mesa: helper function for scissor box of gl_framebuffer

Add helper convenience function that intersects the scissor values
against a passed bounding box. In addition, to avoid replicated code,
make the function _mesa_scissor_bounding_box() use this new function.

Reviewed-by: Ian Romanick <[email protected]>
Signed-off-by: Kevin Rogovin <[email protected]>

2 files changed, 35 insertions, 15 deletions

diff --git a/src/mesa/main/framebuffer.c b/src/mesa/main/framebuffer.c
index f49d74c89f0..77c04b8dab8 100644
--- a/src/mesa/main/framebuffer.c
+++ b/src/mesa/main/framebuffer.c
@@ -357,30 +357,20 @@ update_framebuffer_size(struct gl_context *ctx, struct gl_framebuffer *fb)
 }
 
 
+
 /**
- * Calculate the inclusive bounding box for the scissor of a specific viewport
+ * Given a bounding box, intersect the bounding box with the scissor of
+ * a specified vieport.
  *
  * \param ctx     GL context.
- * \param buffer  Framebuffer to be checked against
  * \param idx     Index of the desired viewport
  * \param bbox    Bounding box for the scissored viewport.  Stored as xmin,
  *                xmax, ymin, ymax.
- *
- * \warning This function assumes that the framebuffer dimensions are up to
- * date (e.g., update_framebuffer_size has been recently called on \c buffer).
- *
- * \sa _mesa_clip_to_region
  */
 void
-_mesa_scissor_bounding_box(const struct gl_context *ctx,
-                           const struct gl_framebuffer *buffer,
-                           unsigned idx, int *bbox)
+_mesa_intersect_scissor_bounding_box(const struct gl_context *ctx,
+                                     unsigned idx, int *bbox)
 {
-   bbox[0] = 0;
-   bbox[2] = 0;
-   bbox[1] = buffer->Width;
-   bbox[3] = buffer->Height;
-
    if (ctx->Scissor.EnableFlags & (1u << idx)) {
       if (ctx->Scissor.ScissorArray[idx].X > bbox[0]) {
          bbox[0] = ctx->Scissor.ScissorArray[idx].X;
@@ -402,6 +392,33 @@ _mesa_scissor_bounding_box(const struct gl_context *ctx,
          bbox[2] = bbox[3];
       }
    }
+}
+
+/**
+ * Calculate the inclusive bounding box for the scissor of a specific viewport
+ *
+ * \param ctx     GL context.
+ * \param buffer  Framebuffer to be checked against
+ * \param idx     Index of the desired viewport
+ * \param bbox    Bounding box for the scissored viewport.  Stored as xmin,
+ *                xmax, ymin, ymax.
+ *
+ * \warning This function assumes that the framebuffer dimensions are up to
+ * date (e.g., update_framebuffer_size has been recently called on \c buffer).
+ *
+ * \sa _mesa_clip_to_region
+ */
+void
+_mesa_scissor_bounding_box(const struct gl_context *ctx,
+                           const struct gl_framebuffer *buffer,
+                           unsigned idx, int *bbox)
+{
+   bbox[0] = 0;
+   bbox[2] = 0;
+   bbox[1] = buffer->Width;
+   bbox[3] = buffer->Height;
+
+   _mesa_intersect_scissor_bounding_box(ctx, idx, bbox);
 
    assert(bbox[0] <= bbox[1]);
    assert(bbox[2] <= bbox[3]);
diff --git a/src/mesa/main/framebuffer.h b/src/mesa/main/framebuffer.h
index ca286e9a992..08e43222045 100644
--- a/src/mesa/main/framebuffer.h
+++ b/src/mesa/main/framebuffer.h
@@ -75,6 +75,9 @@ extern void
 _mesa_scissor_bounding_box(const struct gl_context *ctx,
                            const struct gl_framebuffer *buffer,
                            unsigned idx, int *bbox);
+extern void
+_mesa_intersect_scissor_bounding_box(const struct gl_context *ctx,
+                                     unsigned idx, int *bbox);
 
 static inline GLuint
 _mesa_geometric_width(const struct gl_framebuffer *buffer)