template code for span functions for flat, memory-based frame buffers
diff --git a/src/mesa/swrast/s_spantemp.h b/src/mesa/swrast/s_spantemp.h
new file mode 100644
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+++ b/src/mesa/swrast/s_spantemp.h
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+/* $Id: s_spantemp.h,v 1.1 2002/11/13 16:54:01 brianp Exp $ */
+
+/*
+ * Mesa 3-D graphics library
+ * Version:  5.1
+ *
+ * Copyright (C) 1999-2002  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.
+ */
+
+
+/*
+ * Templates for the span/pixel-array write/read functions called via
+ * swrast.  This is intended for memory-based framebuffers (like OSMesa).
+ *
+ * Define the following macros before including this file:
+ *   NAME(PREFIX)  to generate the function name
+ *   SPAN_VARS  to declare any local variables
+ *   INIT_PIXEL_PTR(P, X, Y)  to initialize a pointer to a pixel
+ *   INC_PIXEL_PTR(P)  to increment a pixel pointer by one pixel
+ *   STORE_RGB_PIXEL(P, R, G, B)  to store RGB values in  pixel P
+ *   STORE_RGBA_PIXEL(P, R, G, B, A)  to store RGBA values in pixel P
+ *   FETCH_RGBA_PIXEL(R, G, B, A, P)  to fetch RGBA values from pixel P
+ * For color index mode:
+ *   STORE_CI_PIXEL(P, CI)  to store a color index in pixel P
+ *   FETCH_CI_PIXEL(CI, P)  to fetch a pixel index from pixel P
+ */
+
+
+#ifdef STORE_RGBA_PIXEL
+
+static void
+NAME(write_rgba_span)( const GLcontext *ctx, GLuint n, GLint x, GLint y,
+                       CONST GLchan rgba[][4], const GLubyte mask[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   INIT_PIXEL_PTR(pixel, x, y);
+   if (mask) {
+      for (i = 0; i < n; i++) {
+         if (mask[i]) {
+            STORE_RGBA_PIXEL(pixel, rgba[i][RCOMP], rgba[i][GCOMP],
+                             rgba[i][BCOMP], rgba[i][ACOMP]);
+         }
+         INC_PIXEL_PTR(pixel);
+      }
+   }
+   else {
+      for (i = 0; i < n; i++) {
+         STORE_RGBA_PIXEL(pixel, rgba[i][RCOMP], rgba[i][GCOMP],
+                          rgba[i][BCOMP], rgba[i][ACOMP]);
+         INC_PIXEL_PTR(pixel);
+      }
+   }
+}
+
+static void
+NAME(write_rgb_span)( const GLcontext *ctx, GLuint n, GLint x, GLint y,
+                      CONST GLchan rgb[][3], const GLubyte mask[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   INIT_PIXEL_PTR(pixel, x, y);
+   if (mask) {
+      for (i = 0; i < n; i++) {
+         if (mask[i]) {
+            STORE_RGB_PIXEL(pixel, rgb[i][RCOMP], rgb[i][GCOMP],
+                            rgb[i][BCOMP]);
+         }
+         INC_PIXEL_PTR(pixel);
+      }
+   }
+   else {
+      for (i = 0; i < n; i++) {
+         STORE_RGB_PIXEL(pixel, rgb[i][RCOMP], rgb[i][GCOMP],
+                         rgb[i][BCOMP]);
+         INC_PIXEL_PTR(pixel);
+      }
+   }
+}
+
+static void
+NAME(write_monorgba_span)( const GLcontext *ctx, GLuint n, GLint x, GLint y,
+                           const GLchan color[4], const GLubyte mask[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   INIT_PIXEL_PTR(pixel, x, y);
+   if (mask) {
+      for (i = 0; i < n; i++) {
+         if (mask[i]) {
+            STORE_RGBA_PIXEL(pixel, color[RCOMP], color[GCOMP],
+                             color[BCOMP], color[ACOMP]);
+         }
+         INC_PIXEL_PTR(pixel);
+      }
+   }
+   else {
+      for (i = 0; i < n; i++) {
+         STORE_RGBA_PIXEL(pixel, color[RCOMP], color[GCOMP],
+                          color[BCOMP], color[ACOMP]);
+         INC_PIXEL_PTR(pixel);
+      }
+   }
+}
+
+static void
+NAME(write_rgba_pixels)( const GLcontext *ctx, GLuint n,
+                         const GLint x[], const GLint y[],
+                         CONST GLchan rgba[][4], const GLubyte mask[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   if (mask) {
+      for (i = 0; i < n; i++) {
+         if (mask[i]) {
+            INIT_PIXEL_PTR(pixel, x[i], y[i]);
+            STORE_RGBA_PIXEL(pixel, rgba[i][RCOMP], rgba[i][GCOMP],
+                             rgba[i][BCOMP], rgba[i][ACOMP]);
+         }
+      }
+   }
+}
+
+static void
+NAME(write_monorgba_pixels)( const GLcontext *ctx,
+                             GLuint n, const GLint x[], const GLint y[],
+                             const GLchan color[4], const GLubyte mask[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   if (mask) {
+      for (i = 0; i < n; i++) {
+         if (mask[i]) {
+            INIT_PIXEL_PTR(pixel, x[i], y[i]);
+            STORE_RGBA_PIXEL(pixel, color[RCOMP], color[GCOMP],
+                             color[BCOMP], color[ACOMP]);
