Mesa (master): texstore: Add a generic implementation of GL_ARB_clear_texture

[Neil Roberts]

Module: Mesa
Branch: master
Commit: df9945ca26203b5f39d273cbaa1966650f8190a9
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=df9945ca26203b5f39d273cbaa1966650f8190a9

Author: Neil Roberts <neil at linux.intel.com>
Date:   Tue Jun 10 16:19:58 2014 +0100

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 at 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 c87e407..aea53f8 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 c4cfffd..dd1e1d0 100644
--- a/src/mesa/main/texstore.h
+++ b/src/mesa/main/texstore.h
@@ -118,6 +118,13 @@ _mesa_store_texsubimage(struct gl_context *ctx, GLuint dims,
 
 
 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,
                                 GLsizei imageSize, const GLvoid *data);