New triangle rasterization code. Store per-span initial/step values in the

new triangle_span struct.  Much cleaner code and possibilities for future
optimizations.

1 files changed, 79 insertions, 0 deletions

diff --git a/src/mesa/swrast/s_trispan.h b/src/mesa/swrast/s_trispan.h
new file mode 100644
index 0000000000..cd577f51ca
--- /dev/null
+++ b/src/mesa/swrast/s_trispan.h
@@ -0,0 +1,79 @@
+/* $Id: s_trispan.h,v 1.1 2001/05/14 16:23:04 brianp Exp $ */
+
+/*
+ * Mesa 3-D graphics library
+ * Version:  3.5
+ *
+ * Copyright (C) 1999-2001  Brian Paul   All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+#ifndef S_TRISPAN_H
+#define S_TRISPAN_H
+
+
+/*
+ * The triangle_span structure is used by the triangle template code in
+ * s_tritemp.h.  It describes how colors, Z, texcoords, etc are to be
+ * interpolated across each scanline of triangle.
+ * With this structure it's easy to hand-off span rasterization to a
+ * subroutine instead of doing it all inline like we used to do.
+ * It also cleans up the local variable namespace a great deal.
+ *
+ * It would be interesting to experiment with multiprocessor rasterization
+ * with this structure.  The triangle rasterizer could simply emit a
+ * stream of these structures which would be consumed by one or more
+ * span-processing threads which could run in parallel.
+ */
+
+
+#define SPAN_RGBA         0x01
+#define SPAN_SPEC         0x02
+#define SPAN_INDEX        0x04
+#define SPAN_Z            0x08
+#define SPAN_FOG          0x10
+#define SPAN_TEXTURE      0x20
+#define SPAN_INT_TEXTURE  0x40
+#define SPAN_LAMBDA       0x80
+
+
+struct triangle_span {
+   GLint x, y;
+   GLuint count;
+   GLuint activeMask;  /* OR of the SPAN_* flags */
+   GLfixed red, redStep;
+   GLfixed green, greenStep;
+   GLfixed blue, blueStep;
+   GLfixed alpha, alphaStep;
+   GLfixed specRed, specRedStep;
+   GLfixed specGreen, specGreenStep;
+   GLfixed specBlue, specBlueStep;
+   GLfixed index, indexStep;
+   GLfixed z, zStep;
+   GLfloat fog, fogStep;
+   GLfloat tex[MAX_TEXTURE_UNITS][4], texStep[MAX_TEXTURE_UNITS][4];
+   GLfixed intTex[2], intTexStep[2];
+   /* Needed for texture lambda (LOD) computation */
+   GLfloat rho[MAX_TEXTURE_UNITS];
+   GLfloat texWidth[MAX_TEXTURE_UNITS], texHeight[MAX_TEXTURE_UNITS];
+};
+
+
+#endif /* S_TRISPAN_H */