From f699389818f1f11f3edddcdddcd0a43be21ba4c0 Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Tue, 18 Mar 2008 14:06:47 -0700
Subject: [PATCH] Add i830_transform_is_affine and
 i830_get_transformed_coordinates_3d.

These are needed to deal with projective transforms in the composite
operation.
---
 src/i830.h     |  7 +++++++
 src/i830_exa.c | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/src/i830.h b/src/i830.h
index ee0f03ad..512938cd 100644
--- a/src/i830.h
+++ b/src/i830.h
@@ -790,6 +790,9 @@ Bool i830_check_composite(int op, PicturePtr pSrc, PicturePtr pMask,
 Bool i830_prepare_composite(int op, PicturePtr pSrc, PicturePtr pMask,
 			    PicturePtr pDst, PixmapPtr pSrcPixmap,
 			    PixmapPtr pMaskPixmap, PixmapPtr pDstPixmap);
+Bool
+i830_transform_is_affine (PictTransformPtr t);
+
 void i830_composite(PixmapPtr pDst, int srcX, int srcY,
 		    int maskX, int maskY, int dstX, int dstY, int w, int h);
 void i830_done_composite(PixmapPtr pDst);
@@ -812,6 +815,10 @@ void
 i830_get_transformed_coordinates(int x, int y, PictTransformPtr transform,
 				 float *x_out, float *y_out);
 
+void
+i830_get_transformed_coordinates_3d(int x, int y, PictTransformPtr transform,
+				    float *x_out, float *y_out, float *z_out);
+
 void i830_enter_render(ScrnInfoPtr);
 
 static inline int i830_fb_compression_supported(I830Ptr pI830)
diff --git a/src/i830_exa.c b/src/i830_exa.c
index bf9fc669..0206ab91 100644
--- a/src/i830_exa.c
+++ b/src/i830_exa.c
@@ -363,6 +363,45 @@ i830_get_transformed_coordinates(int x, int y, PictTransformPtr transform,
     }
 }
 
+**
+ * Returns the un-normalized floating-point coordinates transformed by the given transform.
+ *
+ * transform may be null.
+ */
+void
+i830_get_transformed_coordinates_3d(int x, int y, PictTransformPtr transform,
+				    float *x_out, float *y_out, float *w_out)
+{
+    if (transform == NULL) {
+	*x_out = x;
+	*y_out = y;
+	*w_out = 1;
+    } else {
+	PictVector v;
+
+        v.vector[0] = IntToxFixed(x);
+        v.vector[1] = IntToxFixed(y);
+        v.vector[2] = xFixed1;
+        PictureTransformPoint3d(transform, &v);
+	*x_out = xFixedToFloat(v.vector[0]);
+	*y_out = xFixedToFloat(v.vector[1]);
+	*w_out = xFixedToFloat(v.vector[2]);
+    }
+}
+
+/**
+ * Returns whether the provided transform is affine.
+ *
+ * transform may be null.
+ */
+Bool
+i830_transform_is_affine (PictTransformPtr t)
+{
+    if (t == NULL)
+	return TRUE;
+    return t->matrix[2][0] == 0 && t->matrix[2][1] == 0;
+}
+
 /*
  * TODO:
  *   - Dual head?