From cc0a69e101e0f89c53675c350206d507f756f865 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <mail@baedert.org>
Date: Tue, 27 Mar 2018 13:24:14 +0200
Subject: [PATCH] gl renderer: Fix some crashes

When the first op is a modelview or projection change.
---
 gsk/gl/gskglrenderops.c | 32 ++++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/gsk/gl/gskglrenderops.c b/gsk/gl/gskglrenderops.c
index be61a0bd3b..c7134297a4 100644
--- a/gsk/gl/gskglrenderops.c
+++ b/gsk/gl/gskglrenderops.c
@@ -115,17 +115,25 @@ ops_set_modelview (RenderOpBuilder         *builder,
 {
   RenderOp op;
   graphene_matrix_t prev_mv;
-  RenderOp *last_op;
 
   if (builder->current_program &&
       memcmp (&builder->program_state[builder->current_program->index].modelview, modelview,
               sizeof (graphene_matrix_t)) == 0)
     return *modelview;
 
-  last_op = &g_array_index (builder->render_ops, RenderOp, builder->render_ops->len - 1);
-  if (last_op->op == OP_CHANGE_MODELVIEW)
+  if (builder->render_ops->len > 0)
     {
-      last_op->modelview = *modelview;
+      RenderOp *last_op = &g_array_index (builder->render_ops, RenderOp, builder->render_ops->len - 1);
+      if (last_op->op == OP_CHANGE_MODELVIEW)
+        {
+          last_op->modelview = *modelview;
+        }
+      else
+        {
+          op.op = OP_CHANGE_MODELVIEW;
+          op.modelview = *modelview;
+          g_array_append_val (builder->render_ops, op);
+        }
     }
   else
     {
@@ -149,12 +157,20 @@ ops_set_projection (RenderOpBuilder         *builder,
 {
   RenderOp op;
   graphene_matrix_t prev_mv;
-  RenderOp *last_op;
 
-  last_op = &g_array_index (builder->render_ops, RenderOp, builder->render_ops->len - 1);
-  if (last_op->op == OP_CHANGE_PROJECTION)
+  if (builder->render_ops->len > 0)
     {
-      last_op->projection = *projection;
+      RenderOp *last_op = &g_array_index (builder->render_ops, RenderOp, builder->render_ops->len - 1);
+      if (last_op->op == OP_CHANGE_PROJECTION)
+        {
+          last_op->projection = *projection;
+        }
+      else
+        {
+          op.op = OP_CHANGE_PROJECTION;
+          op.projection = *projection;
+          g_array_append_val (builder->render_ops, op);
+        }
     }
   else
     {