

===================================================================

M	source/blender/draw/intern/draw_manager.c
M	source/blender/gpu/GPU_select.h
M	source/blender/gpu/intern/gpu_select_pick.c

===================================================================

diff --git a/source/blender/draw/intern/draw_manager.c b/source/blender/draw/intern/draw_manager.c
index 9dd6d08afcc..8a532ecdb7d 100644
--- a/source/blender/draw/intern/draw_manager.c
+++ b/source/blender/draw/intern/draw_manager.c
@@ -59,6 +59,7 @@
 #include "GPU_uniformbuffer.h"
 #include "GPU_viewport.h"
 #include "GPU_matrix.h"
+#include "GPU_select.h"
 
 #include "IMB_colormanagement.h"
 
@@ -2547,8 +2548,23 @@ void DRW_framebuffer_select_id_release(ARegion *ar)
 /* Read a block of pixels from the select frame buffer. */
 void DRW_framebuffer_select_id_read(const rcti *rect, uint *r_buf)
 {
+	/* clamp rect by texture */
+	rcti r = {
+		.xmin = 0,
+		.xmax = GPU_texture_width(g_select_buffer.texture_u32),
+		.ymin = 0,
+		.ymax = GPU_texture_height(g_select_buffer.texture_u32),
+	};
+
+	rcti rect_clamp = *rect;
+	BLI_rcti_isect(&r, rect, &rect_clamp);
+
 	GPU_texture_read_rect(
-	        g_select_buffer.texture_u32, GPU_DATA_UNSIGNED_INT, rect, r_buf);
+	        g_select_buffer.texture_u32, GPU_DATA_UNSIGNED_INT, &rect_clamp, r_buf);
+
+	if (!BLI_rcti_compare(rect, &rect_clamp)) {
+		GPU_select_buffer_stride_realign(rect, &rect_clamp, r_buf);
+	}
 }
 
 /** \} */
diff --git a/source/blender/gpu/GPU_select.h b/source/blender/gpu/GPU_select.h
index e1396b49c15..b9dbeeccf30 100644
--- a/source/blender/gpu/GPU_select.h
+++ b/source/blender/gpu/GPU_select.h
@@ -52,5 +52,6 @@ void GPU_select_cache_end(void);
 
 /* utilities */
 const uint *GPU_select_buffer_near(const uint *buffer, int hits);
+void GPU_select_buffer_stride_realign(const struct rcti *src, const struct rcti *dst, uint *r_buf);
 
 #endif
diff --git a/source/blender/gpu/intern/gpu_select_pick.c b/source/blender/gpu/intern/gpu_select_pick.c
index 22388deccdb..bfd2f3c1ee7 100644
--- a/source/blender/gpu/intern/gpu_select_pick.c
+++ b/source/blender/gpu/intern/gpu_select_pick.c
@@ -90,6 +90,30 @@ static void rect_subregion_stride_calc(const rcti *src, const rcti *dst, SubRect
 	r_sub->skip     = (uint)(src_x - dst_x);
 }
 
+void GPU_select_buffer_stride_realign(
+        const rcti *src, const rcti *dst, uint *r_buf)
+{
+	SubRectStride sub;
+	rect_subregion_stride_calc(src, dst, &sub);
+
+	int last_px_written = sub.span * sub.span_len - 1;
+	int last_px_id = sub.start + last_px_written + (sub.span_len - 1) * sub.skip;
+
+	while (sub.span_len--) {
+		int i;
+		for (i = sub.span; i--;) {
+			r_buf[last_px_id--] = r_buf[last_px_written--];
+		}
+		if (last_px_written < 0) {
+			break;
+		}
+		for (i = sub.skip; i--;) {
+			r_buf[last_px_id--] = 0u;
+		}
+	}
+	memset(r_buf, 0, (last_px_id + 1) * sizeof(*r_buf));
+}
+
 /**
  * Ignore depth clearing as a change,
  * only check if its been changed _and_ filled in (ignore clearing since XRAY does this).