ngl: Fix offscreen rendering with transforms

There was confusion here about the handling of the
modelview transform. The modelview transform we are
getting is already set up for rendering the node
we are given, so keep it - except for possible adding
an extra scale on top when the texture would otherwise
be too big.

diff --git a/gsk/ngl/gsknglrenderjob.c b/gsk/ngl/gsknglrenderjob.c
index 08e99a7d196be43c2fd8729b28fd85a0a9f68c98..1e62b4ecc7d65932dc616fa0a415f09d88d902ad 100644 (file)
--- a/gsk/ngl/gsknglrenderjob.c
+++ b/gsk/ngl/gsknglrenderjob.c
@@ -3566,8 +3566,8 @@ gsk_ngl_render_job_visit_node_with_offscreen (GskNglRenderJob       *job,
 
   float scaled_width;
   float scaled_height;
-  float scale_x = job->scale_x;
-  float scale_y = job->scale_y;
+  float downscale_x = 1;
+  float downscale_y = 1;
 
   g_assert (job->command_queue->max_texture_size > 0);
 
@@ -3578,17 +3578,17 @@ gsk_ngl_render_job_visit_node_with_offscreen (GskNglRenderJob       *job,
   {
     int max_texture_size = job->command_queue->max_texture_size;
 
-    scaled_width = ceilf (offscreen->bounds->size.width * scale_x);
+    scaled_width = ceilf (offscreen->bounds->size.width * job->scale_x);
     if (scaled_width > max_texture_size)
       {
-        scale_x *= (float)max_texture_size / scaled_width;
+        downscale_x = (float)max_texture_size / scaled_width;
         scaled_width = max_texture_size;
       }
 
-    scaled_height = ceilf (offscreen->bounds->size.height * scale_y);
+    scaled_height = ceilf (offscreen->bounds->size.height * job->scale_y);
     if (scaled_height > max_texture_size)
       {
-        scale_y *= (float)max_texture_size / scaled_height;
+        downscale_y = (float)max_texture_size / scaled_height;
         scaled_height = max_texture_size;
       }
   }
@@ -3632,10 +3632,9 @@ gsk_ngl_render_job_visit_node_with_offscreen (GskNglRenderJob       *job,
 
   gsk_ngl_render_job_set_viewport (job, &viewport, &prev_viewport);
   gsk_ngl_render_job_set_projection_from_rect (job, &job->viewport, &prev_projection);
-  gsk_ngl_render_job_set_modelview (job, gsk_transform_scale (NULL, scale_x, scale_y));
+  if (downscale_x != 1 || downscale_y != 1)
+    gsk_ngl_render_job_push_modelview (job, gsk_transform_scale (NULL, downscale_x, downscale_y));
   prev_alpha = gsk_ngl_render_job_set_alpha (job, 1.0f);
-  job->offset_x = offset_x;
-  job->offset_y = offset_y;
 
   prev_fbo = gsk_ngl_command_queue_bind_framebuffer (job->command_queue, render_target->framebuffer_id);
   gsk_ngl_command_queue_clear (job->command_queue, 0, &job->viewport);
@@ -3648,7 +3647,8 @@ gsk_ngl_render_job_visit_node_with_offscreen (GskNglRenderJob       *job,
   if (offscreen->reset_clip)
     gsk_ngl_render_job_pop_clip (job);
 
-  gsk_ngl_render_job_pop_modelview (job);
+  if (downscale_x != 1 || downscale_y != 1)
+    gsk_ngl_render_job_pop_modelview (job);
   gsk_ngl_render_job_set_viewport (job, &prev_viewport, NULL);
   gsk_ngl_render_job_set_projection (job, &prev_projection);
   gsk_ngl_render_job_set_alpha (job, prev_alpha);