+         }
+      }
+   }
+}
+
+static void
+NAME(read_rgba_span)( const GLcontext *ctx, GLuint n, GLint x, GLint y,
+                      GLchan rgba[][4] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   INIT_PIXEL_PTR(pixel, x, y);
+   for (i = 0; i < n; i++) {
+      FETCH_RGBA_PIXEL(rgba[i][RCOMP], rgba[i][GCOMP], rgba[i][BCOMP],
+                       rgba[i][ACOMP], pixel);
+      INC_PIXEL_PTR(pixel);
+   }
+}
+
+static void
+NAME(read_rgba_pixels)( const GLcontext *ctx,
+                        GLuint n, const GLint x[], const GLint y[],
+                        GLchan rgba[][4], const GLubyte mask[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   for (i = 0; i < n; i++) {
+      if (mask[i]) {
+         INIT_PIXEL_PTR(pixel, x[i], y[i]);
+         FETCH_RGBA_PIXEL(rgba[i][RCOMP], rgba[i][GCOMP], rgba[i][BCOMP],
+                          rgba[i][ACOMP], pixel);
+      }
+   }
+}
+
+
+#endif /* STORE_RGBA_PIXEL */
+
+
+
+#ifdef STORE_CI_PIXEL
+
+static void
+NAME(write_index32_span)( const GLcontext *ctx, GLuint n, GLint x, GLint y,
+                          const GLuint index[], const GLubyte mask[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   INIT_PIXEL_PTR(pixel, x, y);
+   if (mask) {
+      for (i = 0; i < n; i++) {
+         if (mask[i]) {
+            STORE_CI_PIXEL(pixel, index[i]);
+         }
+         INC_PIXEL_PTR(pixel);
+      }
+   }
+   else if (sizeof(*pixel) == sizeof(GLuint)) {
+      _mesa_memcpy(pixel, index, n * sizeof(GLuint));
+   }
+   else {
+      for (i = 0; i < n; i++) {
+         STORE_CI_PIXEL(pixel, index[i]);
+         INC_PIXEL_PTR(pixel);
+      }
+   }
+}
+
+
+static void
+NAME(write_index8_span)( const GLcontext *ctx, GLuint n, GLint x, GLint y,
+                         const GLubyte index[], const GLubyte mask[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   INIT_PIXEL_PTR(pixel, x, y);
+   if (mask) {
+      for (i = 0; i < n; i++) {
+         if (mask[i]) {
+            STORE_CI_PIXEL(pixel, index[i]);
+         }
+         INC_PIXEL_PTR(pixel);
+      }
+   }
+   else if (sizeof(*pixel) == sizeof(GLubyte)) {
+      _mesa_memcpy(pixel, index, n * sizeof(GLubyte));
+   }
+   else {
+      for (i = 0; i < n; i++) {
+         STORE_CI_PIXEL(pixel, index[i]);
+         INC_PIXEL_PTR(pixel);
+      }
+   }
+}
+
+
+static void
+NAME(write_monoindex_span)( const GLcontext *ctx, GLuint n, GLint x, GLint y,
+                            GLuint colorIndex, const GLubyte mask[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   INIT_PIXEL_PTR(pixel, x, y);
+   for (i = 0; i < n; i++) {
+      if (mask[i]) {
+         STORE_CI_PIXEL(pixel, colorIndex);
+      }
+      INC_PIXEL_PTR(pixel);
+   }
+}
+
+
+static void
+NAME(write_index_pixels)( const GLcontext *ctx,
+                          GLuint n, const GLint x[], const GLint y[],
+                          const GLuint index[], const GLubyte mask[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   for (i = 0; i < n; i++) {
+      if (mask[i]) {
+         INIT_PIXEL_PTR(pixel, x[i], y[i]);
+         STORE_CI_PIXEL(pixel, index[i]);
+      }
+   }
+}
+
+
+static void
+NAME(write_monoindex_pixels)( const GLcontext *ctx,
+                              GLuint n, const GLint x[], const GLint y[],
+                              GLuint colorIndex, const GLubyte mask[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   for (i = 0; i < n; i++) {
+      if (mask[i]) {
+         INIT_PIXEL_PTR(pixel, x[i], y[i]);
+         STORE_CI_PIXEL(pixel, colorIndex);
+      }
+   }
+}
+
+
+static void
+NAME(read_index_span)( const GLcontext *ctx,
+                       GLuint n, GLint x, GLint y, GLuint index[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   INIT_PIXEL_PTR(pixel, x, y);
+   for (i = 0; i < n; i++) {
+      FETCH_CI_PIXEL(index[i], pixel);
+      INC_PIXEL_PTR(pixel);
+   }
+}
+
+
+static void
+NAME(read_index_pixels)( const GLcontext *ctx,
+                         GLuint n, const GLint x[], const GLint y[],
+                         GLuint index[], const GLubyte mask[] )
+{
+#ifdef SPAN_VARS
+   SPAN_VARS
+#endif
+   GLuint i;
+   for (i = 0; i < n; i++) {
+      if (mask[i] ) {
+         INIT_PIXEL_PTR(pixel, x[i], y[i]);
+         FETCH_CI_PIXEL(index[i], pixel);
+      }
+   }
+}
+
+#endif /* STORE_CI_PIXEL */
+
+
+
+#undef NAME
+#undef INIT_PIXEL_PTR
+#undef INC_PIXEL_PTR
+#undef STORE_RGB_PIXEL
+#undef STORE_RGBA_PIXEL
+#undef FETCH_RGBA_PIXEL
+#undef STORE_CI_PIXEL
+#undef FETCH_CI_PIXEL