From df9945ca26203b5f39d273cbaa1966650f8190a9 Mon Sep 17 00:00:00 2001
From: Neil Roberts <neil@linux.intel.com>
Date: Tue, 10 Jun 2014 16:19:58 +0100
Subject: [PATCH] texstore: Add a generic implementation of
 GL_ARB_clear_texture

Adds an implmentation of the ClearTexSubImage driver entry point that just
maps the texture and writes the values in. The extension is not yet enabled by
default because it doesn't work with multisample textures as they don't have a
simple linear layout.

Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
---
 src/mesa/main/texstore.c | 72 ++++++++++++++++++++++++++++++++++++++++
 src/mesa/main/texstore.h |  7 ++++
 2 files changed, 79 insertions(+)

diff --git a/src/mesa/main/texstore.c b/src/mesa/main/texstore.c
index c87e407fac3..aea53f8d120 100644
--- a/src/mesa/main/texstore.c
+++ b/src/mesa/main/texstore.c
@@ -4094,6 +4094,78 @@ _mesa_store_texsubimage(struct gl_context *ctx, GLuint dims,
                      format, type, pixels, packing, "glTexSubImage");
 }
 
+static void
+clear_image_to_zero(GLubyte *dstMap, GLint dstRowStride,
+                    GLsizei width, GLsizei height,
+                    GLsizei clearValueSize)
+{
+   GLsizei y;
+
+   for (y = 0; y < height; y++) {
+      memset(dstMap, 0, clearValueSize * width);
+      dstMap += dstRowStride;
+   }
+}
+
+static void
+clear_image_to_value(GLubyte *dstMap, GLint dstRowStride,
+                     GLsizei width, GLsizei height,
+                     const GLvoid *clearValue,
+                     GLsizei clearValueSize)
+{
+   GLsizei y, x;
+
+   for (y = 0; y < height; y++) {
+      for (x = 0; x < width; x++) {
+         memcpy(dstMap, clearValue, clearValueSize);
+         dstMap += clearValueSize;
+      }
+      dstMap += dstRowStride - clearValueSize * width;
+   }
+}
+
+/*
+ * Fallback for Driver.ClearTexSubImage().
+ */
+void
+_mesa_store_cleartexsubimage(struct gl_context *ctx,
+                             struct gl_texture_image *texImage,
+                             GLint xoffset, GLint yoffset, GLint zoffset,
+                             GLsizei width, GLsizei height, GLsizei depth,
+                             const GLvoid *clearValue)
+{
+   GLubyte *dstMap;
+   GLint dstRowStride;
+   GLsizeiptr clearValueSize;
+   GLsizei z;
+
+   clearValueSize = _mesa_get_format_bytes(texImage->TexFormat);
+
+   for (z = 0; z < depth; z++) {
+      ctx->Driver.MapTextureImage(ctx, texImage,
+                                  z + zoffset, xoffset, yoffset,
+                                  width, height,
+                                  GL_MAP_WRITE_BIT,
+                                  &dstMap, &dstRowStride);
+      if (dstMap == NULL) {
+         _mesa_error(ctx, GL_OUT_OF_MEMORY, "glClearTex*Image");
+         return;
+      }
+
+      if (clearValue) {
+         clear_image_to_value(dstMap, dstRowStride,
+                              width, height,
+                              clearValue,
+                              clearValueSize);
+      } else {
+         clear_image_to_zero(dstMap, dstRowStride,
+                             width, height,
+                             clearValueSize);
+      }
+
+      ctx->Driver.UnmapTextureImage(ctx, texImage, z + zoffset);
+   }
+}
 
 /**
  * Fallback for Driver.CompressedTexImage()
diff --git a/src/mesa/main/texstore.h b/src/mesa/main/texstore.h
index c4cfffde677..dd1e1d01562 100644
--- a/src/mesa/main/texstore.h
+++ b/src/mesa/main/texstore.h
@@ -117,6 +117,13 @@ _mesa_store_texsubimage(struct gl_context *ctx, GLuint dims,
                         const struct gl_pixelstore_attrib *packing);
 
 
+extern void
+_mesa_store_cleartexsubimage(struct gl_context *ctx,
+                             struct gl_texture_image *texImage,
+                             GLint xoffset, GLint yoffset, GLint zoffset,
+                             GLsizei width, GLsizei height, GLsizei depth,
+                             const GLvoid *clearValue);
+
 extern void
 _mesa_store_compressed_teximage(struct gl_context *ctx, GLuint dims,
                                 struct gl_texture_image *texImage,
-- 
2.30.2