X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=src%2Fmesa%2Fstate_tracker%2Fst_atom_scissor.c;h=eb13877787b7df717c517ddfebb18804b87452f1;hb=c4529d10bed098b8d3d694f2a333f9afabbabbf9;hp=3fd59e1945c2677b2de1cf8bbc3fd3388c7f50a8;hpb=c417a2c3f37a6a28947db5dc5aa240473d29dd19;p=mesa.git

diff --git a/src/mesa/state_tracker/st_atom_scissor.c b/src/mesa/state_tracker/st_atom_scissor.c
index 3fd59e1945c..eb13877787b 100644
--- a/src/mesa/state_tracker/st_atom_scissor.c
+++ b/src/mesa/state_tracker/st_atom_scissor.c
@@ -31,6 +31,7 @@
   */
  
 
+#include "main/macros.h"
 #include "st_context.h"
 #include "pipe/p_context.h"
 #include "st_atom.h"
@@ -43,7 +44,8 @@ static void
 update_scissor( struct st_context *st )
 {
    struct pipe_scissor_state scissor;
-   const struct gl_framebuffer *fb = st->ctx->DrawBuffer;
+   const struct gl_context *ctx = st->ctx;
+   const struct gl_framebuffer *fb = ctx->DrawBuffer;
    GLint miny, maxy;
 
    scissor.minx = 0;
@@ -51,28 +53,35 @@ update_scissor( struct st_context *st )
    scissor.maxx = fb->Width;
    scissor.maxy = fb->Height;
 
-   if (st->ctx->Scissor.Enabled) {
-      if ((GLuint)st->ctx->Scissor.X > scissor.minx)
-         scissor.minx = st->ctx->Scissor.X;
-      if ((GLuint)st->ctx->Scissor.Y > scissor.miny)
-         scissor.miny = st->ctx->Scissor.Y;
+   if (ctx->Scissor.Enabled) {
+      /* need to be careful here with xmax or ymax < 0 */
+      GLint xmax = MAX2(0, ctx->Scissor.X + ctx->Scissor.Width);
+      GLint ymax = MAX2(0, ctx->Scissor.Y + ctx->Scissor.Height);
 
-      if ((GLuint)st->ctx->Scissor.X + st->ctx->Scissor.Width < scissor.maxx)
-         scissor.maxx = st->ctx->Scissor.X + st->ctx->Scissor.Width;
-      if ((GLuint)st->ctx->Scissor.Y + st->ctx->Scissor.Height < scissor.maxy)
-         scissor.maxy = st->ctx->Scissor.Y + st->ctx->Scissor.Height;
+      if (ctx->Scissor.X > (GLint)scissor.minx)
+         scissor.minx = ctx->Scissor.X;
+      if (ctx->Scissor.Y > (GLint)scissor.miny)
+         scissor.miny = ctx->Scissor.Y;
+
+      if (xmax < (GLint) scissor.maxx)
+         scissor.maxx = xmax;
+      if (ymax < (GLint) scissor.maxy)
+         scissor.maxy = ymax;
 
       /* check for null space */
       if (scissor.minx >= scissor.maxx || scissor.miny >= scissor.maxy)
          scissor.minx = scissor.miny = scissor.maxx = scissor.maxy = 0;
    }
 
-   /* Now invert Y.  Pipe drivers use the convention Y=0=top for surfaces
+   /* Now invert Y if needed.
+    * Gallium drivers use the convention Y=0=top for surfaces.
     */
-   miny = fb->Height - scissor.maxy;
-   maxy = fb->Height - scissor.miny;
-   scissor.miny = miny;
-   scissor.maxy = maxy;
+   if (st_fb_orientation(fb) == Y_0_TOP) {
+      miny = fb->Height - scissor.maxy;
+      maxy = fb->Height - scissor.miny;
+      scissor.miny = miny;
+      scissor.maxy = maxy;
+   }
 
    if (memcmp(&scissor, &st->state.scissor, sizeof(scissor)) != 0) {
       /* state has changed */